about summary refs log tree commit diff
diff options
context:
space:
mode:
-rw-r--r--.mailmap1
-rw-r--r--Cargo.lock4
-rw-r--r--RELEASES.md126
-rw-r--r--compiler/rustc_attr_parsing/messages.ftl8
-rw-r--r--compiler/rustc_attr_parsing/src/attributes/codegen_attrs.rs69
-rw-r--r--compiler/rustc_attr_parsing/src/context.rs6
-rw-r--r--compiler/rustc_attr_parsing/src/session_diagnostics.rs28
-rw-r--r--compiler/rustc_builtin_macros/src/deriving/bounds.rs39
-rw-r--r--compiler/rustc_builtin_macros/src/lib.rs1
-rw-r--r--compiler/rustc_codegen_llvm/src/asm.rs1
-rw-r--r--compiler/rustc_codegen_llvm/src/base.rs24
-rw-r--r--compiler/rustc_codegen_llvm/src/builder.rs9
-rw-r--r--compiler/rustc_codegen_llvm/src/common.rs14
-rw-r--r--compiler/rustc_codegen_llvm/src/consts.rs226
-rw-r--r--compiler/rustc_codegen_llvm/src/context.rs110
-rw-r--r--compiler/rustc_codegen_llvm/src/llvm/ffi.rs1
-rw-r--r--compiler/rustc_codegen_llvm/src/llvm/mod.rs4
-rw-r--r--compiler/rustc_codegen_llvm/src/llvm_util.rs57
-rw-r--r--compiler/rustc_codegen_ssa/src/codegen_attrs.rs6
-rw-r--r--compiler/rustc_codegen_ssa/src/mir/rvalue.rs41
-rw-r--r--compiler/rustc_codegen_ssa/src/traits/builder.rs41
-rw-r--r--compiler/rustc_const_eval/src/interpret/place.rs2
-rw-r--r--compiler/rustc_const_eval/src/interpret/step.rs16
-rw-r--r--compiler/rustc_feature/src/builtin_attrs.rs8
-rw-r--r--compiler/rustc_hir/src/attrs/data_structures.rs6
-rw-r--r--compiler/rustc_hir/src/attrs/encode_cross_crate.rs2
-rw-r--r--compiler/rustc_hir/src/lang_items.rs1
-rw-r--r--compiler/rustc_hir_analysis/src/check/mod.rs44
-rw-r--r--compiler/rustc_hir_analysis/src/check/region.rs24
-rw-r--r--compiler/rustc_hir_analysis/src/check/wfcheck.rs13
-rw-r--r--compiler/rustc_hir_analysis/src/coherence/builtin.rs15
-rw-r--r--compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs2400
-rw-r--r--compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs22
-rw-r--r--compiler/rustc_infer/src/traits/engine.rs17
-rw-r--r--compiler/rustc_lint/src/unused.rs8
-rw-r--r--compiler/rustc_llvm/build.rs1
-rw-r--r--compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp264
-rw-r--r--compiler/rustc_llvm/src/lib.rs6
-rw-r--r--compiler/rustc_middle/messages.ftl2
-rw-r--r--compiler/rustc_middle/src/middle/codegen_fn_attrs.rs6
-rw-r--r--compiler/rustc_middle/src/mir/syntax.rs8
-rw-r--r--compiler/rustc_middle/src/ty/util.rs9
-rw-r--r--compiler/rustc_mir_transform/src/dest_prop.rs43
-rw-r--r--compiler/rustc_passes/src/check_attr.rs2
-rw-r--r--compiler/rustc_span/src/symbol.rs2
-rw-r--r--compiler/rustc_trait_selection/src/traits/misc.rs38
-rw-r--r--library/alloc/src/collections/btree/map/entry.rs6
-rw-r--r--library/alloc/src/vec/peek_mut.rs4
-rw-r--r--library/alloctests/tests/vec.rs4
-rw-r--r--library/core/src/array/mod.rs5
-rw-r--r--library/core/src/cmp.rs9
-rw-r--r--library/core/src/lib.rs1
-rw-r--r--library/core/src/marker.rs33
-rw-r--r--library/core/src/mem/transmutability.rs6
-rw-r--r--library/core/src/os/darwin/mod.rs19
-rw-r--r--library/core/src/os/darwin/objc.rs113
-rw-r--r--library/core/src/os/mod.rs24
-rw-r--r--library/core/src/tuple.rs10
-rw-r--r--library/coretests/tests/ascii.rs7
-rw-r--r--library/std/src/os/darwin/mod.rs2
-rw-r--r--library/std/src/os/darwin/objc.rs13
-rw-r--r--library/std/src/sys/fs/unix.rs120
-rw-r--r--library/test/src/cli.rs4
-rw-r--r--src/bootstrap/README.md15
-rw-r--r--src/bootstrap/bootstrap.py6
-rw-r--r--src/bootstrap/src/core/build_steps/llvm.rs4
-rw-r--r--src/bootstrap/src/core/build_steps/test.rs3
-rw-r--r--src/bootstrap/src/core/build_steps/tool.rs5
-rw-r--r--src/bootstrap/src/core/builder/cargo.rs7
-rw-r--r--src/bootstrap/src/core/config/config.rs109
-rw-r--r--src/ci/docker/README.md8
-rw-r--r--src/ci/docker/host-aarch64/aarch64-gnu-llvm-20/Dockerfile (renamed from src/ci/docker/host-aarch64/aarch64-gnu-llvm-19/Dockerfile)8
-rw-r--r--src/ci/docker/host-x86_64/x86_64-gnu-llvm-19/Dockerfile66
-rw-r--r--src/ci/github-actions/jobs.yml35
-rw-r--r--src/doc/rustc/src/target-tier-policy.md2
-rw-r--r--src/doc/rustc/src/tests/index.md12
-rw-r--r--src/tools/compiletest/src/common.rs4
-rw-r--r--src/tools/compiletest/src/directives/needs.rs13
-rw-r--r--src/tools/compiletest/src/executor.rs9
-rw-r--r--src/tools/compiletest/src/lib.rs2
-rw-r--r--src/tools/miri/tests/fail/both_borrows/issue-miri-1050-1.rs2
-rw-r--r--src/tools/miri/tests/fail/both_borrows/issue-miri-1050-2.rs2
-rw-r--r--src/tools/miri/tests/fail/both_borrows/return_invalid_shr.stack.stderr2
-rw-r--r--src/tools/miri/tests/fail/both_borrows/return_invalid_shr.tree.stderr2
-rw-r--r--src/tools/miri/tests/fail/both_borrows/return_invalid_shr_option.stack.stderr2
-rw-r--r--src/tools/miri/tests/fail/both_borrows/return_invalid_shr_option.tree.stderr2
-rw-r--r--src/tools/miri/tests/fail/both_borrows/return_invalid_shr_tuple.stack.stderr2
-rw-r--r--src/tools/miri/tests/fail/both_borrows/return_invalid_shr_tuple.tree.stderr2
-rw-r--r--src/tools/miri/tests/fail/overlapping_assignment_aggregate.rs18
-rw-r--r--src/tools/miri/tests/fail/overlapping_assignment_aggregate.stderr15
-rw-r--r--src/tools/miri/tests/fail/validity/nonzero.stderr2
-rw-r--r--src/tools/miri/tests/pass/overlapping_assignment_aggregate_scalar.rs19
-rw-r--r--src/tools/opt-dist/src/training.rs1
-rw-r--r--src/tools/tidy/src/pal.rs1
-rw-r--r--tests/assembly-llvm/riscv-soft-abi-with-float-features.rs10
-rw-r--r--tests/assembly-llvm/x86_64-bigint-helpers.rs1
-rw-r--r--tests/assembly-llvm/x86_64-cmp.rs73
-rw-r--r--tests/codegen-llvm/asm/riscv-clobbers.rs2
-rw-r--r--tests/codegen-llvm/auxiliary/darwin_objc_aux.rs27
-rw-r--r--tests/codegen-llvm/comparison-operators-2-struct.rs1
-rw-r--r--tests/codegen-llvm/comparison-operators-2-tuple.rs1
-rw-r--r--tests/codegen-llvm/darwin-no-objc.rs52
-rw-r--r--tests/codegen-llvm/darwin-objc-abi-v1.rs100
-rw-r--r--tests/codegen-llvm/darwin-objc-abi-v2.rs185
-rw-r--r--tests/codegen-llvm/darwin-objc-cross-crate.rs58
-rw-r--r--tests/codegen-llvm/enum/enum-aggregate.rs1
-rw-r--r--tests/codegen-llvm/enum/enum-discriminant-eq.rs1
-rw-r--r--tests/codegen-llvm/integer-cmp.rs36
-rw-r--r--tests/codegen-llvm/intrinsics/three_way_compare.rs1
-rw-r--r--tests/codegen-llvm/issues/and-masked-comparison-131162.rs1
-rw-r--r--tests/codegen-llvm/issues/issue-101082.rs1
-rw-r--r--tests/codegen-llvm/issues/issue-129795.rs1
-rw-r--r--tests/codegen-llvm/issues/iter-max-no-unwrap-failed-129583.rs1
-rw-r--r--tests/codegen-llvm/issues/looping-over-ne-bytes-133528.rs1
-rw-r--r--tests/codegen-llvm/option-niche-eq.rs1
-rw-r--r--tests/codegen-llvm/rust-abi-arch-specific-adjustment.rs8
-rw-r--r--tests/codegen-llvm/slice-last-elements-optimization.rs1
-rw-r--r--tests/codegen-llvm/swap-small-types.rs1
-rw-r--r--tests/codegen-llvm/try_question_mark_nop.rs31
-rw-r--r--tests/codegen-llvm/union-aggregate.rs1
-rw-r--r--tests/mir-opt/dest-prop/aggregate.rewrap.DestinationPropagation.panic-abort.diff19
-rw-r--r--tests/mir-opt/dest-prop/aggregate.rewrap.DestinationPropagation.panic-unwind.diff19
-rw-r--r--tests/mir-opt/dest-prop/aggregate.rs51
-rw-r--r--tests/mir-opt/dest-prop/aggregate.swap.DestinationPropagation.panic-abort.diff22
-rw-r--r--tests/mir-opt/dest-prop/aggregate.swap.DestinationPropagation.panic-unwind.diff22
-rw-r--r--tests/ui/README.md6
-rw-r--r--tests/ui/abi/sparcv8plus-llvm19.rs42
-rw-r--r--tests/ui/abi/sparcv8plus-llvm19.sparc.stderr8
-rw-r--r--tests/ui/abi/sparcv8plus-llvm19.sparc_cpu_v9.stderr8
-rw-r--r--tests/ui/abi/sparcv8plus-llvm19.sparc_cpu_v9_feature_v8plus.stderr8
-rw-r--r--tests/ui/abi/sparcv8plus-llvm19.sparc_feature_v8plus.stderr8
-rw-r--r--tests/ui/abi/sparcv8plus-llvm19.sparcv8plus.stderr8
-rw-r--r--tests/ui/abi/sparcv8plus.rs1
-rw-r--r--tests/ui/abi/sparcv8plus.sparc.stderr2
-rw-r--r--tests/ui/abi/sparcv8plus.sparc_cpu_v9.stderr2
-rw-r--r--tests/ui/abi/sparcv8plus.sparc_cpu_v9_feature_v8plus.stderr2
-rw-r--r--tests/ui/abi/sparcv8plus.sparc_feature_v8plus.stderr2
-rw-r--r--tests/ui/abi/sparcv8plus.sparcv8plus.stderr2
-rw-r--r--tests/ui/asm/loongarch/bad-reg.loongarch32_ilp32d.stderr12
-rw-r--r--tests/ui/asm/loongarch/bad-reg.loongarch32_ilp32s.stderr20
-rw-r--r--tests/ui/asm/loongarch/bad-reg.loongarch64_lp64d.stderr12
-rw-r--r--tests/ui/asm/loongarch/bad-reg.loongarch64_lp64s.stderr20
-rw-r--r--tests/ui/asm/loongarch/bad-reg.rs1
-rw-r--r--tests/ui/associated-types/associated-types-for-unimpl-trait.fixed2
-rw-r--r--tests/ui/borrowck/format-args-temporary-scopes.e2024.stderr27
-rw-r--r--tests/ui/borrowck/format-args-temporary-scopes.rs21
-rw-r--r--tests/ui/coercion/coerce-block-tail.stderr7
-rw-r--r--tests/ui/coercion/coerce-box-new-to-unboxed.rs4
-rw-r--r--tests/ui/coercion/coerce-box-new-to-unboxed.stderr19
-rw-r--r--tests/ui/const-generics/adt_const_params/auxiliary/unsized_const_param.rs2
-rw-r--r--tests/ui/const-generics/adt_const_params/const_param_ty_bad.rs2
-rw-r--r--tests/ui/const-generics/adt_const_params/const_param_ty_bad.stderr42
-rw-r--r--tests/ui/const-generics/adt_const_params/const_param_ty_dyn_compatibility.rs5
-rw-r--r--tests/ui/const-generics/adt_const_params/const_param_ty_dyn_compatibility.stderr19
-rw-r--r--tests/ui/const-generics/adt_const_params/const_param_ty_generic_bounds_do_not_hold.rs2
-rw-r--r--tests/ui/const-generics/adt_const_params/const_param_ty_generic_bounds_do_not_hold.stderr24
-rw-r--r--tests/ui/const-generics/adt_const_params/const_param_ty_good.rs8
-rw-r--r--tests/ui/const-generics/adt_const_params/const_param_ty_impl_bad_field.rs4
-rw-r--r--tests/ui/const-generics/adt_const_params/const_param_ty_impl_bad_field.stderr10
-rw-r--r--tests/ui/const-generics/adt_const_params/const_param_ty_impl_no_structural_eq.rs8
-rw-r--r--tests/ui/const-generics/adt_const_params/const_param_ty_impl_no_structural_eq.stderr28
-rw-r--r--tests/ui/const-generics/adt_const_params/const_param_ty_impl_union.rs4
-rw-r--r--tests/ui/const-generics/adt_const_params/const_param_ty_impl_union.stderr10
-rw-r--r--tests/ui/const-generics/adt_const_params/nested_bad_const_param_ty.rs3
-rw-r--r--tests/ui/const-generics/adt_const_params/nested_bad_const_param_ty.stderr63
-rw-r--r--tests/ui/const-generics/adt_const_params/non_valtreeable_const_arg-2.stderr6
-rw-r--r--tests/ui/const-generics/adt_const_params/reference_pointee_is_const_param-1.rs4
-rw-r--r--tests/ui/const-generics/adt_const_params/reference_pointee_is_const_param-1.stderr6
-rw-r--r--tests/ui/const-generics/adt_const_params/reference_pointee_is_const_param-2.rs4
-rw-r--r--tests/ui/const-generics/adt_const_params/reference_pointee_is_const_param-2.stderr6
-rw-r--r--tests/ui/const-generics/adt_const_params/trait_objects_as_a_const_generic.rs4
-rw-r--r--tests/ui/const-generics/adt_const_params/trait_objects_as_a_const_generic.stderr6
-rw-r--r--tests/ui/const-generics/adt_const_params/unsized_field-1.rs5
-rw-r--r--tests/ui/const-generics/adt_const_params/unsized_field-1.stderr28
-rw-r--r--tests/ui/const-generics/adt_const_params/unsized_field-2.rs14
-rw-r--r--tests/ui/const-generics/adt_const_params/unsized_field-2.stderr27
-rw-r--r--tests/ui/const-generics/adt_const_params/unsizing-wfcheck-issue-126272.rs1
-rw-r--r--tests/ui/const-generics/adt_const_params/unsizing-wfcheck-issue-126272.stderr51
-rw-r--r--tests/ui/const-generics/const-param-with-additional-obligations.rs4
-rw-r--r--tests/ui/const-generics/generic_const_parameter_types/no_const_param_ty_bound.stderr2
-rw-r--r--tests/ui/const-generics/issue-66451.rs6
-rw-r--r--tests/ui/const-generics/issues/issue-63322-forbid-dyn.full.stderr2
-rw-r--r--tests/ui/const-generics/slice-const-param-mismatch.adt_const_params.stderr22
-rw-r--r--tests/ui/const-generics/slice-const-param.rs2
-rw-r--r--tests/ui/const-generics/transmute-const-param-static-reference.adt_const_params.stderr12
-rw-r--r--tests/ui/const-generics/transmute-const-param-static-reference.rs2
-rw-r--r--tests/ui/const-generics/unsized_const_params/symbol_mangling_v0_str.rs4
-rw-r--r--tests/ui/consts/const_refs_to_static_fail.stderr2
-rw-r--r--tests/ui/consts/const_refs_to_static_fail_invalid.stderr4
-rw-r--r--tests/ui/consts/miri_unleashed/const_refers_to_static.stderr2
-rw-r--r--tests/ui/consts/miri_unleashed/const_refers_to_static_cross_crate.stderr6
-rw-r--r--tests/ui/darwin-objc/darwin-objc-bad-arg.rs36
-rw-r--r--tests/ui/darwin-objc/darwin-objc-bad-arg.stderr50
-rw-r--r--tests/ui/darwin-objc/darwin-objc-bad-const.rs17
-rw-r--r--tests/ui/darwin-objc/darwin-objc-bad-const.stderr19
-rw-r--r--tests/ui/darwin-objc/darwin-objc-bad-ref.rs31
-rw-r--r--tests/ui/darwin-objc/darwin-objc-bad-ref.stderr39
-rw-r--r--tests/ui/darwin-objc/darwin-objc-class-selector.rs31
-rw-r--r--tests/ui/darwin-objc/darwin-objc-class.rs39
-rw-r--r--tests/ui/darwin-objc/darwin-objc-selector.rs36
-rw-r--r--tests/ui/dist/cranelift-x86_64-unknown-linux-gnu-dist.rs1
-rw-r--r--tests/ui/drop/super-let-tail-expr-drop-order.rs192
-rw-r--r--tests/ui/feature-gates/feature-gate-adt_const_params.rs6
-rw-r--r--tests/ui/feature-gates/feature-gate-adt_const_params.stderr12
-rw-r--r--tests/ui/layout/thaw-transmute-invalid-enum.rs1
-rw-r--r--tests/ui/layout/thaw-transmute-invalid-enum.stderr19
-rw-r--r--tests/ui/lifetimes/issue-105507.fixed2
-rw-r--r--tests/ui/lint/unused_parens_follow_ident.fixed17
-rw-r--r--tests/ui/lint/unused_parens_follow_ident.rs17
-rw-r--r--tests/ui/lint/unused_parens_follow_ident.stderr31
-rw-r--r--tests/ui/parser/expr-as-stmt.fixed4
-rw-r--r--tests/ui/suggestions/apitit-unimplemented-method.rs5
-rw-r--r--tests/ui/suggestions/apitit-unimplemented-method.stderr10
-rw-r--r--tests/ui/suggestions/auxiliary/dep.rs14
-rw-r--r--tests/ui/suggestions/missing-bound-in-derive-copy-impl-2.fixed2
-rw-r--r--tests/ui/suggestions/missing-bound-in-derive-copy-impl-3.fixed2
-rw-r--r--tests/ui/suggestions/trait-impl-bound-suggestions.fixed4
-rw-r--r--tests/ui/symbol-names/const-generics-structural-demangling.rs8
-rw-r--r--tests/ui/type-inference/has_sigdrop.rs18
219 files changed, 4290 insertions, 2348 deletions
diff --git a/.mailmap b/.mailmap
index 6e3eed1226e..0f7bc5e38bd 100644
--- a/.mailmap
+++ b/.mailmap
@@ -609,6 +609,7 @@ Shohei Wada <pc@wada314.jp>
 Shotaro Yamada <sinkuu@sinkuu.xyz>
 Shotaro Yamada <sinkuu@sinkuu.xyz> <sinkuu@users.noreply.github.com>
 Shyam Sundar B <shyambaskaran@outlook.com>
+Sidney Cammeresi <sac@cheesecake.org> <sac@readyset.io>
 Simon Barber-Dueck <sbarberdueck@gmail.com> Simon BD <simon@server>
 Simon Sapin <simon@exyr.org> <simon.sapin@exyr.org>
 Simonas Kazlauskas <git@kazlauskas.me> Simonas Kazlauskas <github@kazlauskas.me>
diff --git a/Cargo.lock b/Cargo.lock
index 4677d34d2a6..d39cfefea0c 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4817,9 +4817,9 @@ dependencies = [
 
 [[package]]
 name = "rustfix"
-version = "0.8.1"
+version = "0.8.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "81864b097046da5df3758fdc6e4822bbb70afa06317e8ca45ea1b51cb8c5e5a4"
+checksum = "82fa69b198d894d84e23afde8e9ab2af4400b2cba20d6bf2b428a8b01c222c5a"
 dependencies = [
  "serde",
  "serde_json",
diff --git a/RELEASES.md b/RELEASES.md
index 33abe45ce46..2b65d070d5f 100644
--- a/RELEASES.md
+++ b/RELEASES.md
@@ -1,3 +1,129 @@
+Version 1.90 (2025-09-18)
+==========================
+
+<a id="1.90-Language"></a>
+
+Language
+--------
+- [Split up the `unknown_or_malformed_diagnostic_attributes` lint](https://github.com/rust-lang/rust/pull/140717). This lint has been split up into four finer-grained lints, with `unknown_or_malformed_diagnostic_attributes` now being the lint group that contains these lints:
+    1. `unknown_diagnostic_attributes`: unknown to the current compiler
+    2. `misplaced_diagnostic_attributes`: placed on the wrong item
+    3. `malformed_diagnostic_attributes`: malformed attribute syntax or options
+    4. `malformed_diagnostic_format_literals`: malformed format string literal
+- [Allow constants whose final value has references to mutable/external memory, but reject such constants as patterns](https://github.com/rust-lang/rust/pull/140942)
+- [Allow volatile access to non-Rust memory, including address 0](https://github.com/rust-lang/rust/pull/141260)
+
+
+<a id="1.90-Compiler"></a>
+
+Compiler
+--------
+- [Use `lld` by default on `x86_64-unknown-linux-gnu`](https://github.com/rust-lang/rust/pull/140525).
+- [Tier 3 `musl` targets now link dynamically by default](https://github.com/rust-lang/rust/pull/144410). Affected targets:
+    - `mips64-unknown-linux-muslabi64`
+    - `powerpc64-unknown-linux-musl`
+    - `powerpc-unknown-linux-musl`
+    - `powerpc-unknown-linux-muslspe`
+    - `riscv32gc-unknown-linux-musl`
+    - `s390x-unknown-linux-musl`
+    - `thumbv7neon-unknown-linux-musleabihf`
+
+
+<a id="1.90-Platform-Support"></a>
+
+Platform Support
+----------------
+- [Demote `x86_64-apple-darwin` to Tier 2 with host tools](https://github.com/rust-lang/rust/pull/145252)
+
+
+Refer to Rust's [platform support page][platform-support-doc]
+for more information on Rust's tiered platform support.
+
+[platform-support-doc]: https://doc.rust-lang.org/rustc/platform-support.html
+
+<a id="1.90-Libraries"></a>
+
+Libraries
+---------
+- [Stabilize `u*::{checked,overflowing,saturating,wrapping}_sub_signed`](https://github.com/rust-lang/rust/issues/126043)
+- [Allow comparisons between `CStr`, `CString`, and `Cow<CStr>`](https://github.com/rust-lang/rust/pull/137268)
+- [Remove some unsized tuple impls since unsized tuples can't be constructed](https://github.com/rust-lang/rust/pull/138340)
+- [Set `MSG_NOSIGNAL` for `UnixStream`](https://github.com/rust-lang/rust/pull/140005)
+- [`proc_macro::Ident::new` now supports `$crate`.](https://github.com/rust-lang/rust/pull/141996)
+- [Guarantee the pointer returned from `Thread::into_raw` has at least 8 bytes of alignment](https://github.com/rust-lang/rust/pull/143859)
+
+
+<a id="1.90-Stabilized-APIs"></a>
+
+Stabilized APIs
+---------------
+
+- [`u{n}::checked_sub_signed`](https://doc.rust-lang.org/stable/std/primitive.usize.html#method.checked_sub_signed)
+- [`u{n}::overflowing_sub_signed`](https://doc.rust-lang.org/stable/std/primitive.usize.html#method.overflowing_sub_signed)
+- [`u{n}::saturating_sub_signed`](https://doc.rust-lang.org/stable/std/primitive.usize.html#method.saturating_sub_signed)
+- [`u{n}::wrapping_sub_signed`](https://doc.rust-lang.org/stable/std/primitive.usize.html#method.wrapping_sub_signed)
+- [`impl Copy for IntErrorKind`](https://doc.rust-lang.org/stable/std/num/enum.IntErrorKind.html#impl-Copy-for-IntErrorKind)
+- [`impl Hash for IntErrorKind`](https://doc.rust-lang.org/stable/std/num/enum.IntErrorKind.html#impl-Hash-for-IntErrorKind)
+- [`impl PartialEq<&CStr> for CStr`](https://doc.rust-lang.org/stable/std/ffi/struct.CStr.html#impl-PartialEq%3C%26CStr%3E-for-CStr)
+- [`impl PartialEq<CString> for CStr`](https://doc.rust-lang.org/stable/std/ffi/struct.CStr.html#impl-PartialEq%3CCString%3E-for-CStr)
+- [`impl PartialEq<Cow<CStr>> for CStr`](https://doc.rust-lang.org/stable/std/ffi/struct.CStr.html#impl-PartialEq%3CCow%3C'_,+CStr%3E%3E-for-CStr)
+- [`impl PartialEq<&CStr> for CString`](https://doc.rust-lang.org/stable/std/ffi/struct.CString.html#impl-PartialEq%3C%26CStr%3E-for-CString)
+- [`impl PartialEq<CStr> for CString`](https://doc.rust-lang.org/stable/std/ffi/struct.CString.html#impl-PartialEq%3CCStr%3E-for-CString)
+- [`impl PartialEq<Cow<CStr>> for CString`](https://doc.rust-lang.org/stable/std/ffi/struct.CString.html#impl-PartialEq%3CCow%3C'_,+CStr%3E%3E-for-CString)
+- [`impl PartialEq<&CStr> for Cow<CStr>`](https://doc.rust-lang.org/stable/std/borrow/enum.Cow.html#impl-PartialEq%3C%26CStr%3E-for-Cow%3C'_,+CStr%3E)
+- [`impl PartialEq<CStr> for Cow<CStr>`](https://doc.rust-lang.org/stable/std/borrow/enum.Cow.html#impl-PartialEq%3CCStr%3E-for-Cow%3C'_,+CStr%3E)
+- [`impl PartialEq<CString> for Cow<CStr>`](https://doc.rust-lang.org/stable/std/borrow/enum.Cow.html#impl-PartialEq%3CCString%3E-for-Cow%3C'_,+CStr%3E)
+
+
+These previously stable APIs are now stable in const contexts:
+
+- [`<[T]>::reverse`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.reverse)
+- [`f32::floor`](https://doc.rust-lang.org/stable/std/primitive.f32.html#method.floor)
+- [`f32::ceil`](https://doc.rust-lang.org/stable/std/primitive.f32.html#method.ceil)
+- [`f32::trunc`](https://doc.rust-lang.org/stable/std/primitive.f32.html#method.trunc)
+- [`f32::fract`](https://doc.rust-lang.org/stable/std/primitive.f32.html#method.fract)
+- [`f32::round`](https://doc.rust-lang.org/stable/std/primitive.f32.html#method.round)
+- [`f32::round_ties_even`](https://doc.rust-lang.org/stable/std/primitive.f32.html#method.round_ties_even)
+- [`f64::floor`](https://doc.rust-lang.org/stable/std/primitive.f64.html#method.floor)
+- [`f64::ceil`](https://doc.rust-lang.org/stable/std/primitive.f64.html#method.ceil)
+- [`f64::trunc`](https://doc.rust-lang.org/stable/std/primitive.f64.html#method.trunc)
+- [`f64::fract`](https://doc.rust-lang.org/stable/std/primitive.f64.html#method.fract)
+- [`f64::round`](https://doc.rust-lang.org/stable/std/primitive.f64.html#method.round)
+- [`f64::round_ties_even`](https://doc.rust-lang.org/stable/std/primitive.f64.html#method.round_ties_even)
+
+
+<a id="1.90-Cargo"></a>
+
+Cargo
+-----
+- [Add `http.proxy-cainfo` config for proxy certs](https://github.com/rust-lang/cargo/pull/15374/)
+- [Use `gix` for `cargo package`](https://github.com/rust-lang/cargo/pull/15534/)
+- [feat(publish): Stabilize multi-package publishing](https://github.com/rust-lang/cargo/pull/15636/)
+
+<a id="1.90-Rustdoc"></a>
+
+Rustdoc
+-----
+- [Add ways to collapse all impl blocks](https://github.com/rust-lang/rust/pull/141663). Previously the "Summary" button and "-" keyboard shortcut would never collapse `impl` blocks, now they do when shift is held
+- [Display unsafe attributes with `unsafe()` wrappers](https://github.com/rust-lang/rust/pull/143662)
+
+
+<a id="1.90-Compatibility-Notes"></a>
+
+Compatibility Notes
+-------------------
+- [Use `lld` by default on `x86_64-unknown-linux-gnu`](https://github.com/rust-lang/rust/pull/140525).
+  See also <https://blog.rust-lang.org/2025/09/01/rust-lld-on-1.90.0-stable/>.
+- [Make `core::iter::Fuse`'s `Default` impl construct `I::default()` internally as promised in the docs instead of always being empty](https://github.com/rust-lang/rust/pull/140985)
+- [Set `MSG_NOSIGNAL` for `UnixStream`](https://github.com/rust-lang/rust/pull/140005)
+  This may change program behavior but results in the same behavior as other primitives (e.g., stdout, network sockets).
+  Programs relying on signals to terminate them should update handling of sockets to handle errors on write by exiting.
+- [On Unix `std::env::home_dir` will use the fallback if the `HOME` environment variable is empty](https://github.com/rust-lang/rust/pull/141840)
+- We now [reject unsupported `extern "{abi}"`s consistently in all positions](https://github.com/rust-lang/rust/pull/142134). This primarily affects the use of implementing traits on an `extern "{abi}"` function pointer, like `extern "stdcall" fn()`, on a platform that doesn't support that, like aarch64-unknown-linux-gnu. Direct usage of these unsupported ABI strings by declaring or defining functions was already rejected, so this is only a change for consistency.
+- [const-eval: error when initializing a static writes to that static](https://github.com/rust-lang/rust/pull/143084)
+- [Check that the `proc_macro_derive` macro has correct arguments when applied to the crate root](https://github.com/rust-lang/rust/pull/143607)
+
+
 Version 1.89.0 (2025-08-07)
 ==========================
 
diff --git a/compiler/rustc_attr_parsing/messages.ftl b/compiler/rustc_attr_parsing/messages.ftl
index 839a5d23c3b..81ec17077c1 100644
--- a/compiler/rustc_attr_parsing/messages.ftl
+++ b/compiler/rustc_attr_parsing/messages.ftl
@@ -122,6 +122,14 @@ attr_parsing_null_on_export = `export_name` may not contain null characters
 
 attr_parsing_null_on_link_section = `link_section` may not contain null characters
 
+attr_parsing_null_on_objc_class = `objc::class!` may not contain null characters
+
+attr_parsing_null_on_objc_selector = `objc::selector!` may not contain null characters
+
+attr_parsing_objc_class_expected_string_literal = `objc::class!` expected a string literal
+
+attr_parsing_objc_selector_expected_string_literal = `objc::selector!` expected a string literal
+
 attr_parsing_repr_ident =
     meta item in `repr` must be an identifier
 
diff --git a/compiler/rustc_attr_parsing/src/attributes/codegen_attrs.rs b/compiler/rustc_attr_parsing/src/attributes/codegen_attrs.rs
index d5d51f2e79a..262b8213977 100644
--- a/compiler/rustc_attr_parsing/src/attributes/codegen_attrs.rs
+++ b/compiler/rustc_attr_parsing/src/attributes/codegen_attrs.rs
@@ -2,7 +2,10 @@ use rustc_hir::attrs::{CoverageAttrKind, OptimizeAttr, SanitizerSet, UsedBy};
 use rustc_session::parse::feature_err;
 
 use super::prelude::*;
-use crate::session_diagnostics::{NakedFunctionIncompatibleAttribute, NullOnExport};
+use crate::session_diagnostics::{
+    NakedFunctionIncompatibleAttribute, NullOnExport, NullOnObjcClass, NullOnObjcSelector,
+    ObjcClassExpectedStringLiteral, ObjcSelectorExpectedStringLiteral,
+};
 
 pub(crate) struct OptimizeParser;
 
@@ -150,6 +153,70 @@ impl<S: Stage> SingleAttributeParser<S> for ExportNameParser {
     }
 }
 
+pub(crate) struct ObjcClassParser;
+
+impl<S: Stage> SingleAttributeParser<S> for ObjcClassParser {
+    const PATH: &[rustc_span::Symbol] = &[sym::rustc_objc_class];
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const ALLOWED_TARGETS: AllowedTargets =
+        AllowedTargets::AllowList(&[Allow(Target::ForeignStatic)]);
+    const TEMPLATE: AttributeTemplate = template!(NameValueStr: "ClassName");
+
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
+        let Some(nv) = args.name_value() else {
+            cx.expected_name_value(cx.attr_span, None);
+            return None;
+        };
+        let Some(classname) = nv.value_as_str() else {
+            // `#[rustc_objc_class = ...]` is expected to be used as an implementatioin detail
+            // inside a standard library macro, but `cx.expected_string_literal` exposes too much.
+            // Use a custom error message instead.
+            cx.emit_err(ObjcClassExpectedStringLiteral { span: nv.value_span });
+            return None;
+        };
+        if classname.as_str().contains('\0') {
+            // `#[rustc_objc_class = ...]` will be converted to a null-terminated string,
+            // so it may not contain any null characters.
+            cx.emit_err(NullOnObjcClass { span: nv.value_span });
+            return None;
+        }
+        Some(AttributeKind::ObjcClass { classname, span: cx.attr_span })
+    }
+}
+
+pub(crate) struct ObjcSelectorParser;
+
+impl<S: Stage> SingleAttributeParser<S> for ObjcSelectorParser {
+    const PATH: &[rustc_span::Symbol] = &[sym::rustc_objc_selector];
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const ALLOWED_TARGETS: AllowedTargets =
+        AllowedTargets::AllowList(&[Allow(Target::ForeignStatic)]);
+    const TEMPLATE: AttributeTemplate = template!(NameValueStr: "methodName");
+
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
+        let Some(nv) = args.name_value() else {
+            cx.expected_name_value(cx.attr_span, None);
+            return None;
+        };
+        let Some(methname) = nv.value_as_str() else {
+            // `#[rustc_objc_selector = ...]` is expected to be used as an implementatioin detail
+            // inside a standard library macro, but `cx.expected_string_literal` exposes too much.
+            // Use a custom error message instead.
+            cx.emit_err(ObjcSelectorExpectedStringLiteral { span: nv.value_span });
+            return None;
+        };
+        if methname.as_str().contains('\0') {
+            // `#[rustc_objc_selector = ...]` will be converted to a null-terminated string,
+            // so it may not contain any null characters.
+            cx.emit_err(NullOnObjcSelector { span: nv.value_span });
+            return None;
+        }
+        Some(AttributeKind::ObjcSelector { methname, span: cx.attr_span })
+    }
+}
+
 #[derive(Default)]
 pub(crate) struct NakedParser {
     span: Option<Span>,
diff --git a/compiler/rustc_attr_parsing/src/context.rs b/compiler/rustc_attr_parsing/src/context.rs
index d7998048be5..58b13292484 100644
--- a/compiler/rustc_attr_parsing/src/context.rs
+++ b/compiler/rustc_attr_parsing/src/context.rs
@@ -20,8 +20,8 @@ use crate::attributes::allow_unstable::{
 use crate::attributes::body::CoroutineParser;
 use crate::attributes::codegen_attrs::{
     ColdParser, CoverageParser, ExportNameParser, ForceTargetFeatureParser, NakedParser,
-    NoMangleParser, OptimizeParser, SanitizeParser, TargetFeatureParser, TrackCallerParser,
-    UsedParser,
+    NoMangleParser, ObjcClassParser, ObjcSelectorParser, OptimizeParser, SanitizeParser,
+    TargetFeatureParser, TrackCallerParser, UsedParser,
 };
 use crate::attributes::confusables::ConfusablesParser;
 use crate::attributes::crate_level::{
@@ -185,6 +185,8 @@ attribute_parsers!(
         Single<LinkageParser>,
         Single<MoveSizeLimitParser>,
         Single<MustUseParser>,
+        Single<ObjcClassParser>,
+        Single<ObjcSelectorParser>,
         Single<OptimizeParser>,
         Single<PathAttributeParser>,
         Single<PatternComplexityLimitParser>,
diff --git a/compiler/rustc_attr_parsing/src/session_diagnostics.rs b/compiler/rustc_attr_parsing/src/session_diagnostics.rs
index 32ea9005a97..2c2b14c8a68 100644
--- a/compiler/rustc_attr_parsing/src/session_diagnostics.rs
+++ b/compiler/rustc_attr_parsing/src/session_diagnostics.rs
@@ -460,6 +460,34 @@ pub(crate) struct NullOnLinkSection {
 }
 
 #[derive(Diagnostic)]
+#[diag(attr_parsing_null_on_objc_class)]
+pub(crate) struct NullOnObjcClass {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(attr_parsing_null_on_objc_selector)]
+pub(crate) struct NullOnObjcSelector {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(attr_parsing_objc_class_expected_string_literal)]
+pub(crate) struct ObjcClassExpectedStringLiteral {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(attr_parsing_objc_selector_expected_string_literal)]
+pub(crate) struct ObjcSelectorExpectedStringLiteral {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
 #[diag(attr_parsing_stability_outside_std, code = E0734)]
 pub(crate) struct StabilityOutsideStd {
     #[primary_span]
diff --git a/compiler/rustc_builtin_macros/src/deriving/bounds.rs b/compiler/rustc_builtin_macros/src/deriving/bounds.rs
index dd8f0e46a0e..63342880b09 100644
--- a/compiler/rustc_builtin_macros/src/deriving/bounds.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/bounds.rs
@@ -51,43 +51,4 @@ pub(crate) fn expand_deriving_const_param_ty(
     };
 
     trait_def.expand(cx, mitem, item, push);
-
-    let trait_def = TraitDef {
-        span,
-        path: path_std!(marker::UnsizedConstParamTy),
-        skip_path_as_bound: false,
-        needs_copy_as_bound_if_packed: false,
-        additional_bounds: vec![ty::Ty::Path(path_std!(cmp::Eq))],
-        supports_unions: false,
-        methods: Vec::new(),
-        associated_types: Vec::new(),
-        is_const,
-        is_staged_api_crate: cx.ecfg.features.staged_api(),
-    };
-
-    trait_def.expand(cx, mitem, item, push);
-}
-
-pub(crate) fn expand_deriving_unsized_const_param_ty(
-    cx: &ExtCtxt<'_>,
-    span: Span,
-    mitem: &MetaItem,
-    item: &Annotatable,
-    push: &mut dyn FnMut(Annotatable),
-    is_const: bool,
-) {
-    let trait_def = TraitDef {
-        span,
-        path: path_std!(marker::UnsizedConstParamTy),
-        skip_path_as_bound: false,
-        needs_copy_as_bound_if_packed: false,
-        additional_bounds: vec![ty::Ty::Path(path_std!(cmp::Eq))],
-        supports_unions: false,
-        methods: Vec::new(),
-        associated_types: Vec::new(),
-        is_const,
-        is_staged_api_crate: cx.ecfg.features.staged_api(),
-    };
-
-    trait_def.expand(cx, mitem, item, push);
 }
diff --git a/compiler/rustc_builtin_macros/src/lib.rs b/compiler/rustc_builtin_macros/src/lib.rs
index 1bcea95fbb7..4541e2cd3b4 100644
--- a/compiler/rustc_builtin_macros/src/lib.rs
+++ b/compiler/rustc_builtin_macros/src/lib.rs
@@ -129,7 +129,6 @@ pub fn register_builtin_macros(resolver: &mut dyn ResolverExpand) {
         Clone: clone::expand_deriving_clone,
         Copy: bounds::expand_deriving_copy,
         ConstParamTy: bounds::expand_deriving_const_param_ty,
-        UnsizedConstParamTy: bounds::expand_deriving_unsized_const_param_ty,
         Debug: debug::expand_deriving_debug,
         Default: default::expand_deriving_default,
         Eq: eq::expand_deriving_eq,
diff --git a/compiler/rustc_codegen_llvm/src/asm.rs b/compiler/rustc_codegen_llvm/src/asm.rs
index 38c1d3b53e8..b79176e9098 100644
--- a/compiler/rustc_codegen_llvm/src/asm.rs
+++ b/compiler/rustc_codegen_llvm/src/asm.rs
@@ -240,6 +240,7 @@ impl<'ll, 'tcx> AsmBuilderMethods<'tcx> for Builder<'_, 'll, 'tcx> {
                 }
                 InlineAsmArch::RiscV32 | InlineAsmArch::RiscV64 => {
                     constraints.extend_from_slice(&[
+                        "~{fflags}".to_string(),
                         "~{vtype}".to_string(),
                         "~{vl}".to_string(),
                         "~{vxsat}".to_string(),
diff --git a/compiler/rustc_codegen_llvm/src/base.rs b/compiler/rustc_codegen_llvm/src/base.rs
index 9cc5d8dbc21..978134cc32b 100644
--- a/compiler/rustc_codegen_llvm/src/base.rs
+++ b/compiler/rustc_codegen_llvm/src/base.rs
@@ -109,18 +109,36 @@ pub(crate) fn compile_codegen_unit(
                 attributes::apply_to_llfn(entry, llvm::AttributePlace::Function, &attrs);
             }
 
+            // Define Objective-C module info and module flags. Note, the module info will
+            // also be added to the `llvm.compiler.used` variable, created later.
+            //
+            // These are only necessary when we need the linker to do its Objective-C-specific
+            // magic. We could theoretically do it unconditionally, but at a slight cost to linker
+            // performance in the common case where it's unnecessary.
+            if !cx.objc_classrefs.borrow().is_empty() || !cx.objc_selrefs.borrow().is_empty() {
+                if cx.objc_abi_version() == 1 {
+                    cx.define_objc_module_info();
+                }
+                cx.add_objc_module_flags();
+            }
+
             // Finalize code coverage by injecting the coverage map. Note, the coverage map will
             // also be added to the `llvm.compiler.used` variable, created next.
             if cx.sess().instrument_coverage() {
                 cx.coverageinfo_finalize();
             }
 
-            // Create the llvm.used and llvm.compiler.used variables.
+            // Create the llvm.used variable.
             if !cx.used_statics.is_empty() {
                 cx.create_used_variable_impl(c"llvm.used", &cx.used_statics);
             }
-            if !cx.compiler_used_statics.is_empty() {
-                cx.create_used_variable_impl(c"llvm.compiler.used", &cx.compiler_used_statics);
+
+            // Create the llvm.compiler.used variable.
+            {
+                let compiler_used_statics = cx.compiler_used_statics.borrow();
+                if !compiler_used_statics.is_empty() {
+                    cx.create_used_variable_impl(c"llvm.compiler.used", &compiler_used_statics);
+                }
             }
 
             // Run replace-all-uses-with for statics that need it. This must
diff --git a/compiler/rustc_codegen_llvm/src/builder.rs b/compiler/rustc_codegen_llvm/src/builder.rs
index 7d0691366e6..0f17cc9063a 100644
--- a/compiler/rustc_codegen_llvm/src/builder.rs
+++ b/compiler/rustc_codegen_llvm/src/builder.rs
@@ -1091,16 +1091,11 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         ty: Ty<'tcx>,
         lhs: Self::Value,
         rhs: Self::Value,
-    ) -> Option<Self::Value> {
-        // FIXME: See comment on the definition of `three_way_compare`.
-        if crate::llvm_util::get_version() < (20, 0, 0) {
-            return None;
-        }
-
+    ) -> Self::Value {
         let size = ty.primitive_size(self.tcx);
         let name = if ty.is_signed() { "llvm.scmp" } else { "llvm.ucmp" };
 
-        Some(self.call_intrinsic(name, &[self.type_i8(), self.type_ix(size.bits())], &[lhs, rhs]))
+        self.call_intrinsic(name, &[self.type_i8(), self.type_ix(size.bits())], &[lhs, rhs])
     }
 
     /* Miscellaneous instructions */
diff --git a/compiler/rustc_codegen_llvm/src/common.rs b/compiler/rustc_codegen_llvm/src/common.rs
index 11b79a7fe68..aa2df46329f 100644
--- a/compiler/rustc_codegen_llvm/src/common.rs
+++ b/compiler/rustc_codegen_llvm/src/common.rs
@@ -108,6 +108,10 @@ impl<'ll, CX: Borrow<SCx<'ll>>> GenericCx<'ll, CX> {
         bytes_in_context(self.llcx(), bytes)
     }
 
+    pub(crate) fn null_terminate_const_bytes(&self, bytes: &[u8]) -> &'ll Value {
+        null_terminate_bytes_in_context(self.llcx(), bytes)
+    }
+
     pub(crate) fn const_get_elt(&self, v: &'ll Value, idx: u64) -> &'ll Value {
         unsafe {
             let idx = c_uint::try_from(idx).expect("LLVMGetAggregateElement index overflow");
@@ -381,6 +385,16 @@ pub(crate) fn bytes_in_context<'ll>(llcx: &'ll llvm::Context, bytes: &[u8]) -> &
     }
 }
 
+pub(crate) fn null_terminate_bytes_in_context<'ll>(
+    llcx: &'ll llvm::Context,
+    bytes: &[u8],
+) -> &'ll Value {
+    unsafe {
+        let ptr = bytes.as_ptr() as *const c_char;
+        llvm::LLVMConstStringInContext2(llcx, ptr, bytes.len(), FALSE)
+    }
+}
+
 pub(crate) fn named_struct<'ll>(ty: &'ll Type, elts: &[&'ll Value]) -> &'ll Value {
     let len = c_uint::try_from(elts.len()).expect("LLVMConstStructInContext elements len overflow");
     unsafe { llvm::LLVMConstNamedStruct(ty, elts.as_ptr(), len) }
diff --git a/compiler/rustc_codegen_llvm/src/consts.rs b/compiler/rustc_codegen_llvm/src/consts.rs
index dc9bb743560..a110ecbb75d 100644
--- a/compiler/rustc_codegen_llvm/src/consts.rs
+++ b/compiler/rustc_codegen_llvm/src/consts.rs
@@ -16,6 +16,7 @@ use rustc_middle::mir::mono::MonoItem;
 use rustc_middle::ty::layout::{HasTypingEnv, LayoutOf};
 use rustc_middle::ty::{self, Instance};
 use rustc_middle::{bug, span_bug};
+use rustc_span::Symbol;
 use tracing::{debug, instrument, trace};
 
 use crate::common::CodegenCx;
@@ -331,6 +332,10 @@ impl<'ll> CodegenCx<'ll, '_> {
             }
 
             g
+        } else if let Some(classname) = fn_attrs.objc_class {
+            self.get_objc_classref(classname)
+        } else if let Some(methname) = fn_attrs.objc_selector {
+            self.get_objc_selref(methname)
         } else {
             check_and_apply_linkage(self, fn_attrs, llty, sym, def_id)
         };
@@ -543,8 +548,225 @@ impl<'ll> CodegenCx<'ll, '_> {
 
     /// Add a global value to a list to be stored in the `llvm.compiler.used` variable,
     /// an array of ptr.
-    pub(crate) fn add_compiler_used_global(&mut self, global: &'ll Value) {
-        self.compiler_used_statics.push(global);
+    pub(crate) fn add_compiler_used_global(&self, global: &'ll Value) {
+        self.compiler_used_statics.borrow_mut().push(global);
+    }
+
+    // We do our best here to match what Clang does when compiling Objective-C natively.
+    // See Clang's `CGObjCCommonMac::CreateCStringLiteral`:
+    // https://github.com/llvm/llvm-project/blob/llvmorg-20.1.8/clang/lib/CodeGen/CGObjCMac.cpp#L4134
+    fn define_objc_classname(&self, classname: &str) -> &'ll Value {
+        assert_eq!(self.objc_abi_version(), 1);
+
+        let llval = self.null_terminate_const_bytes(classname.as_bytes());
+        let llty = self.val_ty(llval);
+        let sym = self.generate_local_symbol_name("OBJC_CLASS_NAME_");
+        let g = self.define_global(&sym, llty).unwrap_or_else(|| {
+            bug!("symbol `{}` is already defined", sym);
+        });
+        set_global_alignment(self, g, self.tcx.data_layout.i8_align.abi);
+        llvm::set_initializer(g, llval);
+        llvm::set_linkage(g, llvm::Linkage::PrivateLinkage);
+        llvm::set_section(g, c"__TEXT,__cstring,cstring_literals");
+        llvm::LLVMSetGlobalConstant(g, llvm::TRUE);
+        llvm::LLVMSetUnnamedAddress(g, llvm::UnnamedAddr::Global);
+        self.add_compiler_used_global(g);
+
+        g
+    }
+
+    // We do our best here to match what Clang does when compiling Objective-C natively.
+    // See Clang's `ObjCNonFragileABITypesHelper`:
+    // https://github.com/llvm/llvm-project/blob/llvmorg-20.1.8/clang/lib/CodeGen/CGObjCMac.cpp#L6052
+    fn get_objc_class_t(&self) -> &'ll Type {
+        if let Some(class_t) = self.objc_class_t.get() {
+            return class_t;
+        }
+
+        assert_eq!(self.objc_abi_version(), 2);
+
+        // struct _class_t {
+        //     struct _class_t* isa;
+        //     struct _class_t* const superclass;
+        //     void* cache;
+        //     IMP* vtable;
+        //     struct class_ro_t* ro;
+        // }
+
+        let class_t = self.type_named_struct("struct._class_t");
+        let els = [self.type_ptr(); 5];
+        let packed = false;
+        self.set_struct_body(class_t, &els, packed);
+
+        self.objc_class_t.set(Some(class_t));
+        class_t
+    }
+
+    // We do our best here to match what Clang does when compiling Objective-C natively. We
+    // deduplicate references within a CGU, but we need a reference definition in each referencing
+    // CGU. All attempts at using external references to a single reference definition result in
+    // linker errors.
+    fn get_objc_classref(&self, classname: Symbol) -> &'ll Value {
+        let mut classrefs = self.objc_classrefs.borrow_mut();
+        if let Some(classref) = classrefs.get(&classname).copied() {
+            return classref;
+        }
+
+        let g = match self.objc_abi_version() {
+            1 => {
+                // See Clang's `CGObjCMac::EmitClassRefFromId`:
+                // https://github.com/llvm/llvm-project/blob/llvmorg-20.1.8/clang/lib/CodeGen/CGObjCMac.cpp#L5205
+                let llval = self.define_objc_classname(classname.as_str());
+                let llty = self.type_ptr();
+                let sym = self.generate_local_symbol_name("OBJC_CLASS_REFERENCES_");
+                let g = self.define_global(&sym, llty).unwrap_or_else(|| {
+                    bug!("symbol `{}` is already defined", sym);
+                });
+                set_global_alignment(self, g, self.tcx.data_layout.pointer_align().abi);
+                llvm::set_initializer(g, llval);
+                llvm::set_linkage(g, llvm::Linkage::PrivateLinkage);
+                llvm::set_section(g, c"__OBJC,__cls_refs,literal_pointers,no_dead_strip");
+                self.add_compiler_used_global(g);
+                g
+            }
+            2 => {
+                // See Clang's `CGObjCNonFragileABIMac::EmitClassRefFromId`:
+                // https://github.com/llvm/llvm-project/blob/llvmorg-20.1.8/clang/lib/CodeGen/CGObjCMac.cpp#L7423
+                let llval = {
+                    let extern_sym = format!("OBJC_CLASS_$_{}", classname.as_str());
+                    let extern_llty = self.get_objc_class_t();
+                    self.declare_global(&extern_sym, extern_llty)
+                };
+                let llty = self.type_ptr();
+                let sym = self.generate_local_symbol_name("OBJC_CLASSLIST_REFERENCES_$_");
+                let g = self.define_global(&sym, llty).unwrap_or_else(|| {
+                    bug!("symbol `{}` is already defined", sym);
+                });
+                set_global_alignment(self, g, self.tcx.data_layout.pointer_align().abi);
+                llvm::set_initializer(g, llval);
+                llvm::set_linkage(g, llvm::Linkage::InternalLinkage);
+                llvm::set_section(g, c"__DATA,__objc_classrefs,regular,no_dead_strip");
+                self.add_compiler_used_global(g);
+                g
+            }
+            _ => unreachable!(),
+        };
+
+        classrefs.insert(classname, g);
+        g
+    }
+
+    // We do our best here to match what Clang does when compiling Objective-C natively. We
+    // deduplicate references within a CGU, but we need a reference definition in each referencing
+    // CGU. All attempts at using external references to a single reference definition result in
+    // linker errors.
+    //
+    // Newer versions of Apple Clang generate calls to `@"objc_msgSend$methname"` selector stub
+    // functions. We don't currently do that. The code we generate is closer to what Apple Clang
+    // generates with the `-fno-objc-msgsend-selector-stubs` option.
+    fn get_objc_selref(&self, methname: Symbol) -> &'ll Value {
+        let mut selrefs = self.objc_selrefs.borrow_mut();
+        if let Some(selref) = selrefs.get(&methname).copied() {
+            return selref;
+        }
+
+        let abi_version = self.objc_abi_version();
+
+        // See Clang's `CGObjCCommonMac::CreateCStringLiteral`:
+        // https://github.com/llvm/llvm-project/blob/llvmorg-20.1.8/clang/lib/CodeGen/CGObjCMac.cpp#L4134
+        let methname_llval = self.null_terminate_const_bytes(methname.as_str().as_bytes());
+        let methname_llty = self.val_ty(methname_llval);
+        let methname_sym = self.generate_local_symbol_name("OBJC_METH_VAR_NAME_");
+        let methname_g = self.define_global(&methname_sym, methname_llty).unwrap_or_else(|| {
+            bug!("symbol `{}` is already defined", methname_sym);
+        });
+        set_global_alignment(self, methname_g, self.tcx.data_layout.i8_align.abi);
+        llvm::set_initializer(methname_g, methname_llval);
+        llvm::set_linkage(methname_g, llvm::Linkage::PrivateLinkage);
+        llvm::set_section(
+            methname_g,
+            match abi_version {
+                1 => c"__TEXT,__cstring,cstring_literals",
+                2 => c"__TEXT,__objc_methname,cstring_literals",
+                _ => unreachable!(),
+            },
+        );
+        llvm::LLVMSetGlobalConstant(methname_g, llvm::TRUE);
+        llvm::LLVMSetUnnamedAddress(methname_g, llvm::UnnamedAddr::Global);
+        self.add_compiler_used_global(methname_g);
+
+        // See Clang's `CGObjCMac::EmitSelectorAddr`:
+        // https://github.com/llvm/llvm-project/blob/llvmorg-20.1.8/clang/lib/CodeGen/CGObjCMac.cpp#L5243
+        // And Clang's `CGObjCNonFragileABIMac::EmitSelectorAddr`:
+        // https://github.com/llvm/llvm-project/blob/llvmorg-20.1.8/clang/lib/CodeGen/CGObjCMac.cpp#L7586
+        let selref_llval = methname_g;
+        let selref_llty = self.type_ptr();
+        let selref_sym = self.generate_local_symbol_name("OBJC_SELECTOR_REFERENCES_");
+        let selref_g = self.define_global(&selref_sym, selref_llty).unwrap_or_else(|| {
+            bug!("symbol `{}` is already defined", selref_sym);
+        });
+        set_global_alignment(self, selref_g, self.tcx.data_layout.pointer_align().abi);
+        llvm::set_initializer(selref_g, selref_llval);
+        llvm::set_externally_initialized(selref_g, true);
+        llvm::set_linkage(
+            selref_g,
+            match abi_version {
+                1 => llvm::Linkage::PrivateLinkage,
+                2 => llvm::Linkage::InternalLinkage,
+                _ => unreachable!(),
+            },
+        );
+        llvm::set_section(
+            selref_g,
+            match abi_version {
+                1 => c"__OBJC,__message_refs,literal_pointers,no_dead_strip",
+                2 => c"__DATA,__objc_selrefs,literal_pointers,no_dead_strip",
+                _ => unreachable!(),
+            },
+        );
+        self.add_compiler_used_global(selref_g);
+
+        selrefs.insert(methname, selref_g);
+        selref_g
+    }
+
+    // We do our best here to match what Clang does when compiling Objective-C natively.
+    // See Clang's `ObjCTypesHelper`:
+    // https://github.com/llvm/llvm-project/blob/llvmorg-20.1.8/clang/lib/CodeGen/CGObjCMac.cpp#L5936
+    // And Clang's `CGObjCMac::EmitModuleInfo`:
+    // https://github.com/llvm/llvm-project/blob/llvmorg-20.1.8/clang/lib/CodeGen/CGObjCMac.cpp#L5151
+    pub(crate) fn define_objc_module_info(&mut self) {
+        assert_eq!(self.objc_abi_version(), 1);
+
+        // struct _objc_module {
+        //     long version;                // Hardcoded to 7 in Clang.
+        //     long size;                   // sizeof(struct _objc_module)
+        //     char* name;                  // Hardcoded to classname "" in Clang.
+        //     struct _objc_symtab* symtab; // Null without class or category definitions.
+        //  }
+
+        let llty = self.type_named_struct("struct._objc_module");
+        let i32_llty = self.type_i32();
+        let ptr_llty = self.type_ptr();
+        let packed = false;
+        self.set_struct_body(llty, &[i32_llty, i32_llty, ptr_llty, ptr_llty], packed);
+
+        let version = self.const_uint(i32_llty, 7);
+        let size = self.const_uint(i32_llty, 16);
+        let name = self.define_objc_classname("");
+        let symtab = self.const_null(ptr_llty);
+        let llval = crate::common::named_struct(llty, &[version, size, name, symtab]);
+
+        let sym = "OBJC_MODULES";
+        let g = self.define_global(&sym, llty).unwrap_or_else(|| {
+            bug!("symbol `{}` is already defined", sym);
+        });
+        set_global_alignment(self, g, self.tcx.data_layout.pointer_align().abi);
+        llvm::set_initializer(g, llval);
+        llvm::set_linkage(g, llvm::Linkage::PrivateLinkage);
+        llvm::set_section(g, c"__OBJC,__module_info,regular,no_dead_strip");
+
+        self.add_compiler_used_global(g);
     }
 }
 
diff --git a/compiler/rustc_codegen_llvm/src/context.rs b/compiler/rustc_codegen_llvm/src/context.rs
index a69fa54a54a..4a8ea11a3a8 100644
--- a/compiler/rustc_codegen_llvm/src/context.rs
+++ b/compiler/rustc_codegen_llvm/src/context.rs
@@ -26,7 +26,7 @@ use rustc_session::config::{
     BranchProtection, CFGuard, CFProtection, CrateType, DebugInfo, FunctionReturn, PAuthKey, PacRet,
 };
 use rustc_span::source_map::Spanned;
-use rustc_span::{DUMMY_SP, Span};
+use rustc_span::{DUMMY_SP, Span, Symbol};
 use rustc_symbol_mangling::mangle_internal_symbol;
 use rustc_target::spec::{HasTargetSpec, RelocModel, SmallDataThresholdSupport, Target, TlsModel};
 use smallvec::SmallVec;
@@ -119,7 +119,7 @@ pub(crate) struct FullCx<'ll, 'tcx> {
 
     /// Statics that will be placed in the llvm.compiler.used variable
     /// See <https://llvm.org/docs/LangRef.html#the-llvm-compiler-used-global-variable> for details
-    pub compiler_used_statics: Vec<&'ll Value>,
+    pub compiler_used_statics: RefCell<Vec<&'ll Value>>,
 
     /// Mapping of non-scalar types to llvm types.
     pub type_lowering: RefCell<FxHashMap<(Ty<'tcx>, Option<VariantIdx>), &'ll Type>>,
@@ -146,6 +146,15 @@ pub(crate) struct FullCx<'ll, 'tcx> {
     /// `global_asm!` needs to be able to find this new global so that it can
     /// compute the correct mangled symbol name to insert into the asm.
     pub renamed_statics: RefCell<FxHashMap<DefId, &'ll Value>>,
+
+    /// Cached Objective-C class type
+    pub objc_class_t: Cell<Option<&'ll Type>>,
+
+    /// Cache of Objective-C class references
+    pub objc_classrefs: RefCell<FxHashMap<Symbol, &'ll Value>>,
+
+    /// Cache of Objective-C selector references
+    pub objc_selrefs: RefCell<FxHashMap<Symbol, &'ll Value>>,
 }
 
 fn to_llvm_tls_model(tls_model: TlsModel) -> llvm::ThreadLocalMode {
@@ -172,35 +181,6 @@ pub(crate) unsafe fn create_module<'ll>(
     let mut target_data_layout = sess.target.data_layout.to_string();
     let llvm_version = llvm_util::get_version();
 
-    if llvm_version < (20, 0, 0) {
-        if sess.target.arch == "aarch64" || sess.target.arch.starts_with("arm64") {
-            // LLVM 20 defines three additional address spaces for alternate
-            // pointer kinds used in Windows.
-            // See https://github.com/llvm/llvm-project/pull/111879
-            target_data_layout =
-                target_data_layout.replace("-p270:32:32-p271:32:32-p272:64:64", "");
-        }
-        if sess.target.arch.starts_with("sparc") {
-            // LLVM 20 updates the sparc layout to correctly align 128 bit integers to 128 bit.
-            // See https://github.com/llvm/llvm-project/pull/106951
-            target_data_layout = target_data_layout.replace("-i128:128", "");
-        }
-        if sess.target.arch.starts_with("mips64") {
-            // LLVM 20 updates the mips64 layout to correctly align 128 bit integers to 128 bit.
-            // See https://github.com/llvm/llvm-project/pull/112084
-            target_data_layout = target_data_layout.replace("-i128:128", "");
-        }
-        if sess.target.arch.starts_with("powerpc64") {
-            // LLVM 20 updates the powerpc64 layout to correctly align 128 bit integers to 128 bit.
-            // See https://github.com/llvm/llvm-project/pull/118004
-            target_data_layout = target_data_layout.replace("-i128:128", "");
-        }
-        if sess.target.arch.starts_with("wasm32") || sess.target.arch.starts_with("wasm64") {
-            // LLVM 20 updates the wasm(32|64) layout to correctly align 128 bit integers to 128 bit.
-            // See https://github.com/llvm/llvm-project/pull/119204
-            target_data_layout = target_data_layout.replace("-i128:128", "");
-        }
-    }
     if llvm_version < (21, 0, 0) {
         if sess.target.arch == "nvptx64" {
             // LLVM 21 updated the default layout on nvptx: https://github.com/llvm/llvm-project/pull/124961
@@ -644,7 +624,7 @@ impl<'ll, 'tcx> CodegenCx<'ll, 'tcx> {
                 const_globals: Default::default(),
                 statics_to_rauw: RefCell::new(Vec::new()),
                 used_statics: Vec::new(),
-                compiler_used_statics: Vec::new(),
+                compiler_used_statics: Default::default(),
                 type_lowering: Default::default(),
                 scalar_lltypes: Default::default(),
                 coverage_cx,
@@ -655,6 +635,9 @@ impl<'ll, 'tcx> CodegenCx<'ll, 'tcx> {
                 intrinsics: Default::default(),
                 local_gen_sym_counter: Cell::new(0),
                 renamed_statics: Default::default(),
+                objc_class_t: Cell::new(None),
+                objc_classrefs: Default::default(),
+                objc_selrefs: Default::default(),
             },
             PhantomData,
         )
@@ -679,6 +662,69 @@ impl<'ll, 'tcx> CodegenCx<'ll, 'tcx> {
         llvm::set_linkage(g, llvm::Linkage::AppendingLinkage);
         llvm::set_section(g, c"llvm.metadata");
     }
+
+    /// The Objective-C ABI that is used.
+    ///
+    /// This corresponds to the `-fobjc-abi-version=` flag in Clang / GCC.
+    pub(crate) fn objc_abi_version(&self) -> u32 {
+        assert!(self.tcx.sess.target.is_like_darwin);
+        if self.tcx.sess.target.arch == "x86" && self.tcx.sess.target.os == "macos" {
+            // 32-bit x86 macOS uses ABI version 1 (a.k.a. the "fragile ABI").
+            1
+        } else {
+            // All other Darwin-like targets we support use ABI version 2
+            // (a.k.a the "non-fragile ABI").
+            2
+        }
+    }
+
+    // We do our best here to match what Clang does when compiling Objective-C natively.
+    // See Clang's `CGObjCCommonMac::EmitImageInfo`:
+    // https://github.com/llvm/llvm-project/blob/llvmorg-20.1.8/clang/lib/CodeGen/CGObjCMac.cpp#L5085
+    pub(crate) fn add_objc_module_flags(&self) {
+        let abi_version = self.objc_abi_version();
+
+        llvm::add_module_flag_u32(
+            self.llmod,
+            llvm::ModuleFlagMergeBehavior::Error,
+            "Objective-C Version",
+            abi_version,
+        );
+
+        llvm::add_module_flag_u32(
+            self.llmod,
+            llvm::ModuleFlagMergeBehavior::Error,
+            "Objective-C Image Info Version",
+            0,
+        );
+
+        llvm::add_module_flag_str(
+            self.llmod,
+            llvm::ModuleFlagMergeBehavior::Error,
+            "Objective-C Image Info Section",
+            match abi_version {
+                1 => "__OBJC,__image_info,regular",
+                2 => "__DATA,__objc_imageinfo,regular,no_dead_strip",
+                _ => unreachable!(),
+            },
+        );
+
+        if self.tcx.sess.target.env == "sim" {
+            llvm::add_module_flag_u32(
+                self.llmod,
+                llvm::ModuleFlagMergeBehavior::Error,
+                "Objective-C Is Simulated",
+                1 << 5,
+            );
+        }
+
+        llvm::add_module_flag_u32(
+            self.llmod,
+            llvm::ModuleFlagMergeBehavior::Error,
+            "Objective-C Class Properties",
+            1 << 6,
+        );
+    }
 }
 impl<'ll> SimpleCx<'ll> {
     pub(crate) fn get_type_of_global(&self, val: &'ll Value) -> &'ll Type {
diff --git a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
index 0679f55ab7f..e125aba6afc 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
@@ -1237,6 +1237,7 @@ unsafe extern "C" {
     pub(crate) safe fn LLVMSetGlobalConstant(GlobalVar: &Value, IsConstant: Bool);
     pub(crate) safe fn LLVMSetTailCall(CallInst: &Value, IsTailCall: Bool);
     pub(crate) safe fn LLVMSetTailCallKind(CallInst: &Value, kind: TailCallKind);
+    pub(crate) safe fn LLVMSetExternallyInitialized(GlobalVar: &Value, IsExtInit: Bool);
 
     // Operations on attributes
     pub(crate) fn LLVMCreateStringAttribute(
diff --git a/compiler/rustc_codegen_llvm/src/llvm/mod.rs b/compiler/rustc_codegen_llvm/src/llvm/mod.rs
index d6974e22c85..1115d82fa85 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/mod.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/mod.rs
@@ -258,6 +258,10 @@ pub(crate) fn set_alignment(llglobal: &Value, align: Align) {
     }
 }
 
+pub(crate) fn set_externally_initialized(llglobal: &Value, is_ext_init: bool) {
+    LLVMSetExternallyInitialized(llglobal, is_ext_init.to_llvm_bool());
+}
+
 /// Get the `name`d comdat from `llmod` and assign it to `llglobal`.
 ///
 /// Inserts the comdat into `llmod` if it does not exist.
diff --git a/compiler/rustc_codegen_llvm/src/llvm_util.rs b/compiler/rustc_codegen_llvm/src/llvm_util.rs
index d927ffd78c2..8461c8b03d5 100644
--- a/compiler/rustc_codegen_llvm/src/llvm_util.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm_util.rs
@@ -246,9 +246,6 @@ pub(crate) fn to_llvm_features<'a>(sess: &Session, s: &'a str) -> Option<LLVMFea
         ("aarch64", "pmuv3") => Some(LLVMFeature::new("perfmon")),
         ("aarch64", "paca") => Some(LLVMFeature::new("pauth")),
         ("aarch64", "pacg") => Some(LLVMFeature::new("pauth")),
-        // Before LLVM 20 those two features were packaged together as b16b16
-        ("aarch64", "sve-b16b16") if get_version().0 < 20 => Some(LLVMFeature::new("b16b16")),
-        ("aarch64", "sme-b16b16") if get_version().0 < 20 => Some(LLVMFeature::new("b16b16")),
         ("aarch64", "flagm2") => Some(LLVMFeature::new("altnzcv")),
         // Rust ties fp and neon together.
         ("aarch64", "neon") => Some(LLVMFeature::with_dependencies(
@@ -262,57 +259,17 @@ pub(crate) fn to_llvm_features<'a>(sess: &Session, s: &'a str) -> Option<LLVMFea
         // Filter out features that are not supported by the current LLVM version
         ("aarch64", "fpmr") => None, // only existed in 18
         ("arm", "fp16") => Some(LLVMFeature::new("fullfp16")),
-        // NVPTX targets added in LLVM 20
-        ("nvptx64", "sm_100") if get_version().0 < 20 => None,
-        ("nvptx64", "sm_100a") if get_version().0 < 20 => None,
-        ("nvptx64", "sm_101") if get_version().0 < 20 => None,
-        ("nvptx64", "sm_101a") if get_version().0 < 20 => None,
-        ("nvptx64", "sm_120") if get_version().0 < 20 => None,
-        ("nvptx64", "sm_120a") if get_version().0 < 20 => None,
-        ("nvptx64", "ptx86") if get_version().0 < 20 => None,
-        ("nvptx64", "ptx87") if get_version().0 < 20 => None,
         // Filter out features that are not supported by the current LLVM version
-        ("loongarch64", "div32" | "lam-bh" | "lamcas" | "ld-seq-sa" | "scq")
-            if get_version().0 < 20 =>
-        {
-            None
-        }
         ("loongarch32" | "loongarch64", "32s") if get_version().0 < 21 => None,
-        // Filter out features that are not supported by the current LLVM version
-        ("riscv32" | "riscv64", "zacas" | "rva23u64" | "supm") if get_version().0 < 20 => None,
-        (
-            "s390x",
-            "message-security-assist-extension12"
-            | "concurrent-functions"
-            | "miscellaneous-extensions-4"
-            | "vector-enhancements-3"
-            | "vector-packed-decimal-enhancement-3",
-        ) if get_version().0 < 20 => None,
         // Enable the evex512 target feature if an avx512 target feature is enabled.
         ("x86", s) if s.starts_with("avx512") => Some(LLVMFeature::with_dependencies(
             s,
             smallvec![TargetFeatureFoldStrength::EnableOnly("evex512")],
         )),
-        // Support for `wide-arithmetic` will first land in LLVM 20 as part of
-        // llvm/llvm-project#111598
-        ("wasm32" | "wasm64", "wide-arithmetic") if get_version() < (20, 0, 0) => None,
         ("sparc", "leoncasa") => Some(LLVMFeature::new("hasleoncasa")),
-        // In LLVM 19, there is no `v8plus` feature and `v9` means "SPARC-V9 instruction available and SPARC-V8+ ABI used".
-        // https://github.com/llvm/llvm-project/blob/llvmorg-19.1.0/llvm/lib/Target/Sparc/MCTargetDesc/SparcELFObjectWriter.cpp#L27-L28
-        // Before LLVM 19, there was no `v8plus` feature and `v9` means "SPARC-V9 instruction available".
-        // https://github.com/llvm/llvm-project/blob/llvmorg-18.1.0/llvm/lib/Target/Sparc/MCTargetDesc/SparcELFObjectWriter.cpp#L26
-        ("sparc", "v8plus") if get_version().0 == 19 => Some(LLVMFeature::new("v9")),
         ("powerpc", "power8-crypto") => Some(LLVMFeature::new("crypto")),
-        // These new `amx` variants and `movrs` were introduced in LLVM20
-        ("x86", "amx-avx512" | "amx-fp8" | "amx-movrs" | "amx-tf32" | "amx-transpose")
-            if get_version().0 < 20 =>
-        {
-            None
-        }
-        ("x86", "movrs") if get_version().0 < 20 => None,
         ("x86", "avx10.1") => Some(LLVMFeature::new("avx10.1-512")),
-        ("x86", "avx10.2") if get_version().0 < 20 => None,
-        ("x86", "avx10.2") if get_version().0 >= 20 => Some(LLVMFeature::new("avx10.2-512")),
+        ("x86", "avx10.2") => Some(LLVMFeature::new("avx10.2-512")),
         ("x86", "apxf") => Some(LLVMFeature::with_dependencies(
             "egpr",
             smallvec![
@@ -716,17 +673,7 @@ pub(crate) fn global_llvm_features(
     };
 
     // Features implied by an implicit or explicit `--target`.
-    features.extend(
-        sess.target
-            .features
-            .split(',')
-            .filter(|v| !v.is_empty())
-            // Drop +v8plus feature introduced in LLVM 20.
-            // (Hard-coded target features do not go through `to_llvm_feature` since they already
-            // are LLVM feature names, hence we need a special case here.)
-            .filter(|v| *v != "+v8plus" || get_version() >= (20, 0, 0))
-            .map(String::from),
-    );
+    features.extend(sess.target.features.split(',').filter(|v| !v.is_empty()).map(String::from));
 
     if wants_wasm_eh(sess) && sess.panic_strategy() == PanicStrategy::Unwind {
         features.push("+exception-handling".into());
diff --git a/compiler/rustc_codegen_ssa/src/codegen_attrs.rs b/compiler/rustc_codegen_ssa/src/codegen_attrs.rs
index dc500c363f4..32ae810ecc8 100644
--- a/compiler/rustc_codegen_ssa/src/codegen_attrs.rs
+++ b/compiler/rustc_codegen_ssa/src/codegen_attrs.rs
@@ -296,6 +296,12 @@ fn process_builtin_attrs(
                 AttributeKind::Sanitize { span, .. } => {
                     interesting_spans.sanitize = Some(*span);
                 }
+                AttributeKind::ObjcClass { classname, .. } => {
+                    codegen_fn_attrs.objc_class = Some(*classname);
+                }
+                AttributeKind::ObjcSelector { methname, .. } => {
+                    codegen_fn_attrs.objc_selector = Some(*methname);
+                }
                 _ => {}
             }
         }
diff --git a/compiler/rustc_codegen_ssa/src/mir/rvalue.rs b/compiler/rustc_codegen_ssa/src/mir/rvalue.rs
index f6f2e3f2a3a..4c9bb7cf8a8 100644
--- a/compiler/rustc_codegen_ssa/src/mir/rvalue.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/rvalue.rs
@@ -1,5 +1,5 @@
 use itertools::Itertools as _;
-use rustc_abi::{self as abi, FIRST_VARIANT};
+use rustc_abi::{self as abi, BackendRepr, FIRST_VARIANT};
 use rustc_middle::ty::adjustment::PointerCoercion;
 use rustc_middle::ty::layout::{HasTyCtxt, HasTypingEnv, LayoutOf, TyAndLayout};
 use rustc_middle::ty::{self, Instance, Ty, TyCtxt};
@@ -25,6 +25,15 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         match *rvalue {
             mir::Rvalue::Use(ref operand) => {
                 let cg_operand = self.codegen_operand(bx, operand);
+                // Crucially, we do *not* use `OperandValue::Ref` for types with
+                // `BackendRepr::Scalar | BackendRepr::ScalarPair`. This ensures we match the MIR
+                // semantics regarding when assignment operators allow overlap of LHS and RHS.
+                if matches!(
+                    cg_operand.layout.backend_repr,
+                    BackendRepr::Scalar(..) | BackendRepr::ScalarPair(..),
+                ) {
+                    debug_assert!(!matches!(cg_operand.val, OperandValue::Ref(..)));
+                }
                 // FIXME: consider not copying constants through stack. (Fixable by codegen'ing
                 // constants into `OperandValue::Ref`; why don’t we do that yet if we don’t?)
                 cg_operand.val.store(bx, dest);
@@ -892,36 +901,8 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 }
             }
             mir::BinOp::Cmp => {
-                use std::cmp::Ordering;
                 assert!(!is_float);
-                if let Some(value) = bx.three_way_compare(lhs_ty, lhs, rhs) {
-                    return value;
-                }
-                let pred = |op| base::bin_op_to_icmp_predicate(op, is_signed);
-                if bx.cx().tcx().sess.opts.optimize == OptLevel::No {
-                    // FIXME: This actually generates tighter assembly, and is a classic trick
-                    // <https://graphics.stanford.edu/~seander/bithacks.html#CopyIntegerSign>
-                    // However, as of 2023-11 it optimizes worse in things like derived
-                    // `PartialOrd`, so only use it in debug for now. Once LLVM can handle it
-                    // better (see <https://github.com/llvm/llvm-project/issues/73417>), it'll
-                    // be worth trying it in optimized builds as well.
-                    let is_gt = bx.icmp(pred(mir::BinOp::Gt), lhs, rhs);
-                    let gtext = bx.zext(is_gt, bx.type_i8());
-                    let is_lt = bx.icmp(pred(mir::BinOp::Lt), lhs, rhs);
-                    let ltext = bx.zext(is_lt, bx.type_i8());
-                    bx.unchecked_ssub(gtext, ltext)
-                } else {
-                    // These operations are those expected by `tests/codegen-llvm/integer-cmp.rs`,
-                    // from <https://github.com/rust-lang/rust/pull/63767>.
-                    let is_lt = bx.icmp(pred(mir::BinOp::Lt), lhs, rhs);
-                    let is_ne = bx.icmp(pred(mir::BinOp::Ne), lhs, rhs);
-                    let ge = bx.select(
-                        is_ne,
-                        bx.cx().const_i8(Ordering::Greater as i8),
-                        bx.cx().const_i8(Ordering::Equal as i8),
-                    );
-                    bx.select(is_lt, bx.cx().const_i8(Ordering::Less as i8), ge)
-                }
+                bx.three_way_compare(lhs_ty, lhs, rhs)
             }
             mir::BinOp::AddWithOverflow
             | mir::BinOp::SubWithOverflow
diff --git a/compiler/rustc_codegen_ssa/src/traits/builder.rs b/compiler/rustc_codegen_ssa/src/traits/builder.rs
index f417d1a7bf7..4a5694e97fa 100644
--- a/compiler/rustc_codegen_ssa/src/traits/builder.rs
+++ b/compiler/rustc_codegen_ssa/src/traits/builder.rs
@@ -3,6 +3,7 @@ use std::ops::Deref;
 
 use rustc_abi::{Align, Scalar, Size, WrappingRange};
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrs;
+use rustc_middle::mir;
 use rustc_middle::ty::layout::{FnAbiOf, LayoutOf, TyAndLayout};
 use rustc_middle::ty::{AtomicOrdering, Instance, Ty};
 use rustc_session::config::OptLevel;
@@ -405,15 +406,41 @@ pub trait BuilderMethods<'a, 'tcx>:
     fn fcmp(&mut self, op: RealPredicate, lhs: Self::Value, rhs: Self::Value) -> Self::Value;
 
     /// Returns `-1` if `lhs < rhs`, `0` if `lhs == rhs`, and `1` if `lhs > rhs`.
-    // FIXME: Move the default implementation from `codegen_scalar_binop` into this method and
-    // remove the `Option` return once LLVM 20 is the minimum version.
     fn three_way_compare(
         &mut self,
-        _ty: Ty<'tcx>,
-        _lhs: Self::Value,
-        _rhs: Self::Value,
-    ) -> Option<Self::Value> {
-        None
+        ty: Ty<'tcx>,
+        lhs: Self::Value,
+        rhs: Self::Value,
+    ) -> Self::Value {
+        // FIXME: This implementation was designed around LLVM's ability to optimize, but `cg_llvm`
+        // overrides this to just use `@llvm.scmp`/`ucmp` since LLVM 20. This default impl should be
+        // reevaluated with respect to the remaining backends like cg_gcc, whether they might use
+        // specialized implementations as well, or continue to use a generic implementation here.
+        use std::cmp::Ordering;
+        let pred = |op| crate::base::bin_op_to_icmp_predicate(op, ty.is_signed());
+        if self.cx().sess().opts.optimize == OptLevel::No {
+            // This actually generates tighter assembly, and is a classic trick:
+            // <https://graphics.stanford.edu/~seander/bithacks.html#CopyIntegerSign>.
+            // However, as of 2023-11 it optimized worse in LLVM in things like derived
+            // `PartialOrd`, so we were only using it in debug. Since LLVM now uses its own
+            // intrinsics, it may be be worth trying it in optimized builds for other backends.
+            let is_gt = self.icmp(pred(mir::BinOp::Gt), lhs, rhs);
+            let gtext = self.zext(is_gt, self.type_i8());
+            let is_lt = self.icmp(pred(mir::BinOp::Lt), lhs, rhs);
+            let ltext = self.zext(is_lt, self.type_i8());
+            self.unchecked_ssub(gtext, ltext)
+        } else {
+            // These operations were better optimized by LLVM, before `@llvm.scmp`/`ucmp` in 20.
+            // See <https://github.com/rust-lang/rust/pull/63767>.
+            let is_lt = self.icmp(pred(mir::BinOp::Lt), lhs, rhs);
+            let is_ne = self.icmp(pred(mir::BinOp::Ne), lhs, rhs);
+            let ge = self.select(
+                is_ne,
+                self.cx().const_i8(Ordering::Greater as i8),
+                self.cx().const_i8(Ordering::Equal as i8),
+            );
+            self.select(is_lt, self.cx().const_i8(Ordering::Less as i8), ge)
+        }
     }
 
     fn memcpy(
diff --git a/compiler/rustc_const_eval/src/interpret/place.rs b/compiler/rustc_const_eval/src/interpret/place.rs
index a86fdf80f60..cd34892f029 100644
--- a/compiler/rustc_const_eval/src/interpret/place.rs
+++ b/compiler/rustc_const_eval/src/interpret/place.rs
@@ -858,7 +858,7 @@ where
     /// Also, if you use this you are responsible for validating that things get copied at the
     /// right type.
     #[instrument(skip(self), level = "trace")]
-    fn copy_op_no_validate(
+    pub(super) fn copy_op_no_validate(
         &mut self,
         src: &impl Projectable<'tcx, M::Provenance>,
         dest: &impl Writeable<'tcx, M::Provenance>,
diff --git a/compiler/rustc_const_eval/src/interpret/step.rs b/compiler/rustc_const_eval/src/interpret/step.rs
index 23d362de308..46950d60f8c 100644
--- a/compiler/rustc_const_eval/src/interpret/step.rs
+++ b/compiler/rustc_const_eval/src/interpret/step.rs
@@ -310,7 +310,6 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         operands: &IndexSlice<FieldIdx, mir::Operand<'tcx>>,
         dest: &PlaceTy<'tcx, M::Provenance>,
     ) -> InterpResult<'tcx> {
-        self.write_uninit(dest)?; // make sure all the padding ends up as uninit
         let (variant_index, variant_dest, active_field_index) = match *kind {
             mir::AggregateKind::Adt(_, variant_index, _, _, active_field_index) => {
                 let variant_dest = self.project_downcast(dest, variant_index)?;
@@ -346,9 +345,20 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
             let field_index = active_field_index.unwrap_or(field_index);
             let field_dest = self.project_field(&variant_dest, field_index)?;
             let op = self.eval_operand(operand, Some(field_dest.layout))?;
-            self.copy_op(&op, &field_dest)?;
+            // We validate manually below so we don't have to do it here.
+            self.copy_op_no_validate(&op, &field_dest, /*allow_transmute*/ false)?;
         }
-        self.write_discriminant(variant_index, dest)
+        self.write_discriminant(variant_index, dest)?;
+        // Validate that the entire thing is valid, and reset padding that might be in between the
+        // fields.
+        if M::enforce_validity(self, dest.layout()) {
+            self.validate_operand(
+                dest,
+                M::enforce_validity_recursively(self, dest.layout()),
+                /*reset_provenance_and_padding*/ true,
+            )?;
+        }
+        interp_ok(())
     }
 
     /// Repeats `operand` into the destination. `dest` must have array type, and that type
diff --git a/compiler/rustc_feature/src/builtin_attrs.rs b/compiler/rustc_feature/src/builtin_attrs.rs
index 129ab7eccb5..99d6e93faa9 100644
--- a/compiler/rustc_feature/src/builtin_attrs.rs
+++ b/compiler/rustc_feature/src/builtin_attrs.rs
@@ -1057,6 +1057,14 @@ pub static BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
         rustc_std_internal_symbol, Normal, template!(Word), WarnFollowing,
         EncodeCrossCrate::No,
     ),
+    rustc_attr!(
+        rustc_objc_class, Normal, template!(NameValueStr: "ClassName"), ErrorPreceding,
+        EncodeCrossCrate::No,
+    ),
+    rustc_attr!(
+        rustc_objc_selector, Normal, template!(NameValueStr: "methodName"), ErrorPreceding,
+        EncodeCrossCrate::No,
+    ),
 
     // ==========================================================================
     // Internal attributes, Macro related:
diff --git a/compiler/rustc_hir/src/attrs/data_structures.rs b/compiler/rustc_hir/src/attrs/data_structures.rs
index ea11a99efbc..04b144abd03 100644
--- a/compiler/rustc_hir/src/attrs/data_structures.rs
+++ b/compiler/rustc_hir/src/attrs/data_structures.rs
@@ -594,6 +594,12 @@ pub enum AttributeKind {
     /// Represents `#[non_exhaustive]`
     NonExhaustive(Span),
 
+    /// Represents `#[rustc_objc_class]`
+    ObjcClass { classname: Symbol, span: Span },
+
+    /// Represents `#[rustc_objc_selector]`
+    ObjcSelector { methname: Symbol, span: Span },
+
     /// Represents `#[optimize(size|speed)]`
     Optimize(OptimizeAttr, Span),
 
diff --git a/compiler/rustc_hir/src/attrs/encode_cross_crate.rs b/compiler/rustc_hir/src/attrs/encode_cross_crate.rs
index 55521c15854..cb4feeb05f1 100644
--- a/compiler/rustc_hir/src/attrs/encode_cross_crate.rs
+++ b/compiler/rustc_hir/src/attrs/encode_cross_crate.rs
@@ -69,6 +69,8 @@ impl AttributeKind {
             NoMangle(..) => Yes, // Needed for rustdoc
             NoStd(..) => No,
             NonExhaustive(..) => Yes, // Needed for rustdoc
+            ObjcClass { .. } => No,
+            ObjcSelector { .. } => No,
             Optimize(..) => No,
             ParenSugar(..) => No,
             PassByValue(..) => Yes,
diff --git a/compiler/rustc_hir/src/lang_items.rs b/compiler/rustc_hir/src/lang_items.rs
index 67d2f15d414..2e099a97b65 100644
--- a/compiler/rustc_hir/src/lang_items.rs
+++ b/compiler/rustc_hir/src/lang_items.rs
@@ -370,7 +370,6 @@ language_item_table! {
     CoercePointeeValidated, sym::coerce_pointee_validated, coerce_pointee_validated_trait, Target::Trait,     GenericRequirement::Exact(0);
 
     ConstParamTy,            sym::const_param_ty,      const_param_ty_trait,       Target::Trait,          GenericRequirement::Exact(0);
-    UnsizedConstParamTy,     sym::unsized_const_param_ty, unsized_const_param_ty_trait, Target::Trait, GenericRequirement::Exact(0);
 
     Poll,                    sym::Poll,                poll,                       Target::Enum,           GenericRequirement::None;
     PollReady,               sym::Ready,               poll_ready_variant,         Target::Variant,        GenericRequirement::None;
diff --git a/compiler/rustc_hir_analysis/src/check/mod.rs b/compiler/rustc_hir_analysis/src/check/mod.rs
index 63d0f400aef..e70d5505aae 100644
--- a/compiler/rustc_hir_analysis/src/check/mod.rs
+++ b/compiler/rustc_hir_analysis/src/check/mod.rs
@@ -70,6 +70,7 @@ pub mod intrinsic;
 mod region;
 pub mod wfcheck;
 
+use std::borrow::Cow;
 use std::num::NonZero;
 
 pub use check::{check_abi, check_custom_abi};
@@ -86,7 +87,7 @@ use rustc_middle::query::Providers;
 use rustc_middle::ty::error::{ExpectedFound, TypeError};
 use rustc_middle::ty::print::with_types_for_signature;
 use rustc_middle::ty::{
-    self, GenericArgs, GenericArgsRef, GenericParamDefKind, Ty, TyCtxt, TypingMode,
+    self, GenericArgs, GenericArgsRef, OutlivesPredicate, Region, Ty, TyCtxt, TypingMode,
 };
 use rustc_middle::{bug, span_bug};
 use rustc_session::parse::feature_err;
@@ -335,6 +336,7 @@ fn bounds_from_generic_predicates<'tcx>(
     assoc: ty::AssocItem,
 ) -> (String, String) {
     let mut types: FxIndexMap<Ty<'tcx>, Vec<DefId>> = FxIndexMap::default();
+    let mut regions: FxIndexMap<Region<'tcx>, Vec<Region<'tcx>>> = FxIndexMap::default();
     let mut projections = vec![];
     for (predicate, _) in predicates {
         debug!("predicate {:?}", predicate);
@@ -351,20 +353,23 @@ fn bounds_from_generic_predicates<'tcx>(
             ty::ClauseKind::Projection(projection_pred) => {
                 projections.push(bound_predicate.rebind(projection_pred));
             }
+            ty::ClauseKind::RegionOutlives(OutlivesPredicate(a, b)) => {
+                regions.entry(a).or_default().push(b);
+            }
             _ => {}
         }
     }
 
     let mut where_clauses = vec![];
     let generics = tcx.generics_of(assoc.def_id);
-    let types_str = generics
+    let params = generics
         .own_params
         .iter()
-        .filter(|p| matches!(p.kind, GenericParamDefKind::Type { synthetic: false, .. }))
-        .map(|p| {
-            // we just checked that it's a type, so the unwrap can't fail
-            let ty = tcx.mk_param_from_def(p).as_type().unwrap();
-            if let Some(bounds) = types.get(&ty) {
+        .filter(|p| !p.kind.is_synthetic())
+        .map(|p| match tcx.mk_param_from_def(p).kind() {
+            ty::GenericArgKind::Type(ty) => {
+                let bounds =
+                    types.get(&ty).map(Cow::Borrowed).unwrap_or_else(|| Cow::Owned(Vec::new()));
                 let mut bounds_str = vec![];
                 for bound in bounds.iter().copied() {
                     let mut projections_str = vec![];
@@ -377,7 +382,11 @@ fn bounds_from_generic_predicates<'tcx>(
                             projections_str.push(format!("{} = {}", name, p.term));
                         }
                     }
-                    let bound_def_path = tcx.def_path_str(bound);
+                    let bound_def_path = if tcx.is_lang_item(bound, LangItem::MetaSized) {
+                        String::from("?Sized")
+                    } else {
+                        tcx.def_path_str(bound)
+                    };
                     if projections_str.is_empty() {
                         where_clauses.push(format!("{}: {}", ty, bound_def_path));
                     } else {
@@ -393,8 +402,21 @@ fn bounds_from_generic_predicates<'tcx>(
                 } else {
                     format!("{}: {}", ty, bounds_str.join(" + "))
                 }
-            } else {
-                ty.to_string()
+            }
+            ty::GenericArgKind::Const(ct) => {
+                format!("const {ct}: {}", tcx.type_of(p.def_id).skip_binder())
+            }
+            ty::GenericArgKind::Lifetime(region) => {
+                if let Some(v) = regions.get(&region)
+                    && !v.is_empty()
+                {
+                    format!(
+                        "{region}: {}",
+                        v.into_iter().map(Region::to_string).collect::<Vec<_>>().join(" + ")
+                    )
+                } else {
+                    region.to_string()
+                }
             }
         })
         .collect::<Vec<_>>();
@@ -409,7 +431,7 @@ fn bounds_from_generic_predicates<'tcx>(
     }
 
     let generics =
-        if types_str.is_empty() { "".to_string() } else { format!("<{}>", types_str.join(", ")) };
+        if params.is_empty() { "".to_string() } else { format!("<{}>", params.join(", ")) };
 
     let where_clauses = if where_clauses.is_empty() {
         "".to_string()
diff --git a/compiler/rustc_hir_analysis/src/check/region.rs b/compiler/rustc_hir_analysis/src/check/region.rs
index 2ba7ed46f92..43e6f5fe104 100644
--- a/compiler/rustc_hir_analysis/src/check/region.rs
+++ b/compiler/rustc_hir_analysis/src/check/region.rs
@@ -467,8 +467,12 @@ fn resolve_local<'tcx>(
     // A, but the inner rvalues `a()` and `b()` have an extended lifetime
     // due to rule C.
 
-    if let_kind == LetKind::Super {
-        if let Some(scope) = visitor.extended_super_lets.remove(&pat.unwrap().hir_id.local_id) {
+    let extend_initializer = match let_kind {
+        LetKind::Regular => true,
+        LetKind::Super
+            if let Some(scope) =
+                visitor.extended_super_lets.remove(&pat.unwrap().hir_id.local_id) =>
+        {
             // This expression was lifetime-extended by a parent let binding. E.g.
             //
             //     let a = {
@@ -481,7 +485,10 @@ fn resolve_local<'tcx>(
             // Processing of `let a` will have already decided to extend the lifetime of this
             // `super let` to its own var_scope. We use that scope.
             visitor.cx.var_parent = scope;
-        } else {
+            // Extend temporaries to live in the same scope as the parent `let`'s bindings.
+            true
+        }
+        LetKind::Super => {
             // This `super let` is not subject to lifetime extension from a parent let binding. E.g.
             //
             //     identity({ super let x = temp(); &x }).method();
@@ -493,10 +500,17 @@ fn resolve_local<'tcx>(
             if let Some(inner_scope) = visitor.cx.var_parent {
                 (visitor.cx.var_parent, _) = visitor.scope_tree.default_temporary_scope(inner_scope)
             }
+            // Don't lifetime-extend child `super let`s or block tail expressions' temporaries in
+            // the initializer when this `super let` is not itself extended by a parent `let`
+            // (#145784). Block tail expressions are temporary drop scopes in Editions 2024 and
+            // later, their temps shouldn't outlive the block in e.g. `f(pin!({ &temp() }))`.
+            false
         }
-    }
+    };
 
-    if let Some(expr) = init {
+    if let Some(expr) = init
+        && extend_initializer
+    {
         record_rvalue_scope_if_borrow_expr(visitor, expr, visitor.cx.var_parent);
 
         if let Some(pat) = pat {
diff --git a/compiler/rustc_hir_analysis/src/check/wfcheck.rs b/compiler/rustc_hir_analysis/src/check/wfcheck.rs
index d33f1f3e12a..0a555c7f6e9 100644
--- a/compiler/rustc_hir_analysis/src/check/wfcheck.rs
+++ b/compiler/rustc_hir_analysis/src/check/wfcheck.rs
@@ -819,17 +819,7 @@ fn check_param_wf(tcx: TyCtxt<'_>, param: &ty::GenericParamDef) -> Result<(), Er
             let span = tcx.def_span(param.def_id);
             let def_id = param.def_id.expect_local();
 
-            if tcx.features().unsized_const_params() {
-                enter_wf_checking_ctxt(tcx, tcx.local_parent(def_id), |wfcx| {
-                    wfcx.register_bound(
-                        ObligationCause::new(span, def_id, ObligationCauseCode::ConstParam(ty)),
-                        wfcx.param_env,
-                        ty,
-                        tcx.require_lang_item(LangItem::UnsizedConstParamTy, span),
-                    );
-                    Ok(())
-                })
-            } else if tcx.features().adt_const_params() {
+            if tcx.features().adt_const_params() {
                 enter_wf_checking_ctxt(tcx, tcx.local_parent(def_id), |wfcx| {
                     wfcx.register_bound(
                         ObligationCause::new(span, def_id, ObligationCauseCode::ConstParam(ty)),
@@ -880,7 +870,6 @@ fn check_param_wf(tcx: TyCtxt<'_>, param: &ty::GenericParamDef) -> Result<(), Er
                     tcx,
                     tcx.param_env(param.def_id),
                     ty,
-                    LangItem::ConstParamTy,
                     cause,
                 ) {
                     // Can never implement `ConstParamTy`, don't suggest anything.
diff --git a/compiler/rustc_hir_analysis/src/coherence/builtin.rs b/compiler/rustc_hir_analysis/src/coherence/builtin.rs
index 32b175611ce..0b9a01d6042 100644
--- a/compiler/rustc_hir_analysis/src/coherence/builtin.rs
+++ b/compiler/rustc_hir_analysis/src/coherence/builtin.rs
@@ -1,7 +1,6 @@
 //! Check properties that are required by built-in traits and set
 //! up data structures required by type-checking/codegen.
 
-use std::assert_matches::assert_matches;
 use std::collections::BTreeMap;
 
 use rustc_data_structures::fx::FxHashSet;
@@ -40,10 +39,7 @@ pub(super) fn check_trait<'tcx>(
     checker.check(lang_items.async_drop_trait(), visit_implementation_of_drop)?;
     checker.check(lang_items.copy_trait(), visit_implementation_of_copy)?;
     checker.check(lang_items.const_param_ty_trait(), |checker| {
-        visit_implementation_of_const_param_ty(checker, LangItem::ConstParamTy)
-    })?;
-    checker.check(lang_items.unsized_const_param_ty_trait(), |checker| {
-        visit_implementation_of_const_param_ty(checker, LangItem::UnsizedConstParamTy)
+        visit_implementation_of_const_param_ty(checker)
     })?;
     checker.check(lang_items.coerce_unsized_trait(), visit_implementation_of_coerce_unsized)?;
     checker
@@ -138,12 +134,7 @@ fn visit_implementation_of_copy(checker: &Checker<'_>) -> Result<(), ErrorGuaran
     }
 }
 
-fn visit_implementation_of_const_param_ty(
-    checker: &Checker<'_>,
-    kind: LangItem,
-) -> Result<(), ErrorGuaranteed> {
-    assert_matches!(kind, LangItem::ConstParamTy | LangItem::UnsizedConstParamTy);
-
+fn visit_implementation_of_const_param_ty(checker: &Checker<'_>) -> Result<(), ErrorGuaranteed> {
     let tcx = checker.tcx;
     let header = checker.impl_header;
     let impl_did = checker.impl_def_id;
@@ -157,7 +148,7 @@ fn visit_implementation_of_const_param_ty(
     }
 
     let cause = traits::ObligationCause::misc(DUMMY_SP, impl_did);
-    match type_allowed_to_implement_const_param_ty(tcx, param_env, self_type, kind, cause) {
+    match type_allowed_to_implement_const_param_ty(tcx, param_env, self_type, cause) {
         Ok(()) => Ok(()),
         Err(ConstParamTyImplementationError::InfrigingFields(fields)) => {
             let span = tcx.hir_expect_item(impl_did).expect_impl().self_ty.span;
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
index 44a6084ebd5..7ca8580e098 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
@@ -1,3 +1,4 @@
+use std::ops::Deref;
 use std::{fmt, iter, mem};
 
 use itertools::Itertools;
@@ -7,7 +8,7 @@ use rustc_errors::{Applicability, Diag, ErrorGuaranteed, MultiSpan, a_or_an, lis
 use rustc_hir::def::{CtorKind, CtorOf, DefKind, Res};
 use rustc_hir::def_id::DefId;
 use rustc_hir::intravisit::Visitor;
-use rustc_hir::{ExprKind, HirId, LangItem, Node, QPath};
+use rustc_hir::{Expr, ExprKind, HirId, LangItem, Node, QPath};
 use rustc_hir_analysis::check::potentially_plural_count;
 use rustc_hir_analysis::hir_ty_lowering::{HirTyLowerer, PermitVariants};
 use rustc_index::IndexVec;
@@ -565,358 +566,27 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         tuple_arguments: TupleArgumentsFlag,
     ) -> ErrorGuaranteed {
         // Next, let's construct the error
-        let (error_span, call_ident, full_call_span, call_name, is_method) = match &call_expr.kind {
-            hir::ExprKind::Call(
-                hir::Expr { hir_id, span, kind: hir::ExprKind::Path(qpath), .. },
-                _,
-            ) => {
-                if let Res::Def(DefKind::Ctor(of, _), _) =
-                    self.typeck_results.borrow().qpath_res(qpath, *hir_id)
-                {
-                    let name = match of {
-                        CtorOf::Struct => "struct",
-                        CtorOf::Variant => "enum variant",
-                    };
-                    (call_span, None, *span, name, false)
-                } else {
-                    (call_span, None, *span, "function", false)
-                }
-            }
-            hir::ExprKind::Call(hir::Expr { span, .. }, _) => {
-                (call_span, None, *span, "function", false)
-            }
-            hir::ExprKind::MethodCall(path_segment, _, _, span) => {
-                let ident_span = path_segment.ident.span;
-                let ident_span = if let Some(args) = path_segment.args {
-                    ident_span.with_hi(args.span_ext.hi())
-                } else {
-                    ident_span
-                };
-                (*span, Some(path_segment.ident), ident_span, "method", true)
-            }
-            k => span_bug!(call_span, "checking argument types on a non-call: `{:?}`", k),
-        };
-        let args_span = error_span.trim_start(full_call_span).unwrap_or(error_span);
-
-        // Don't print if it has error types or is just plain `_`
-        fn has_error_or_infer<'tcx>(tys: impl IntoIterator<Item = Ty<'tcx>>) -> bool {
-            tys.into_iter().any(|ty| ty.references_error() || ty.is_ty_var())
-        }
-
-        let tcx = self.tcx;
-
-        // Get the argument span in the context of the call span so that
-        // suggestions and labels are (more) correct when an arg is a
-        // macro invocation.
-        let normalize_span = |span: Span| -> Span {
-            let normalized_span = span.find_ancestor_inside_same_ctxt(error_span).unwrap_or(span);
-            // Sometimes macros mess up the spans, so do not normalize the
-            // arg span to equal the error span, because that's less useful
-            // than pointing out the arg expr in the wrong context.
-            if normalized_span.source_equal(error_span) { span } else { normalized_span }
-        };
-
-        // Precompute the provided types and spans, since that's all we typically need for below
-        let provided_arg_tys: IndexVec<ProvidedIdx, (Ty<'tcx>, Span)> = provided_args
-            .iter()
-            .map(|expr| {
-                let ty = self
-                    .typeck_results
-                    .borrow()
-                    .expr_ty_adjusted_opt(*expr)
-                    .unwrap_or_else(|| Ty::new_misc_error(tcx));
-                (self.resolve_vars_if_possible(ty), normalize_span(expr.span))
-            })
-            .collect();
-        let callee_expr = match &call_expr.peel_blocks().kind {
-            hir::ExprKind::Call(callee, _) => Some(*callee),
-            hir::ExprKind::MethodCall(_, receiver, ..) => {
-                if let Some((DefKind::AssocFn, def_id)) =
-                    self.typeck_results.borrow().type_dependent_def(call_expr.hir_id)
-                    && let Some(assoc) = tcx.opt_associated_item(def_id)
-                    && assoc.is_method()
-                {
-                    Some(*receiver)
-                } else {
-                    None
-                }
-            }
-            _ => None,
-        };
-        let callee_ty = callee_expr
-            .and_then(|callee_expr| self.typeck_results.borrow().expr_ty_adjusted_opt(callee_expr));
-
-        // Obtain another method on `Self` that have similar name.
-        let similar_assoc = |call_name: Ident| -> Option<(ty::AssocItem, ty::FnSig<'_>)> {
-            if let Some(callee_ty) = callee_ty
-                && let Ok(Some(assoc)) = self.probe_op(
-                    call_name.span,
-                    MethodCall,
-                    Some(call_name),
-                    None,
-                    IsSuggestion(true),
-                    callee_ty.peel_refs(),
-                    callee_expr.unwrap().hir_id,
-                    TraitsInScope,
-                    |mut ctxt| ctxt.probe_for_similar_candidate(),
-                )
-                && assoc.is_method()
-            {
-                let args = self.infcx.fresh_args_for_item(call_name.span, assoc.def_id);
-                let fn_sig = tcx.fn_sig(assoc.def_id).instantiate(tcx, args);
-
-                self.instantiate_binder_with_fresh_vars(
-                    call_name.span,
-                    BoundRegionConversionTime::FnCall,
-                    fn_sig,
-                );
-            }
-            None
-        };
-
-        let suggest_confusable = |err: &mut Diag<'_>| {
-            let Some(call_name) = call_ident else {
-                return;
-            };
-            let Some(callee_ty) = callee_ty else {
-                return;
-            };
-            let input_types: Vec<Ty<'_>> = provided_arg_tys.iter().map(|(ty, _)| *ty).collect();
-            // Check for other methods in the following order
-            //  - methods marked as `rustc_confusables` with the provided arguments
-            //  - methods with the same argument type/count and short levenshtein distance
-            //  - methods marked as `rustc_confusables` (done)
-            //  - methods with short levenshtein distance
-
-            // Look for commonly confusable method names considering arguments.
-            if let Some(_name) = self.confusable_method_name(
-                err,
-                callee_ty.peel_refs(),
-                call_name,
-                Some(input_types.clone()),
-            ) {
-                return;
-            }
-            // Look for method names with short levenshtein distance, considering arguments.
-            if let Some((assoc, fn_sig)) = similar_assoc(call_name)
-                && fn_sig.inputs()[1..]
-                    .iter()
-                    .zip(input_types.iter())
-                    .all(|(expected, found)| self.may_coerce(*expected, *found))
-                && fn_sig.inputs()[1..].len() == input_types.len()
-            {
-                let assoc_name = assoc.name();
-                err.span_suggestion_verbose(
-                    call_name.span,
-                    format!("you might have meant to use `{}`", assoc_name),
-                    assoc_name,
-                    Applicability::MaybeIncorrect,
-                );
-                return;
-            }
-            // Look for commonly confusable method names disregarding arguments.
-            if let Some(_name) =
-                self.confusable_method_name(err, callee_ty.peel_refs(), call_name, None)
-            {
-                return;
-            }
-            // Look for similarly named methods with levenshtein distance with the right
-            // number of arguments.
-            if let Some((assoc, fn_sig)) = similar_assoc(call_name)
-                && fn_sig.inputs()[1..].len() == input_types.len()
-            {
-                err.span_note(
-                    tcx.def_span(assoc.def_id),
-                    format!(
-                        "there's is a method with similar name `{}`, but the arguments don't match",
-                        assoc.name(),
-                    ),
-                );
-                return;
-            }
-            // Fallthrough: look for similarly named methods with levenshtein distance.
-            if let Some((assoc, _)) = similar_assoc(call_name) {
-                err.span_note(
-                    tcx.def_span(assoc.def_id),
-                    format!(
-                        "there's is a method with similar name `{}`, but their argument count \
-                         doesn't match",
-                        assoc.name(),
-                    ),
-                );
-                return;
-            }
-        };
-        // A "softer" version of the `demand_compatible`, which checks types without persisting them,
-        // and treats error types differently
-        // This will allow us to "probe" for other argument orders that would likely have been correct
-        let check_compatible = |provided_idx: ProvidedIdx, expected_idx: ExpectedIdx| {
-            if provided_idx.as_usize() == expected_idx.as_usize() {
-                return compatibility_diagonal[provided_idx].clone();
-            }
-
-            let (formal_input_ty, expected_input_ty) = formal_and_expected_inputs[expected_idx];
-            // If either is an error type, we defy the usual convention and consider them to *not* be
-            // coercible. This prevents our error message heuristic from trying to pass errors into
-            // every argument.
-            if (formal_input_ty, expected_input_ty).references_error() {
-                return Compatibility::Incompatible(None);
-            }
 
-            let (arg_ty, arg_span) = provided_arg_tys[provided_idx];
-
-            let expectation = Expectation::rvalue_hint(self, expected_input_ty);
-            let coerced_ty = expectation.only_has_type(self).unwrap_or(formal_input_ty);
-            let can_coerce = self.may_coerce(arg_ty, coerced_ty);
-            if !can_coerce {
-                return Compatibility::Incompatible(Some(ty::error::TypeError::Sorts(
-                    ty::error::ExpectedFound::new(coerced_ty, arg_ty),
-                )));
-            }
-
-            // Using probe here, since we don't want this subtyping to affect inference.
-            let subtyping_error = self.probe(|_| {
-                self.at(&self.misc(arg_span), self.param_env)
-                    .sup(DefineOpaqueTypes::Yes, formal_input_ty, coerced_ty)
-                    .err()
-            });
-
-            // Same as above: if either the coerce type or the checked type is an error type,
-            // consider them *not* compatible.
-            let references_error = (coerced_ty, arg_ty).references_error();
-            match (references_error, subtyping_error) {
-                (false, None) => Compatibility::Compatible,
-                (_, subtyping_error) => Compatibility::Incompatible(subtyping_error),
-            }
-        };
-
-        let mk_trace = |span, (formal_ty, expected_ty), provided_ty| {
-            let mismatched_ty = if expected_ty == provided_ty {
-                // If expected == provided, then we must have failed to sup
-                // the formal type. Avoid printing out "expected Ty, found Ty"
-                // in that case.
-                formal_ty
-            } else {
-                expected_ty
-            };
-            TypeTrace::types(&self.misc(span), mismatched_ty, provided_ty)
-        };
-
-        // The algorithm here is inspired by levenshtein distance and longest common subsequence.
-        // We'll try to detect 4 different types of mistakes:
-        // - An extra parameter has been provided that doesn't satisfy *any* of the other inputs
-        // - An input is missing, which isn't satisfied by *any* of the other arguments
-        // - Some number of arguments have been provided in the wrong order
-        // - A type is straight up invalid
-
-        // First, let's find the errors
-        let (mut errors, matched_inputs) =
-            ArgMatrix::new(provided_args.len(), formal_and_expected_inputs.len(), check_compatible)
-                .find_errors();
+        let mut fn_call_diag_ctxt = FnCallDiagCtxt::new(
+            self,
+            compatibility_diagonal,
+            formal_and_expected_inputs,
+            provided_args,
+            c_variadic,
+            err_code,
+            fn_def_id,
+            call_span,
+            call_expr,
+            tuple_arguments,
+        );
 
         // First, check if we just need to wrap some arguments in a tuple.
-        if let Some((mismatch_idx, terr)) =
-            compatibility_diagonal.iter_enumerated().find_map(|(i, c)| {
-                if let Compatibility::Incompatible(Some(terr)) = c {
-                    Some((i, *terr))
-                } else {
-                    None
-                }
-            })
-        {
-            // Is the first bad expected argument a tuple?
-            // Do we have as many extra provided arguments as the tuple's length?
-            // If so, we might have just forgotten to wrap some args in a tuple.
-            if let Some(ty::Tuple(tys)) =
-                formal_and_expected_inputs.get(mismatch_idx.to_expected_idx()).map(|tys| tys.1.kind())
-                // If the tuple is unit, we're not actually wrapping any arguments.
-                && !tys.is_empty()
-                && provided_arg_tys.len() == formal_and_expected_inputs.len() - 1 + tys.len()
-            {
-                // Wrap up the N provided arguments starting at this position in a tuple.
-                let provided_args_to_tuple = &provided_arg_tys[mismatch_idx..];
-                let (provided_args_to_tuple, provided_args_after_tuple) =
-                    provided_args_to_tuple.split_at(tys.len());
-                let provided_as_tuple =
-                    Ty::new_tup_from_iter(tcx, provided_args_to_tuple.iter().map(|&(ty, _)| ty));
-
-                let mut satisfied = true;
-                // Check if the newly wrapped tuple + rest of the arguments are compatible.
-                for ((_, expected_ty), provided_ty) in std::iter::zip(
-                    formal_and_expected_inputs[mismatch_idx.to_expected_idx()..].iter(),
-                    [provided_as_tuple]
-                        .into_iter()
-                        .chain(provided_args_after_tuple.iter().map(|&(ty, _)| ty)),
-                ) {
-                    if !self.may_coerce(provided_ty, *expected_ty) {
-                        satisfied = false;
-                        break;
-                    }
-                }
+        if let Some(err) = fn_call_diag_ctxt.check_wrap_args_in_tuple() {
+            return err;
+        }
 
-                // If they're compatible, suggest wrapping in an arg, and we're done!
-                // Take some care with spans, so we don't suggest wrapping a macro's
-                // innards in parenthesis, for example.
-                if satisfied
-                    && let &[(_, hi @ lo)] | &[(_, lo), .., (_, hi)] = provided_args_to_tuple
-                {
-                    let mut err;
-                    if tys.len() == 1 {
-                        // A tuple wrap suggestion actually occurs within,
-                        // so don't do anything special here.
-                        err = self.err_ctxt().report_and_explain_type_error(
-                            mk_trace(
-                                lo,
-                                formal_and_expected_inputs[mismatch_idx.to_expected_idx()],
-                                provided_arg_tys[mismatch_idx].0,
-                            ),
-                            self.param_env,
-                            terr,
-                        );
-                        err.span_label(
-                            full_call_span,
-                            format!("arguments to this {call_name} are incorrect"),
-                        );
-                    } else {
-                        err = self.dcx().struct_span_err(
-                            full_call_span,
-                            format!(
-                                "{call_name} takes {}{} but {} {} supplied",
-                                if c_variadic { "at least " } else { "" },
-                                potentially_plural_count(
-                                    formal_and_expected_inputs.len(),
-                                    "argument"
-                                ),
-                                potentially_plural_count(provided_args.len(), "argument"),
-                                pluralize!("was", provided_args.len())
-                            ),
-                        );
-                        err.code(err_code.to_owned());
-                        err.multipart_suggestion_verbose(
-                            "wrap these arguments in parentheses to construct a tuple",
-                            vec![
-                                (lo.shrink_to_lo(), "(".to_string()),
-                                (hi.shrink_to_hi(), ")".to_string()),
-                            ],
-                            Applicability::MachineApplicable,
-                        );
-                    };
-                    self.label_fn_like(
-                        &mut err,
-                        fn_def_id,
-                        callee_ty,
-                        call_expr,
-                        None,
-                        Some(mismatch_idx.as_usize()),
-                        &matched_inputs,
-                        &formal_and_expected_inputs,
-                        is_method,
-                        tuple_arguments,
-                    );
-                    suggest_confusable(&mut err);
-                    return err.emit();
-                }
-            }
+        if let Some(fallback_error) = fn_call_diag_ctxt.ensure_has_errors() {
+            return fallback_error;
         }
 
         // Okay, so here's where it gets complicated in regards to what errors
@@ -926,608 +596,47 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         //   2) Valid but incorrect arguments
         //   3) Invalid arguments
         //      - Currently I think this only comes up with `CyclicTy`
-        //
+
         // We first need to go through, remove those from (3) and emit those
         // as their own error, particularly since they're error code and
         // message is special. From what I can tell, we *must* emit these
         // here (vs somewhere prior to this function) since the arguments
         // become invalid *because* of how they get used in the function.
         // It is what it is.
-
-        if errors.is_empty() {
-            if cfg!(debug_assertions) {
-                span_bug!(error_span, "expected errors from argument matrix");
-            } else {
-                let mut err =
-                    self.dcx().create_err(errors::ArgMismatchIndeterminate { span: error_span });
-                suggest_confusable(&mut err);
-                return err.emit();
-            }
+        if let Some(err) = fn_call_diag_ctxt.filter_out_invalid_arguments()
+            && fn_call_diag_ctxt.errors.is_empty()
+        {
+            // We're done if we found errors, but we already emitted them.
+            return err;
         }
 
-        let detect_dotdot = |err: &mut Diag<'_>, ty: Ty<'_>, expr: &hir::Expr<'_>| {
-            if let ty::Adt(adt, _) = ty.kind()
-                && self.tcx().is_lang_item(adt.did(), hir::LangItem::RangeFull)
-                && let hir::ExprKind::Struct(
-                    hir::QPath::LangItem(hir::LangItem::RangeFull, _),
-                    [],
-                    _,
-                ) = expr.kind
-            {
-                // We have `Foo(a, .., c)`, where the user might be trying to use the "rest" syntax
-                // from default field values, which is not supported on tuples.
-                let explanation = if self.tcx.features().default_field_values() {
-                    "this is only supported on non-tuple struct literals"
-                } else if self.tcx.sess.is_nightly_build() {
-                    "this is only supported on non-tuple struct literals when \
-                     `#![feature(default_field_values)]` is enabled"
-                } else {
-                    "this is not supported"
-                };
-                let msg = format!(
-                    "you might have meant to use `..` to skip providing a value for \
-                     expected fields, but {explanation}; it is instead interpreted as a \
-                     `std::ops::RangeFull` literal",
-                );
-                err.span_help(expr.span, msg);
-            }
-        };
+        assert!(!fn_call_diag_ctxt.errors.is_empty());
 
-        let mut reported = None;
-        errors.retain(|error| {
-            let Error::Invalid(provided_idx, expected_idx, Compatibility::Incompatible(Some(e))) =
-                error
-            else {
-                return true;
-            };
-            let (provided_ty, provided_span) = provided_arg_tys[*provided_idx];
-            let trace =
-                mk_trace(provided_span, formal_and_expected_inputs[*expected_idx], provided_ty);
-            if !matches!(trace.cause.as_failure_code(*e), FailureCode::Error0308) {
-                let mut err =
-                    self.err_ctxt().report_and_explain_type_error(trace, self.param_env, *e);
-                suggest_confusable(&mut err);
-                reported = Some(err.emit());
-                return false;
-            }
-            true
-        });
-
-        // We're done if we found errors, but we already emitted them.
-        if let Some(reported) = reported
-            && errors.is_empty()
-        {
-            return reported;
+        // Last special case: if there is only one "Incompatible" error, just emit that
+        if let Some(err) = fn_call_diag_ctxt.check_single_incompatible() {
+            return err;
         }
-        assert!(!errors.is_empty());
 
         // Okay, now that we've emitted the special errors separately, we
         // are only left missing/extra/swapped and mismatched arguments, both
         // can be collated pretty easily if needed.
 
-        // Next special case: if there is only one "Incompatible" error, just emit that
-        if let &[
-            Error::Invalid(provided_idx, expected_idx, Compatibility::Incompatible(Some(err))),
-        ] = &errors[..]
-        {
-            let (formal_ty, expected_ty) = formal_and_expected_inputs[expected_idx];
-            let (provided_ty, provided_arg_span) = provided_arg_tys[provided_idx];
-            let trace = mk_trace(provided_arg_span, (formal_ty, expected_ty), provided_ty);
-            let mut err = self.err_ctxt().report_and_explain_type_error(trace, self.param_env, err);
-            self.emit_coerce_suggestions(
-                &mut err,
-                provided_args[provided_idx],
-                provided_ty,
-                Expectation::rvalue_hint(self, expected_ty)
-                    .only_has_type(self)
-                    .unwrap_or(formal_ty),
-                None,
-                None,
-            );
-            err.span_label(full_call_span, format!("arguments to this {call_name} are incorrect"));
-
-            self.label_generic_mismatches(
-                &mut err,
-                fn_def_id,
-                &matched_inputs,
-                &provided_arg_tys,
-                &formal_and_expected_inputs,
-                is_method,
-            );
-
-            if let hir::ExprKind::MethodCall(_, rcvr, _, _) = call_expr.kind
-                && provided_idx.as_usize() == expected_idx.as_usize()
-            {
-                self.note_source_of_type_mismatch_constraint(
-                    &mut err,
-                    rcvr,
-                    crate::demand::TypeMismatchSource::Arg {
-                        call_expr,
-                        incompatible_arg: provided_idx.as_usize(),
-                    },
-                );
-            }
-
-            self.suggest_ptr_null_mut(
-                expected_ty,
-                provided_ty,
-                provided_args[provided_idx],
-                &mut err,
-            );
-
-            self.suggest_deref_unwrap_or(
-                &mut err,
-                callee_ty,
-                call_ident,
-                expected_ty,
-                provided_ty,
-                provided_args[provided_idx],
-                is_method,
-            );
-
-            // Call out where the function is defined
-            self.label_fn_like(
-                &mut err,
-                fn_def_id,
-                callee_ty,
-                call_expr,
-                Some(expected_ty),
-                Some(expected_idx.as_usize()),
-                &matched_inputs,
-                &formal_and_expected_inputs,
-                is_method,
-                tuple_arguments,
-            );
-            suggest_confusable(&mut err);
-            detect_dotdot(&mut err, provided_ty, provided_args[provided_idx]);
-            return err.emit();
-        }
-
         // Special case, we found an extra argument is provided, which is very common in practice.
         // but there is a obviously better removing suggestion compared to the current one,
         // try to find the argument with Error type, if we removed it all the types will become good,
         // then we will replace the current suggestion.
-        if let [Error::Extra(provided_idx)] = &errors[..] {
-            let remove_idx_is_perfect = |idx: usize| -> bool {
-                let removed_arg_tys = provided_arg_tys
-                    .iter()
-                    .enumerate()
-                    .filter_map(|(j, arg)| if idx == j { None } else { Some(arg) })
-                    .collect::<IndexVec<ProvidedIdx, _>>();
-                std::iter::zip(formal_and_expected_inputs.iter(), removed_arg_tys.iter()).all(
-                    |((expected_ty, _), (provided_ty, _))| {
-                        !provided_ty.references_error()
-                            && self.may_coerce(*provided_ty, *expected_ty)
-                    },
-                )
-            };
+        fn_call_diag_ctxt.maybe_optimize_extra_arg_suggestion();
 
-            if !remove_idx_is_perfect(provided_idx.as_usize()) {
-                if let Some(i) = (0..provided_args.len()).find(|&i| remove_idx_is_perfect(i)) {
-                    errors = vec![Error::Extra(ProvidedIdx::from_usize(i))];
-                }
-            }
-        }
+        let mut err = fn_call_diag_ctxt.initial_final_diagnostic();
+        fn_call_diag_ctxt.suggest_confusable(&mut err);
 
-        let mut err = if formal_and_expected_inputs.len() == provided_args.len() {
-            struct_span_code_err!(
-                self.dcx(),
-                full_call_span,
-                E0308,
-                "arguments to this {} are incorrect",
-                call_name,
-            )
-        } else {
-            self.dcx()
-                .struct_span_err(
-                    full_call_span,
-                    format!(
-                        "this {} takes {}{} but {} {} supplied",
-                        call_name,
-                        if c_variadic { "at least " } else { "" },
-                        potentially_plural_count(formal_and_expected_inputs.len(), "argument"),
-                        potentially_plural_count(provided_args.len(), "argument"),
-                        pluralize!("was", provided_args.len())
-                    ),
-                )
-                .with_code(err_code.to_owned())
-        };
+        // As we encounter issues, keep track of what we want to provide for the suggestion.
 
-        suggest_confusable(&mut err);
-        // As we encounter issues, keep track of what we want to provide for the suggestion
-        let mut labels = vec![];
-        // If there is a single error, we give a specific suggestion; otherwise, we change to
-        // "did you mean" with the suggested function call
-        enum SuggestionText {
-            None,
-            Provide(bool),
-            Remove(bool),
-            Swap,
-            Reorder,
-            DidYouMean,
-        }
-        let mut suggestion_text = SuggestionText::None;
-
-        let ty_to_snippet = |ty: Ty<'tcx>, expected_idx: ExpectedIdx| {
-            if ty.is_unit() {
-                "()".to_string()
-            } else if ty.is_suggestable(tcx, false) {
-                format!("/* {ty} */")
-            } else if let Some(fn_def_id) = fn_def_id
-                && self.tcx.def_kind(fn_def_id).is_fn_like()
-                && let self_implicit =
-                    matches!(call_expr.kind, hir::ExprKind::MethodCall(..)) as usize
-                && let Some(Some(arg)) =
-                    self.tcx.fn_arg_idents(fn_def_id).get(expected_idx.as_usize() + self_implicit)
-                && arg.name != kw::SelfLower
-            {
-                format!("/* {} */", arg.name)
-            } else {
-                "/* value */".to_string()
-            }
-        };
-
-        let mut errors = errors.into_iter().peekable();
-        let mut only_extras_so_far = errors
-            .peek()
-            .is_some_and(|first| matches!(first, Error::Extra(arg_idx) if arg_idx.index() == 0));
-        let mut prev_extra_idx = None;
-        let mut suggestions = vec![];
-        while let Some(error) = errors.next() {
-            only_extras_so_far &= matches!(error, Error::Extra(_));
-
-            match error {
-                Error::Invalid(provided_idx, expected_idx, compatibility) => {
-                    let (formal_ty, expected_ty) = formal_and_expected_inputs[expected_idx];
-                    let (provided_ty, provided_span) = provided_arg_tys[provided_idx];
-                    if let Compatibility::Incompatible(error) = compatibility {
-                        let trace = mk_trace(provided_span, (formal_ty, expected_ty), provided_ty);
-                        if let Some(e) = error {
-                            self.err_ctxt().note_type_err(
-                                &mut err,
-                                &trace.cause,
-                                None,
-                                Some(self.param_env.and(trace.values)),
-                                e,
-                                true,
-                                None,
-                            );
-                        }
-                    }
+        let (mut suggestions, labels, suggestion_text) =
+            fn_call_diag_ctxt.labels_and_suggestion_text(&mut err);
 
-                    self.emit_coerce_suggestions(
-                        &mut err,
-                        provided_args[provided_idx],
-                        provided_ty,
-                        Expectation::rvalue_hint(self, expected_ty)
-                            .only_has_type(self)
-                            .unwrap_or(formal_ty),
-                        None,
-                        None,
-                    );
-                    detect_dotdot(&mut err, provided_ty, provided_args[provided_idx]);
-                }
-                Error::Extra(arg_idx) => {
-                    let (provided_ty, provided_span) = provided_arg_tys[arg_idx];
-                    let provided_ty_name = if !has_error_or_infer([provided_ty]) {
-                        // FIXME: not suggestable, use something else
-                        format!(" of type `{provided_ty}`")
-                    } else {
-                        "".to_string()
-                    };
-                    let idx = if provided_arg_tys.len() == 1 {
-                        "".to_string()
-                    } else {
-                        format!(" #{}", arg_idx.as_usize() + 1)
-                    };
-                    labels.push((
-                        provided_span,
-                        format!("unexpected argument{idx}{provided_ty_name}"),
-                    ));
-                    let mut span = provided_span;
-                    if span.can_be_used_for_suggestions()
-                        && error_span.can_be_used_for_suggestions()
-                    {
-                        if arg_idx.index() > 0
-                            && let Some((_, prev)) =
-                                provided_arg_tys.get(ProvidedIdx::from_usize(arg_idx.index() - 1))
-                        {
-                            // Include previous comma
-                            span = prev.shrink_to_hi().to(span);
-                        }
-
-                        // Is last argument for deletion in a row starting from the 0-th argument?
-                        // Then delete the next comma, so we are not left with `f(, ...)`
-                        //
-                        //     fn f() {}
-                        //   - f(0, 1,)
-                        //   + f()
-                        let trim_next_comma = match errors.peek() {
-                            Some(Error::Extra(provided_idx))
-                                if only_extras_so_far
-                                    && provided_idx.index() > arg_idx.index() + 1 =>
-                            // If the next Error::Extra ("next") doesn't next to current ("current"),
-                            // fn foo(_: (), _: u32) {}
-                            // - foo("current", (), 1u32, "next")
-                            // + foo((), 1u32)
-                            // If the previous error is not a `Error::Extra`, then do not trim the next comma
-                            // - foo((), "current", 42u32, "next")
-                            // + foo((), 42u32)
-                            {
-                                prev_extra_idx.is_none_or(|prev_extra_idx| {
-                                    prev_extra_idx + 1 == arg_idx.index()
-                                })
-                            }
-                            // If no error left, we need to delete the next comma
-                            None if only_extras_so_far => true,
-                            // Not sure if other error type need to be handled as well
-                            _ => false,
-                        };
-
-                        if trim_next_comma {
-                            let next = provided_arg_tys
-                                .get(arg_idx + 1)
-                                .map(|&(_, sp)| sp)
-                                .unwrap_or_else(|| {
-                                    // Try to move before `)`. Note that `)` here is not necessarily
-                                    // the latin right paren, it could be a Unicode-confusable that
-                                    // looks like a `)`, so we must not use `- BytePos(1)`
-                                    // manipulations here.
-                                    self.tcx().sess.source_map().end_point(call_expr.span)
-                                });
-
-                            // Include next comma
-                            span = span.until(next);
-                        }
-
-                        suggestions.push((span, String::new()));
-
-                        suggestion_text = match suggestion_text {
-                            SuggestionText::None => SuggestionText::Remove(false),
-                            SuggestionText::Remove(_) => SuggestionText::Remove(true),
-                            _ => SuggestionText::DidYouMean,
-                        };
-                        prev_extra_idx = Some(arg_idx.index())
-                    }
-                    detect_dotdot(&mut err, provided_ty, provided_args[arg_idx]);
-                }
-                Error::Missing(expected_idx) => {
-                    // If there are multiple missing arguments adjacent to each other,
-                    // then we can provide a single error.
-
-                    let mut missing_idxs = vec![expected_idx];
-                    while let Some(e) = errors.next_if(|e| {
-                        matches!(e, Error::Missing(next_expected_idx)
-                            if *next_expected_idx == *missing_idxs.last().unwrap() + 1)
-                    }) {
-                        match e {
-                            Error::Missing(expected_idx) => missing_idxs.push(expected_idx),
-                            _ => unreachable!(
-                                "control flow ensures that we should always get an `Error::Missing`"
-                            ),
-                        }
-                    }
-
-                    // NOTE: Because we might be re-arranging arguments, might have extra
-                    // arguments, etc. it's hard to *really* know where we should provide
-                    // this error label, so as a heuristic, we point to the provided arg, or
-                    // to the call if the missing inputs pass the provided args.
-                    match &missing_idxs[..] {
-                        &[expected_idx] => {
-                            let (_, input_ty) = formal_and_expected_inputs[expected_idx];
-                            let span = if let Some((_, arg_span)) =
-                                provided_arg_tys.get(expected_idx.to_provided_idx())
-                            {
-                                *arg_span
-                            } else {
-                                args_span
-                            };
-                            let rendered = if !has_error_or_infer([input_ty]) {
-                                format!(" of type `{input_ty}`")
-                            } else {
-                                "".to_string()
-                            };
-                            labels.push((
-                                span,
-                                format!(
-                                    "argument #{}{rendered} is missing",
-                                    expected_idx.as_usize() + 1
-                                ),
-                            ));
-
-                            suggestion_text = match suggestion_text {
-                                SuggestionText::None => SuggestionText::Provide(false),
-                                SuggestionText::Provide(_) => SuggestionText::Provide(true),
-                                _ => SuggestionText::DidYouMean,
-                            };
-                        }
-                        &[first_idx, second_idx] => {
-                            let (_, first_expected_ty) = formal_and_expected_inputs[first_idx];
-                            let (_, second_expected_ty) = formal_and_expected_inputs[second_idx];
-                            let span = if let (Some((_, first_span)), Some((_, second_span))) = (
-                                provided_arg_tys.get(first_idx.to_provided_idx()),
-                                provided_arg_tys.get(second_idx.to_provided_idx()),
-                            ) {
-                                first_span.to(*second_span)
-                            } else {
-                                args_span
-                            };
-                            let rendered =
-                                if !has_error_or_infer([first_expected_ty, second_expected_ty]) {
-                                    format!(
-                                        " of type `{first_expected_ty}` and `{second_expected_ty}`"
-                                    )
-                                } else {
-                                    "".to_string()
-                                };
-                            labels.push((span, format!("two arguments{rendered} are missing")));
-                            suggestion_text = match suggestion_text {
-                                SuggestionText::None | SuggestionText::Provide(_) => {
-                                    SuggestionText::Provide(true)
-                                }
-                                _ => SuggestionText::DidYouMean,
-                            };
-                        }
-                        &[first_idx, second_idx, third_idx] => {
-                            let (_, first_expected_ty) = formal_and_expected_inputs[first_idx];
-                            let (_, second_expected_ty) = formal_and_expected_inputs[second_idx];
-                            let (_, third_expected_ty) = formal_and_expected_inputs[third_idx];
-                            let span = if let (Some((_, first_span)), Some((_, third_span))) = (
-                                provided_arg_tys.get(first_idx.to_provided_idx()),
-                                provided_arg_tys.get(third_idx.to_provided_idx()),
-                            ) {
-                                first_span.to(*third_span)
-                            } else {
-                                args_span
-                            };
-                            let rendered = if !has_error_or_infer([
-                                first_expected_ty,
-                                second_expected_ty,
-                                third_expected_ty,
-                            ]) {
-                                format!(
-                                    " of type `{first_expected_ty}`, `{second_expected_ty}`, and `{third_expected_ty}`"
-                                )
-                            } else {
-                                "".to_string()
-                            };
-                            labels.push((span, format!("three arguments{rendered} are missing")));
-                            suggestion_text = match suggestion_text {
-                                SuggestionText::None | SuggestionText::Provide(_) => {
-                                    SuggestionText::Provide(true)
-                                }
-                                _ => SuggestionText::DidYouMean,
-                            };
-                        }
-                        missing_idxs => {
-                            let first_idx = *missing_idxs.first().unwrap();
-                            let last_idx = *missing_idxs.last().unwrap();
-                            // NOTE: Because we might be re-arranging arguments, might have extra arguments, etc.
-                            // It's hard to *really* know where we should provide this error label, so this is a
-                            // decent heuristic
-                            let span = if let (Some((_, first_span)), Some((_, last_span))) = (
-                                provided_arg_tys.get(first_idx.to_provided_idx()),
-                                provided_arg_tys.get(last_idx.to_provided_idx()),
-                            ) {
-                                first_span.to(*last_span)
-                            } else {
-                                args_span
-                            };
-                            labels.push((span, "multiple arguments are missing".to_string()));
-                            suggestion_text = match suggestion_text {
-                                SuggestionText::None | SuggestionText::Provide(_) => {
-                                    SuggestionText::Provide(true)
-                                }
-                                _ => SuggestionText::DidYouMean,
-                            };
-                        }
-                    }
-                }
-                Error::Swap(
-                    first_provided_idx,
-                    second_provided_idx,
-                    first_expected_idx,
-                    second_expected_idx,
-                ) => {
-                    let (first_provided_ty, first_span) = provided_arg_tys[first_provided_idx];
-                    let (_, first_expected_ty) = formal_and_expected_inputs[first_expected_idx];
-                    let first_provided_ty_name = if !has_error_or_infer([first_provided_ty]) {
-                        format!(", found `{first_provided_ty}`")
-                    } else {
-                        String::new()
-                    };
-                    labels.push((
-                        first_span,
-                        format!("expected `{first_expected_ty}`{first_provided_ty_name}"),
-                    ));
-
-                    let (second_provided_ty, second_span) = provided_arg_tys[second_provided_idx];
-                    let (_, second_expected_ty) = formal_and_expected_inputs[second_expected_idx];
-                    let second_provided_ty_name = if !has_error_or_infer([second_provided_ty]) {
-                        format!(", found `{second_provided_ty}`")
-                    } else {
-                        String::new()
-                    };
-                    labels.push((
-                        second_span,
-                        format!("expected `{second_expected_ty}`{second_provided_ty_name}"),
-                    ));
-
-                    suggestion_text = match suggestion_text {
-                        SuggestionText::None => SuggestionText::Swap,
-                        _ => SuggestionText::DidYouMean,
-                    };
-                }
-                Error::Permutation(args) => {
-                    for (dst_arg, dest_input) in args {
-                        let (_, expected_ty) = formal_and_expected_inputs[dst_arg];
-                        let (provided_ty, provided_span) = provided_arg_tys[dest_input];
-                        let provided_ty_name = if !has_error_or_infer([provided_ty]) {
-                            format!(", found `{provided_ty}`")
-                        } else {
-                            String::new()
-                        };
-                        labels.push((
-                            provided_span,
-                            format!("expected `{expected_ty}`{provided_ty_name}"),
-                        ));
-                    }
-
-                    suggestion_text = match suggestion_text {
-                        SuggestionText::None => SuggestionText::Reorder,
-                        _ => SuggestionText::DidYouMean,
-                    };
-                }
-            }
-        }
-
-        self.label_generic_mismatches(
-            &mut err,
-            fn_def_id,
-            &matched_inputs,
-            &provided_arg_tys,
-            &formal_and_expected_inputs,
-            is_method,
-        );
-
-        // Incorporate the argument changes in the removal suggestion.
-        // When a type is *missing*, and the rest are additional, we want to suggest these with a
-        // multipart suggestion, but in order to do so we need to figure out *where* the arg that
-        // was provided but had the wrong type should go, because when looking at `expected_idx`
-        // that is the position in the argument list in the definition, while `provided_idx` will
-        // not be present. So we have to look at what the *last* provided position was, and point
-        // one after to suggest the replacement. FIXME(estebank): This is hacky, and there's
-        // probably a better more involved change we can make to make this work.
-        // For example, if we have
-        // ```
-        // fn foo(i32, &'static str) {}
-        // foo((), (), ());
-        // ```
-        // what should be suggested is
-        // ```
-        // foo(/* i32 */, /* &str */);
-        // ```
-        // which includes the replacement of the first two `()` for the correct type, and the
-        // removal of the last `()`.
-        let mut prev = -1;
-        for (expected_idx, provided_idx) in matched_inputs.iter_enumerated() {
-            // We want to point not at the *current* argument expression index, but rather at the
-            // index position where it *should have been*, which is *after* the previous one.
-            if let Some(provided_idx) = provided_idx {
-                prev = provided_idx.index() as i64;
-                continue;
-            }
-            let idx = ProvidedIdx::from_usize((prev + 1) as usize);
-            if let Some((_, arg_span)) = provided_arg_tys.get(idx) {
-                prev += 1;
-                // There is a type that was *not* found anywhere, so it isn't a move, but a
-                // replacement and we look at what type it should have been. This will allow us
-                // To suggest a multipart suggestion when encountering `foo(1, "")` where the def
-                // was `fn foo(())`.
-                let (_, expected_ty) = formal_and_expected_inputs[expected_idx];
-                suggestions.push((*arg_span, ty_to_snippet(expected_ty, expected_idx)));
-            }
-        }
+        fn_call_diag_ctxt.label_generic_mismatches(&mut err);
+        fn_call_diag_ctxt.append_arguments_changes(&mut suggestions);
 
         // If we have less than 5 things to say, it would be useful to call out exactly what's wrong
         if labels.len() <= 5 {
@@ -1537,113 +646,30 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
 
         // Call out where the function is defined
-        self.label_fn_like(
+        fn_call_diag_ctxt.label_fn_like(
             &mut err,
             fn_def_id,
-            callee_ty,
+            fn_call_diag_ctxt.callee_ty,
             call_expr,
             None,
             None,
-            &matched_inputs,
-            &formal_and_expected_inputs,
-            is_method,
+            &fn_call_diag_ctxt.matched_inputs,
+            &fn_call_diag_ctxt.formal_and_expected_inputs,
+            fn_call_diag_ctxt.call_metadata.is_method,
             tuple_arguments,
         );
 
         // And add a suggestion block for all of the parameters
-        let suggestion_text = match suggestion_text {
-            SuggestionText::None => None,
-            SuggestionText::Provide(plural) => {
-                Some(format!("provide the argument{}", if plural { "s" } else { "" }))
-            }
-            SuggestionText::Remove(plural) => {
-                err.multipart_suggestion_verbose(
-                    format!("remove the extra argument{}", if plural { "s" } else { "" }),
-                    suggestions,
-                    Applicability::HasPlaceholders,
-                );
-                None
-            }
-            SuggestionText::Swap => Some("swap these arguments".to_string()),
-            SuggestionText::Reorder => Some("reorder these arguments".to_string()),
-            SuggestionText::DidYouMean => Some("did you mean".to_string()),
-        };
-        if let Some(suggestion_text) = suggestion_text
-            && !full_call_span.in_external_macro(self.sess().source_map())
+        if let Some(suggestion_message) =
+            FnCallDiagCtxt::format_suggestion_text(&mut err, suggestions, suggestion_text)
+            && !fn_call_diag_ctxt.call_is_in_macro()
         {
-            let source_map = self.sess().source_map();
-            let suggestion_span = if let Some(args_span) = error_span.trim_start(full_call_span) {
-                // Span of the braces, e.g. `(a, b, c)`.
-                args_span
-            } else {
-                // The arg span of a function call that wasn't even given braces
-                // like what might happen with delegation reuse.
-                // e.g. `reuse HasSelf::method;` should suggest `reuse HasSelf::method($args);`.
-                full_call_span.shrink_to_hi()
-            };
-
-            // Controls how the arguments should be listed in the suggestion.
-            enum ArgumentsFormatting {
-                SingleLine,
-                Multiline { fallback_indent: String, brace_indent: String },
-            }
-            let arguments_formatting = {
-                let mut provided_inputs = matched_inputs.iter().filter_map(|a| *a);
-                if let Some(brace_indent) = source_map.indentation_before(suggestion_span)
-                    && let Some(first_idx) = provided_inputs.by_ref().next()
-                    && let Some(last_idx) = provided_inputs.by_ref().next()
-                    && let (_, first_span) = provided_arg_tys[first_idx]
-                    && let (_, last_span) = provided_arg_tys[last_idx]
-                    && source_map.is_multiline(first_span.to(last_span))
-                    && let Some(fallback_indent) = source_map.indentation_before(first_span)
-                {
-                    ArgumentsFormatting::Multiline { fallback_indent, brace_indent }
-                } else {
-                    ArgumentsFormatting::SingleLine
-                }
-            };
+            let (suggestion_span, suggestion_code) = fn_call_diag_ctxt.suggestion_code();
 
-            let mut suggestion = "(".to_owned();
-            let mut needs_comma = false;
-            for (expected_idx, provided_idx) in matched_inputs.iter_enumerated() {
-                if needs_comma {
-                    suggestion += ",";
-                }
-                match &arguments_formatting {
-                    ArgumentsFormatting::SingleLine if needs_comma => suggestion += " ",
-                    ArgumentsFormatting::SingleLine => {}
-                    ArgumentsFormatting::Multiline { .. } => suggestion += "\n",
-                }
-                needs_comma = true;
-                let (suggestion_span, suggestion_text) = if let Some(provided_idx) = provided_idx
-                    && let (_, provided_span) = provided_arg_tys[*provided_idx]
-                    && let Ok(arg_text) = source_map.span_to_snippet(provided_span)
-                {
-                    (Some(provided_span), arg_text)
-                } else {
-                    // Propose a placeholder of the correct type
-                    let (_, expected_ty) = formal_and_expected_inputs[expected_idx];
-                    (None, ty_to_snippet(expected_ty, expected_idx))
-                };
-                if let ArgumentsFormatting::Multiline { fallback_indent, .. } =
-                    &arguments_formatting
-                {
-                    let indent = suggestion_span
-                        .and_then(|span| source_map.indentation_before(span))
-                        .unwrap_or_else(|| fallback_indent.clone());
-                    suggestion += &indent;
-                }
-                suggestion += &suggestion_text;
-            }
-            if let ArgumentsFormatting::Multiline { brace_indent, .. } = arguments_formatting {
-                suggestion += ",\n";
-                suggestion += &brace_indent;
-            }
-            suggestion += ")";
             err.span_suggestion_verbose(
                 suggestion_span,
-                suggestion_text,
-                suggestion,
+                suggestion_message,
+                suggestion_code,
                 Applicability::HasPlaceholders,
             );
         }
@@ -2836,3 +1862,1333 @@ impl FnParam<'_> {
         D(*self, idx)
     }
 }
+
+struct FnCallDiagCtxt<'a, 'b, 'tcx> {
+    arg_matching_ctxt: ArgMatchingCtxt<'a, 'b, 'tcx>,
+    errors: Vec<Error<'tcx>>,
+    matched_inputs: IndexVec<ExpectedIdx, Option<ProvidedIdx>>,
+}
+
+impl<'a, 'b, 'tcx> Deref for FnCallDiagCtxt<'a, 'b, 'tcx> {
+    type Target = ArgMatchingCtxt<'a, 'b, 'tcx>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.arg_matching_ctxt
+    }
+}
+
+// Controls how the arguments should be listed in the suggestion.
+enum ArgumentsFormatting {
+    SingleLine,
+    Multiline { fallback_indent: String, brace_indent: String },
+}
+
+impl<'a, 'b, 'tcx> FnCallDiagCtxt<'a, 'b, 'tcx> {
+    fn new(
+        arg: &'a FnCtxt<'b, 'tcx>,
+        compatibility_diagonal: IndexVec<ProvidedIdx, Compatibility<'tcx>>,
+        formal_and_expected_inputs: IndexVec<ExpectedIdx, (Ty<'tcx>, Ty<'tcx>)>,
+        provided_args: IndexVec<ProvidedIdx, &'tcx Expr<'tcx>>,
+        c_variadic: bool,
+        err_code: ErrCode,
+        fn_def_id: Option<DefId>,
+        call_span: Span,
+        call_expr: &'tcx Expr<'tcx>,
+        tuple_arguments: TupleArgumentsFlag,
+    ) -> Self {
+        let arg_matching_ctxt = ArgMatchingCtxt::new(
+            arg,
+            compatibility_diagonal,
+            formal_and_expected_inputs,
+            provided_args,
+            c_variadic,
+            err_code,
+            fn_def_id,
+            call_span,
+            call_expr,
+            tuple_arguments,
+        );
+
+        // The algorithm here is inspired by levenshtein distance and longest common subsequence.
+        // We'll try to detect 4 different types of mistakes:
+        // - An extra parameter has been provided that doesn't satisfy *any* of the other inputs
+        // - An input is missing, which isn't satisfied by *any* of the other arguments
+        // - Some number of arguments have been provided in the wrong order
+        // - A type is straight up invalid
+        let (errors, matched_inputs) = ArgMatrix::new(
+            arg_matching_ctxt.provided_args.len(),
+            arg_matching_ctxt.formal_and_expected_inputs.len(),
+            |provided, expected| arg_matching_ctxt.check_compatible(provided, expected),
+        )
+        .find_errors();
+
+        FnCallDiagCtxt { arg_matching_ctxt, errors, matched_inputs }
+    }
+
+    fn check_wrap_args_in_tuple(&self) -> Option<ErrorGuaranteed> {
+        if let Some((mismatch_idx, terr)) = self.first_incompatible_error() {
+            // Is the first bad expected argument a tuple?
+            // Do we have as many extra provided arguments as the tuple's length?
+            // If so, we might have just forgotten to wrap some args in a tuple.
+            if let Some(ty::Tuple(tys)) =
+               self.formal_and_expected_inputs.get(mismatch_idx.to_expected_idx()).map(|tys| tys.1.kind())
+                // If the tuple is unit, we're not actually wrapping any arguments.
+                && !tys.is_empty()
+                && self.provided_arg_tys.len() == self.formal_and_expected_inputs.len() - 1 + tys.len()
+            {
+                // Wrap up the N provided arguments starting at this position in a tuple.
+                let provided_args_to_tuple = &self.provided_arg_tys[mismatch_idx..];
+                let (provided_args_to_tuple, provided_args_after_tuple) =
+                    provided_args_to_tuple.split_at(tys.len());
+                let provided_as_tuple = Ty::new_tup_from_iter(
+                    self.tcx,
+                    provided_args_to_tuple.iter().map(|&(ty, _)| ty),
+                );
+
+                let mut satisfied = true;
+                // Check if the newly wrapped tuple + rest of the arguments are compatible.
+                for ((_, expected_ty), provided_ty) in std::iter::zip(
+                    self.formal_and_expected_inputs[mismatch_idx.to_expected_idx()..].iter(),
+                    [provided_as_tuple]
+                        .into_iter()
+                        .chain(provided_args_after_tuple.iter().map(|&(ty, _)| ty)),
+                ) {
+                    if !self.may_coerce(provided_ty, *expected_ty) {
+                        satisfied = false;
+                        break;
+                    }
+                }
+
+                // If they're compatible, suggest wrapping in an arg, and we're done!
+                // Take some care with spans, so we don't suggest wrapping a macro's
+                // innards in parenthesis, for example.
+                if satisfied
+                    && let &[(_, hi @ lo)] | &[(_, lo), .., (_, hi)] = provided_args_to_tuple
+                {
+                    let mut err;
+                    if tys.len() == 1 {
+                        // A tuple wrap suggestion actually occurs within,
+                        // so don't do anything special here.
+                        err = self.err_ctxt().report_and_explain_type_error(
+                            self.arg_matching_ctxt.args_ctxt.call_ctxt.mk_trace(
+                                lo,
+                                self.formal_and_expected_inputs[mismatch_idx.to_expected_idx()],
+                                self.provided_arg_tys[mismatch_idx].0,
+                            ),
+                            self.param_env,
+                            terr,
+                        );
+                        let call_name = self.call_metadata.call_name;
+                        err.span_label(
+                            self.call_metadata.full_call_span,
+                            format!("arguments to this {call_name} are incorrect"),
+                        );
+                    } else {
+                        let call_name = self.call_metadata.call_name;
+                        err = self.dcx().struct_span_err(
+                            self.arg_matching_ctxt.args_ctxt.call_metadata.full_call_span,
+                            format!(
+                                "{call_name} takes {}{} but {} {} supplied",
+                                if self.c_variadic { "at least " } else { "" },
+                                potentially_plural_count(
+                                    self.formal_and_expected_inputs.len(),
+                                    "argument"
+                                ),
+                                potentially_plural_count(self.provided_args.len(), "argument"),
+                                pluralize!("was", self.provided_args.len())
+                            ),
+                        );
+                        err.code(self.err_code.to_owned());
+                        err.multipart_suggestion_verbose(
+                            "wrap these arguments in parentheses to construct a tuple",
+                            vec![
+                                (lo.shrink_to_lo(), "(".to_string()),
+                                (hi.shrink_to_hi(), ")".to_string()),
+                            ],
+                            Applicability::MachineApplicable,
+                        );
+                    };
+                    self.arg_matching_ctxt.args_ctxt.call_ctxt.fn_ctxt.label_fn_like(
+                        &mut err,
+                        self.fn_def_id,
+                        self.callee_ty,
+                        self.call_expr,
+                        None,
+                        Some(mismatch_idx.as_usize()),
+                        &self.matched_inputs,
+                        &self.formal_and_expected_inputs,
+                        self.call_metadata.is_method,
+                        self.tuple_arguments,
+                    );
+                    self.suggest_confusable(&mut err);
+                    Some(err.emit())
+                } else {
+                    None
+                }
+            } else {
+                None
+            }
+        } else {
+            None
+        }
+    }
+
+    fn ensure_has_errors(&self) -> Option<ErrorGuaranteed> {
+        if self.errors.is_empty() {
+            if cfg!(debug_assertions) {
+                span_bug!(self.call_metadata.error_span, "expected errors from argument matrix");
+            } else {
+                let mut err = self.dcx().create_err(errors::ArgMismatchIndeterminate {
+                    span: self.call_metadata.error_span,
+                });
+                self.arg_matching_ctxt.suggest_confusable(&mut err);
+                return Some(err.emit());
+            }
+        }
+
+        None
+    }
+
+    fn detect_dotdot(&self, err: &mut Diag<'_>, ty: Ty<'tcx>, expr: &hir::Expr<'tcx>) {
+        if let ty::Adt(adt, _) = ty.kind()
+            && self.tcx().is_lang_item(adt.did(), hir::LangItem::RangeFull)
+            && let hir::ExprKind::Struct(hir::QPath::LangItem(hir::LangItem::RangeFull, _), [], _) =
+                expr.kind
+        {
+            // We have `Foo(a, .., c)`, where the user might be trying to use the "rest" syntax
+            // from default field values, which is not supported on tuples.
+            let explanation = if self.tcx.features().default_field_values() {
+                "this is only supported on non-tuple struct literals"
+            } else if self.tcx.sess.is_nightly_build() {
+                "this is only supported on non-tuple struct literals when \
+                 `#![feature(default_field_values)]` is enabled"
+            } else {
+                "this is not supported"
+            };
+            let msg = format!(
+                "you might have meant to use `..` to skip providing a value for \
+                 expected fields, but {explanation}; it is instead interpreted as a \
+                 `std::ops::RangeFull` literal",
+            );
+            err.span_help(expr.span, msg);
+        }
+    }
+
+    fn filter_out_invalid_arguments(&mut self) -> Option<ErrorGuaranteed> {
+        let mut reported = None;
+
+        self.errors.retain(|error| {
+            let Error::Invalid(provided_idx, expected_idx, Compatibility::Incompatible(Some(e))) =
+                error
+            else {
+                return true;
+            };
+            let (provided_ty, provided_span) =
+                self.arg_matching_ctxt.provided_arg_tys[*provided_idx];
+            let trace = self.arg_matching_ctxt.mk_trace(
+                provided_span,
+                self.arg_matching_ctxt.formal_and_expected_inputs[*expected_idx],
+                provided_ty,
+            );
+            if !matches!(trace.cause.as_failure_code(*e), FailureCode::Error0308) {
+                let mut err = self.arg_matching_ctxt.err_ctxt().report_and_explain_type_error(
+                    trace,
+                    self.arg_matching_ctxt.param_env,
+                    *e,
+                );
+                self.arg_matching_ctxt.suggest_confusable(&mut err);
+                reported = Some(err.emit());
+                return false;
+            }
+            true
+        });
+
+        reported
+    }
+
+    fn check_single_incompatible(&self) -> Option<ErrorGuaranteed> {
+        if let &[
+            Error::Invalid(provided_idx, expected_idx, Compatibility::Incompatible(Some(err))),
+        ] = &self.errors[..]
+        {
+            let (formal_ty, expected_ty) = self.formal_and_expected_inputs[expected_idx];
+            let (provided_ty, provided_arg_span) = self.provided_arg_tys[provided_idx];
+            let trace = self.mk_trace(provided_arg_span, (formal_ty, expected_ty), provided_ty);
+            let mut err = self.err_ctxt().report_and_explain_type_error(trace, self.param_env, err);
+            self.emit_coerce_suggestions(
+                &mut err,
+                self.provided_args[provided_idx],
+                provided_ty,
+                Expectation::rvalue_hint(self.fn_ctxt, expected_ty)
+                    .only_has_type(self.fn_ctxt)
+                    .unwrap_or(formal_ty),
+                None,
+                None,
+            );
+            let call_name = self.call_metadata.call_name;
+            err.span_label(
+                self.call_metadata.full_call_span,
+                format!("arguments to this {call_name} are incorrect"),
+            );
+
+            self.fn_ctxt.label_generic_mismatches(
+                &mut err,
+                self.fn_def_id,
+                &self.matched_inputs,
+                &self.provided_arg_tys,
+                &self.formal_and_expected_inputs,
+                self.call_metadata.is_method,
+            );
+
+            if let hir::ExprKind::MethodCall(_, rcvr, _, _) =
+                self.arg_matching_ctxt.args_ctxt.call_ctxt.call_expr.kind
+                && provided_idx.as_usize() == expected_idx.as_usize()
+            {
+                self.note_source_of_type_mismatch_constraint(
+                    &mut err,
+                    rcvr,
+                    crate::demand::TypeMismatchSource::Arg {
+                        call_expr: self.call_expr,
+                        incompatible_arg: provided_idx.as_usize(),
+                    },
+                );
+            }
+
+            self.suggest_ptr_null_mut(
+                expected_ty,
+                provided_ty,
+                self.provided_args[provided_idx],
+                &mut err,
+            );
+
+            self.suggest_deref_unwrap_or(
+                &mut err,
+                self.callee_ty,
+                self.call_metadata.call_ident,
+                expected_ty,
+                provided_ty,
+                self.provided_args[provided_idx],
+                self.call_metadata.is_method,
+            );
+
+            // Call out where the function is defined
+            self.label_fn_like(
+                &mut err,
+                self.fn_def_id,
+                self.callee_ty,
+                self.call_expr,
+                Some(expected_ty),
+                Some(expected_idx.as_usize()),
+                &self.matched_inputs,
+                &self.formal_and_expected_inputs,
+                self.call_metadata.is_method,
+                self.tuple_arguments,
+            );
+            self.arg_matching_ctxt.suggest_confusable(&mut err);
+            self.detect_dotdot(&mut err, provided_ty, self.provided_args[provided_idx]);
+            return Some(err.emit());
+        }
+
+        None
+    }
+
+    fn maybe_optimize_extra_arg_suggestion(&mut self) {
+        if let [Error::Extra(provided_idx)] = &self.errors[..] {
+            if !self.remove_idx_is_perfect(provided_idx.as_usize()) {
+                if let Some(i) = (0..self.args_ctxt.call_ctxt.provided_args.len())
+                    .find(|&i| self.remove_idx_is_perfect(i))
+                {
+                    self.errors = vec![Error::Extra(ProvidedIdx::from_usize(i))];
+                }
+            }
+        }
+    }
+
+    fn initial_final_diagnostic(&self) -> Diag<'_> {
+        if self.formal_and_expected_inputs.len() == self.provided_args.len() {
+            struct_span_code_err!(
+                self.dcx(),
+                self.call_metadata.full_call_span,
+                E0308,
+                "arguments to this {} are incorrect",
+                self.call_metadata.call_name,
+            )
+        } else {
+            self.arg_matching_ctxt
+                .dcx()
+                .struct_span_err(
+                    self.call_metadata.full_call_span,
+                    format!(
+                        "this {} takes {}{} but {} {} supplied",
+                        self.call_metadata.call_name,
+                        if self.c_variadic { "at least " } else { "" },
+                        potentially_plural_count(self.formal_and_expected_inputs.len(), "argument"),
+                        potentially_plural_count(self.provided_args.len(), "argument"),
+                        pluralize!("was", self.provided_args.len())
+                    ),
+                )
+                .with_code(self.err_code.to_owned())
+        }
+    }
+
+    fn labels_and_suggestion_text(
+        &self,
+        err: &mut Diag<'_>,
+    ) -> (Vec<(Span, String)>, Vec<(Span, String)>, SuggestionText) {
+        // Don't print if it has error types or is just plain `_`
+        fn has_error_or_infer<'tcx>(tys: impl IntoIterator<Item = Ty<'tcx>>) -> bool {
+            tys.into_iter().any(|ty| ty.references_error() || ty.is_ty_var())
+        }
+
+        let mut labels = Vec::new();
+        let mut suggestion_text = SuggestionText::None;
+
+        let mut errors = self.errors.iter().peekable();
+        let mut only_extras_so_far = errors
+            .peek()
+            .is_some_and(|first| matches!(first, Error::Extra(arg_idx) if arg_idx.index() == 0));
+        let mut prev_extra_idx = None;
+        let mut suggestions = vec![];
+        while let Some(error) = errors.next() {
+            only_extras_so_far &= matches!(error, Error::Extra(_));
+
+            match error {
+                Error::Invalid(provided_idx, expected_idx, compatibility) => {
+                    let (formal_ty, expected_ty) =
+                        self.arg_matching_ctxt.args_ctxt.call_ctxt.formal_and_expected_inputs
+                            [*expected_idx];
+                    let (provided_ty, provided_span) =
+                        self.arg_matching_ctxt.provided_arg_tys[*provided_idx];
+                    if let Compatibility::Incompatible(error) = compatibility {
+                        let trace = self.arg_matching_ctxt.args_ctxt.call_ctxt.mk_trace(
+                            provided_span,
+                            (formal_ty, expected_ty),
+                            provided_ty,
+                        );
+                        if let Some(e) = error {
+                            self.err_ctxt().note_type_err(
+                                err,
+                                &trace.cause,
+                                None,
+                                Some(self.param_env.and(trace.values)),
+                                *e,
+                                true,
+                                None,
+                            );
+                        }
+                    }
+
+                    self.emit_coerce_suggestions(
+                        err,
+                        self.provided_args[*provided_idx],
+                        provided_ty,
+                        Expectation::rvalue_hint(self.fn_ctxt, expected_ty)
+                            .only_has_type(self.fn_ctxt)
+                            .unwrap_or(formal_ty),
+                        None,
+                        None,
+                    );
+                    self.detect_dotdot(err, provided_ty, self.provided_args[*provided_idx]);
+                }
+                Error::Extra(arg_idx) => {
+                    let (provided_ty, provided_span) = self.provided_arg_tys[*arg_idx];
+                    let provided_ty_name = if !has_error_or_infer([provided_ty]) {
+                        // FIXME: not suggestable, use something else
+                        format!(" of type `{provided_ty}`")
+                    } else {
+                        "".to_string()
+                    };
+                    let idx = if self.provided_arg_tys.len() == 1 {
+                        "".to_string()
+                    } else {
+                        format!(" #{}", arg_idx.as_usize() + 1)
+                    };
+                    labels.push((
+                        provided_span,
+                        format!("unexpected argument{idx}{provided_ty_name}"),
+                    ));
+                    let mut span = provided_span;
+                    if span.can_be_used_for_suggestions()
+                        && self.call_metadata.error_span.can_be_used_for_suggestions()
+                    {
+                        if arg_idx.index() > 0
+                            && let Some((_, prev)) = self
+                                .provided_arg_tys
+                                .get(ProvidedIdx::from_usize(arg_idx.index() - 1))
+                        {
+                            // Include previous comma
+                            span = prev.shrink_to_hi().to(span);
+                        }
+
+                        // Is last argument for deletion in a row starting from the 0-th argument?
+                        // Then delete the next comma, so we are not left with `f(, ...)`
+                        //
+                        //     fn f() {}
+                        //   - f(0, 1,)
+                        //   + f()
+                        let trim_next_comma = match errors.peek() {
+                            Some(Error::Extra(provided_idx))
+                                if only_extras_so_far
+                                    && provided_idx.index() > arg_idx.index() + 1 =>
+                            // If the next Error::Extra ("next") doesn't next to current ("current"),
+                            // fn foo(_: (), _: u32) {}
+                            // - foo("current", (), 1u32, "next")
+                            // + foo((), 1u32)
+                            // If the previous error is not a `Error::Extra`, then do not trim the next comma
+                            // - foo((), "current", 42u32, "next")
+                            // + foo((), 42u32)
+                            {
+                                prev_extra_idx.is_none_or(|prev_extra_idx| {
+                                    prev_extra_idx + 1 == arg_idx.index()
+                                })
+                            }
+                            // If no error left, we need to delete the next comma
+                            None if only_extras_so_far => true,
+                            // Not sure if other error type need to be handled as well
+                            _ => false,
+                        };
+
+                        if trim_next_comma {
+                            let next = self
+                                .provided_arg_tys
+                                .get(*arg_idx + 1)
+                                .map(|&(_, sp)| sp)
+                                .unwrap_or_else(|| {
+                                    // Try to move before `)`. Note that `)` here is not necessarily
+                                    // the latin right paren, it could be a Unicode-confusable that
+                                    // looks like a `)`, so we must not use `- BytePos(1)`
+                                    // manipulations here.
+                                    self.arg_matching_ctxt
+                                        .tcx()
+                                        .sess
+                                        .source_map()
+                                        .end_point(self.call_expr.span)
+                                });
+
+                            // Include next comma
+                            span = span.until(next);
+                        }
+
+                        suggestions.push((span, String::new()));
+
+                        suggestion_text = match suggestion_text {
+                            SuggestionText::None => SuggestionText::Remove(false),
+                            SuggestionText::Remove(_) => SuggestionText::Remove(true),
+                            _ => SuggestionText::DidYouMean,
+                        };
+                        prev_extra_idx = Some(arg_idx.index())
+                    }
+                    self.detect_dotdot(err, provided_ty, self.provided_args[*arg_idx]);
+                }
+                Error::Missing(expected_idx) => {
+                    // If there are multiple missing arguments adjacent to each other,
+                    // then we can provide a single error.
+
+                    let mut missing_idxs = vec![*expected_idx];
+                    while let Some(e) = errors.next_if(|e| {
+                        matches!(e, Error::Missing(next_expected_idx)
+                            if *next_expected_idx == *missing_idxs.last().unwrap() + 1)
+                    }) {
+                        match e {
+                            Error::Missing(expected_idx) => missing_idxs.push(*expected_idx),
+                            _ => unreachable!(
+                                "control flow ensures that we should always get an `Error::Missing`"
+                            ),
+                        }
+                    }
+
+                    // NOTE: Because we might be re-arranging arguments, might have extra
+                    // arguments, etc. it's hard to *really* know where we should provide
+                    // this error label, so as a heuristic, we point to the provided arg, or
+                    // to the call if the missing inputs pass the provided args.
+                    match &missing_idxs[..] {
+                        &[expected_idx] => {
+                            let (_, input_ty) = self.formal_and_expected_inputs[expected_idx];
+                            let span = if let Some((_, arg_span)) =
+                                self.provided_arg_tys.get(expected_idx.to_provided_idx())
+                            {
+                                *arg_span
+                            } else {
+                                self.args_span
+                            };
+                            let rendered = if !has_error_or_infer([input_ty]) {
+                                format!(" of type `{input_ty}`")
+                            } else {
+                                "".to_string()
+                            };
+                            labels.push((
+                                span,
+                                format!(
+                                    "argument #{}{rendered} is missing",
+                                    expected_idx.as_usize() + 1
+                                ),
+                            ));
+
+                            suggestion_text = match suggestion_text {
+                                SuggestionText::None => SuggestionText::Provide(false),
+                                SuggestionText::Provide(_) => SuggestionText::Provide(true),
+                                _ => SuggestionText::DidYouMean,
+                            };
+                        }
+                        &[first_idx, second_idx] => {
+                            let (_, first_expected_ty) = self.formal_and_expected_inputs[first_idx];
+                            let (_, second_expected_ty) =
+                                self.formal_and_expected_inputs[second_idx];
+                            let span = if let (Some((_, first_span)), Some((_, second_span))) = (
+                                self.provided_arg_tys.get(first_idx.to_provided_idx()),
+                                self.provided_arg_tys.get(second_idx.to_provided_idx()),
+                            ) {
+                                first_span.to(*second_span)
+                            } else {
+                                self.args_span
+                            };
+                            let rendered =
+                                if !has_error_or_infer([first_expected_ty, second_expected_ty]) {
+                                    format!(
+                                        " of type `{first_expected_ty}` and `{second_expected_ty}`"
+                                    )
+                                } else {
+                                    "".to_string()
+                                };
+                            labels.push((span, format!("two arguments{rendered} are missing")));
+                            suggestion_text = match suggestion_text {
+                                SuggestionText::None | SuggestionText::Provide(_) => {
+                                    SuggestionText::Provide(true)
+                                }
+                                _ => SuggestionText::DidYouMean,
+                            };
+                        }
+                        &[first_idx, second_idx, third_idx] => {
+                            let (_, first_expected_ty) = self.formal_and_expected_inputs[first_idx];
+                            let (_, second_expected_ty) =
+                                self.formal_and_expected_inputs[second_idx];
+                            let (_, third_expected_ty) = self.formal_and_expected_inputs[third_idx];
+                            let span = if let (Some((_, first_span)), Some((_, third_span))) = (
+                                self.provided_arg_tys.get(first_idx.to_provided_idx()),
+                                self.provided_arg_tys.get(third_idx.to_provided_idx()),
+                            ) {
+                                first_span.to(*third_span)
+                            } else {
+                                self.args_span
+                            };
+                            let rendered = if !has_error_or_infer([
+                                first_expected_ty,
+                                second_expected_ty,
+                                third_expected_ty,
+                            ]) {
+                                format!(
+                                    " of type `{first_expected_ty}`, `{second_expected_ty}`, and `{third_expected_ty}`"
+                                )
+                            } else {
+                                "".to_string()
+                            };
+                            labels.push((span, format!("three arguments{rendered} are missing")));
+                            suggestion_text = match suggestion_text {
+                                SuggestionText::None | SuggestionText::Provide(_) => {
+                                    SuggestionText::Provide(true)
+                                }
+                                _ => SuggestionText::DidYouMean,
+                            };
+                        }
+                        missing_idxs => {
+                            let first_idx = *missing_idxs.first().unwrap();
+                            let last_idx = *missing_idxs.last().unwrap();
+                            // NOTE: Because we might be re-arranging arguments, might have extra arguments, etc.
+                            // It's hard to *really* know where we should provide this error label, so this is a
+                            // decent heuristic
+                            let span = if let (Some((_, first_span)), Some((_, last_span))) = (
+                                self.provided_arg_tys.get(first_idx.to_provided_idx()),
+                                self.provided_arg_tys.get(last_idx.to_provided_idx()),
+                            ) {
+                                first_span.to(*last_span)
+                            } else {
+                                self.args_span
+                            };
+                            labels.push((span, "multiple arguments are missing".to_string()));
+                            suggestion_text = match suggestion_text {
+                                SuggestionText::None | SuggestionText::Provide(_) => {
+                                    SuggestionText::Provide(true)
+                                }
+                                _ => SuggestionText::DidYouMean,
+                            };
+                        }
+                    }
+                }
+                Error::Swap(
+                    first_provided_idx,
+                    second_provided_idx,
+                    first_expected_idx,
+                    second_expected_idx,
+                ) => {
+                    let (first_provided_ty, first_span) =
+                        self.provided_arg_tys[*first_provided_idx];
+                    let (_, first_expected_ty) =
+                        self.formal_and_expected_inputs[*first_expected_idx];
+                    let first_provided_ty_name = if !has_error_or_infer([first_provided_ty]) {
+                        format!(", found `{first_provided_ty}`")
+                    } else {
+                        String::new()
+                    };
+                    labels.push((
+                        first_span,
+                        format!("expected `{first_expected_ty}`{first_provided_ty_name}"),
+                    ));
+
+                    let (second_provided_ty, second_span) =
+                        self.provided_arg_tys[*second_provided_idx];
+                    let (_, second_expected_ty) =
+                        self.formal_and_expected_inputs[*second_expected_idx];
+                    let second_provided_ty_name = if !has_error_or_infer([second_provided_ty]) {
+                        format!(", found `{second_provided_ty}`")
+                    } else {
+                        String::new()
+                    };
+                    labels.push((
+                        second_span,
+                        format!("expected `{second_expected_ty}`{second_provided_ty_name}"),
+                    ));
+
+                    suggestion_text = match suggestion_text {
+                        SuggestionText::None => SuggestionText::Swap,
+                        _ => SuggestionText::DidYouMean,
+                    };
+                }
+                Error::Permutation(args) => {
+                    for (dst_arg, dest_input) in args {
+                        let (_, expected_ty) = self.formal_and_expected_inputs[*dst_arg];
+                        let (provided_ty, provided_span) = self.provided_arg_tys[*dest_input];
+                        let provided_ty_name = if !has_error_or_infer([provided_ty]) {
+                            format!(", found `{provided_ty}`")
+                        } else {
+                            String::new()
+                        };
+                        labels.push((
+                            provided_span,
+                            format!("expected `{expected_ty}`{provided_ty_name}"),
+                        ));
+                    }
+
+                    suggestion_text = match suggestion_text {
+                        SuggestionText::None => SuggestionText::Reorder,
+                        _ => SuggestionText::DidYouMean,
+                    };
+                }
+            }
+        }
+
+        (suggestions, labels, suggestion_text)
+    }
+
+    fn label_generic_mismatches(&self, err: &mut Diag<'b>) {
+        self.fn_ctxt.label_generic_mismatches(
+            err,
+            self.fn_def_id,
+            &self.matched_inputs,
+            &self.provided_arg_tys,
+            &self.formal_and_expected_inputs,
+            self.call_metadata.is_method,
+        );
+    }
+
+    /// Incorporate the argument changes in the removal suggestion.
+    ///
+    /// When a type is *missing*, and the rest are additional, we want to suggest these with a
+    /// multipart suggestion, but in order to do so we need to figure out *where* the arg that
+    /// was provided but had the wrong type should go, because when looking at `expected_idx`
+    /// that is the position in the argument list in the definition, while `provided_idx` will
+    /// not be present. So we have to look at what the *last* provided position was, and point
+    /// one after to suggest the replacement.
+    fn append_arguments_changes(&self, suggestions: &mut Vec<(Span, String)>) {
+        // FIXME(estebank): This is hacky, and there's
+        // probably a better more involved change we can make to make this work.
+        // For example, if we have
+        // ```
+        // fn foo(i32, &'static str) {}
+        // foo((), (), ());
+        // ```
+        // what should be suggested is
+        // ```
+        // foo(/* i32 */, /* &str */);
+        // ```
+        // which includes the replacement of the first two `()` for the correct type, and the
+        // removal of the last `()`.
+
+        let mut prev = -1;
+        for (expected_idx, provided_idx) in self.matched_inputs.iter_enumerated() {
+            // We want to point not at the *current* argument expression index, but rather at the
+            // index position where it *should have been*, which is *after* the previous one.
+            if let Some(provided_idx) = provided_idx {
+                prev = provided_idx.index() as i64;
+                continue;
+            }
+            let idx = ProvidedIdx::from_usize((prev + 1) as usize);
+            if let Some((_, arg_span)) = self.provided_arg_tys.get(idx) {
+                prev += 1;
+                // There is a type that was *not* found anywhere, so it isn't a move, but a
+                // replacement and we look at what type it should have been. This will allow us
+                // To suggest a multipart suggestion when encountering `foo(1, "")` where the def
+                // was `fn foo(())`.
+                let (_, expected_ty) = self.formal_and_expected_inputs[expected_idx];
+                suggestions.push((*arg_span, self.ty_to_snippet(expected_ty, expected_idx)));
+            }
+        }
+    }
+
+    fn format_suggestion_text(
+        err: &mut Diag<'_>,
+        suggestions: Vec<(Span, String)>,
+        suggestion_text: SuggestionText,
+    ) -> Option<String> {
+        let suggestion_text = match suggestion_text {
+            SuggestionText::None => None,
+            SuggestionText::Provide(plural) => {
+                Some(format!("provide the argument{}", if plural { "s" } else { "" }))
+            }
+            SuggestionText::Remove(plural) => {
+                err.multipart_suggestion_verbose(
+                    format!("remove the extra argument{}", if plural { "s" } else { "" }),
+                    suggestions,
+                    Applicability::HasPlaceholders,
+                );
+                None
+            }
+            SuggestionText::Swap => Some("swap these arguments".to_string()),
+            SuggestionText::Reorder => Some("reorder these arguments".to_string()),
+            SuggestionText::DidYouMean => Some("did you mean".to_string()),
+        };
+        suggestion_text
+    }
+
+    fn arguments_formatting(&self, suggestion_span: Span) -> ArgumentsFormatting {
+        let source_map = self.sess().source_map();
+        let mut provided_inputs = self.matched_inputs.iter().filter_map(|a| *a);
+        if let Some(brace_indent) = source_map.indentation_before(suggestion_span)
+            && let Some(first_idx) = provided_inputs.by_ref().next()
+            && let Some(last_idx) = provided_inputs.by_ref().next()
+            && let (_, first_span) = self.provided_arg_tys[first_idx]
+            && let (_, last_span) = self.provided_arg_tys[last_idx]
+            && source_map.is_multiline(first_span.to(last_span))
+            && let Some(fallback_indent) = source_map.indentation_before(first_span)
+        {
+            ArgumentsFormatting::Multiline { fallback_indent, brace_indent }
+        } else {
+            ArgumentsFormatting::SingleLine
+        }
+    }
+
+    fn suggestion_code(&self) -> (Span, String) {
+        let source_map = self.sess().source_map();
+        let suggestion_span = if let Some(args_span) =
+            self.call_metadata.error_span.trim_start(self.call_metadata.full_call_span)
+        {
+            // Span of the braces, e.g. `(a, b, c)`.
+            args_span
+        } else {
+            // The arg span of a function call that wasn't even given braces
+            // like what might happen with delegation reuse.
+            // e.g. `reuse HasSelf::method;` should suggest `reuse HasSelf::method($args);`.
+            self.call_metadata.full_call_span.shrink_to_hi()
+        };
+
+        let arguments_formatting = self.arguments_formatting(suggestion_span);
+
+        let mut suggestion = "(".to_owned();
+        let mut needs_comma = false;
+        for (expected_idx, provided_idx) in self.matched_inputs.iter_enumerated() {
+            if needs_comma {
+                suggestion += ",";
+            }
+            match &arguments_formatting {
+                ArgumentsFormatting::SingleLine if needs_comma => suggestion += " ",
+                ArgumentsFormatting::SingleLine => {}
+                ArgumentsFormatting::Multiline { .. } => suggestion += "\n",
+            }
+            needs_comma = true;
+            let (suggestion_span, suggestion_text) = if let Some(provided_idx) = provided_idx
+                && let (_, provided_span) = self.provided_arg_tys[*provided_idx]
+                && let Ok(arg_text) = source_map.span_to_snippet(provided_span)
+            {
+                (Some(provided_span), arg_text)
+            } else {
+                // Propose a placeholder of the correct type
+                let (_, expected_ty) = self.formal_and_expected_inputs[expected_idx];
+                (None, self.ty_to_snippet(expected_ty, expected_idx))
+            };
+            if let ArgumentsFormatting::Multiline { fallback_indent, .. } = &arguments_formatting {
+                let indent = suggestion_span
+                    .and_then(|span| source_map.indentation_before(span))
+                    .unwrap_or_else(|| fallback_indent.clone());
+                suggestion += &indent;
+            }
+            suggestion += &suggestion_text;
+        }
+        if let ArgumentsFormatting::Multiline { brace_indent, .. } = arguments_formatting {
+            suggestion += ",\n";
+            suggestion += &brace_indent;
+        }
+        suggestion += ")";
+
+        (suggestion_span, suggestion)
+    }
+}
+
+struct ArgMatchingCtxt<'a, 'b, 'tcx> {
+    args_ctxt: ArgsCtxt<'a, 'b, 'tcx>,
+    provided_arg_tys: IndexVec<ProvidedIdx, (Ty<'tcx>, Span)>,
+}
+
+impl<'a, 'b, 'tcx> Deref for ArgMatchingCtxt<'a, 'b, 'tcx> {
+    type Target = ArgsCtxt<'a, 'b, 'tcx>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.args_ctxt
+    }
+}
+
+impl<'a, 'b, 'tcx> ArgMatchingCtxt<'a, 'b, 'tcx> {
+    fn new(
+        arg: &'a FnCtxt<'b, 'tcx>,
+        compatibility_diagonal: IndexVec<ProvidedIdx, Compatibility<'tcx>>,
+        formal_and_expected_inputs: IndexVec<ExpectedIdx, (Ty<'tcx>, Ty<'tcx>)>,
+        provided_args: IndexVec<ProvidedIdx, &'tcx Expr<'tcx>>,
+        c_variadic: bool,
+        err_code: ErrCode,
+        fn_def_id: Option<DefId>,
+        call_span: Span,
+        call_expr: &'tcx Expr<'tcx>,
+        tuple_arguments: TupleArgumentsFlag,
+    ) -> Self {
+        let args_ctxt = ArgsCtxt::new(
+            arg,
+            compatibility_diagonal,
+            formal_and_expected_inputs,
+            provided_args,
+            c_variadic,
+            err_code,
+            fn_def_id,
+            call_span,
+            call_expr,
+            tuple_arguments,
+        );
+        let provided_arg_tys = args_ctxt.provided_arg_tys();
+
+        ArgMatchingCtxt { args_ctxt, provided_arg_tys }
+    }
+
+    fn suggest_confusable(&self, err: &mut Diag<'_>) {
+        let Some(call_name) = self.call_metadata.call_ident else {
+            return;
+        };
+        let Some(callee_ty) = self.callee_ty else {
+            return;
+        };
+        let input_types: Vec<Ty<'_>> = self.provided_arg_tys.iter().map(|(ty, _)| *ty).collect();
+
+        // Check for other methods in the following order
+        //  - methods marked as `rustc_confusables` with the provided arguments
+        //  - methods with the same argument type/count and short levenshtein distance
+        //  - methods marked as `rustc_confusables` (done)
+        //  - methods with short levenshtein distance
+
+        // Look for commonly confusable method names considering arguments.
+        if let Some(_name) = self.confusable_method_name(
+            err,
+            callee_ty.peel_refs(),
+            call_name,
+            Some(input_types.clone()),
+        ) {
+            return;
+        }
+        // Look for method names with short levenshtein distance, considering arguments.
+        if let Some((assoc, fn_sig)) = self.similar_assoc(call_name)
+            && fn_sig.inputs()[1..]
+                .iter()
+                .zip(input_types.iter())
+                .all(|(expected, found)| self.may_coerce(*expected, *found))
+            && fn_sig.inputs()[1..].len() == input_types.len()
+        {
+            let assoc_name = assoc.name();
+            err.span_suggestion_verbose(
+                call_name.span,
+                format!("you might have meant to use `{}`", assoc_name),
+                assoc_name,
+                Applicability::MaybeIncorrect,
+            );
+            return;
+        }
+    }
+
+    /// A "softer" version of the `demand_compatible`, which checks types without persisting them,
+    /// and treats error types differently
+    /// This will allow us to "probe" for other argument orders that would likely have been correct
+    fn check_compatible(
+        &self,
+        provided_idx: ProvidedIdx,
+        expected_idx: ExpectedIdx,
+    ) -> Compatibility<'tcx> {
+        if provided_idx.as_usize() == expected_idx.as_usize() {
+            return self.compatibility_diagonal[provided_idx].clone();
+        }
+
+        let (formal_input_ty, expected_input_ty) = self.formal_and_expected_inputs[expected_idx];
+        // If either is an error type, we defy the usual convention and consider them to *not* be
+        // coercible. This prevents our error message heuristic from trying to pass errors into
+        // every argument.
+        if (formal_input_ty, expected_input_ty).references_error() {
+            return Compatibility::Incompatible(None);
+        }
+
+        let (arg_ty, arg_span) = self.provided_arg_tys[provided_idx];
+
+        let expectation = Expectation::rvalue_hint(self.fn_ctxt, expected_input_ty);
+        let coerced_ty = expectation.only_has_type(self.fn_ctxt).unwrap_or(formal_input_ty);
+        let can_coerce = self.may_coerce(arg_ty, coerced_ty);
+        if !can_coerce {
+            return Compatibility::Incompatible(Some(ty::error::TypeError::Sorts(
+                ty::error::ExpectedFound::new(coerced_ty, arg_ty),
+            )));
+        }
+
+        // Using probe here, since we don't want this subtyping to affect inference.
+        let subtyping_error = self.probe(|_| {
+            self.at(&self.misc(arg_span), self.param_env)
+                .sup(DefineOpaqueTypes::Yes, formal_input_ty, coerced_ty)
+                .err()
+        });
+
+        // Same as above: if either the coerce type or the checked type is an error type,
+        // consider them *not* compatible.
+        let references_error = (coerced_ty, arg_ty).references_error();
+        match (references_error, subtyping_error) {
+            (false, None) => Compatibility::Compatible,
+            (_, subtyping_error) => Compatibility::Incompatible(subtyping_error),
+        }
+    }
+
+    fn remove_idx_is_perfect(&self, idx: usize) -> bool {
+        let removed_arg_tys = self
+            .provided_arg_tys
+            .iter()
+            .enumerate()
+            .filter_map(|(j, arg)| if idx == j { None } else { Some(arg) })
+            .collect::<IndexVec<ProvidedIdx, _>>();
+        std::iter::zip(self.formal_and_expected_inputs.iter(), removed_arg_tys.iter()).all(
+            |((expected_ty, _), (provided_ty, _))| {
+                !provided_ty.references_error() && self.may_coerce(*provided_ty, *expected_ty)
+            },
+        )
+    }
+}
+
+struct ArgsCtxt<'a, 'b, 'tcx> {
+    call_ctxt: CallCtxt<'a, 'b, 'tcx>,
+    call_metadata: CallMetadata,
+    args_span: Span,
+}
+
+impl<'a, 'b, 'tcx> Deref for ArgsCtxt<'a, 'b, 'tcx> {
+    type Target = CallCtxt<'a, 'b, 'tcx>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.call_ctxt
+    }
+}
+
+impl<'a, 'b, 'tcx> ArgsCtxt<'a, 'b, 'tcx> {
+    fn new(
+        arg: &'a FnCtxt<'b, 'tcx>,
+        compatibility_diagonal: IndexVec<ProvidedIdx, Compatibility<'tcx>>,
+        formal_and_expected_inputs: IndexVec<ExpectedIdx, (Ty<'tcx>, Ty<'tcx>)>,
+        provided_args: IndexVec<ProvidedIdx, &'tcx Expr<'tcx>>,
+        c_variadic: bool,
+        err_code: ErrCode,
+        fn_def_id: Option<DefId>,
+        call_span: Span,
+        call_expr: &'tcx Expr<'tcx>,
+        tuple_arguments: TupleArgumentsFlag,
+    ) -> Self {
+        let call_ctxt: CallCtxt<'_, '_, '_> = CallCtxt::new(
+            arg,
+            compatibility_diagonal,
+            formal_and_expected_inputs,
+            provided_args,
+            c_variadic,
+            err_code,
+            fn_def_id,
+            call_span,
+            call_expr,
+            tuple_arguments,
+        );
+
+        let call_metadata = call_ctxt.call_metadata();
+        let args_span = call_metadata
+            .error_span
+            .trim_start(call_metadata.full_call_span)
+            .unwrap_or(call_metadata.error_span);
+
+        ArgsCtxt { args_span, call_metadata, call_ctxt }
+    }
+
+    /// Get the argument span in the context of the call span so that
+    /// suggestions and labels are (more) correct when an arg is a
+    /// macro invocation.
+    fn normalize_span(&self, span: Span) -> Span {
+        let normalized_span =
+            span.find_ancestor_inside_same_ctxt(self.call_metadata.error_span).unwrap_or(span);
+        // Sometimes macros mess up the spans, so do not normalize the
+        // arg span to equal the error span, because that's less useful
+        // than pointing out the arg expr in the wrong context.
+        if normalized_span.source_equal(self.call_metadata.error_span) {
+            span
+        } else {
+            normalized_span
+        }
+    }
+
+    /// Computes the provided types and spans.
+    fn provided_arg_tys(&self) -> IndexVec<ProvidedIdx, (Ty<'tcx>, Span)> {
+        self.call_ctxt
+            .provided_args
+            .iter()
+            .map(|expr| {
+                let ty = self
+                    .call_ctxt
+                    .fn_ctxt
+                    .typeck_results
+                    .borrow()
+                    .expr_ty_adjusted_opt(*expr)
+                    .unwrap_or_else(|| Ty::new_misc_error(self.call_ctxt.fn_ctxt.tcx));
+                (
+                    self.call_ctxt.fn_ctxt.resolve_vars_if_possible(ty),
+                    self.normalize_span(expr.span),
+                )
+            })
+            .collect()
+    }
+
+    // Obtain another method on `Self` that have similar name.
+    fn similar_assoc(&self, call_name: Ident) -> Option<(ty::AssocItem, ty::FnSig<'tcx>)> {
+        if let Some(callee_ty) = self.call_ctxt.callee_ty
+            && let Ok(Some(assoc)) = self.call_ctxt.fn_ctxt.probe_op(
+                call_name.span,
+                MethodCall,
+                Some(call_name),
+                None,
+                IsSuggestion(true),
+                callee_ty.peel_refs(),
+                self.call_ctxt.callee_expr.unwrap().hir_id,
+                TraitsInScope,
+                |mut ctxt| ctxt.probe_for_similar_candidate(),
+            )
+            && assoc.is_method()
+        {
+            let args =
+                self.call_ctxt.fn_ctxt.infcx.fresh_args_for_item(call_name.span, assoc.def_id);
+            let fn_sig = self
+                .call_ctxt
+                .fn_ctxt
+                .tcx
+                .fn_sig(assoc.def_id)
+                .instantiate(self.call_ctxt.fn_ctxt.tcx, args);
+
+            self.call_ctxt.fn_ctxt.instantiate_binder_with_fresh_vars(
+                call_name.span,
+                BoundRegionConversionTime::FnCall,
+                fn_sig,
+            );
+        }
+        None
+    }
+
+    fn call_is_in_macro(&self) -> bool {
+        self.call_metadata.full_call_span.in_external_macro(self.sess().source_map())
+    }
+}
+
+struct CallMetadata {
+    error_span: Span,
+    call_ident: Option<Ident>,
+    full_call_span: Span,
+    call_name: &'static str,
+    is_method: bool,
+}
+
+struct CallCtxt<'a, 'b, 'tcx> {
+    fn_ctxt: &'a FnCtxt<'b, 'tcx>,
+    compatibility_diagonal: IndexVec<ProvidedIdx, Compatibility<'tcx>>,
+    formal_and_expected_inputs: IndexVec<ExpectedIdx, (Ty<'tcx>, Ty<'tcx>)>,
+    provided_args: IndexVec<ProvidedIdx, &'tcx hir::Expr<'tcx>>,
+    c_variadic: bool,
+    err_code: ErrCode,
+    fn_def_id: Option<DefId>,
+    call_span: Span,
+    call_expr: &'tcx hir::Expr<'tcx>,
+    tuple_arguments: TupleArgumentsFlag,
+    callee_expr: Option<&'tcx Expr<'tcx>>,
+    callee_ty: Option<Ty<'tcx>>,
+}
+
+impl<'a, 'b, 'tcx> Deref for CallCtxt<'a, 'b, 'tcx> {
+    type Target = &'a FnCtxt<'b, 'tcx>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.fn_ctxt
+    }
+}
+
+impl<'a, 'b, 'tcx> CallCtxt<'a, 'b, 'tcx> {
+    fn new(
+        fn_ctxt: &'a FnCtxt<'b, 'tcx>,
+        compatibility_diagonal: IndexVec<ProvidedIdx, Compatibility<'tcx>>,
+        formal_and_expected_inputs: IndexVec<ExpectedIdx, (Ty<'tcx>, Ty<'tcx>)>,
+        provided_args: IndexVec<ProvidedIdx, &'tcx hir::Expr<'tcx>>,
+        c_variadic: bool,
+        err_code: ErrCode,
+        fn_def_id: Option<DefId>,
+        call_span: Span,
+        call_expr: &'tcx hir::Expr<'tcx>,
+        tuple_arguments: TupleArgumentsFlag,
+    ) -> CallCtxt<'a, 'b, 'tcx> {
+        let callee_expr = match &call_expr.peel_blocks().kind {
+            hir::ExprKind::Call(callee, _) => Some(*callee),
+            hir::ExprKind::MethodCall(_, receiver, ..) => {
+                if let Some((DefKind::AssocFn, def_id)) =
+                    fn_ctxt.typeck_results.borrow().type_dependent_def(call_expr.hir_id)
+                    && let Some(assoc) = fn_ctxt.tcx.opt_associated_item(def_id)
+                    && assoc.is_method()
+                {
+                    Some(*receiver)
+                } else {
+                    None
+                }
+            }
+            _ => None,
+        };
+
+        let callee_ty = callee_expr.and_then(|callee_expr| {
+            fn_ctxt.typeck_results.borrow().expr_ty_adjusted_opt(callee_expr)
+        });
+
+        CallCtxt {
+            fn_ctxt,
+            compatibility_diagonal,
+            formal_and_expected_inputs,
+            provided_args,
+            c_variadic,
+            err_code,
+            fn_def_id,
+            call_span,
+            call_expr,
+            tuple_arguments,
+            callee_expr,
+            callee_ty,
+        }
+    }
+
+    fn call_metadata(&self) -> CallMetadata {
+        match &self.call_expr.kind {
+            hir::ExprKind::Call(
+                hir::Expr { hir_id, span, kind: hir::ExprKind::Path(qpath), .. },
+                _,
+            ) => {
+                if let Res::Def(DefKind::Ctor(of, _), _) =
+                    self.typeck_results.borrow().qpath_res(qpath, *hir_id)
+                {
+                    let name = match of {
+                        CtorOf::Struct => "struct",
+                        CtorOf::Variant => "enum variant",
+                    };
+                    CallMetadata {
+                        error_span: self.call_span,
+                        call_ident: None,
+                        full_call_span: *span,
+                        call_name: name,
+                        is_method: false,
+                    }
+                } else {
+                    CallMetadata {
+                        error_span: self.call_span,
+                        call_ident: None,
+                        full_call_span: *span,
+                        call_name: "function",
+                        is_method: false,
+                    }
+                }
+            }
+            hir::ExprKind::Call(hir::Expr { span, .. }, _) => CallMetadata {
+                error_span: self.call_span,
+                call_ident: None,
+                full_call_span: *span,
+                call_name: "function",
+                is_method: false,
+            },
+            hir::ExprKind::MethodCall(path_segment, _, _, span) => {
+                let ident_span = path_segment.ident.span;
+                let ident_span = if let Some(args) = path_segment.args {
+                    ident_span.with_hi(args.span_ext.hi())
+                } else {
+                    ident_span
+                };
+                CallMetadata {
+                    error_span: *span,
+                    call_ident: Some(path_segment.ident),
+                    full_call_span: ident_span,
+                    call_name: "method",
+                    is_method: true,
+                }
+            }
+            k => span_bug!(self.call_span, "checking argument types on a non-call: `{:?}`", k),
+        }
+    }
+
+    fn mk_trace(
+        &self,
+        span: Span,
+        (formal_ty, expected_ty): (Ty<'tcx>, Ty<'tcx>),
+        provided_ty: Ty<'tcx>,
+    ) -> TypeTrace<'tcx> {
+        let mismatched_ty = if expected_ty == provided_ty {
+            // If expected == provided, then we must have failed to sup
+            // the formal type. Avoid printing out "expected Ty, found Ty"
+            // in that case.
+            formal_ty
+        } else {
+            expected_ty
+        };
+        TypeTrace::types(&self.misc(span), mismatched_ty, provided_ty)
+    }
+
+    fn ty_to_snippet(&self, ty: Ty<'tcx>, expected_idx: ExpectedIdx) -> String {
+        if ty.is_unit() {
+            "()".to_string()
+        } else if ty.is_suggestable(self.tcx, false) {
+            format!("/* {ty} */")
+        } else if let Some(fn_def_id) = self.fn_def_id
+            && self.tcx.def_kind(fn_def_id).is_fn_like()
+            && let self_implicit =
+                matches!(self.call_expr.kind, hir::ExprKind::MethodCall(..)) as usize
+            && let Some(Some(arg)) =
+                self.tcx.fn_arg_idents(fn_def_id).get(expected_idx.as_usize() + self_implicit)
+            && arg.name != kw::SelfLower
+        {
+            format!("/* {} */", arg.name)
+        } else {
+            "/* value */".to_string()
+        }
+    }
+
+    fn first_incompatible_error(&self) -> Option<(ProvidedIdx, TypeError<'tcx>)> {
+        self.compatibility_diagonal.iter_enumerated().find_map(|(i, c)| {
+            if let Compatibility::Incompatible(Some(terr)) = c { Some((i, *terr)) } else { None }
+        })
+    }
+}
+
+enum SuggestionText {
+    None,
+    Provide(bool),
+    Remove(bool),
+    Swap,
+    Reorder,
+    DidYouMean,
+}
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
index 1998a1884b7..a5c6a7f34ef 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
@@ -3021,6 +3021,28 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         )
                     {
                         let deref_kind = if checked_ty.is_box() {
+                            // detect Box::new(..)
+                            if let ExprKind::Call(box_new, [_]) = expr.kind
+                                && let ExprKind::Path(qpath) = &box_new.kind
+                                && let Res::Def(DefKind::AssocFn, fn_id) =
+                                    self.typeck_results.borrow().qpath_res(qpath, box_new.hir_id)
+                                && let Some(impl_id) = self.tcx.inherent_impl_of_assoc(fn_id)
+                                && self.tcx.type_of(impl_id).skip_binder().is_box()
+                                && self.tcx.item_name(fn_id) == sym::new
+                            {
+                                let l_paren = self.tcx.sess.source_map().next_point(box_new.span);
+                                let r_paren = self.tcx.sess.source_map().end_point(expr.span);
+                                return Some((
+                                    vec![
+                                        (box_new.span.to(l_paren), String::new()),
+                                        (r_paren, String::new()),
+                                    ],
+                                    "consider removing the Box".to_string(),
+                                    Applicability::MachineApplicable,
+                                    false,
+                                    false,
+                                ));
+                            }
                             "unboxing the value"
                         } else if checked_ty.is_ref() {
                             "dereferencing the borrow"
diff --git a/compiler/rustc_infer/src/traits/engine.rs b/compiler/rustc_infer/src/traits/engine.rs
index 9a66bd0574c..4a252719694 100644
--- a/compiler/rustc_infer/src/traits/engine.rs
+++ b/compiler/rustc_infer/src/traits/engine.rs
@@ -72,12 +72,27 @@ pub trait TraitEngine<'tcx, E: 'tcx>: 'tcx {
             self.register_predicate_obligation(infcx, obligation);
         }
     }
-
+    /// Go over the list of pending obligations and try to evaluate them.
+    ///
+    /// For each result:
+    /// Ok: remove the obligation from the list
+    /// Ambiguous: leave the obligation in the list to be evaluated later
+    /// Err: remove the obligation from the list and return an error
+    ///
+    /// Returns a list of errors from obligations that evaluated to Err.
     #[must_use]
     fn select_where_possible(&mut self, infcx: &InferCtxt<'tcx>) -> Vec<E>;
 
     fn collect_remaining_errors(&mut self, infcx: &InferCtxt<'tcx>) -> Vec<E>;
 
+    /// Evaluate all pending obligations, return error if they can't be evaluated.
+    ///
+    /// For each result:
+    /// Ok: remove the obligation from the list
+    /// Ambiguous: remove the obligation from the list and return an error
+    /// Err: remove the obligation from the list and return an error
+    ///
+    /// Returns a list of errors from obligations that evaluated to Ambiguous or Err.
     #[must_use]
     fn select_all_or_error(&mut self, infcx: &InferCtxt<'tcx>) -> Vec<E> {
         let errors = self.select_where_possible(infcx);
diff --git a/compiler/rustc_lint/src/unused.rs b/compiler/rustc_lint/src/unused.rs
index 22d89d24612..edbbfba4f34 100644
--- a/compiler/rustc_lint/src/unused.rs
+++ b/compiler/rustc_lint/src/unused.rs
@@ -843,6 +843,10 @@ trait UnusedDelimLint {
                 && !snip.ends_with(' ')
             {
                 " "
+            } else if let Ok(snip) = sm.span_to_prev_source(value_span)
+                && snip.ends_with(|c: char| c.is_alphanumeric())
+            {
+                " "
             } else {
                 ""
             };
@@ -852,6 +856,10 @@ trait UnusedDelimLint {
                 && !snip.starts_with(' ')
             {
                 " "
+            } else if let Ok(snip) = sm.span_to_prev_source(value_span)
+                && snip.starts_with(|c: char| c.is_alphanumeric())
+            {
+                " "
             } else {
                 ""
             };
diff --git a/compiler/rustc_llvm/build.rs b/compiler/rustc_llvm/build.rs
index 9d21d0d22e3..2cfda7a5fb4 100644
--- a/compiler/rustc_llvm/build.rs
+++ b/compiler/rustc_llvm/build.rs
@@ -16,7 +16,6 @@ const OPTIONAL_COMPONENTS: &[&str] = &[
     "mips",
     "powerpc",
     "systemz",
-    "jsbackend",
     "webassembly",
     "msp430",
     "sparc",
diff --git a/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
index 3bb1533c2fe..ab5d5c03e81 100644
--- a/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
@@ -79,122 +79,6 @@ extern "C" void LLVMRustTimeTraceProfilerFinish(const char *FileName) {
   timeTraceProfilerCleanup();
 }
 
-#ifdef LLVM_COMPONENT_X86
-#define SUBTARGET_X86 SUBTARGET(X86)
-#else
-#define SUBTARGET_X86
-#endif
-
-#ifdef LLVM_COMPONENT_ARM
-#define SUBTARGET_ARM SUBTARGET(ARM)
-#else
-#define SUBTARGET_ARM
-#endif
-
-#ifdef LLVM_COMPONENT_AARCH64
-#define SUBTARGET_AARCH64 SUBTARGET(AArch64)
-#else
-#define SUBTARGET_AARCH64
-#endif
-
-#ifdef LLVM_COMPONENT_AVR
-#define SUBTARGET_AVR SUBTARGET(AVR)
-#else
-#define SUBTARGET_AVR
-#endif
-
-#ifdef LLVM_COMPONENT_M68k
-#define SUBTARGET_M68K SUBTARGET(M68k)
-#else
-#define SUBTARGET_M68K
-#endif
-
-#ifdef LLVM_COMPONENT_CSKY
-#define SUBTARGET_CSKY SUBTARGET(CSKY)
-#else
-#define SUBTARGET_CSKY
-#endif
-
-#ifdef LLVM_COMPONENT_MIPS
-#define SUBTARGET_MIPS SUBTARGET(Mips)
-#else
-#define SUBTARGET_MIPS
-#endif
-
-#ifdef LLVM_COMPONENT_POWERPC
-#define SUBTARGET_PPC SUBTARGET(PPC)
-#else
-#define SUBTARGET_PPC
-#endif
-
-#ifdef LLVM_COMPONENT_SYSTEMZ
-#define SUBTARGET_SYSTEMZ SUBTARGET(SystemZ)
-#else
-#define SUBTARGET_SYSTEMZ
-#endif
-
-#ifdef LLVM_COMPONENT_MSP430
-#define SUBTARGET_MSP430 SUBTARGET(MSP430)
-#else
-#define SUBTARGET_MSP430
-#endif
-
-#ifdef LLVM_COMPONENT_RISCV
-#define SUBTARGET_RISCV SUBTARGET(RISCV)
-#else
-#define SUBTARGET_RISCV
-#endif
-
-#ifdef LLVM_COMPONENT_SPARC
-#define SUBTARGET_SPARC SUBTARGET(Sparc)
-#else
-#define SUBTARGET_SPARC
-#endif
-
-#ifdef LLVM_COMPONENT_XTENSA
-#define SUBTARGET_XTENSA SUBTARGET(XTENSA)
-#else
-#define SUBTARGET_XTENSA
-#endif
-
-#ifdef LLVM_COMPONENT_HEXAGON
-#define SUBTARGET_HEXAGON SUBTARGET(Hexagon)
-#else
-#define SUBTARGET_HEXAGON
-#endif
-
-#ifdef LLVM_COMPONENT_LOONGARCH
-#define SUBTARGET_LOONGARCH SUBTARGET(LoongArch)
-#else
-#define SUBTARGET_LOONGARCH
-#endif
-
-#define GEN_SUBTARGETS                                                         \
-  SUBTARGET_X86                                                                \
-  SUBTARGET_ARM                                                                \
-  SUBTARGET_AARCH64                                                            \
-  SUBTARGET_AVR                                                                \
-  SUBTARGET_M68K                                                               \
-  SUBTARGET_CSKY                                                               \
-  SUBTARGET_MIPS                                                               \
-  SUBTARGET_PPC                                                                \
-  SUBTARGET_SYSTEMZ                                                            \
-  SUBTARGET_MSP430                                                             \
-  SUBTARGET_SPARC                                                              \
-  SUBTARGET_HEXAGON                                                            \
-  SUBTARGET_XTENSA                                                             \
-  SUBTARGET_RISCV                                                              \
-  SUBTARGET_LOONGARCH
-
-#define SUBTARGET(x)                                                           \
-  namespace llvm {                                                             \
-  extern const SubtargetFeatureKV x##FeatureKV[];                              \
-  extern const SubtargetFeatureKV x##SubTypeKV[];                              \
-  }
-
-GEN_SUBTARGETS
-#undef SUBTARGET
-
 // This struct and various functions are sort of a hack right now, but the
 // problem is that we've got in-memory LLVM modules after we generate and
 // optimize all codegen-units for one compilation in rustc. To be compatible
@@ -340,14 +224,6 @@ static FloatABI::ABIType fromRust(LLVMRustFloatABI RustFloatAbi) {
   report_fatal_error("Bad FloatABI.");
 }
 
-/// getLongestEntryLength - Return the length of the longest entry in the table.
-template <typename KV> static size_t getLongestEntryLength(ArrayRef<KV> Table) {
-  size_t MaxLen = 0;
-  for (auto &I : Table)
-    MaxLen = std::max(MaxLen, std::strlen(I.Key));
-  return MaxLen;
-}
-
 extern "C" void LLVMRustPrintTargetCPUs(LLVMTargetMachineRef TM,
                                         RustStringRef OutStr) {
   ArrayRef<SubtargetSubTypeKV> CPUTable =
@@ -468,7 +344,6 @@ extern "C" LLVMTargetMachineRef LLVMRustCreateTargetMachine(
   Options.EmitStackSizeSection = EmitStackSizeSection;
 
   if (ArgsCstrBuff != nullptr) {
-#if LLVM_VERSION_GE(20, 0)
     size_t buffer_offset = 0;
     assert(ArgsCstrBuff[ArgsCstrBuffLen - 1] == '\0');
     auto Arg0 = std::string(ArgsCstrBuff);
@@ -486,33 +361,6 @@ extern "C" LLVMTargetMachineRef LLVMRustCreateTargetMachine(
     OS.flush();
     Options.MCOptions.Argv0 = Arg0;
     Options.MCOptions.CommandlineArgs = CommandlineArgs;
-#else
-    size_t buffer_offset = 0;
-    assert(ArgsCstrBuff[ArgsCstrBuffLen - 1] == '\0');
-
-    const size_t arg0_len = std::strlen(ArgsCstrBuff);
-    char *arg0 = new char[arg0_len + 1];
-    memcpy(arg0, ArgsCstrBuff, arg0_len);
-    arg0[arg0_len] = '\0';
-    buffer_offset += arg0_len + 1;
-
-    const size_t num_cmd_arg_strings = std::count(
-        &ArgsCstrBuff[buffer_offset], &ArgsCstrBuff[ArgsCstrBuffLen], '\0');
-
-    std::string *cmd_arg_strings = new std::string[num_cmd_arg_strings];
-    for (size_t i = 0; i < num_cmd_arg_strings; ++i) {
-      assert(buffer_offset < ArgsCstrBuffLen);
-      const size_t len = std::strlen(ArgsCstrBuff + buffer_offset);
-      cmd_arg_strings[i] = std::string(&ArgsCstrBuff[buffer_offset], len);
-      buffer_offset += len + 1;
-    }
-
-    assert(buffer_offset == ArgsCstrBuffLen);
-
-    Options.MCOptions.Argv0 = arg0;
-    Options.MCOptions.CommandLineArgs =
-        llvm::ArrayRef<std::string>(cmd_arg_strings, num_cmd_arg_strings);
-#endif
   }
 
 #if LLVM_VERSION_GE(21, 0)
@@ -526,12 +374,6 @@ extern "C" LLVMTargetMachineRef LLVMRustCreateTargetMachine(
 }
 
 extern "C" void LLVMRustDisposeTargetMachine(LLVMTargetMachineRef TM) {
-#if LLVM_VERSION_LT(20, 0)
-  MCTargetOptions &MCOptions = unwrap(TM)->Options.MCOptions;
-  delete[] MCOptions.Argv0;
-  delete[] MCOptions.CommandLineArgs.data();
-#endif
-
   delete unwrap(TM);
 }
 
@@ -812,14 +654,9 @@ extern "C" LLVMRustResult LLVMRustOptimize(
   // the PassBuilder does not create a pipeline.
   std::vector<std::function<void(ModulePassManager &, OptimizationLevel)>>
       PipelineStartEPCallbacks;
-#if LLVM_VERSION_GE(20, 0)
   std::vector<std::function<void(ModulePassManager &, OptimizationLevel,
                                  ThinOrFullLTOPhase)>>
       OptimizerLastEPCallbacks;
-#else
-  std::vector<std::function<void(ModulePassManager &, OptimizationLevel)>>
-      OptimizerLastEPCallbacks;
-#endif
 
   if (!IsLinkerPluginLTO && SanitizerOptions && SanitizerOptions->SanitizeCFI &&
       !NoPrepopulatePasses) {
@@ -871,12 +708,8 @@ extern "C" LLVMRustResult LLVMRustOptimize(
           SanitizerOptions->SanitizeDataFlowABIList +
               SanitizerOptions->SanitizeDataFlowABIListLen);
       OptimizerLastEPCallbacks.push_back(
-#if LLVM_VERSION_GE(20, 0)
           [ABIListFiles](ModulePassManager &MPM, OptimizationLevel Level,
                          ThinOrFullLTOPhase phase) {
-#else
-          [ABIListFiles](ModulePassManager &MPM, OptimizationLevel Level) {
-#endif
             MPM.addPass(DataFlowSanitizerPass(ABIListFiles));
           });
     }
@@ -887,66 +720,48 @@ extern "C" LLVMRustResult LLVMRustOptimize(
           SanitizerOptions->SanitizeMemoryRecover,
           /*CompileKernel=*/false,
           /*EagerChecks=*/true);
-      OptimizerLastEPCallbacks.push_back(
-#if LLVM_VERSION_GE(20, 0)
-          [Options](ModulePassManager &MPM, OptimizationLevel Level,
-                    ThinOrFullLTOPhase phase) {
-#else
-          [Options](ModulePassManager &MPM, OptimizationLevel Level) {
-#endif
-            MPM.addPass(MemorySanitizerPass(Options));
-          });
+      OptimizerLastEPCallbacks.push_back([Options](ModulePassManager &MPM,
+                                                   OptimizationLevel Level,
+                                                   ThinOrFullLTOPhase phase) {
+        MPM.addPass(MemorySanitizerPass(Options));
+      });
     }
 
     if (SanitizerOptions->SanitizeThread) {
-      OptimizerLastEPCallbacks.push_back(
-#if LLVM_VERSION_GE(20, 0)
-          [](ModulePassManager &MPM, OptimizationLevel Level,
-             ThinOrFullLTOPhase phase) {
-#else
-          [](ModulePassManager &MPM, OptimizationLevel Level) {
-#endif
-            MPM.addPass(ModuleThreadSanitizerPass());
-            MPM.addPass(
-                createModuleToFunctionPassAdaptor(ThreadSanitizerPass()));
-          });
+      OptimizerLastEPCallbacks.push_back([](ModulePassManager &MPM,
+                                            OptimizationLevel Level,
+                                            ThinOrFullLTOPhase phase) {
+        MPM.addPass(ModuleThreadSanitizerPass());
+        MPM.addPass(createModuleToFunctionPassAdaptor(ThreadSanitizerPass()));
+      });
     }
 
     if (SanitizerOptions->SanitizeAddress ||
         SanitizerOptions->SanitizeKernelAddress) {
-      OptimizerLastEPCallbacks.push_back(
-#if LLVM_VERSION_GE(20, 0)
-          [SanitizerOptions, TM](ModulePassManager &MPM,
-                                 OptimizationLevel Level,
-                                 ThinOrFullLTOPhase phase) {
-#else
-          [SanitizerOptions, TM](ModulePassManager &MPM,
-                                 OptimizationLevel Level) {
-#endif
-            auto CompileKernel = SanitizerOptions->SanitizeKernelAddress;
-            AddressSanitizerOptions opts = AddressSanitizerOptions{
-                CompileKernel,
-                SanitizerOptions->SanitizeAddressRecover ||
-                    SanitizerOptions->SanitizeKernelAddressRecover,
-                /*UseAfterScope=*/true,
-                AsanDetectStackUseAfterReturnMode::Runtime,
-            };
-            MPM.addPass(AddressSanitizerPass(
-                opts,
-                /*UseGlobalGC*/ true,
-                // UseOdrIndicator should be false on windows machines
-                // https://reviews.llvm.org/D137227
-                !TM->getTargetTriple().isOSWindows()));
-          });
+      OptimizerLastEPCallbacks.push_back([SanitizerOptions,
+                                          TM](ModulePassManager &MPM,
+                                              OptimizationLevel Level,
+                                              ThinOrFullLTOPhase phase) {
+        auto CompileKernel = SanitizerOptions->SanitizeKernelAddress;
+        AddressSanitizerOptions opts = AddressSanitizerOptions{
+            CompileKernel,
+            SanitizerOptions->SanitizeAddressRecover ||
+                SanitizerOptions->SanitizeKernelAddressRecover,
+            /*UseAfterScope=*/true,
+            AsanDetectStackUseAfterReturnMode::Runtime,
+        };
+        MPM.addPass(
+            AddressSanitizerPass(opts,
+                                 /*UseGlobalGC*/ true,
+                                 // UseOdrIndicator should be false on windows
+                                 // machines https://reviews.llvm.org/D137227
+                                 !TM->getTargetTriple().isOSWindows()));
+      });
     }
     if (SanitizerOptions->SanitizeHWAddress) {
       OptimizerLastEPCallbacks.push_back(
-#if LLVM_VERSION_GE(20, 0)
           [SanitizerOptions](ModulePassManager &MPM, OptimizationLevel Level,
                              ThinOrFullLTOPhase phase) {
-#else
-          [SanitizerOptions](ModulePassManager &MPM, OptimizationLevel Level) {
-#endif
             HWAddressSanitizerOptions opts(
                 /*CompileKernel=*/false,
                 SanitizerOptions->SanitizeHWAddressRecover,
@@ -1028,11 +843,7 @@ extern "C" LLVMRustResult LLVMRustOptimize(
     for (const auto &C : PipelineStartEPCallbacks)
       C(MPM, OptLevel);
     for (const auto &C : OptimizerLastEPCallbacks)
-#if LLVM_VERSION_GE(20, 0)
       C(MPM, OptLevel, ThinOrFullLTOPhase::None);
-#else
-      C(MPM, OptLevel);
-#endif
   }
 
   if (ExtraPassesLen) {
@@ -1309,11 +1120,7 @@ struct LLVMRustThinLTOData {
 
   // Not 100% sure what these are, but they impact what's internalized and
   // what's inlined across modules, I believe.
-#if LLVM_VERSION_GE(20, 0)
   FunctionImporter::ImportListsTy ImportLists;
-#else
-  DenseMap<StringRef, FunctionImporter::ImportMapTy> ImportLists;
-#endif
   DenseMap<StringRef, FunctionImporter::ExportSetTy> ExportLists;
   DenseMap<StringRef, GVSummaryMapTy> ModuleToDefinedGVSummaries;
   StringMap<std::map<GlobalValue::GUID, GlobalValue::LinkageTypes>> ResolvedODR;
@@ -1655,13 +1462,8 @@ extern "C" void LLVMRustComputeLTOCacheKey(RustStringRef KeyOut,
   const auto &ExportList = Data->ExportLists.lookup(ModId);
   const auto &ResolvedODR = Data->ResolvedODR.lookup(ModId);
   const auto &DefinedGlobals = Data->ModuleToDefinedGVSummaries.lookup(ModId);
-#if LLVM_VERSION_GE(20, 0)
   DenseSet<GlobalValue::GUID> CfiFunctionDefs;
   DenseSet<GlobalValue::GUID> CfiFunctionDecls;
-#else
-  std::set<GlobalValue::GUID> CfiFunctionDefs;
-  std::set<GlobalValue::GUID> CfiFunctionDecls;
-#endif
 
   // Based on the 'InProcessThinBackend' constructor in LLVM
 #if LLVM_VERSION_GE(21, 0)
@@ -1680,15 +1482,9 @@ extern "C" void LLVMRustComputeLTOCacheKey(RustStringRef KeyOut,
         GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(Name)));
 #endif
 
-#if LLVM_VERSION_GE(20, 0)
   Key = llvm::computeLTOCacheKey(conf, Data->Index, ModId, ImportList,
                                  ExportList, ResolvedODR, DefinedGlobals,
                                  CfiFunctionDefs, CfiFunctionDecls);
-#else
-  llvm::computeLTOCacheKey(Key, conf, Data->Index, ModId, ImportList,
-                           ExportList, ResolvedODR, DefinedGlobals,
-                           CfiFunctionDefs, CfiFunctionDecls);
-#endif
 
   auto OS = RawRustStringOstream(KeyOut);
   OS << Key.str();
diff --git a/compiler/rustc_llvm/src/lib.rs b/compiler/rustc_llvm/src/lib.rs
index ed5edeef161..14e94121d1c 100644
--- a/compiler/rustc_llvm/src/lib.rs
+++ b/compiler/rustc_llvm/src/lib.rs
@@ -180,12 +180,6 @@ pub fn initialize_available_targets() {
         LLVMInitializeSystemZAsmParser
     );
     init_target!(
-        llvm_component = "jsbackend",
-        LLVMInitializeJSBackendTargetInfo,
-        LLVMInitializeJSBackendTarget,
-        LLVMInitializeJSBackendTargetMC
-    );
-    init_target!(
         llvm_component = "msp430",
         LLVMInitializeMSP430TargetInfo,
         LLVMInitializeMSP430Target,
diff --git a/compiler/rustc_middle/messages.ftl b/compiler/rustc_middle/messages.ftl
index 69adb2fe391..279ab9a9d8f 100644
--- a/compiler/rustc_middle/messages.ftl
+++ b/compiler/rustc_middle/messages.ftl
@@ -84,7 +84,7 @@ middle_failed_writing_file =
 # Note: We only mention patterns here since the error can only occur with references, and those
 # are forbidden in const generics.
 middle_invalid_const_in_valtree = constant {$global_const_id} cannot be used as pattern
-    .note = constants that reference mutable or external memory cannot be used as pattern
+    .note = constants that reference mutable or external memory cannot be used as patterns
 
 middle_layout_cycle =
     a cycle occurred during layout computation
diff --git a/compiler/rustc_middle/src/middle/codegen_fn_attrs.rs b/compiler/rustc_middle/src/middle/codegen_fn_attrs.rs
index 8b4503073b0..f0d96c6ac89 100644
--- a/compiler/rustc_middle/src/middle/codegen_fn_attrs.rs
+++ b/compiler/rustc_middle/src/middle/codegen_fn_attrs.rs
@@ -69,6 +69,10 @@ pub struct CodegenFnAttrs {
     /// The `#[patchable_function_entry(...)]` attribute. Indicates how many nops should be around
     /// the function entry.
     pub patchable_function_entry: Option<PatchableFunctionEntry>,
+    /// The `#[rustc_objc_class = "..."]` attribute.
+    pub objc_class: Option<Symbol>,
+    /// The `#[rustc_objc_selector = "..."]` attribute.
+    pub objc_selector: Option<Symbol>,
 }
 
 #[derive(Copy, Clone, Debug, TyEncodable, TyDecodable, HashStable, PartialEq, Eq)]
@@ -185,6 +189,8 @@ impl CodegenFnAttrs {
             instruction_set: None,
             alignment: None,
             patchable_function_entry: None,
+            objc_class: None,
+            objc_selector: None,
         }
     }
 
diff --git a/compiler/rustc_middle/src/mir/syntax.rs b/compiler/rustc_middle/src/mir/syntax.rs
index 3b8def67f92..d402ea4b04f 100644
--- a/compiler/rustc_middle/src/mir/syntax.rs
+++ b/compiler/rustc_middle/src/mir/syntax.rs
@@ -327,9 +327,11 @@ pub enum StatementKind<'tcx> {
     /// interesting for optimizations? Do we want to allow such optimizations?
     ///
     /// **Needs clarification**: We currently require that the LHS place not overlap with any place
-    /// read as part of computation of the RHS for some rvalues (generally those not producing
-    /// primitives). This requirement is under discussion in [#68364]. As a part of this discussion,
-    /// it is also unclear in what order the components are evaluated.
+    /// read as part of computation of the RHS for some rvalues. This requirement is under
+    /// discussion in [#68364]. Specifically, overlap is permitted only for assignments of a type
+    /// with `BackendRepr::Scalar | BackendRepr::ScalarPair` where all the scalar fields are
+    /// [`Scalar::Initialized`][rustc_abi::Scalar::Initialized]. As a part of this discussion, it is
+    /// also unclear in what order the components are evaluated.
     ///
     /// [#68364]: https://github.com/rust-lang/rust/issues/68364
     ///
diff --git a/compiler/rustc_middle/src/ty/util.rs b/compiler/rustc_middle/src/ty/util.rs
index 029586a9c55..b79b67c5927 100644
--- a/compiler/rustc_middle/src/ty/util.rs
+++ b/compiler/rustc_middle/src/ty/util.rs
@@ -1359,6 +1359,7 @@ impl<'tcx> Ty<'tcx> {
     /// 2229 drop reorder migration analysis.
     #[inline]
     pub fn has_significant_drop(self, tcx: TyCtxt<'tcx>, typing_env: ty::TypingEnv<'tcx>) -> bool {
+        assert!(!self.has_non_region_infer());
         // Avoid querying in simple cases.
         match needs_drop_components(tcx, self) {
             Err(AlwaysRequiresDrop) => true,
@@ -1371,14 +1372,6 @@ impl<'tcx> Ty<'tcx> {
                     _ => self,
                 };
 
-                // FIXME(#86868): We should be canonicalizing, or else moving this to a method of inference
-                // context, or *something* like that, but for now just avoid passing inference
-                // variables to queries that can't cope with them. Instead, conservatively
-                // return "true" (may change drop order).
-                if query_ty.has_infer() {
-                    return true;
-                }
-
                 // This doesn't depend on regions, so try to minimize distinct
                 // query keys used.
                 let erased = tcx.normalize_erasing_regions(typing_env, query_ty);
diff --git a/compiler/rustc_mir_transform/src/dest_prop.rs b/compiler/rustc_mir_transform/src/dest_prop.rs
index 9ba2d274691..c57483a6811 100644
--- a/compiler/rustc_mir_transform/src/dest_prop.rs
+++ b/compiler/rustc_mir_transform/src/dest_prop.rs
@@ -567,13 +567,15 @@ fn save_as_intervals<'tcx>(
         // the written-to locals as live in the second half of the statement.
         // We also ensure that operands read by terminators conflict with writes by that terminator.
         // For instance a function call may read args after having written to the destination.
-        VisitPlacesWith(|place, ctxt| match DefUse::for_place(place, ctxt) {
-            DefUse::Def | DefUse::Use | DefUse::PartialWrite => {
-                if let Some(relevant) = relevant.shrink[place.local] {
-                    values.insert(relevant, twostep);
+        VisitPlacesWith(|place: Place<'tcx>, ctxt| {
+            if let Some(relevant) = relevant.shrink[place.local] {
+                match DefUse::for_place(place, ctxt) {
+                    DefUse::Def | DefUse::Use | DefUse::PartialWrite => {
+                        values.insert(relevant, twostep);
+                    }
+                    DefUse::NonUse => {}
                 }
             }
-            DefUse::NonUse => {}
         })
         .visit_terminator(term, loc);
 
@@ -588,15 +590,32 @@ fn save_as_intervals<'tcx>(
             twostep = TwoStepIndex::from_u32(twostep.as_u32() + 1);
             debug_assert_eq!(twostep, two_step_loc(loc, Effect::After));
             append_at(&mut values, &state, twostep);
-            // Ensure we have a non-zero live range even for dead stores. This is done by marking
-            // all the written-to locals as live in the second half of the statement.
-            VisitPlacesWith(|place, ctxt| match DefUse::for_place(place, ctxt) {
-                DefUse::Def | DefUse::PartialWrite => {
-                    if let Some(relevant) = relevant.shrink[place.local] {
-                        values.insert(relevant, twostep);
+            // Like terminators, ensure we have a non-zero live range even for dead stores.
+            // Some rvalues interleave reads and writes, for instance `Rvalue::Aggregate`, see
+            // https://github.com/rust-lang/rust/issues/146383. By precaution, treat statements
+            // as behaving so by default.
+            // We make an exception for simple assignments `_a.stuff = {copy|move} _b.stuff`,
+            // as marking `_b` live here would prevent unification.
+            let is_simple_assignment = match stmt.kind {
+                StatementKind::Assign(box (
+                    lhs,
+                    Rvalue::CopyForDeref(rhs)
+                    | Rvalue::Use(Operand::Copy(rhs) | Operand::Move(rhs)),
+                )) => lhs.projection == rhs.projection,
+                _ => false,
+            };
+            VisitPlacesWith(|place: Place<'tcx>, ctxt| {
+                if let Some(relevant) = relevant.shrink[place.local] {
+                    match DefUse::for_place(place, ctxt) {
+                        DefUse::Def | DefUse::PartialWrite => {
+                            values.insert(relevant, twostep);
+                        }
+                        DefUse::Use if !is_simple_assignment => {
+                            values.insert(relevant, twostep);
+                        }
+                        DefUse::Use | DefUse::NonUse => {}
                     }
                 }
-                DefUse::Use | DefUse::NonUse => {}
             })
             .visit_statement(stmt, loc);
 
diff --git a/compiler/rustc_passes/src/check_attr.rs b/compiler/rustc_passes/src/check_attr.rs
index 2562d2e0b83..60f575cb844 100644
--- a/compiler/rustc_passes/src/check_attr.rs
+++ b/compiler/rustc_passes/src/check_attr.rs
@@ -276,6 +276,8 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                     | AttributeKind::PatternComplexityLimit { .. }
                     | AttributeKind::NoCore { .. }
                     | AttributeKind::NoStd { .. }
+                    | AttributeKind::ObjcClass { .. }
+                    | AttributeKind::ObjcSelector { .. }
                 ) => { /* do nothing  */ }
                 Attribute::Unparsed(attr_item) => {
                     style = Some(attr_item.style);
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index cdb0b5b58da..668e80a26b4 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -1917,6 +1917,8 @@ symbols! {
         rustc_no_mir_inline,
         rustc_nonnull_optimization_guaranteed,
         rustc_nounwind,
+        rustc_objc_class,
+        rustc_objc_selector,
         rustc_object_lifetime_default,
         rustc_on_unimplemented,
         rustc_outlives,
diff --git a/compiler/rustc_trait_selection/src/traits/misc.rs b/compiler/rustc_trait_selection/src/traits/misc.rs
index 393f458bea2..4c25882daa9 100644
--- a/compiler/rustc_trait_selection/src/traits/misc.rs
+++ b/compiler/rustc_trait_selection/src/traits/misc.rs
@@ -1,15 +1,14 @@
 //! Miscellaneous type-system utilities that are too small to deserve their own modules.
 
-use std::assert_matches::assert_matches;
-
 use hir::LangItem;
 use rustc_ast::Mutability;
 use rustc_hir as hir;
 use rustc_infer::infer::{RegionResolutionError, TyCtxtInferExt};
 use rustc_middle::ty::{self, AdtDef, Ty, TyCtxt, TypeVisitableExt, TypingMode};
+use rustc_span::sym;
 
 use crate::regions::InferCtxtRegionExt;
-use crate::traits::{self, FulfillmentError, ObligationCause};
+use crate::traits::{self, FulfillmentError, Obligation, ObligationCause};
 
 pub enum CopyImplementationError<'tcx> {
     InfringingFields(Vec<(&'tcx ty::FieldDef, Ty<'tcx>, InfringingFieldsReason<'tcx>)>),
@@ -98,10 +97,9 @@ pub fn type_allowed_to_implement_const_param_ty<'tcx>(
     tcx: TyCtxt<'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     self_type: Ty<'tcx>,
-    lang_item: LangItem,
     parent_cause: ObligationCause<'tcx>,
 ) -> Result<(), ConstParamTyImplementationError<'tcx>> {
-    assert_matches!(lang_item, LangItem::ConstParamTy | LangItem::UnsizedConstParamTy);
+    let mut need_unstable_feature_bound = false;
 
     let inner_tys: Vec<_> = match *self_type.kind() {
         // Trivially okay as these types are all:
@@ -112,18 +110,14 @@ pub fn type_allowed_to_implement_const_param_ty<'tcx>(
 
         // Handle types gated under `feature(unsized_const_params)`
         // FIXME(unsized_const_params): Make `const N: [u8]` work then forbid references
-        ty::Slice(inner_ty) | ty::Ref(_, inner_ty, Mutability::Not)
-            if lang_item == LangItem::UnsizedConstParamTy =>
-        {
+        ty::Slice(inner_ty) | ty::Ref(_, inner_ty, Mutability::Not) => {
+            need_unstable_feature_bound = true;
             vec![inner_ty]
         }
-        ty::Str if lang_item == LangItem::UnsizedConstParamTy => {
+        ty::Str => {
+            need_unstable_feature_bound = true;
             vec![Ty::new_slice(tcx, tcx.types.u8)]
         }
-        ty::Str | ty::Slice(..) | ty::Ref(_, _, Mutability::Not) => {
-            return Err(ConstParamTyImplementationError::UnsizedConstParamsFeatureRequired);
-        }
-
         ty::Array(inner_ty, _) => vec![inner_ty],
 
         // `str` morally acts like a newtype around `[u8]`
@@ -137,7 +131,7 @@ pub fn type_allowed_to_implement_const_param_ty<'tcx>(
                 adt,
                 args,
                 parent_cause.clone(),
-                lang_item,
+                LangItem::ConstParamTy,
             )
             .map_err(ConstParamTyImplementationError::InfrigingFields)?;
 
@@ -153,11 +147,25 @@ pub fn type_allowed_to_implement_const_param_ty<'tcx>(
         let infcx = tcx.infer_ctxt().build(TypingMode::non_body_analysis());
         let ocx = traits::ObligationCtxt::new_with_diagnostics(&infcx);
 
+        // Make sure impls certain types are gated with #[unstable_feature_bound(unsized_const_params)]
+        if need_unstable_feature_bound {
+            ocx.register_obligation(Obligation::new(
+                tcx,
+                parent_cause.clone(),
+                param_env,
+                ty::ClauseKind::UnstableFeature(sym::unsized_const_params),
+            ));
+
+            if !ocx.select_all_or_error().is_empty() {
+                return Err(ConstParamTyImplementationError::UnsizedConstParamsFeatureRequired);
+            }
+        }
+
         ocx.register_bound(
             parent_cause.clone(),
             param_env,
             inner_ty,
-            tcx.require_lang_item(lang_item, parent_cause.span),
+            tcx.require_lang_item(LangItem::ConstParamTy, parent_cause.span),
         );
 
         let errors = ocx.select_all_or_error();
diff --git a/library/alloc/src/collections/btree/map/entry.rs b/library/alloc/src/collections/btree/map/entry.rs
index ec9b774c308..21486651b0b 100644
--- a/library/alloc/src/collections/btree/map/entry.rs
+++ b/library/alloc/src/collections/btree/map/entry.rs
@@ -271,7 +271,6 @@ impl<'a, K: Ord, V, A: Allocator + Clone> Entry<'a, K, V, A> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(btree_entry_insert)]
     /// use std::collections::BTreeMap;
     ///
     /// let mut map: BTreeMap<&str, String> = BTreeMap::new();
@@ -280,7 +279,7 @@ impl<'a, K: Ord, V, A: Allocator + Clone> Entry<'a, K, V, A> {
     /// assert_eq!(entry.key(), &"poneyland");
     /// ```
     #[inline]
-    #[unstable(feature = "btree_entry_insert", issue = "65225")]
+    #[stable(feature = "btree_entry_insert", since = "CURRENT_RUSTC_VERSION")]
     pub fn insert_entry(self, value: V) -> OccupiedEntry<'a, K, V, A> {
         match self {
             Occupied(mut entry) => {
@@ -379,7 +378,6 @@ impl<'a, K: Ord, V, A: Allocator + Clone> VacantEntry<'a, K, V, A> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(btree_entry_insert)]
     /// use std::collections::BTreeMap;
     /// use std::collections::btree_map::Entry;
     ///
@@ -391,7 +389,7 @@ impl<'a, K: Ord, V, A: Allocator + Clone> VacantEntry<'a, K, V, A> {
     /// }
     /// assert_eq!(map["poneyland"], 37);
     /// ```
-    #[unstable(feature = "btree_entry_insert", issue = "65225")]
+    #[stable(feature = "btree_entry_insert", since = "CURRENT_RUSTC_VERSION")]
     pub fn insert_entry(mut self, value: V) -> OccupiedEntry<'a, K, V, A> {
         let handle = match self.handle {
             None => {
diff --git a/library/alloc/src/vec/peek_mut.rs b/library/alloc/src/vec/peek_mut.rs
index c0dd941ed39..caeaf2799d7 100644
--- a/library/alloc/src/vec/peek_mut.rs
+++ b/library/alloc/src/vec/peek_mut.rs
@@ -29,9 +29,9 @@ impl<'a, T> PeekMut<'a, T> {
 
     /// Removes the peeked value from the vector and returns it.
     #[unstable(feature = "vec_peek_mut", issue = "122742")]
-    pub fn pop(self) -> T {
+    pub fn pop(this: Self) -> T {
         // SAFETY: PeekMut is only constructed if the vec is non-empty
-        unsafe { self.vec.pop().unwrap_unchecked() }
+        unsafe { this.vec.pop().unwrap_unchecked() }
     }
 }
 
diff --git a/library/alloctests/tests/vec.rs b/library/alloctests/tests/vec.rs
index 00f640cd17e..404eb49e1ea 100644
--- a/library/alloctests/tests/vec.rs
+++ b/library/alloctests/tests/vec.rs
@@ -15,7 +15,7 @@ use std::ops::Bound::*;
 use std::panic::{AssertUnwindSafe, catch_unwind};
 use std::rc::Rc;
 use std::sync::atomic::{AtomicU32, Ordering};
-use std::vec::{Drain, IntoIter};
+use std::vec::{Drain, IntoIter, PeekMut};
 
 use crate::testing::macros::struct_with_counted_drop;
 
@@ -2647,7 +2647,7 @@ fn test_peek_mut() {
         assert_eq!(*p, 2);
         *p = 0;
         assert_eq!(*p, 0);
-        p.pop();
+        PeekMut::pop(p);
         assert_eq!(vec.len(), 1);
     } else {
         unreachable!()
diff --git a/library/core/src/array/mod.rs b/library/core/src/array/mod.rs
index d14419a23a1..d713e575b58 100644
--- a/library/core/src/array/mod.rs
+++ b/library/core/src/array/mod.rs
@@ -472,6 +472,11 @@ impl<T: Copy> SpecArrayClone for T {
 // The Default impls cannot be done with const generics because `[T; 0]` doesn't
 // require Default to be implemented, and having different impl blocks for
 // different numbers isn't supported yet.
+//
+// Trying to improve the `[T; 0]` situation has proven to be difficult.
+// Please see these issues for more context on past attempts and crater runs:
+// - https://github.com/rust-lang/rust/issues/61415
+// - https://github.com/rust-lang/rust/pull/145457
 
 macro_rules! array_impl_default {
     {$n:expr, $t:ident $($ts:ident)*} => {
diff --git a/library/core/src/cmp.rs b/library/core/src/cmp.rs
index 94536f25b41..95896ab1441 100644
--- a/library/core/src/cmp.rs
+++ b/library/core/src/cmp.rs
@@ -334,9 +334,8 @@ pub macro PartialEq($item:item) {
 #[doc(alias = "!=")]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_diagnostic_item = "Eq"]
-#[const_trait]
 #[rustc_const_unstable(feature = "const_cmp", issue = "143800")]
-pub trait Eq: [const] PartialEq<Self> + PointeeSized {
+pub const trait Eq: [const] PartialEq<Self> + PointeeSized {
     // this method is used solely by `impl Eq or #[derive(Eq)]` to assert that every component of a
     // type implements `Eq` itself. The current deriving infrastructure means doing this assertion
     // without using a method on this trait is nearly impossible.
@@ -966,9 +965,8 @@ impl<T: Clone> Clone for Reverse<T> {
 #[doc(alias = ">=")]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_diagnostic_item = "Ord"]
-#[const_trait]
 #[rustc_const_unstable(feature = "const_cmp", issue = "143800")]
-pub trait Ord: [const] Eq + [const] PartialOrd<Self> + PointeeSized {
+pub const trait Ord: [const] Eq + [const] PartialOrd<Self> + PointeeSized {
     /// This method returns an [`Ordering`] between `self` and `other`.
     ///
     /// By convention, `self.cmp(&other)` returns the ordering matching the expression
@@ -1352,9 +1350,8 @@ pub macro Ord($item:item) {
 )]
 #[rustc_diagnostic_item = "PartialOrd"]
 #[allow(multiple_supertrait_upcastable)] // FIXME(sized_hierarchy): remove this
-#[const_trait]
 #[rustc_const_unstable(feature = "const_cmp", issue = "143800")]
-pub trait PartialOrd<Rhs: PointeeSized = Self>: PartialEq<Rhs> + PointeeSized {
+pub const trait PartialOrd<Rhs: PointeeSized = Self>: PartialEq<Rhs> + PointeeSized {
     /// This method returns an ordering between `self` and `other` values if one exists.
     ///
     /// # Examples
diff --git a/library/core/src/lib.rs b/library/core/src/lib.rs
index 86a68e18b0a..5d52bfb1b12 100644
--- a/library/core/src/lib.rs
+++ b/library/core/src/lib.rs
@@ -313,6 +313,7 @@ pub mod io;
 pub mod iter;
 pub mod net;
 pub mod option;
+pub mod os;
 pub mod panic;
 pub mod panicking;
 #[unstable(feature = "pattern_type_macro", issue = "123646")]
diff --git a/library/core/src/marker.rs b/library/core/src/marker.rs
index d03d7a43469..1c100312a9a 100644
--- a/library/core/src/marker.rs
+++ b/library/core/src/marker.rs
@@ -1083,7 +1083,7 @@ pub trait Tuple {}
 // We name this differently than the derive macro so that the `adt_const_params` can
 // be used independently of `unsized_const_params` without requiring a full path
 // to the derive macro every time it is used. This should be renamed on stabilization.
-pub trait ConstParamTy_: UnsizedConstParamTy + StructuralPartialEq + Eq {}
+pub trait ConstParamTy_: StructuralPartialEq + Eq {}
 
 /// Derive macro generating an impl of the trait `ConstParamTy`.
 #[rustc_builtin_macro]
@@ -1093,23 +1093,6 @@ pub macro ConstParamTy($item:item) {
     /* compiler built-in */
 }
 
-#[lang = "unsized_const_param_ty"]
-#[unstable(feature = "unsized_const_params", issue = "95174")]
-#[diagnostic::on_unimplemented(message = "`{Self}` can't be used as a const parameter type")]
-/// A marker for types which can be used as types of `const` generic parameters.
-///
-/// Equivalent to [`ConstParamTy_`] except that this is used by
-/// the `unsized_const_params` to allow for fake unstable impls.
-pub trait UnsizedConstParamTy: StructuralPartialEq + Eq {}
-
-/// Derive macro generating an impl of the trait `ConstParamTy`.
-#[rustc_builtin_macro]
-#[allow_internal_unstable(unsized_const_params)]
-#[unstable(feature = "unsized_const_params", issue = "95174")]
-pub macro UnsizedConstParamTy($item:item) {
-    /* compiler built-in */
-}
-
 // FIXME(adt_const_params): handle `ty::FnDef`/`ty::Closure`
 marker_impls! {
     #[unstable(feature = "adt_const_params", issue = "95174")]
@@ -1124,17 +1107,11 @@ marker_impls! {
 
 marker_impls! {
     #[unstable(feature = "unsized_const_params", issue = "95174")]
-    UnsizedConstParamTy for
-        usize, u8, u16, u32, u64, u128,
-        isize, i8, i16, i32, i64, i128,
-        bool,
-        char,
-        (),
-        {T: UnsizedConstParamTy, const N: usize} [T; N],
-
+    #[unstable_feature_bound(unsized_const_params)]
+    ConstParamTy_ for
         str,
-        {T: UnsizedConstParamTy} [T],
-        {T: UnsizedConstParamTy + ?Sized} &T,
+        {T: ConstParamTy_} [T],
+        {T: ConstParamTy_ + ?Sized} &T,
 }
 
 /// A common trait implemented by all function pointers.
diff --git a/library/core/src/mem/transmutability.rs b/library/core/src/mem/transmutability.rs
index 782b826448a..f36cb8cddb8 100644
--- a/library/core/src/mem/transmutability.rs
+++ b/library/core/src/mem/transmutability.rs
@@ -1,4 +1,4 @@
-use crate::marker::{ConstParamTy_, UnsizedConstParamTy};
+use crate::marker::ConstParamTy_;
 
 /// Marks that `Src` is transmutable into `Self`.
 ///
@@ -83,6 +83,7 @@ use crate::marker::{ConstParamTy_, UnsizedConstParamTy};
 /// Furthermore, stability does not imply portability. For example, the size of
 /// `usize` is stable, but not portable.
 #[unstable(feature = "transmutability", issue = "99571")]
+#[unstable_feature_bound(transmutability)]
 #[lang = "transmute_trait"]
 #[rustc_deny_explicit_impl]
 #[rustc_do_not_implement_via_object]
@@ -288,9 +289,8 @@ pub struct Assume {
 }
 
 #[unstable(feature = "transmutability", issue = "99571")]
+#[unstable_feature_bound(transmutability)]
 impl ConstParamTy_ for Assume {}
-#[unstable(feature = "transmutability", issue = "99571")]
-impl UnsizedConstParamTy for Assume {}
 
 impl Assume {
     /// With this, [`TransmuteFrom`] does not assume you have ensured any safety
diff --git a/library/core/src/os/darwin/mod.rs b/library/core/src/os/darwin/mod.rs
new file mode 100644
index 00000000000..8426d82b8ce
--- /dev/null
+++ b/library/core/src/os/darwin/mod.rs
@@ -0,0 +1,19 @@
+//! Platform-specific extensions to `core` for Darwin / Apple platforms.
+//!
+//! This is available on the following operating systems:
+//! - macOS
+//! - iOS
+//! - tvOS
+//! - watchOS
+//! - visionOS
+//!
+//! Note: This module is called "Darwin" as that's the name of the underlying
+//! core OS of the above operating systems, but it should not be confused with
+//! the `-darwin` suffix in the `x86_64-apple-darwin` and
+//! `aarch64-apple-darwin` target names, which are mostly named that way for
+//! legacy reasons.
+
+#![unstable(feature = "darwin_objc", issue = "145496")]
+#![doc(cfg(target_vendor = "apple"))]
+
+pub mod objc;
diff --git a/library/core/src/os/darwin/objc.rs b/library/core/src/os/darwin/objc.rs
new file mode 100644
index 00000000000..928cb54e82c
--- /dev/null
+++ b/library/core/src/os/darwin/objc.rs
@@ -0,0 +1,113 @@
+//! Defines types and macros for Objective-C interoperability.
+
+#![unstable(feature = "darwin_objc", issue = "145496")]
+#![allow(nonstandard_style)]
+
+use crate::fmt;
+
+/// Equivalent to Objective-C’s `struct objc_class` type.
+#[cfg_attr(not(doc), repr(u8))] // An implementation detail we don't want to show up in rustdoc
+pub enum objc_class {
+    #[unstable(
+        feature = "objc_class_variant",
+        reason = "temporary implementation detail",
+        issue = "none"
+    )]
+    #[doc(hidden)]
+    __variant1,
+    #[unstable(
+        feature = "objc_class_variant",
+        reason = "temporary implementation detail",
+        issue = "none"
+    )]
+    #[doc(hidden)]
+    __variant2,
+}
+
+impl fmt::Debug for objc_class {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("objc_class").finish()
+    }
+}
+
+/// Equivalent to Objective-C’s `struct objc_selector` type.
+#[cfg_attr(not(doc), repr(u8))] // An implementation detail we don't want to show up in rustdoc
+pub enum objc_selector {
+    #[unstable(
+        feature = "objc_selector_variant",
+        reason = "temporary implementation detail",
+        issue = "none"
+    )]
+    #[doc(hidden)]
+    __variant1,
+    #[unstable(
+        feature = "objc_selector_variant",
+        reason = "temporary implementation detail",
+        issue = "none"
+    )]
+    #[doc(hidden)]
+    __variant2,
+}
+
+impl fmt::Debug for objc_selector {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("objc_selector").finish()
+    }
+}
+
+/// Equivalent to Objective-C’s `Class` type.
+pub type Class = *mut objc_class;
+
+/// Equivalent to Objective-C’s `SEL` type.
+pub type SEL = *mut objc_selector;
+
+/// Gets a reference to an Objective-C class.
+///
+/// This macro will yield an expression of type [`Class`] for the given class name string literal.
+///
+/// # Example
+///
+/// ```no_run
+/// #![feature(darwin_objc)]
+/// use core::os::darwin::objc;
+///
+/// let string_class = objc::class!("NSString");
+/// ```
+#[allow_internal_unstable(rustc_attrs)]
+pub macro class($classname:expr) {{
+    // Since static Objective-C class references actually end up with multiple definitions
+    // across dylib boundaries, we only expose the value of the static and don't provide a way to
+    // get the address of or a reference to the static.
+    unsafe extern "C" {
+        #[rustc_objc_class = $classname]
+        safe static VAL: $crate::os::darwin::objc::Class;
+    }
+    VAL
+}}
+
+/// Gets a reference to an Objective-C selector.
+///
+/// This macro will yield an expression of type [`SEL`] for the given method name string literal.
+///
+/// It is similar to Objective-C’s `@selector` directive.
+///
+/// # Examples
+///
+/// ```no_run
+/// #![feature(darwin_objc)]
+/// use core::os::darwin::objc;
+///
+/// let alloc_sel = objc::selector!("alloc");
+/// let init_sel = objc::selector!("initWithCString:encoding:");
+/// ```
+#[allow_internal_unstable(rustc_attrs)]
+pub macro selector($methname:expr) {{
+    // Since static Objective-C selector references actually end up with multiple definitions
+    // across dylib boundaries, we only expose the value of the static and don't provide a way to
+    // get the address of or a reference to the static.
+    unsafe extern "C" {
+        #[rustc_objc_selector = $methname]
+        safe static VAL: $crate::os::darwin::objc::SEL;
+    }
+    VAL
+}}
diff --git a/library/core/src/os/mod.rs b/library/core/src/os/mod.rs
new file mode 100644
index 00000000000..897f59f530e
--- /dev/null
+++ b/library/core/src/os/mod.rs
@@ -0,0 +1,24 @@
+//! OS-specific functionality.
+
+#![unstable(feature = "darwin_objc", issue = "145496")]
+
+#[cfg(all(
+    doc,
+    any(
+        all(target_arch = "wasm32", not(target_os = "wasi")),
+        all(target_vendor = "fortanix", target_env = "sgx")
+    )
+))]
+#[unstable(issue = "none", feature = "std_internals")]
+pub mod darwin {}
+
+// darwin
+#[cfg(not(all(
+    doc,
+    any(
+        all(target_arch = "wasm32", not(target_os = "wasi")),
+        all(target_vendor = "fortanix", target_env = "sgx")
+    )
+)))]
+#[cfg(any(target_vendor = "apple", doc))]
+pub mod darwin;
diff --git a/library/core/src/tuple.rs b/library/core/src/tuple.rs
index 3892f831076..c57a8d81ade 100644
--- a/library/core/src/tuple.rs
+++ b/library/core/src/tuple.rs
@@ -1,7 +1,7 @@
 // See core/src/primitive_docs.rs for documentation.
 
 use crate::cmp::Ordering::{self, *};
-use crate::marker::{ConstParamTy_, StructuralPartialEq, UnsizedConstParamTy};
+use crate::marker::{ConstParamTy_, StructuralPartialEq};
 use crate::ops::ControlFlow::{self, Break, Continue};
 
 // Recursive macro for implementing n-ary tuple functions and operations
@@ -47,19 +47,13 @@ macro_rules! tuple_impls {
         maybe_tuple_doc! {
             $($T)+ @
             #[unstable(feature = "adt_const_params", issue = "95174")]
+            #[unstable_feature_bound(unsized_const_params)]
             impl<$($T: ConstParamTy_),+> ConstParamTy_ for ($($T,)+)
             {}
         }
 
         maybe_tuple_doc! {
             $($T)+ @
-            #[unstable(feature = "unsized_const_params", issue = "95174")]
-            impl<$($T: UnsizedConstParamTy),+> UnsizedConstParamTy for ($($T,)+)
-            {}
-        }
-
-        maybe_tuple_doc! {
-            $($T)+ @
             #[unstable(feature = "structural_match", issue = "31434")]
             impl<$($T),+> StructuralPartialEq for ($($T,)+)
             {}
diff --git a/library/coretests/tests/ascii.rs b/library/coretests/tests/ascii.rs
index ce09ee507f1..297aa114e00 100644
--- a/library/coretests/tests/ascii.rs
+++ b/library/coretests/tests/ascii.rs
@@ -505,3 +505,10 @@ fn test_escape_ascii_iter() {
     let _ = it.advance_back_by(4);
     assert_eq!(it.to_string(), r#"fastpath\xffremainder"#);
 }
+
+#[test]
+fn test_invalid_u8() {
+    for c in 128..=255 {
+        assert_eq!(core::ascii::Char::from_u8(c), None);
+    }
+}
diff --git a/library/std/src/os/darwin/mod.rs b/library/std/src/os/darwin/mod.rs
index 3b1bd974fa3..ff184f477fb 100644
--- a/library/std/src/os/darwin/mod.rs
+++ b/library/std/src/os/darwin/mod.rs
@@ -17,6 +17,8 @@
 #![doc(cfg(target_vendor = "apple"))]
 
 pub mod fs;
+pub mod objc;
+
 // deprecated, but used for public reexport under `std::os::unix::raw`, as
 // well as `std::os::macos`/`std::os::ios`, because those modules precede the
 // decision to remove these.
diff --git a/library/std/src/os/darwin/objc.rs b/library/std/src/os/darwin/objc.rs
new file mode 100644
index 00000000000..a4b31fee7c5
--- /dev/null
+++ b/library/std/src/os/darwin/objc.rs
@@ -0,0 +1,13 @@
+//! Defines types and macros for Objective-C interoperability.
+//!
+//! This module re-exports all the items in [`core::os::darwin::objc`].
+//!
+//! [`core::os::darwin::objc`]: ../../../../core/os/darwin/objc/index.html "mod core::os::darwin::objc"
+
+#![unstable(feature = "darwin_objc", issue = "145496")]
+
+// We can't generate an intra-doc link for this automatically since `core::os::darwin` isn't
+// compiled into `core` on every platform even though it's documented on every platform.
+// We just link to it directly in the module documentation above instead.
+#[cfg(not(doc))]
+pub use core::os::darwin::objc::*;
diff --git a/library/std/src/sys/fs/unix.rs b/library/std/src/sys/fs/unix.rs
index dfd6ce56a76..33a1e7ff5e4 100644
--- a/library/std/src/sys/fs/unix.rs
+++ b/library/std/src/sys/fs/unix.rs
@@ -21,29 +21,31 @@ use libc::fstatat as fstatat64;
 #[cfg(any(all(target_os = "linux", not(target_env = "musl")), target_os = "hurd"))]
 use libc::fstatat64;
 #[cfg(any(
+    target_os = "aix",
     target_os = "android",
-    target_os = "solaris",
+    target_os = "freebsd",
     target_os = "fuchsia",
-    target_os = "redox",
     target_os = "illumos",
-    target_os = "aix",
     target_os = "nto",
+    target_os = "redox",
+    target_os = "solaris",
     target_os = "vita",
     all(target_os = "linux", target_env = "musl"),
 ))]
 use libc::readdir as readdir64;
 #[cfg(not(any(
+    target_os = "aix",
     target_os = "android",
-    target_os = "linux",
-    target_os = "solaris",
+    target_os = "freebsd",
+    target_os = "fuchsia",
+    target_os = "hurd",
     target_os = "illumos",
     target_os = "l4re",
-    target_os = "fuchsia",
-    target_os = "redox",
-    target_os = "aix",
+    target_os = "linux",
     target_os = "nto",
+    target_os = "redox",
+    target_os = "solaris",
     target_os = "vita",
-    target_os = "hurd",
 )))]
 use libc::readdir_r as readdir64_r;
 #[cfg(any(all(target_os = "linux", not(target_env = "musl")), target_os = "hurd"))]
@@ -271,16 +273,17 @@ unsafe impl Send for Dir {}
 unsafe impl Sync for Dir {}
 
 #[cfg(any(
+    target_os = "aix",
     target_os = "android",
-    target_os = "linux",
-    target_os = "solaris",
-    target_os = "illumos",
+    target_os = "freebsd",
     target_os = "fuchsia",
-    target_os = "redox",
-    target_os = "aix",
+    target_os = "hurd",
+    target_os = "illumos",
+    target_os = "linux",
     target_os = "nto",
+    target_os = "redox",
+    target_os = "solaris",
     target_os = "vita",
-    target_os = "hurd",
 ))]
 pub struct DirEntry {
     dir: Arc<InnerReadDir>,
@@ -295,16 +298,17 @@ pub struct DirEntry {
 // we're not using the immediate `d_name` on these targets. Keeping this as an
 // `entry` field in `DirEntry` helps reduce the `cfg` boilerplate elsewhere.
 #[cfg(any(
+    target_os = "aix",
     target_os = "android",
-    target_os = "linux",
-    target_os = "solaris",
-    target_os = "illumos",
+    target_os = "freebsd",
     target_os = "fuchsia",
-    target_os = "redox",
-    target_os = "aix",
+    target_os = "hurd",
+    target_os = "illumos",
+    target_os = "linux",
     target_os = "nto",
+    target_os = "redox",
+    target_os = "solaris",
     target_os = "vita",
-    target_os = "hurd",
 ))]
 struct dirent64_min {
     d_ino: u64,
@@ -319,16 +323,17 @@ struct dirent64_min {
 }
 
 #[cfg(not(any(
+    target_os = "aix",
     target_os = "android",
-    target_os = "linux",
-    target_os = "solaris",
-    target_os = "illumos",
+    target_os = "freebsd",
     target_os = "fuchsia",
-    target_os = "redox",
-    target_os = "aix",
+    target_os = "hurd",
+    target_os = "illumos",
+    target_os = "linux",
     target_os = "nto",
+    target_os = "redox",
+    target_os = "solaris",
     target_os = "vita",
-    target_os = "hurd",
 )))]
 pub struct DirEntry {
     dir: Arc<InnerReadDir>,
@@ -698,16 +703,17 @@ impl Iterator for ReadDir {
     type Item = io::Result<DirEntry>;
 
     #[cfg(any(
+        target_os = "aix",
         target_os = "android",
-        target_os = "linux",
-        target_os = "solaris",
+        target_os = "freebsd",
         target_os = "fuchsia",
-        target_os = "redox",
+        target_os = "hurd",
         target_os = "illumos",
-        target_os = "aix",
+        target_os = "linux",
         target_os = "nto",
+        target_os = "redox",
+        target_os = "solaris",
         target_os = "vita",
-        target_os = "hurd",
     ))]
     fn next(&mut self) -> Option<io::Result<DirEntry>> {
         use crate::sys::os::{errno, set_errno};
@@ -768,6 +774,9 @@ impl Iterator for ReadDir {
                 // only access those bytes.
                 #[cfg(not(target_os = "vita"))]
                 let entry = dirent64_min {
+                    #[cfg(target_os = "freebsd")]
+                    d_ino: (*entry_ptr).d_fileno,
+                    #[cfg(not(target_os = "freebsd"))]
                     d_ino: (*entry_ptr).d_ino as u64,
                     #[cfg(not(any(
                         target_os = "solaris",
@@ -791,16 +800,17 @@ impl Iterator for ReadDir {
     }
 
     #[cfg(not(any(
+        target_os = "aix",
         target_os = "android",
-        target_os = "linux",
-        target_os = "solaris",
+        target_os = "freebsd",
         target_os = "fuchsia",
-        target_os = "redox",
+        target_os = "hurd",
         target_os = "illumos",
-        target_os = "aix",
+        target_os = "linux",
         target_os = "nto",
+        target_os = "redox",
+        target_os = "solaris",
         target_os = "vita",
-        target_os = "hurd",
     )))]
     fn next(&mut self) -> Option<io::Result<DirEntry>> {
         if self.end_of_stream {
@@ -970,36 +980,32 @@ impl DirEntry {
     }
 
     #[cfg(any(
-        target_os = "linux",
+        target_os = "aix",
+        target_os = "android",
         target_os = "cygwin",
         target_os = "emscripten",
-        target_os = "android",
-        target_os = "solaris",
-        target_os = "illumos",
-        target_os = "haiku",
-        target_os = "l4re",
-        target_os = "fuchsia",
-        target_os = "redox",
-        target_os = "vxworks",
         target_os = "espidf",
+        target_os = "freebsd",
+        target_os = "fuchsia",
+        target_os = "haiku",
         target_os = "horizon",
-        target_os = "vita",
-        target_os = "aix",
-        target_os = "nto",
         target_os = "hurd",
+        target_os = "illumos",
+        target_os = "l4re",
+        target_os = "linux",
+        target_os = "nto",
+        target_os = "redox",
         target_os = "rtems",
+        target_os = "solaris",
+        target_os = "vita",
+        target_os = "vxworks",
         target_vendor = "apple",
     ))]
     pub fn ino(&self) -> u64 {
         self.entry.d_ino as u64
     }
 
-    #[cfg(any(
-        target_os = "freebsd",
-        target_os = "openbsd",
-        target_os = "netbsd",
-        target_os = "dragonfly"
-    ))]
+    #[cfg(any(target_os = "openbsd", target_os = "netbsd", target_os = "dragonfly"))]
     pub fn ino(&self) -> u64 {
         self.entry.d_fileno as u64
     }
@@ -1014,7 +1020,6 @@ impl DirEntry {
     #[cfg(any(
         target_os = "netbsd",
         target_os = "openbsd",
-        target_os = "freebsd",
         target_os = "dragonfly",
         target_vendor = "apple",
     ))]
@@ -1030,7 +1035,6 @@ impl DirEntry {
     #[cfg(not(any(
         target_os = "netbsd",
         target_os = "openbsd",
-        target_os = "freebsd",
         target_os = "dragonfly",
         target_vendor = "apple",
     )))]
@@ -1040,6 +1044,7 @@ impl DirEntry {
 
     #[cfg(not(any(
         target_os = "android",
+        target_os = "freebsd",
         target_os = "linux",
         target_os = "solaris",
         target_os = "illumos",
@@ -1055,6 +1060,7 @@ impl DirEntry {
     }
     #[cfg(any(
         target_os = "android",
+        target_os = "freebsd",
         target_os = "linux",
         target_os = "solaris",
         target_os = "illumos",
diff --git a/library/test/src/cli.rs b/library/test/src/cli.rs
index 1b3f9e2564c..35291cc15c9 100644
--- a/library/test/src/cli.rs
+++ b/library/test/src/cli.rs
@@ -57,6 +57,7 @@ fn optgroups() -> getopts::Options {
         .optflag("", "test", "Run tests and not benchmarks")
         .optflag("", "bench", "Run benchmarks instead of tests")
         .optflag("", "list", "List all tests and benchmarks")
+        .optflag("", "fail-fast", "Don't start new tests after the first failure")
         .optflag("h", "help", "Display this message")
         .optopt("", "logfile", "Write logs to the specified file (deprecated)", "PATH")
         .optflag(
@@ -260,6 +261,7 @@ fn parse_opts_impl(matches: getopts::Matches) -> OptRes {
     // Unstable flags
     let force_run_in_process = unstable_optflag!(matches, allow_unstable, "force-run-in-process");
     let exclude_should_panic = unstable_optflag!(matches, allow_unstable, "exclude-should-panic");
+    let fail_fast = unstable_optflag!(matches, allow_unstable, "fail-fast");
     let time_options = get_time_options(&matches, allow_unstable)?;
     let shuffle = get_shuffle(&matches, allow_unstable)?;
     let shuffle_seed = get_shuffle_seed(&matches, allow_unstable)?;
@@ -306,7 +308,7 @@ fn parse_opts_impl(matches: getopts::Matches) -> OptRes {
         skip,
         time_options,
         options,
-        fail_fast: false,
+        fail_fast,
     };
 
     Ok(test_opts)
diff --git a/src/bootstrap/README.md b/src/bootstrap/README.md
index 2965174b45b..12e09cb07db 100644
--- a/src/bootstrap/README.md
+++ b/src/bootstrap/README.md
@@ -63,6 +63,21 @@ build/
     debug/
     release/
 
+  # Build directory for various tools like `typos` that are only ever
+  # built for the host system, and always with stage0 cargo.
+  misc-tools/
+    bin/
+    target/
+
+  # Directory where js dependencies like tsc and eslint are stored.
+  node_modules/
+    .bin/
+
+  # Copy of package.json and package-lock.json, because npm requires these
+  # to be in the same directory as `node_modules`.
+  package.json
+  package-lock.json
+
   # Output of the dist-related steps like dist-std, dist-rustc, and dist-docs
   dist/
 
diff --git a/src/bootstrap/bootstrap.py b/src/bootstrap/bootstrap.py
index 2ece53eb0cc..19e87f9c293 100644
--- a/src/bootstrap/bootstrap.py
+++ b/src/bootstrap/bootstrap.py
@@ -1039,6 +1039,9 @@ class RustBuild(object):
         # See also: <https://github.com/rust-lang/rust/issues/70208>.
         if "CARGO_BUILD_TARGET" in env:
             del env["CARGO_BUILD_TARGET"]
+        # if in CI, don't use incremental build when building bootstrap.
+        if "GITHUB_ACTIONS" in env:
+            env["CARGO_INCREMENTAL"] = "0"
         env["CARGO_TARGET_DIR"] = build_dir
         env["RUSTC"] = self.rustc()
         env["LD_LIBRARY_PATH"] = (
@@ -1145,7 +1148,8 @@ class RustBuild(object):
             os.path.join(self.rust_root, "src/bootstrap/Cargo.toml"),
             "-Zroot-dir=" + self.rust_root,
         ]
-        args.extend("--verbose" for _ in range(self.verbose))
+        # verbose cargo output is very noisy, so only enable it with -vv
+        args.extend("--verbose" for _ in range(self.verbose - 1))
 
         if "BOOTSTRAP_TRACING" in env:
             args.append("--features=tracing")
diff --git a/src/bootstrap/src/core/build_steps/llvm.rs b/src/bootstrap/src/core/build_steps/llvm.rs
index 83ed7430c39..d43d261ad6c 100644
--- a/src/bootstrap/src/core/build_steps/llvm.rs
+++ b/src/bootstrap/src/core/build_steps/llvm.rs
@@ -619,11 +619,11 @@ fn check_llvm_version(builder: &Builder<'_>, llvm_config: &Path) {
     let version = get_llvm_version(builder, llvm_config);
     let mut parts = version.split('.').take(2).filter_map(|s| s.parse::<u32>().ok());
     if let (Some(major), Some(_minor)) = (parts.next(), parts.next())
-        && major >= 19
+        && major >= 20
     {
         return;
     }
-    panic!("\n\nbad LLVM version: {version}, need >=19\n\n")
+    panic!("\n\nbad LLVM version: {version}, need >=20\n\n")
 }
 
 fn configure_cmake(
diff --git a/src/bootstrap/src/core/build_steps/test.rs b/src/bootstrap/src/core/build_steps/test.rs
index 723ba80eaf8..e7f5879b5f5 100644
--- a/src/bootstrap/src/core/build_steps/test.rs
+++ b/src/bootstrap/src/core/build_steps/test.rs
@@ -3418,9 +3418,6 @@ impl Step for TierCheck {
         );
         cargo.arg(builder.src.join("src/doc/rustc/src/platform-support.md"));
         cargo.arg(builder.rustc(self.test_compiler));
-        if builder.is_verbose() {
-            cargo.arg("--verbose");
-        }
 
         let _guard = builder.msg_test(
             "platform support check",
diff --git a/src/bootstrap/src/core/build_steps/tool.rs b/src/bootstrap/src/core/build_steps/tool.rs
index dcc4898cae1..4f096d50ea5 100644
--- a/src/bootstrap/src/core/build_steps/tool.rs
+++ b/src/bootstrap/src/core/build_steps/tool.rs
@@ -394,6 +394,9 @@ macro_rules! bootstrap_tool {
         }
 
         impl<'a> Builder<'a> {
+            /// Ensure a tool is built, then get the path to its executable.
+            ///
+            /// The actual building, if any, will be handled via [`ToolBuild`].
             pub fn tool_exe(&self, tool: Tool) -> PathBuf {
                 match tool {
                     $(Tool::$name =>
@@ -1552,6 +1555,8 @@ pub const TEST_FLOAT_PARSE_ALLOW_FEATURES: &str = "f16,cfg_target_has_reliable_f
 impl Builder<'_> {
     /// Gets a `BootstrapCommand` which is ready to run `tool` in `stage` built for
     /// `host`.
+    ///
+    /// This also ensures that the given tool is built (using [`ToolBuild`]).
     pub fn tool_cmd(&self, tool: Tool) -> BootstrapCommand {
         let mut cmd = command(self.tool_exe(tool));
         let compiler = self.compiler(0, self.config.host_target);
diff --git a/src/bootstrap/src/core/builder/cargo.rs b/src/bootstrap/src/core/builder/cargo.rs
index 924bb4adb42..8e65ec7ce50 100644
--- a/src/bootstrap/src/core/builder/cargo.rs
+++ b/src/bootstrap/src/core/builder/cargo.rs
@@ -1133,7 +1133,7 @@ impl Builder<'_> {
             cargo.env("RUSTC_BACKTRACE_ON_ICE", "1");
         }
 
-        if self.is_verbose() {
+        if self.is_verbose_than(1) {
             // This provides very useful logs especially when debugging build cache-related stuff.
             cargo.env("CARGO_LOG", "cargo::core::compiler::fingerprint=info");
         }
@@ -1275,8 +1275,9 @@ impl Builder<'_> {
             cargo.env("WINAPI_NO_BUNDLED_LIBRARIES", "1");
         }
 
-        for _ in 0..self.verbosity {
-            cargo.arg("-v");
+        // verbose cargo output is very noisy, so only enable it with -vv
+        for _ in 0..self.verbosity.saturating_sub(1) {
+            cargo.arg("--verbose");
         }
 
         match (mode, self.config.rust_codegen_units_std, self.config.rust_codegen_units) {
diff --git a/src/bootstrap/src/core/config/config.rs b/src/bootstrap/src/core/config/config.rs
index 678a9b63952..0213047f3a1 100644
--- a/src/bootstrap/src/core/config/config.rs
+++ b/src/bootstrap/src/core/config/config.rs
@@ -1853,13 +1853,7 @@ fn load_toml_config(
         } else {
             toml_path.clone()
         });
-        (
-            get_toml(&toml_path).unwrap_or_else(|e| {
-                eprintln!("ERROR: Failed to parse '{}': {e}", toml_path.display());
-                exit!(2);
-            }),
-            path,
-        )
+        (get_toml(&toml_path).unwrap_or_else(|e| bad_config(&toml_path, e)), path)
     } else {
         (TomlConfig::default(), None)
     }
@@ -1892,10 +1886,8 @@ fn postprocess_toml(
             .unwrap()
             .join(include_path);
 
-        let included_toml = get_toml(&include_path).unwrap_or_else(|e| {
-            eprintln!("ERROR: Failed to parse '{}': {e}", include_path.display());
-            exit!(2);
-        });
+        let included_toml =
+            get_toml(&include_path).unwrap_or_else(|e| bad_config(&include_path, e));
         toml.merge(
             Some(include_path),
             &mut Default::default(),
@@ -2398,3 +2390,98 @@ pub(crate) fn read_file_by_commit<'a>(
     git.arg("show").arg(format!("{commit}:{}", file.to_str().unwrap()));
     git.run_capture_stdout(dwn_ctx.exec_ctx).stdout()
 }
+
+fn bad_config(toml_path: &Path, e: toml::de::Error) -> ! {
+    eprintln!("ERROR: Failed to parse '{}': {e}", toml_path.display());
+    let e_s = e.to_string();
+    if e_s.contains("unknown field")
+        && let Some(field_name) = e_s.split("`").nth(1)
+        && let sections = find_correct_section_for_field(field_name)
+        && !sections.is_empty()
+    {
+        if sections.len() == 1 {
+            match sections[0] {
+                WouldBeValidFor::TopLevel { is_section } => {
+                    if is_section {
+                        eprintln!(
+                            "hint: section name `{field_name}` used as a key within a section"
+                        );
+                    } else {
+                        eprintln!("hint: try using `{field_name}` as a top level key");
+                    }
+                }
+                WouldBeValidFor::Section(section) => {
+                    eprintln!("hint: try moving `{field_name}` to the `{section}` section")
+                }
+            }
+        } else {
+            eprintln!(
+                "hint: `{field_name}` would be valid {}",
+                join_oxford_comma(sections.iter(), "or"),
+            );
+        }
+    }
+
+    exit!(2);
+}
+
+#[derive(Copy, Clone, Debug)]
+enum WouldBeValidFor {
+    TopLevel { is_section: bool },
+    Section(&'static str),
+}
+
+fn join_oxford_comma(
+    mut parts: impl ExactSizeIterator<Item = impl std::fmt::Display>,
+    conj: &str,
+) -> String {
+    use std::fmt::Write;
+    let mut out = String::new();
+
+    assert!(parts.len() > 1);
+    while let Some(part) = parts.next() {
+        if parts.len() == 0 {
+            write!(&mut out, "{conj} {part}")
+        } else {
+            write!(&mut out, "{part}, ")
+        }
+        .unwrap();
+    }
+    out
+}
+
+impl std::fmt::Display for WouldBeValidFor {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::TopLevel { .. } => write!(f, "at top level"),
+            Self::Section(section_name) => write!(f, "in section `{section_name}`"),
+        }
+    }
+}
+
+fn find_correct_section_for_field(field_name: &str) -> Vec<WouldBeValidFor> {
+    let sections = ["build", "install", "llvm", "gcc", "rust", "dist"];
+    sections
+        .iter()
+        .map(Some)
+        .chain([None])
+        .filter_map(|section_name| {
+            let dummy_config_str = if let Some(section_name) = section_name {
+                format!("{section_name}.{field_name} = 0\n")
+            } else {
+                format!("{field_name} = 0\n")
+            };
+            let is_unknown_field = toml::from_str::<toml::Value>(&dummy_config_str)
+                .and_then(TomlConfig::deserialize)
+                .err()
+                .is_some_and(|e| e.to_string().contains("unknown field"));
+            if is_unknown_field {
+                None
+            } else {
+                Some(section_name.copied().map(WouldBeValidFor::Section).unwrap_or_else(|| {
+                    WouldBeValidFor::TopLevel { is_section: sections.contains(&field_name) }
+                }))
+            }
+        })
+        .collect()
+}
diff --git a/src/ci/docker/README.md b/src/ci/docker/README.md
index 488a6a2bce1..4ee02e9bf00 100644
--- a/src/ci/docker/README.md
+++ b/src/ci/docker/README.md
@@ -14,9 +14,9 @@ To run a specific CI job locally, you can use the `citool` Rust crate:
 cargo run --manifest-path src/ci/citool/Cargo.toml run-local <job-name>
 ```
 
-For example, to run the `x86_64-gnu-llvm-19-1` job:
+For example, to run the `x86_64-gnu-llvm-20-1` job:
 ```
-cargo run --manifest-path src/ci/citool/Cargo.toml run-local x86_64-gnu-llvm-19-1
+cargo run --manifest-path src/ci/citool/Cargo.toml run-local x86_64-gnu-llvm-20-1
 ```
 
 The job will output artifacts in an `obj/<image-name>` dir at the root of a repository. Note
@@ -27,10 +27,10 @@ Docker image executed in the given CI job.
 while locally, to the `obj/<image-name>` directory. This is primarily to prevent
 strange linker errors when using multiple Docker images.
 
-For some Linux workflows (for example `x86_64-gnu-llvm-19-N`), the process is more involved. You will need to see which script is executed for the given workflow inside the [`jobs.yml`](../github-actions/jobs.yml) file and pass it through the `DOCKER_SCRIPT` environment variable. For example, to reproduce the `x86_64-gnu-llvm-19-3` workflow, you can run the following script:
+For some Linux workflows (for example `x86_64-gnu-llvm-20-N`), the process is more involved. You will need to see which script is executed for the given workflow inside the [`jobs.yml`](../github-actions/jobs.yml) file and pass it through the `DOCKER_SCRIPT` environment variable. For example, to reproduce the `x86_64-gnu-llvm-20-3` workflow, you can run the following script:
 
 ```
-DOCKER_SCRIPT=x86_64-gnu-llvm3.sh ./src/ci/docker/run.sh x86_64-gnu-llvm-19
+DOCKER_SCRIPT=x86_64-gnu-llvm3.sh ./src/ci/docker/run.sh x86_64-gnu-llvm-20
 ```
 
 ## Local Development
diff --git a/src/ci/docker/host-aarch64/aarch64-gnu-llvm-19/Dockerfile b/src/ci/docker/host-aarch64/aarch64-gnu-llvm-20/Dockerfile
index e73fbe506f7..adbb1f03378 100644
--- a/src/ci/docker/host-aarch64/aarch64-gnu-llvm-19/Dockerfile
+++ b/src/ci/docker/host-aarch64/aarch64-gnu-llvm-20/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:24.10
+FROM ubuntu:25.04
 
 ARG DEBIAN_FRONTEND=noninteractive
 
@@ -15,8 +15,8 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   cmake \
   sudo \
   gdb \
-  llvm-19-tools \
-  llvm-19-dev \
+  llvm-20-tools \
+  llvm-20-dev \
   libedit-dev \
   libssl-dev \
   pkg-config \
@@ -43,7 +43,7 @@ ENV EXTERNAL_LLVM 1
 # Using llvm-link-shared due to libffi issues -- see #34486
 ENV RUST_CONFIGURE_ARGS \
       --build=aarch64-unknown-linux-gnu \
-      --llvm-root=/usr/lib/llvm-19 \
+      --llvm-root=/usr/lib/llvm-20 \
       --enable-llvm-link-shared \
       --set rust.randomize-layout=true \
       --set rust.thin-lto-import-instr-limit=10
diff --git a/src/ci/docker/host-x86_64/x86_64-gnu-llvm-19/Dockerfile b/src/ci/docker/host-x86_64/x86_64-gnu-llvm-19/Dockerfile
deleted file mode 100644
index 5cba7c564f1..00000000000
--- a/src/ci/docker/host-x86_64/x86_64-gnu-llvm-19/Dockerfile
+++ /dev/null
@@ -1,66 +0,0 @@
-FROM ubuntu:24.10
-
-ARG DEBIAN_FRONTEND=noninteractive
-
-RUN apt-get update && apt-get install -y --no-install-recommends \
-  bzip2 \
-  g++ \
-  gcc-multilib \
-  make \
-  ninja-build \
-  file \
-  curl \
-  ca-certificates \
-  python3 \
-  git \
-  cmake \
-  sudo \
-  gdb \
-  llvm-19-tools \
-  llvm-19-dev \
-  libedit-dev \
-  libssl-dev \
-  pkg-config \
-  zlib1g-dev \
-  xz-utils \
-  nodejs \
-  mingw-w64 \
-  # libgccjit dependencies
-  flex \
-  libmpfr-dev \
-  libgmp-dev \
-  libmpc3 \
-  libmpc-dev \
-  && rm -rf /var/lib/apt/lists/*
-
-# Install powershell (universal package) so we can test x.ps1 on Linux
-# FIXME: need a "universal" version that supports libicu74, but for now it still works to ignore that dep.
-RUN curl -sL "https://github.com/PowerShell/PowerShell/releases/download/v7.3.1/powershell_7.3.1-1.deb_amd64.deb" > powershell.deb && \
-    dpkg --ignore-depends=libicu72 -i powershell.deb && \
-    rm -f powershell.deb
-
-COPY scripts/sccache.sh /scripts/
-RUN sh /scripts/sccache.sh
-
-# We are disabling CI LLVM since this builder is intentionally using a host
-# LLVM, rather than the typical src/llvm-project LLVM.
-ENV NO_DOWNLOAD_CI_LLVM 1
-ENV EXTERNAL_LLVM 1
-
-# Using llvm-link-shared due to libffi issues -- see #34486
-ENV RUST_CONFIGURE_ARGS \
-      --build=x86_64-unknown-linux-gnu \
-      --llvm-root=/usr/lib/llvm-19 \
-      --enable-llvm-link-shared \
-      --set rust.randomize-layout=true \
-      --set rust.thin-lto-import-instr-limit=10
-
-COPY scripts/shared.sh /scripts/
-
-COPY scripts/x86_64-gnu-llvm.sh /scripts/
-COPY scripts/x86_64-gnu-llvm2.sh /scripts/
-COPY scripts/x86_64-gnu-llvm3.sh /scripts/
-COPY scripts/stage_2_test_set1.sh /scripts/
-COPY scripts/stage_2_test_set2.sh /scripts/
-
-ENV SCRIPT "Must specify DOCKER_SCRIPT for this image"
diff --git a/src/ci/github-actions/jobs.yml b/src/ci/github-actions/jobs.yml
index 35b9456d37d..b3e3fe7d96a 100644
--- a/src/ci/github-actions/jobs.yml
+++ b/src/ci/github-actions/jobs.yml
@@ -122,19 +122,19 @@ pr:
       # tidy. This speeds up the PR CI job by ~1 minute.
       SKIP_SUBMODULES: src/gcc
     <<: *job-linux-4c
-  - name: x86_64-gnu-llvm-19
+  - name: x86_64-gnu-llvm-20
     env:
       ENABLE_GCC_CODEGEN: "1"
       DOCKER_SCRIPT: x86_64-gnu-llvm.sh
     <<: *job-linux-4c
-  - name: aarch64-gnu-llvm-19-1
+  - name: aarch64-gnu-llvm-20-1
     env:
-      IMAGE: aarch64-gnu-llvm-19
+      IMAGE: aarch64-gnu-llvm-20
       DOCKER_SCRIPT: stage_2_test_set1.sh
     <<: *job-aarch64-linux
-  - name: aarch64-gnu-llvm-19-2
+  - name: aarch64-gnu-llvm-20-2
     env:
-      IMAGE: aarch64-gnu-llvm-19
+      IMAGE: aarch64-gnu-llvm-20
       DOCKER_SCRIPT: stage_2_test_set2.sh
     <<: *job-aarch64-linux
   - name: x86_64-gnu-tools
@@ -397,31 +397,6 @@ auto:
       DOCKER_SCRIPT: x86_64-gnu-llvm3.sh
     <<: *job-linux-4c
 
-  # The x86_64-gnu-llvm-19 job is split into multiple jobs to run tests in parallel.
-  # x86_64-gnu-llvm-19-1 skips tests that run in x86_64-gnu-llvm-19-{2,3}.
-  - name: x86_64-gnu-llvm-19-1
-    env:
-      RUST_BACKTRACE: 1
-      IMAGE: x86_64-gnu-llvm-19
-      DOCKER_SCRIPT: stage_2_test_set2.sh
-    <<: *job-linux-4c
-
-  # Skip tests that run in x86_64-gnu-llvm-19-{1,3}
-  - name: x86_64-gnu-llvm-19-2
-    env:
-      RUST_BACKTRACE: 1
-      IMAGE: x86_64-gnu-llvm-19
-      DOCKER_SCRIPT: x86_64-gnu-llvm2.sh
-    <<: *job-linux-4c
-
-  # Skip tests that run in x86_64-gnu-llvm-19-{1,2}
-  - name: x86_64-gnu-llvm-19-3
-    env:
-      RUST_BACKTRACE: 1
-      IMAGE: x86_64-gnu-llvm-19
-      DOCKER_SCRIPT: x86_64-gnu-llvm3.sh
-    <<: *job-linux-4c
-
   - name: x86_64-gnu-nopt
     <<: *job-linux-4c
 
diff --git a/src/doc/rustc/src/target-tier-policy.md b/src/doc/rustc/src/target-tier-policy.md
index 28d3dc32a63..f6b78eed24f 100644
--- a/src/doc/rustc/src/target-tier-policy.md
+++ b/src/doc/rustc/src/target-tier-policy.md
@@ -701,4 +701,4 @@ RFC process, with approval by the compiler and infra teams. Any such proposal
 will be communicated widely to the Rust community, both when initially proposed
 and before being dropped from a stable release.
 
-[MCP]: https://forge.rust-lang.org/compiler/mcp.html
+[MCP]: https://forge.rust-lang.org/compiler/proposals-and-stabilization.html#how-do-i-submit-an-mcp
diff --git a/src/doc/rustc/src/tests/index.md b/src/doc/rustc/src/tests/index.md
index 7609ed23351..7a108a71beb 100644
--- a/src/doc/rustc/src/tests/index.md
+++ b/src/doc/rustc/src/tests/index.md
@@ -158,6 +158,18 @@ unstable-options` flag. See [tracking issue
 
 The following options affect how tests are executed.
 
+#### `--fail-fast`
+
+Stops tests after the first failure.
+
+If running tests in parallel (which is the default), then tests that have already been started on
+other threads will be allowed to run to completion before the process exits.
+
+Note that when running tests in parallel, the test execution order is non-deterministic:
+if multiple tests would fail, the first failure encountered will be reported.
+
+⚠️ 🚧 This requires the `-Z unstable-options` flag.
+
 #### `--test-threads` _NUM_THREADS_
 
 Sets the number of threads to use for running tests in parallel. By default,
diff --git a/src/tools/compiletest/src/common.rs b/src/tools/compiletest/src/common.rs
index 143ccdcb9e5..6da102b1b5f 100644
--- a/src/tools/compiletest/src/common.rs
+++ b/src/tools/compiletest/src/common.rs
@@ -203,6 +203,10 @@ impl CodegenBackend {
             Self::Llvm => "llvm",
         }
     }
+
+    pub fn is_llvm(self) -> bool {
+        matches!(self, Self::Llvm)
+    }
 }
 
 /// Configuration for `compiletest` *per invocation*.
diff --git a/src/tools/compiletest/src/directives/needs.rs b/src/tools/compiletest/src/directives/needs.rs
index ee46f4c70cb..3b7a9478717 100644
--- a/src/tools/compiletest/src/directives/needs.rs
+++ b/src/tools/compiletest/src/directives/needs.rs
@@ -81,8 +81,8 @@ pub(super) fn handle_needs(
         },
         Need {
             name: "needs-enzyme",
-            condition: config.has_enzyme,
-            ignore_reason: "ignored when LLVM Enzyme is disabled",
+            condition: config.has_enzyme && config.default_codegen_backend.is_llvm(),
+            ignore_reason: "ignored when LLVM Enzyme is disabled or LLVM is not the default codegen backend",
         },
         Need {
             name: "needs-run-enabled",
@@ -161,8 +161,8 @@ pub(super) fn handle_needs(
         },
         Need {
             name: "needs-llvm-zstd",
-            condition: cache.llvm_zstd,
-            ignore_reason: "ignored if LLVM wasn't build with zstd for ELF section compression",
+            condition: cache.llvm_zstd && config.default_codegen_backend.is_llvm(),
+            ignore_reason: "ignored if LLVM wasn't build with zstd for ELF section compression or LLVM is not the default codegen backend",
         },
         Need {
             name: "needs-rustc-debug-assertions",
@@ -279,7 +279,10 @@ pub(super) fn handle_needs(
 
     // Handled elsewhere.
     if name == "needs-llvm-components" {
-        return IgnoreDecision::Continue;
+        if config.default_codegen_backend.is_llvm() {
+            return IgnoreDecision::Continue;
+        }
+        return IgnoreDecision::Ignore { reason: "LLVM specific test".into() };
     }
 
     let mut found_valid = false;
diff --git a/src/tools/compiletest/src/executor.rs b/src/tools/compiletest/src/executor.rs
index 37cc17351d5..c8e13d44573 100644
--- a/src/tools/compiletest/src/executor.rs
+++ b/src/tools/compiletest/src/executor.rs
@@ -295,11 +295,14 @@ fn filter_tests(opts: &Config, tests: Vec<CollectedTest>) -> Vec<CollectedTest>
     let mut filtered = tests;
 
     let matches_filter = |test: &CollectedTest, filter_str: &str| {
-        let filterable_path = test.desc.filterable_path.as_str();
         if opts.filter_exact {
-            filterable_path == filter_str
+            // When `--exact` is used we must use `filterable_path` to get
+            // reasonable filtering behavior.
+            test.desc.filterable_path.as_str() == filter_str
         } else {
-            filterable_path.contains(filter_str)
+            // For compatibility we use the name (which includes the full path)
+            // if `--exact` is not used.
+            test.desc.name.contains(filter_str)
         }
     };
 
diff --git a/src/tools/compiletest/src/lib.rs b/src/tools/compiletest/src/lib.rs
index 5e349a20ed2..ce2a3d4b5fb 100644
--- a/src/tools/compiletest/src/lib.rs
+++ b/src/tools/compiletest/src/lib.rs
@@ -484,7 +484,7 @@ pub fn parse_config(args: Vec<String>) -> Config {
             let value = matches
                 .opt_str("new-output-capture")
                 .or_else(|| env::var("COMPILETEST_NEW_OUTPUT_CAPTURE").ok())
-                .unwrap_or_else(|| "off".to_owned());
+                .unwrap_or_else(|| "on".to_owned());
             parse_bool_option(&value)
                 .unwrap_or_else(|| panic!("unknown `--new-output-capture` value `{value}` given"))
         },
diff --git a/src/tools/miri/tests/fail/both_borrows/issue-miri-1050-1.rs b/src/tools/miri/tests/fail/both_borrows/issue-miri-1050-1.rs
index dd7dae9cecf..d907c5de797 100644
--- a/src/tools/miri/tests/fail/both_borrows/issue-miri-1050-1.rs
+++ b/src/tools/miri/tests/fail/both_borrows/issue-miri-1050-1.rs
@@ -1,4 +1,6 @@
 //@revisions: stack tree
+// Ensure this even hits the aliasing model
+//@compile-flags: -Zmiri-disable-validation
 //@[tree]compile-flags: -Zmiri-tree-borrows
 //@error-in-other-file: pointer not dereferenceable
 
diff --git a/src/tools/miri/tests/fail/both_borrows/issue-miri-1050-2.rs b/src/tools/miri/tests/fail/both_borrows/issue-miri-1050-2.rs
index 5c947e64142..b54f27bb8b2 100644
--- a/src/tools/miri/tests/fail/both_borrows/issue-miri-1050-2.rs
+++ b/src/tools/miri/tests/fail/both_borrows/issue-miri-1050-2.rs
@@ -1,4 +1,6 @@
 //@revisions: stack tree
+// Ensure this even hits the aliasing model
+//@compile-flags: -Zmiri-disable-validation
 //@[tree]compile-flags: -Zmiri-tree-borrows
 //@error-in-other-file: is a dangling pointer
 use std::ptr::NonNull;
diff --git a/src/tools/miri/tests/fail/both_borrows/return_invalid_shr.stack.stderr b/src/tools/miri/tests/fail/both_borrows/return_invalid_shr.stack.stderr
index d52143500c4..7c4fe748701 100644
--- a/src/tools/miri/tests/fail/both_borrows/return_invalid_shr.stack.stderr
+++ b/src/tools/miri/tests/fail/both_borrows/return_invalid_shr.stack.stderr
@@ -11,7 +11,7 @@ help: <TAG> was created by a SharedReadOnly retag at offsets [0x4..0x8]
    |
 LL |     let ret = unsafe { &(*xraw).1 };
    |                        ^^^^^^^^^^
-help: <TAG> was later invalidated at offsets [0x0..0x8] by a write access
+help: <TAG> was later invalidated at offsets [0x4..0x8] by a write access
   --> tests/fail/both_borrows/return_invalid_shr.rs:LL:CC
    |
 LL |     unsafe { *xraw = (42, 23) }; // unfreeze
diff --git a/src/tools/miri/tests/fail/both_borrows/return_invalid_shr.tree.stderr b/src/tools/miri/tests/fail/both_borrows/return_invalid_shr.tree.stderr
index ee0f313d980..a8e3553aae2 100644
--- a/src/tools/miri/tests/fail/both_borrows/return_invalid_shr.tree.stderr
+++ b/src/tools/miri/tests/fail/both_borrows/return_invalid_shr.tree.stderr
@@ -12,7 +12,7 @@ help: the accessed tag <TAG> was created here, in the initial state Frozen
    |
 LL |     let ret = unsafe { &(*xraw).1 };
    |                        ^^^^^^^^^^
-help: the accessed tag <TAG> later transitioned to Disabled due to a foreign write access at offsets [0x0..0x8]
+help: the accessed tag <TAG> later transitioned to Disabled due to a foreign write access at offsets [0x4..0x8]
   --> tests/fail/both_borrows/return_invalid_shr.rs:LL:CC
    |
 LL |     unsafe { *xraw = (42, 23) }; // unfreeze
diff --git a/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_option.stack.stderr b/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_option.stack.stderr
index d66c8eeb1af..8411437ea4c 100644
--- a/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_option.stack.stderr
+++ b/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_option.stack.stderr
@@ -14,7 +14,7 @@ help: <TAG> was created by a SharedReadOnly retag at offsets [0x4..0x8]
    |
 LL |     let ret = Some(unsafe { &(*xraw).1 });
    |               ^^^^^^^^^^^^^^^^^^^^^^^^^^^
-help: <TAG> was later invalidated at offsets [0x0..0x8] by a write access
+help: <TAG> was later invalidated at offsets [0x4..0x8] by a write access
   --> tests/fail/both_borrows/return_invalid_shr_option.rs:LL:CC
    |
 LL |     unsafe { *xraw = (42, 23) }; // unfreeze
diff --git a/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_option.tree.stderr b/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_option.tree.stderr
index 16110e5b062..39da45ad6db 100644
--- a/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_option.tree.stderr
+++ b/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_option.tree.stderr
@@ -12,7 +12,7 @@ help: the accessed tag <TAG> was created here, in the initial state Frozen
    |
 LL |     let ret = Some(unsafe { &(*xraw).1 });
    |               ^^^^^^^^^^^^^^^^^^^^^^^^^^^
-help: the accessed tag <TAG> later transitioned to Disabled due to a foreign write access at offsets [0x0..0x8]
+help: the accessed tag <TAG> later transitioned to Disabled due to a foreign write access at offsets [0x4..0x8]
   --> tests/fail/both_borrows/return_invalid_shr_option.rs:LL:CC
    |
 LL |     unsafe { *xraw = (42, 23) }; // unfreeze
diff --git a/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_tuple.stack.stderr b/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_tuple.stack.stderr
index 727b52ec729..a7c422aa73f 100644
--- a/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_tuple.stack.stderr
+++ b/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_tuple.stack.stderr
@@ -14,7 +14,7 @@ help: <TAG> was created by a SharedReadOnly retag at offsets [0x4..0x8]
    |
 LL |     let ret = (unsafe { &(*xraw).1 },);
    |               ^^^^^^^^^^^^^^^^^^^^^^^^
-help: <TAG> was later invalidated at offsets [0x0..0x8] by a write access
+help: <TAG> was later invalidated at offsets [0x4..0x8] by a write access
   --> tests/fail/both_borrows/return_invalid_shr_tuple.rs:LL:CC
    |
 LL |     unsafe { *xraw = (42, 23) }; // unfreeze
diff --git a/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_tuple.tree.stderr b/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_tuple.tree.stderr
index f93698f570e..66b03e57905 100644
--- a/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_tuple.tree.stderr
+++ b/src/tools/miri/tests/fail/both_borrows/return_invalid_shr_tuple.tree.stderr
@@ -12,7 +12,7 @@ help: the accessed tag <TAG> was created here, in the initial state Frozen
    |
 LL |     let ret = (unsafe { &(*xraw).1 },);
    |               ^^^^^^^^^^^^^^^^^^^^^^^^
-help: the accessed tag <TAG> later transitioned to Disabled due to a foreign write access at offsets [0x0..0x8]
+help: the accessed tag <TAG> later transitioned to Disabled due to a foreign write access at offsets [0x4..0x8]
   --> tests/fail/both_borrows/return_invalid_shr_tuple.rs:LL:CC
    |
 LL |     unsafe { *xraw = (42, 23) }; // unfreeze
diff --git a/src/tools/miri/tests/fail/overlapping_assignment_aggregate.rs b/src/tools/miri/tests/fail/overlapping_assignment_aggregate.rs
new file mode 100644
index 00000000000..8d7b1946242
--- /dev/null
+++ b/src/tools/miri/tests/fail/overlapping_assignment_aggregate.rs
@@ -0,0 +1,18 @@
+//! This is like `pass/overlapping_assignment_aggregate_scalar.rs` but with a non-scalar
+//! type, and that makes it definite UB.
+#![feature(custom_mir, core_intrinsics)]
+#![allow(internal_features)]
+
+use std::intrinsics::mir::*;
+
+#[custom_mir(dialect = "runtime")]
+fn main() {
+    mir! {
+        let _1: ([u8; 1],);
+        {
+            _1.0 = [0_u8; 1];
+            _1 = (_1.0, ); //~ERROR: overlapping ranges
+            Return()
+        }
+    }
+}
diff --git a/src/tools/miri/tests/fail/overlapping_assignment_aggregate.stderr b/src/tools/miri/tests/fail/overlapping_assignment_aggregate.stderr
new file mode 100644
index 00000000000..f2a6d326b71
--- /dev/null
+++ b/src/tools/miri/tests/fail/overlapping_assignment_aggregate.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `copy_nonoverlapping` called on overlapping ranges
+  --> tests/fail/overlapping_assignment_aggregate.rs:LL:CC
+   |
+LL |             _1 = (_1.0, );
+   |             ^^^^^^^^^^^^^ Undefined Behavior occurred here
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at tests/fail/overlapping_assignment_aggregate.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to 1 previous error
+
diff --git a/src/tools/miri/tests/fail/validity/nonzero.stderr b/src/tools/miri/tests/fail/validity/nonzero.stderr
index 0c3a35d6b9f..7be3ef46639 100644
--- a/src/tools/miri/tests/fail/validity/nonzero.stderr
+++ b/src/tools/miri/tests/fail/validity/nonzero.stderr
@@ -2,7 +2,7 @@ error: Undefined Behavior: constructing invalid value: encountered 0, but expect
   --> tests/fail/validity/nonzero.rs:LL:CC
    |
 LL |     let _x = Some(unsafe { NonZero(0) });
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
+   |                            ^^^^^^^^^^ Undefined Behavior occurred here
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/src/tools/miri/tests/pass/overlapping_assignment_aggregate_scalar.rs b/src/tools/miri/tests/pass/overlapping_assignment_aggregate_scalar.rs
new file mode 100644
index 00000000000..0cb2f764242
--- /dev/null
+++ b/src/tools/miri/tests/pass/overlapping_assignment_aggregate_scalar.rs
@@ -0,0 +1,19 @@
+#![feature(custom_mir, core_intrinsics)]
+#![allow(internal_features)]
+
+use std::intrinsics::mir::*;
+
+#[custom_mir(dialect = "runtime")]
+fn main() {
+    mir! {
+        let _1: (u8,);
+        {
+            _1.0 = 0_u8;
+            // This is a scalar type, so overlap is (for now) not UB.
+            // However, we used to treat such overlapping assignments incorrectly
+            // (see <https://github.com/rust-lang/rust/issues/146383#issuecomment-3273224645>).
+            _1 = (_1.0, );
+            Return()
+        }
+    }
+}
diff --git a/src/tools/opt-dist/src/training.rs b/src/tools/opt-dist/src/training.rs
index 4f9352d11b1..b3e95e087e3 100644
--- a/src/tools/opt-dist/src/training.rs
+++ b/src/tools/opt-dist/src/training.rs
@@ -39,7 +39,6 @@ fn init_compiler_benchmarks(
         "--exact-match",
         crates.join(",").as_str(),
     ])
-    .env("RUST_LOG", "collector=debug")
     .env("RUSTC", env.rustc_stage_0().as_str())
     .env("RUSTC_BOOTSTRAP", "1")
     .workdir(&env.rustc_perf_dir());
diff --git a/src/tools/tidy/src/pal.rs b/src/tools/tidy/src/pal.rs
index 5b8b44429bb..991ad55809c 100644
--- a/src/tools/tidy/src/pal.rs
+++ b/src/tools/tidy/src/pal.rs
@@ -53,6 +53,7 @@ const EXCEPTION_PATHS: &[&str] = &[
     // core::ffi contains platform-specific type and linkage configuration
     "library/core/src/ffi/mod.rs",
     "library/core/src/ffi/primitives.rs",
+    "library/core/src/os", // Platform-specific public interfaces
     "library/std/src/sys", // Platform-specific code for std lives here.
     "library/std/src/os",  // Platform-specific public interfaces
     // Temporary `std` exceptions
diff --git a/tests/assembly-llvm/riscv-soft-abi-with-float-features.rs b/tests/assembly-llvm/riscv-soft-abi-with-float-features.rs
index 72cbd3841c1..085ea9facd0 100644
--- a/tests/assembly-llvm/riscv-soft-abi-with-float-features.rs
+++ b/tests/assembly-llvm/riscv-soft-abi-with-float-features.rs
@@ -2,9 +2,6 @@
 //@ assembly-output: emit-asm
 //@ compile-flags: --target riscv64imac-unknown-none-elf -Ctarget-feature=+f,+d
 //@ needs-llvm-components: riscv
-//@ revisions: LLVM-PRE-20 LLVM-POST-20
-//@ [LLVM-PRE-20] max-llvm-major-version: 19
-//@ [LLVM-POST-20] min-llvm-version: 20
 
 #![feature(no_core, lang_items, f16)]
 #![crate_type = "lib"]
@@ -28,11 +25,8 @@ pub extern "C" fn read_f16(x: &f16) -> f16 {
 // CHECK-LABEL: read_f32
 #[no_mangle]
 pub extern "C" fn read_f32(x: &f32) -> f32 {
-    // LLVM-PRE-20: flw fa5, 0(a0)
-    // LLVM-PRE-20-NEXT: fmv.x.w a0, fa5
-    // LLVM-PRE-20-NEXT: ret
-    // LLVM-POST-20: lw a0, 0(a0)
-    // LLVM-POST-20-NEXT: ret
+    // CHECK: lw a0, 0(a0)
+    // CHECK-NEXT: ret
     *x
 }
 
diff --git a/tests/assembly-llvm/x86_64-bigint-helpers.rs b/tests/assembly-llvm/x86_64-bigint-helpers.rs
index c5efda58fd6..64aa0257238 100644
--- a/tests/assembly-llvm/x86_64-bigint-helpers.rs
+++ b/tests/assembly-llvm/x86_64-bigint-helpers.rs
@@ -2,7 +2,6 @@
 //@ assembly-output: emit-asm
 //@ compile-flags: --crate-type=lib -Copt-level=3 -C target-cpu=x86-64-v4
 //@ compile-flags: -C llvm-args=-x86-asm-syntax=intel
-//@ min-llvm-version: 20
 
 #![no_std]
 #![feature(bigint_helper_methods)]
diff --git a/tests/assembly-llvm/x86_64-cmp.rs b/tests/assembly-llvm/x86_64-cmp.rs
index 26c9013d96f..1f1fe7fd005 100644
--- a/tests/assembly-llvm/x86_64-cmp.rs
+++ b/tests/assembly-llvm/x86_64-cmp.rs
@@ -1,12 +1,6 @@
-//@ revisions: LLVM-PRE-20-DEBUG LLVM-20-DEBUG LLVM-PRE-20-OPTIM LLVM-20-OPTIM
-//@ [LLVM-PRE-20-DEBUG] compile-flags: -C opt-level=0
-//@ [LLVM-PRE-20-DEBUG] max-llvm-major-version: 19
-//@ [LLVM-20-DEBUG] compile-flags: -C opt-level=0
-//@ [LLVM-20-DEBUG] min-llvm-version: 20
-//@ [LLVM-PRE-20-OPTIM] compile-flags: -C opt-level=3
-//@ [LLVM-PRE-20-OPTIM] max-llvm-major-version: 19
-//@ [LLVM-20-OPTIM] compile-flags: -C opt-level=3
-//@ [LLVM-20-OPTIM] min-llvm-version: 20
+//@ revisions: DEBUG OPTIM
+//@ [DEBUG] compile-flags: -C opt-level=0
+//@ [OPTIM] compile-flags: -C opt-level=3
 //@ assembly-output: emit-asm
 //@ compile-flags: --crate-type=lib -C llvm-args=-x86-asm-syntax=intel
 //@ only-x86_64
@@ -19,61 +13,22 @@ use std::intrinsics::three_way_compare;
 #[no_mangle]
 // CHECK-LABEL: signed_cmp:
 pub fn signed_cmp(a: i16, b: i16) -> std::cmp::Ordering {
-    // LLVM-PRE-20-DEBUG: cmp
-    // LLVM-PRE-20-DEBUG: setg
-    // LLVM-PRE-20-DEBUG: and
-    // LLVM-PRE-20-DEBUG: cmp
-    // LLVM-PRE-20-DEBUG: setl
-    // LLVM-PRE-20-DEBUG: and
-    // LLVM-PRE-20-DEBUG: sub
-    //
-    // LLVM-20-DEBUG: sub
-    // LLVM-20-DEBUG: setl
-    // LLVM-20-DEBUG: setg
-    // LLVM-20-DEBUG: sub
-    // LLVM-20-DEBUG: ret
-
-    // LLVM-PRE-20-OPTIM: xor
-    // LLVM-PRE-20-OPTIM: cmp
-    // LLVM-PRE-20-OPTIM: setne
-    // LLVM-PRE-20-OPTIM: mov
-    // LLVM-PRE-20-OPTIM: cmovge
-    // LLVM-PRE-20-OPTIM: ret
-    //
-    // LLVM-20-OPTIM: cmp
-    // LLVM-20-OPTIM: setl
-    // LLVM-20-OPTIM: setg
-    // LLVM-20-OPTIM: sub
-    // LLVM-20-OPTIM: ret
+    // DEBUG: sub
+    // OPTIM: cmp
+    // CHECK: setl
+    // CHECK: setg
+    // CHECK: sub
+    // CHECK: ret
     three_way_compare(a, b)
 }
 
 #[no_mangle]
 // CHECK-LABEL: unsigned_cmp:
 pub fn unsigned_cmp(a: u16, b: u16) -> std::cmp::Ordering {
-    // LLVM-PRE-20-DEBUG: cmp
-    // LLVM-PRE-20-DEBUG: seta
-    // LLVM-PRE-20-DEBUG: and
-    // LLVM-PRE-20-DEBUG: cmp
-    // LLVM-PRE-20-DEBUG: setb
-    // LLVM-PRE-20-DEBUG: and
-    // LLVM-PRE-20-DEBUG: sub
-    //
-    // LLVM-20-DEBUG: sub
-    // LLVM-20-DEBUG: seta
-    // LLVM-20-DEBUG: sbb
-    // LLVM-20-DEBUG: ret
-
-    // LLVM-PRE-20-OPTIM: xor
-    // LLVM-PRE-20-OPTIM: cmp
-    // LLVM-PRE-20-OPTIM: setne
-    // LLVM-PRE-20-OPTIM: mov
-    // LLVM-PRE-20-OPTIM: cmovae
-    // LLVM-PRE-20-OPTIM: ret
-    //
-    // LLVM-20-OPTIM: cmp
-    // LLVM-20-OPTIM: seta
-    // LLVM-20-OPTIM: sbb
-    // LLVM-20-OPTIM: ret
+    // DEBUG: sub
+    // OPTIM: cmp
+    // CHECK: seta
+    // CHECK: sbb
+    // CHECK: ret
     three_way_compare(a, b)
 }
diff --git a/tests/codegen-llvm/asm/riscv-clobbers.rs b/tests/codegen-llvm/asm/riscv-clobbers.rs
index e55b6731098..0f235ddcdcc 100644
--- a/tests/codegen-llvm/asm/riscv-clobbers.rs
+++ b/tests/codegen-llvm/asm/riscv-clobbers.rs
@@ -17,7 +17,7 @@ extern crate minicore;
 use minicore::*;
 
 // CHECK-LABEL: @flags_clobber
-// CHECK: call void asm sideeffect "", "~{vtype},~{vl},~{vxsat},~{vxrm}"()
+// CHECK: call void asm sideeffect "", "~{fflags},~{vtype},~{vl},~{vxsat},~{vxrm}"()
 #[no_mangle]
 pub unsafe fn flags_clobber() {
     asm!("", options(nostack, nomem));
diff --git a/tests/codegen-llvm/auxiliary/darwin_objc_aux.rs b/tests/codegen-llvm/auxiliary/darwin_objc_aux.rs
new file mode 100644
index 00000000000..3c35d003c8a
--- /dev/null
+++ b/tests/codegen-llvm/auxiliary/darwin_objc_aux.rs
@@ -0,0 +1,27 @@
+#![crate_type = "lib"]
+#![feature(darwin_objc)]
+
+use std::os::darwin::objc;
+
+#[link(name = "Foundation", kind = "framework")]
+unsafe extern "C" {}
+
+#[inline(always)]
+pub fn inline_get_object_class() -> objc::Class {
+    objc::class!("NSObject")
+}
+
+#[inline(always)]
+pub fn inline_get_alloc_selector() -> objc::SEL {
+    objc::selector!("alloc")
+}
+
+#[inline(never)]
+pub fn never_inline_get_string_class() -> objc::Class {
+    objc::class!("NSString")
+}
+
+#[inline(never)]
+pub fn never_inline_get_init_selector() -> objc::SEL {
+    objc::selector!("init")
+}
diff --git a/tests/codegen-llvm/comparison-operators-2-struct.rs b/tests/codegen-llvm/comparison-operators-2-struct.rs
index e179066ebfd..d44f92f511b 100644
--- a/tests/codegen-llvm/comparison-operators-2-struct.rs
+++ b/tests/codegen-llvm/comparison-operators-2-struct.rs
@@ -1,5 +1,4 @@
 //@ compile-flags: -C opt-level=1
-//@ min-llvm-version: 20
 
 // The `derive(PartialOrd)` for a 2-field type doesn't override `lt`/`le`/`gt`/`ge`.
 // This double-checks that the `Option<Ordering>` intermediate values used
diff --git a/tests/codegen-llvm/comparison-operators-2-tuple.rs b/tests/codegen-llvm/comparison-operators-2-tuple.rs
index 6a7e489c82d..37a7c5dfdaf 100644
--- a/tests/codegen-llvm/comparison-operators-2-tuple.rs
+++ b/tests/codegen-llvm/comparison-operators-2-tuple.rs
@@ -1,5 +1,4 @@
 //@ compile-flags: -C opt-level=1 -Z merge-functions=disabled
-//@ min-llvm-version: 20
 
 #![crate_type = "lib"]
 
diff --git a/tests/codegen-llvm/darwin-no-objc.rs b/tests/codegen-llvm/darwin-no-objc.rs
new file mode 100644
index 00000000000..fda3671fb6d
--- /dev/null
+++ b/tests/codegen-llvm/darwin-no-objc.rs
@@ -0,0 +1,52 @@
+// Test that we don't generate Objective-C definitions or image info unnecessarily.
+
+//@ add-core-stubs
+//@ revisions: i686_apple_darwin
+//@ [i686_apple_darwin] compile-flags: --target i686-apple-darwin
+//@ [i686_apple_darwin] needs-llvm-components: x86
+//@ revisions: x86_64_macos
+//@ [x86_64_macos] compile-flags: --target x86_64-apple-darwin
+//@ [x86_64_macos] needs-llvm-components: x86
+//@ revisions: aarch64_macos
+//@ [aarch64_macos] compile-flags: --target aarch64-apple-darwin
+//@ [aarch64_macos] needs-llvm-components: aarch64
+//@ revisions: i386_ios
+//@ [i386_ios] compile-flags: --target i386-apple-ios
+//@ [i386_ios] needs-llvm-components: x86
+//@ revisions: x86_64_ios
+//@ [x86_64_ios] compile-flags: --target x86_64-apple-ios
+//@ [x86_64_ios] needs-llvm-components: x86
+//@ revisions: armv7s_ios
+//@ [armv7s_ios] compile-flags: --target armv7s-apple-ios
+//@ [armv7s_ios] needs-llvm-components: arm
+//@ revisions: aarch64_ios
+//@ [aarch64_ios] compile-flags: --target aarch64-apple-ios
+//@ [aarch64_ios] needs-llvm-components: aarch64
+//@ revisions: aarch64_ios_sim
+//@ [aarch64_ios_sim] compile-flags: --target aarch64-apple-ios-sim
+//@ [aarch64_ios_sim] needs-llvm-components: aarch64
+
+#![crate_type = "lib"]
+#![feature(no_core, lang_items)]
+#![no_core]
+
+extern crate minicore;
+use minicore::*;
+
+#[no_mangle]
+pub fn foo() {}
+
+// CHECK-NOT: %struct._class_t
+// CHECK-NOT: %struct._objc_module
+// CHECK-NOT: @OBJC_CLASS_NAME_
+// CHECK-NOT: @"OBJC_CLASS_$_{{[0-9A-Z_a-z]+}}"
+// CHECK-NOT: @"OBJC_CLASSLIST_REFERENCES_$_.{{[0-9]+}}"
+// CHECK-NOT: @OBJC_METH_VAR_NAME_
+// CHECK-NOT: @OBJC_SELECTOR_REFERENCES_
+// CHECK-NOT: @OBJC_MODULES
+
+// CHECK-NOT: !"Objective-C Version"
+// CHECK-NOT: !"Objective-C Image Info Version"
+// CHECK-NOT: !"Objective-C Image Info Section"
+// CHECK-NOT: !"Objective-C Is Simulated"
+// CHECK-NOT: !"Objective-C Class Properties"
diff --git a/tests/codegen-llvm/darwin-objc-abi-v1.rs b/tests/codegen-llvm/darwin-objc-abi-v1.rs
new file mode 100644
index 00000000000..0fc1de9332a
--- /dev/null
+++ b/tests/codegen-llvm/darwin-objc-abi-v1.rs
@@ -0,0 +1,100 @@
+// ignore-tidy-linelength
+//@ add-core-stubs
+//@ revisions: i686_apple_darwin
+//@ [i686_apple_darwin] compile-flags: --target i686-apple-darwin
+//@ [i686_apple_darwin] needs-llvm-components: x86
+
+#![crate_type = "lib"]
+#![feature(no_core, lang_items, rustc_attrs)]
+#![no_core]
+
+extern crate minicore;
+use minicore::*;
+
+#[no_mangle]
+pub fn get_class() -> *mut () {
+    unsafe extern "C" {
+        #[rustc_objc_class = "MyClass"]
+        safe static VAL: *mut ();
+    }
+    VAL
+}
+
+#[no_mangle]
+pub fn get_class_again() -> *mut () {
+    // Codegen should de-duplicate this class with the one from get_class above.
+    unsafe extern "C" {
+        #[rustc_objc_class = "MyClass"]
+        safe static VAL: *mut ();
+    }
+    VAL
+}
+
+#[no_mangle]
+pub fn get_selector() -> *mut () {
+    unsafe extern "C" {
+        #[rustc_objc_selector = "myMethod"]
+        safe static VAL: *mut ();
+    }
+    VAL
+}
+
+#[no_mangle]
+pub fn get_selector_again() -> *mut () {
+    // Codegen should de-duplicate this selector with the one from get_selector above.
+    unsafe extern "C" {
+        #[rustc_objc_selector = "myMethod"]
+        safe static VAL: *mut ();
+    }
+    VAL
+}
+
+#[no_mangle]
+pub fn get_other_class() -> *mut () {
+    unsafe extern "C" {
+        #[rustc_objc_class = "OtherClass"]
+        safe static VAL: *mut ();
+    }
+    VAL
+}
+
+#[no_mangle]
+pub fn get_other_selector() -> *mut () {
+    unsafe extern "C" {
+        #[rustc_objc_selector = "otherMethod"]
+        safe static VAL: *mut ();
+    }
+    VAL
+}
+
+// CHECK: %struct._objc_module = type { i32, i32, ptr, ptr }
+
+// CHECK: @OBJC_CLASS_NAME_.{{[0-9]+}} = private unnamed_addr constant [8 x i8] c"MyClass\00", section "__TEXT,__cstring,cstring_literals", align 1
+// CHECK: @OBJC_CLASS_REFERENCES_.{{[0-9]+}} = private global ptr @OBJC_CLASS_NAME_.{{[0-9]+}}, section "__OBJC,__cls_refs,literal_pointers,no_dead_strip", align 4
+// CHECK-NOT: @OBJC_CLASS_NAME_
+// CHECK-NOT: @OBJC_CLASS_REFERENCES_
+
+// CHECK: @OBJC_METH_VAR_NAME_.{{[0-9]+}} = private unnamed_addr constant [9 x i8] c"myMethod\00", section "__TEXT,__cstring,cstring_literals", align 1
+// CHECK: @OBJC_SELECTOR_REFERENCES_.{{[0-9]+}} = private externally_initialized global ptr @OBJC_METH_VAR_NAME_.{{[0-9]+}}, section "__OBJC,__message_refs,literal_pointers,no_dead_strip", align 4
+// CHECK-NOT: @OBJC_METH_VAR_NAME_
+// CHECK-NOT: @OBJC_SELECTOR_REFERENCES_
+
+// CHECK: @OBJC_CLASS_NAME_.{{[0-9]+}} = private unnamed_addr constant [11 x i8] c"OtherClass\00", section "__TEXT,__cstring,cstring_literals", align 1
+// CHECK: @OBJC_CLASS_REFERENCES_.{{[0-9]+}} = private global ptr @OBJC_CLASS_NAME_.{{[0-9]+}}, section "__OBJC,__cls_refs,literal_pointers,no_dead_strip", align 4
+
+// CHECK: @OBJC_METH_VAR_NAME_.{{[0-9]+}} = private unnamed_addr constant [12 x i8] c"otherMethod\00", section "__TEXT,__cstring,cstring_literals", align 1
+// CHECK: @OBJC_SELECTOR_REFERENCES_.{{[0-9]+}} = private externally_initialized global ptr @OBJC_METH_VAR_NAME_.{{[0-9]+}}, section "__OBJC,__message_refs,literal_pointers,no_dead_strip", align 4
+
+// CHECK: @OBJC_CLASS_NAME_.{{[0-9]+}} = private unnamed_addr constant [1 x i8] zeroinitializer, section "__TEXT,__cstring,cstring_literals", align 1
+// CHECK: @OBJC_MODULES = private global %struct._objc_module { i32 7, i32 16, ptr @OBJC_CLASS_NAME_.{{[0-9]+}}, ptr null }, section "__OBJC,__module_info,regular,no_dead_strip", align 4
+
+// CHECK: load ptr, ptr @OBJC_CLASS_REFERENCES_.{{[0-9]+}}, align 4
+// CHECK: load ptr, ptr @OBJC_SELECTOR_REFERENCES_.{{[0-9]+}}, align 4
+// CHECK: load ptr, ptr @OBJC_CLASS_REFERENCES_.{{[0-9]+}}, align 4
+// CHECK: load ptr, ptr @OBJC_SELECTOR_REFERENCES_.{{[0-9]+}}, align 4
+
+// CHECK: !{{[0-9]+}} = !{i32 1, !"Objective-C Version", i32 1}
+// CHECK: !{{[0-9]+}} = !{i32 1, !"Objective-C Image Info Version", i32 0}
+// CHECK: !{{[0-9]+}} = !{i32 1, !"Objective-C Image Info Section", !"__OBJC,__image_info,regular"}
+// CHECK-NOT: !{{[0-9]+}} = !{i32 1, !"Objective-C Is Simulated", i32 32}
+// CHECK: !{{[0-9]+}} = !{i32 1, !"Objective-C Class Properties", i32 64}
diff --git a/tests/codegen-llvm/darwin-objc-abi-v2.rs b/tests/codegen-llvm/darwin-objc-abi-v2.rs
new file mode 100644
index 00000000000..f142371d582
--- /dev/null
+++ b/tests/codegen-llvm/darwin-objc-abi-v2.rs
@@ -0,0 +1,185 @@
+// ignore-tidy-linelength
+//@ add-core-stubs
+//@ revisions: x86_64_macos
+//@ [x86_64_macos] compile-flags: --target x86_64-apple-darwin
+//@ [x86_64_macos] needs-llvm-components: x86
+//@ revisions: aarch64_macos
+//@ [aarch64_macos] compile-flags: --target aarch64-apple-darwin
+//@ [aarch64_macos] needs-llvm-components: aarch64
+//@ revisions: i386_ios
+//@ [i386_ios] compile-flags: --target i386-apple-ios
+//@ [i386_ios] needs-llvm-components: x86
+//@ revisions: x86_64_ios
+//@ [x86_64_ios] compile-flags: --target x86_64-apple-ios
+//@ [x86_64_ios] needs-llvm-components: x86
+//@ revisions: armv7s_ios
+//@ [armv7s_ios] compile-flags: --target armv7s-apple-ios
+//@ [armv7s_ios] needs-llvm-components: arm
+//@ revisions: aarch64_ios
+//@ [aarch64_ios] compile-flags: --target aarch64-apple-ios
+//@ [aarch64_ios] needs-llvm-components: aarch64
+//@ revisions: aarch64_ios_sim
+//@ [aarch64_ios_sim] compile-flags: --target aarch64-apple-ios-sim
+//@ [aarch64_ios_sim] needs-llvm-components: aarch64
+
+#![crate_type = "lib"]
+#![feature(no_core, lang_items, rustc_attrs)]
+#![no_core]
+
+extern crate minicore;
+use minicore::*;
+
+#[no_mangle]
+pub fn get_class() -> *mut () {
+    unsafe extern "C" {
+        #[rustc_objc_class = "MyClass"]
+        safe static VAL: *mut ();
+    }
+    VAL
+}
+
+#[no_mangle]
+pub fn get_class_again() -> *mut () {
+    // Codegen should de-duplicate this class with the one from get_class above.
+    unsafe extern "C" {
+        #[rustc_objc_class = "MyClass"]
+        safe static VAL: *mut ();
+    }
+    VAL
+}
+
+#[no_mangle]
+pub fn get_selector() -> *mut () {
+    unsafe extern "C" {
+        #[rustc_objc_selector = "myMethod"]
+        safe static VAL: *mut ();
+    }
+    VAL
+}
+
+#[no_mangle]
+pub fn get_selector_again() -> *mut () {
+    // Codegen should de-duplicate this selector with the one from get_selector above.
+    unsafe extern "C" {
+        #[rustc_objc_selector = "myMethod"]
+        safe static VAL: *mut ();
+    }
+    VAL
+}
+
+#[no_mangle]
+pub fn get_other_class() -> *mut () {
+    unsafe extern "C" {
+        #[rustc_objc_class = "OtherClass"]
+        safe static VAL: *mut ();
+    }
+    VAL
+}
+
+#[no_mangle]
+pub fn get_other_selector() -> *mut () {
+    unsafe extern "C" {
+        #[rustc_objc_selector = "otherMethod"]
+        safe static VAL: *mut ();
+    }
+    VAL
+}
+
+// CHECK: %struct._class_t = type { ptr, ptr, ptr, ptr, ptr }
+
+// CHECK: @"OBJC_CLASS_$_MyClass" = external global %struct._class_t
+// CHECK: @"OBJC_CLASSLIST_REFERENCES_$_.{{[0-9]+}}" = internal global ptr @"OBJC_CLASS_$_MyClass", section "__DATA,__objc_classrefs,regular,no_dead_strip",
+// x86_64_macos-SAME: align 8
+// aarch64_macos-SAME: align 8
+// i386_ios-SAME: align 4
+// x86_64_ios-SAME: align 8
+// armv7s_ios-SAME: align 4
+// aarch64_ios-SAME: align 8
+// aarch64_ios_sim-SAME: align 8
+// CHECK-NOT: @"OBJC_CLASS_$_MyClass"
+// CHECK-NOT: @"OBJC_CLASSLIST_REFERENCES_$_
+
+// CHECK: @OBJC_METH_VAR_NAME_.{{[0-9]+}} = private unnamed_addr constant [9 x i8] c"myMethod\00", section "__TEXT,__objc_methname,cstring_literals", align 1
+// CHECK: @OBJC_SELECTOR_REFERENCES_.{{[0-9]+}} = internal externally_initialized global ptr @OBJC_METH_VAR_NAME_.{{[0-9]+}}, section "__DATA,__objc_selrefs,literal_pointers,no_dead_strip",
+// x86_64_macos-SAME: align 8
+// aarch64_macos-SAME: align 8
+// i386_ios-SAME: align 4
+// x86_64_ios-SAME: align 8
+// armv7s_ios-SAME: align 4
+// aarch64_ios-SAME: align 8
+// aarch64_ios_sim-SAME: align 8
+// CHECK-NOT: @OBJC_METH_VAR_NAME_
+// CHECK-NOT: @OBJC_SELECTOR_REFERENCES_
+
+// CHECK: @"OBJC_CLASS_$_OtherClass" = external global %struct._class_t
+// CHECK: @"OBJC_CLASSLIST_REFERENCES_$_.{{[0-9]+}}" = internal global ptr @"OBJC_CLASS_$_OtherClass", section "__DATA,__objc_classrefs,regular,no_dead_strip",
+// x86_64_macos-SAME: align 8
+// aarch64_macos-SAME: align 8
+// i386_ios-SAME: align 4
+// x86_64_ios-SAME: align 8
+// armv7s_ios-SAME: align 4
+// aarch64_ios-SAME: align 8
+// aarch64_ios_sim-SAME: align 8
+
+// CHECK: @OBJC_METH_VAR_NAME_.{{[0-9]+}} = private unnamed_addr constant [12 x i8] c"otherMethod\00", section "__TEXT,__objc_methname,cstring_literals", align 1
+// CHECK: @OBJC_SELECTOR_REFERENCES_.{{[0-9]+}} = internal externally_initialized global ptr @OBJC_METH_VAR_NAME_.{{[0-9]+}}, section "__DATA,__objc_selrefs,literal_pointers,no_dead_strip",
+// x86_64_macos-SAME: align 8
+// aarch64_macos-SAME: align 8
+// i386_ios-SAME: align 4
+// x86_64_ios-SAME: align 8
+// armv7s_ios-SAME: align 4
+// aarch64_ios-SAME: align 8
+// aarch64_ios_sim-SAME: align 8
+
+// CHECK-NOT: @OBJC_CLASS_NAME_
+// CHECK-NOT: @OBJC_MODULES
+
+// CHECK: load ptr, ptr @"OBJC_CLASSLIST_REFERENCES_$_.{{[0-9]+}}",
+// x86_64_macos-SAME: align 8
+// aarch64_macos-SAME: align 8
+// i386_ios-SAME: align 4
+// x86_64_ios-SAME: align 8
+// armv7s_ios-SAME: align 4
+// aarch64_ios-SAME: align 8
+// aarch64_ios_sim-SAME: align 8
+
+// CHECK: load ptr, ptr @OBJC_SELECTOR_REFERENCES_.{{[0-9]+}},
+// x86_64_macos-SAME: align 8
+// aarch64_macos-SAME: align 8
+// i386_ios-SAME: align 4
+// x86_64_ios-SAME: align 8
+// armv7s_ios-SAME: align 4
+// aarch64_ios-SAME: align 8
+// aarch64_ios_sim-SAME: align 8
+
+// CHECK: load ptr, ptr @"OBJC_CLASSLIST_REFERENCES_$_.{{[0-9]+}}",
+// x86_64_macos-SAME: align 8
+// aarch64_macos-SAME: align 8
+// i386_ios-SAME: align 4
+// x86_64_ios-SAME: align 8
+// armv7s_ios-SAME: align 4
+// aarch64_ios-SAME: align 8
+// aarch64_ios_sim-SAME: align 8
+
+// CHECK: load ptr, ptr @OBJC_SELECTOR_REFERENCES_.{{[0-9]+}},
+// x86_64_macos-SAME: align 8
+// aarch64_macos-SAME: align 8
+// i386_ios-SAME: align 4
+// x86_64_ios-SAME: align 8
+// armv7s_ios-SAME: align 4
+// aarch64_ios-SAME: align 8
+// aarch64_ios_sim-SAME: align 8
+
+// CHECK: !{{[0-9]+}} = !{i32 1, !"Objective-C Version", i32 2}
+// CHECK: !{{[0-9]+}} = !{i32 1, !"Objective-C Image Info Version", i32 0}
+// CHECK: !{{[0-9]+}} = !{i32 1, !"Objective-C Image Info Section", !"__DATA,__objc_imageinfo,regular,no_dead_strip"}
+
+// x86_64_macos-NOT: !{{[0-9]+}} = !{i32 1, !"Objective-C Is Simulated", i32 32}
+// aarch64_macos-NOT: !{{[0-9]+}} = !{i32 1, !"Objective-C Is Simulated", i32 32}
+// i386_ios: !{{[0-9]+}} = !{i32 1, !"Objective-C Is Simulated", i32 32}
+// x86_64_ios: !{{[0-9]+}} = !{i32 1, !"Objective-C Is Simulated", i32 32}
+// armv7s_ios-NOT: !{{[0-9]+}} = !{i32 1, !"Objective-C Is Simulated", i32 32}
+// aarch64_ios-NOT: !{{[0-9]+}} = !{i32 1, !"Objective-C Is Simulated", i32 32}
+// aarch64_ios_sim: !{{[0-9]+}} = !{i32 1, !"Objective-C Is Simulated", i32 32}
+
+// CHECK: !{{[0-9]+}} = !{i32 1, !"Objective-C Class Properties", i32 64}
diff --git a/tests/codegen-llvm/darwin-objc-cross-crate.rs b/tests/codegen-llvm/darwin-objc-cross-crate.rs
new file mode 100644
index 00000000000..74ad9a27346
--- /dev/null
+++ b/tests/codegen-llvm/darwin-objc-cross-crate.rs
@@ -0,0 +1,58 @@
+// Test that Objective-C class and selector references inlined across crates
+// get defined in this CGU but non-inline references don't.
+
+// ignore-tidy-linelength
+//@ aux-build: darwin_objc_aux.rs
+//@ revisions: x86_64_macos aarch64_macos
+//@ [x86_64_macos] only-x86_64-apple-darwin
+//@ [aarch64_macos] only-aarch64-apple-darwin
+
+#![crate_type = "lib"]
+#![feature(darwin_objc)]
+
+use std::os::darwin::objc;
+
+extern crate darwin_objc_aux as aux;
+
+#[no_mangle]
+pub fn get_object_class() -> objc::Class {
+    aux::inline_get_object_class()
+}
+
+#[no_mangle]
+pub fn get_alloc_selector() -> objc::SEL {
+    aux::inline_get_alloc_selector()
+}
+
+#[no_mangle]
+pub fn get_string_class() -> objc::Class {
+    aux::never_inline_get_string_class()
+}
+
+#[no_mangle]
+pub fn get_init_selector() -> objc::SEL {
+    aux::never_inline_get_init_selector()
+}
+
+// CHECK: %struct._class_t = type { ptr, ptr, ptr, ptr, ptr }
+
+// CHECK: @"OBJC_CLASS_$_NSObject" = external global %struct._class_t
+// CHECK: @"OBJC_CLASSLIST_REFERENCES_$_.{{[0-9]+}}" = internal global ptr @"OBJC_CLASS_$_NSObject", section "__DATA,__objc_classrefs,regular,no_dead_strip", align 8
+
+// CHECK: @OBJC_METH_VAR_NAME_.{{[0-9]+}} = private unnamed_addr constant [6 x i8] c"alloc\00", section "__TEXT,__objc_methname,cstring_literals", align 1
+// CHECK: @OBJC_SELECTOR_REFERENCES_.{{[0-9]+}} = internal externally_initialized global ptr @OBJC_METH_VAR_NAME_.{{[0-9]+}}, section "__DATA,__objc_selrefs,literal_pointers,no_dead_strip", align 8
+
+// CHECK-NOT: @"OBJC_CLASS_$_NSString" = external global %struct._class_t
+// CHECK-NOT: @"OBJC_CLASSLIST_REFERENCES_$_.{{[0-9]+}}" = internal global ptr @"OBJC_CLASS_$_NSString"
+
+// CHECK-NOT: @OBJC_METH_VAR_NAME_.{{[0-9]+}} = private unnamed_addr constant [5 x i8] c"init\00"
+// CHECK-NOT: @OBJC_SELECTOR_REFERENCES_.{{[0-9]+}} = internal externally_initialized global ptr @OBJC_METH_VAR_NAME_.{{[0-9]+}}
+
+// CHECK: load ptr, ptr @"OBJC_CLASSLIST_REFERENCES_$_.{{[0-9]+}}", align 8
+// CHECK: load ptr, ptr @OBJC_SELECTOR_REFERENCES_.{{[0-9]+}}, align 8
+
+// CHECK: !{{[0-9]+}} = !{i32 1, !"Objective-C Version", i32 2}
+// CHECK: !{{[0-9]+}} = !{i32 1, !"Objective-C Image Info Version", i32 0}
+// CHECK: !{{[0-9]+}} = !{i32 1, !"Objective-C Image Info Section", !"__DATA,__objc_imageinfo,regular,no_dead_strip"}
+// CHECK-NOT: !{{[0-9]+}} = !{i32 1, !"Objective-C Is Simulated", i32 32}
+// CHECK: !{{[0-9]+}} = !{i32 1, !"Objective-C Class Properties", i32 64}
diff --git a/tests/codegen-llvm/enum/enum-aggregate.rs b/tests/codegen-llvm/enum/enum-aggregate.rs
index f58d7ef12b6..7d450a89e2e 100644
--- a/tests/codegen-llvm/enum/enum-aggregate.rs
+++ b/tests/codegen-llvm/enum/enum-aggregate.rs
@@ -1,5 +1,4 @@
 //@ compile-flags: -Copt-level=0 -Cno-prepopulate-passes
-//@ min-llvm-version: 19
 //@ only-64bit
 
 #![crate_type = "lib"]
diff --git a/tests/codegen-llvm/enum/enum-discriminant-eq.rs b/tests/codegen-llvm/enum/enum-discriminant-eq.rs
index a1ab5e5c6e2..68cd58643e8 100644
--- a/tests/codegen-llvm/enum/enum-discriminant-eq.rs
+++ b/tests/codegen-llvm/enum/enum-discriminant-eq.rs
@@ -1,5 +1,4 @@
 //@ compile-flags: -Copt-level=3 -Zmerge-functions=disabled
-//@ min-llvm-version: 20
 //@ only-64bit
 //@ revisions: LLVM20 LLVM21
 //@ [LLVM21] min-llvm-version: 21
diff --git a/tests/codegen-llvm/integer-cmp.rs b/tests/codegen-llvm/integer-cmp.rs
index 812fa8e4a42..2233a575f8e 100644
--- a/tests/codegen-llvm/integer-cmp.rs
+++ b/tests/codegen-llvm/integer-cmp.rs
@@ -1,9 +1,6 @@
 // This is test for more optimal Ord implementation for integers.
 // See <https://github.com/rust-lang/rust/issues/63758> for more info.
 
-//@ revisions: llvm-pre-20 llvm-20
-//@ [llvm-20] min-llvm-version: 20
-//@ [llvm-pre-20] max-llvm-major-version: 19
 //@ compile-flags: -C opt-level=3 -Zmerge-functions=disabled
 
 #![crate_type = "lib"]
@@ -13,50 +10,29 @@ use std::cmp::Ordering;
 // CHECK-LABEL: @cmp_signed
 #[no_mangle]
 pub fn cmp_signed(a: i64, b: i64) -> Ordering {
-    // llvm-20: call{{.*}} i8 @llvm.scmp.i8.i64
-    // llvm-pre-20: icmp slt
-    // llvm-pre-20: icmp ne
-    // llvm-pre-20: zext i1
-    // llvm-pre-20: select i1
+    // CHECK: call{{.*}} i8 @llvm.scmp.i8.i64
     a.cmp(&b)
 }
 
 // CHECK-LABEL: @cmp_unsigned
 #[no_mangle]
 pub fn cmp_unsigned(a: u32, b: u32) -> Ordering {
-    // llvm-20: call{{.*}} i8 @llvm.ucmp.i8.i32
-    // llvm-pre-20: icmp ult
-    // llvm-pre-20: icmp ne
-    // llvm-pre-20: zext i1
-    // llvm-pre-20: select i1
+    // CHECK: call{{.*}} i8 @llvm.ucmp.i8.i32
     a.cmp(&b)
 }
 
 // CHECK-LABEL: @cmp_char
 #[no_mangle]
 pub fn cmp_char(a: char, b: char) -> Ordering {
-    // llvm-20: call{{.*}} i8 @llvm.ucmp.i8.i32
-    // llvm-pre-20: icmp ult
-    // llvm-pre-20: icmp ne
-    // llvm-pre-20: zext i1
-    // llvm-pre-20: select i1
+    // CHECK: call{{.*}} i8 @llvm.ucmp.i8.i32
     a.cmp(&b)
 }
 
 // CHECK-LABEL: @cmp_tuple
 #[no_mangle]
 pub fn cmp_tuple(a: (i16, u16), b: (i16, u16)) -> Ordering {
-    // llvm-20-DAG: call{{.*}} i8 @llvm.ucmp.i8.i16
-    // llvm-20-DAG: call{{.*}} i8 @llvm.scmp.i8.i16
-    // llvm-20: ret i8
-    // llvm-pre-20: icmp slt
-    // llvm-pre-20: icmp ne
-    // llvm-pre-20: zext i1
-    // llvm-pre-20: select i1
-    // llvm-pre-20: icmp ult
-    // llvm-pre-20: icmp ne
-    // llvm-pre-20: zext i1
-    // llvm-pre-20: select i1
-    // llvm-pre-20: select i1
+    // CHECK-DAG: call{{.*}} i8 @llvm.ucmp.i8.i16
+    // CHECK-DAG: call{{.*}} i8 @llvm.scmp.i8.i16
+    // CHECK: ret i8
     a.cmp(&b)
 }
diff --git a/tests/codegen-llvm/intrinsics/three_way_compare.rs b/tests/codegen-llvm/intrinsics/three_way_compare.rs
index 95fcb636f7c..89bf69561e9 100644
--- a/tests/codegen-llvm/intrinsics/three_way_compare.rs
+++ b/tests/codegen-llvm/intrinsics/three_way_compare.rs
@@ -2,7 +2,6 @@
 //@ [DEBUG] compile-flags: -C opt-level=0
 //@ [OPTIM] compile-flags: -C opt-level=3
 //@ compile-flags: -C no-prepopulate-passes
-//@ min-llvm-version: 20
 
 #![crate_type = "lib"]
 #![feature(core_intrinsics)]
diff --git a/tests/codegen-llvm/issues/and-masked-comparison-131162.rs b/tests/codegen-llvm/issues/and-masked-comparison-131162.rs
index bdf021092fd..fc4b0341a31 100644
--- a/tests/codegen-llvm/issues/and-masked-comparison-131162.rs
+++ b/tests/codegen-llvm/issues/and-masked-comparison-131162.rs
@@ -1,5 +1,4 @@
 //@ compile-flags: -Copt-level=3
-//@ min-llvm-version: 20
 
 #![crate_type = "lib"]
 
diff --git a/tests/codegen-llvm/issues/issue-101082.rs b/tests/codegen-llvm/issues/issue-101082.rs
index 8d15921ddb4..0c1f90f951a 100644
--- a/tests/codegen-llvm/issues/issue-101082.rs
+++ b/tests/codegen-llvm/issues/issue-101082.rs
@@ -1,6 +1,5 @@
 //@ compile-flags: -Copt-level=3
 //@ revisions: host x86-64 x86-64-v3
-//@ min-llvm-version: 20
 
 //@[host] ignore-x86_64
 
diff --git a/tests/codegen-llvm/issues/issue-129795.rs b/tests/codegen-llvm/issues/issue-129795.rs
index dc64ee35c97..7a928389fab 100644
--- a/tests/codegen-llvm/issues/issue-129795.rs
+++ b/tests/codegen-llvm/issues/issue-129795.rs
@@ -1,5 +1,4 @@
 //@ compile-flags: -Copt-level=3
-//@ min-llvm-version: 20
 #![crate_type = "lib"]
 
 // Ensure that a modulo operation with an operand that is known to be
diff --git a/tests/codegen-llvm/issues/iter-max-no-unwrap-failed-129583.rs b/tests/codegen-llvm/issues/iter-max-no-unwrap-failed-129583.rs
index 4d3fa4993ef..4c4eebeabb5 100644
--- a/tests/codegen-llvm/issues/iter-max-no-unwrap-failed-129583.rs
+++ b/tests/codegen-llvm/issues/iter-max-no-unwrap-failed-129583.rs
@@ -3,7 +3,6 @@
 // use a larger value to prevent unrolling.
 
 //@ compile-flags: -Copt-level=3
-//@ min-llvm-version: 20
 
 #![crate_type = "lib"]
 
diff --git a/tests/codegen-llvm/issues/looping-over-ne-bytes-133528.rs b/tests/codegen-llvm/issues/looping-over-ne-bytes-133528.rs
index 35acf765d69..b686f8c4b3a 100644
--- a/tests/codegen-llvm/issues/looping-over-ne-bytes-133528.rs
+++ b/tests/codegen-llvm/issues/looping-over-ne-bytes-133528.rs
@@ -1,5 +1,4 @@
 //@ compile-flags: -Copt-level=3
-//@ min-llvm-version: 20
 #![crate_type = "lib"]
 
 /// Ensure the function is properly optimized
diff --git a/tests/codegen-llvm/option-niche-eq.rs b/tests/codegen-llvm/option-niche-eq.rs
index 3900cb79aa2..e9c3fa2407e 100644
--- a/tests/codegen-llvm/option-niche-eq.rs
+++ b/tests/codegen-llvm/option-niche-eq.rs
@@ -1,5 +1,4 @@
 //@ revisions: REGULAR LLVM21
-//@ min-llvm-version: 20
 //@ compile-flags: -Copt-level=3 -Zmerge-functions=disabled
 //@ [LLVM21] min-llvm-version: 21
 #![crate_type = "lib"]
diff --git a/tests/codegen-llvm/rust-abi-arch-specific-adjustment.rs b/tests/codegen-llvm/rust-abi-arch-specific-adjustment.rs
index 561f081c700..ffff4b35994 100644
--- a/tests/codegen-llvm/rust-abi-arch-specific-adjustment.rs
+++ b/tests/codegen-llvm/rust-abi-arch-specific-adjustment.rs
@@ -1,15 +1,19 @@
+//@ add-core-stubs
 //@ compile-flags: -Copt-level=3 -C no-prepopulate-passes
 //@ revisions: riscv64 loongarch64
 
-//@[riscv64] only-riscv64
 //@[riscv64] compile-flags: --target riscv64gc-unknown-linux-gnu
 //@[riscv64] needs-llvm-components: riscv
 
-//@[loongarch64] only-loongarch64
 //@[loongarch64] compile-flags: --target loongarch64-unknown-linux-gnu
 //@[loongarch64] needs-llvm-components: loongarch
 
 #![crate_type = "lib"]
+#![feature(no_core)]
+#![no_core]
+
+extern crate minicore;
+use minicore::*;
 
 #[no_mangle]
 // riscv64:     define noundef i8 @arg_attr_u8(i8 noundef zeroext %x)
diff --git a/tests/codegen-llvm/slice-last-elements-optimization.rs b/tests/codegen-llvm/slice-last-elements-optimization.rs
index d982cda709d..77fc1d21cd9 100644
--- a/tests/codegen-llvm/slice-last-elements-optimization.rs
+++ b/tests/codegen-llvm/slice-last-elements-optimization.rs
@@ -1,5 +1,4 @@
 //@ compile-flags: -Copt-level=3
-//@ min-llvm-version: 20
 #![crate_type = "lib"]
 
 // This test verifies that LLVM 20 properly optimizes the bounds check
diff --git a/tests/codegen-llvm/swap-small-types.rs b/tests/codegen-llvm/swap-small-types.rs
index 7aa613ae9c2..0799ff76331 100644
--- a/tests/codegen-llvm/swap-small-types.rs
+++ b/tests/codegen-llvm/swap-small-types.rs
@@ -1,6 +1,5 @@
 //@ compile-flags: -Copt-level=3 -Z merge-functions=disabled
 //@ only-x86_64
-//@ min-llvm-version: 20
 //@ ignore-std-debug-assertions (`ptr::swap_nonoverlapping` has one which blocks some optimizations)
 
 #![crate_type = "lib"]
diff --git a/tests/codegen-llvm/try_question_mark_nop.rs b/tests/codegen-llvm/try_question_mark_nop.rs
index 398c9a580bc..a09fa0a4901 100644
--- a/tests/codegen-llvm/try_question_mark_nop.rs
+++ b/tests/codegen-llvm/try_question_mark_nop.rs
@@ -1,9 +1,6 @@
 //@ compile-flags: -Copt-level=3 -Z merge-functions=disabled
 //@ edition: 2021
 //@ only-x86_64
-//@ revisions: NINETEEN TWENTY
-//@[NINETEEN] exact-llvm-major-version: 19
-//@[TWENTY] min-llvm-version: 20
 
 #![crate_type = "lib"]
 #![feature(try_blocks)]
@@ -17,13 +14,9 @@ pub fn option_nop_match_32(x: Option<u32>) -> Option<u32> {
     // CHECK: start:
     // CHECK-NEXT: [[TRUNC:%.*]] = trunc nuw i32 %0 to i1
 
-    // NINETEEN-NEXT: [[SELECT:%.*]] = select i1 [[TRUNC]], i32 %0, i32 0
-    // NINETEEN-NEXT: [[REG2:%.*]] = insertvalue { i32, i32 } poison, i32 [[SELECT]], 0
-    // NINETEEN-NEXT: [[REG3:%.*]] = insertvalue { i32, i32 } [[REG2]], i32 %1, 1
-
-    // TWENTY-NEXT: [[SELECT:%.*]] = select i1 [[TRUNC]], i32 %1, i32 undef
-    // TWENTY-NEXT: [[REG2:%.*]] = insertvalue { i32, i32 } poison, i32 %0, 0
-    // TWENTY-NEXT: [[REG3:%.*]] = insertvalue { i32, i32 } [[REG2]], i32 [[SELECT]], 1
+    // CHECK-NEXT: [[SELECT:%.*]] = select i1 [[TRUNC]], i32 %1, i32 undef
+    // CHECK-NEXT: [[REG2:%.*]] = insertvalue { i32, i32 } poison, i32 %0, 0
+    // CHECK-NEXT: [[REG3:%.*]] = insertvalue { i32, i32 } [[REG2]], i32 [[SELECT]], 1
 
     // CHECK-NEXT: ret { i32, i32 } [[REG3]]
     match x {
@@ -36,8 +29,8 @@ pub fn option_nop_match_32(x: Option<u32>) -> Option<u32> {
 #[no_mangle]
 pub fn option_nop_traits_32(x: Option<u32>) -> Option<u32> {
     // CHECK: start:
-    // TWENTY-NEXT: %[[IS_SOME:.+]] = trunc nuw i32 %0 to i1
-    // TWENTY-NEXT: select i1 %[[IS_SOME]], i32 %1, i32 undef
+    // CHECK-NEXT: %[[IS_SOME:.+]] = trunc nuw i32 %0 to i1
+    // CHECK-NEXT: select i1 %[[IS_SOME]], i32 %1, i32 undef
     // CHECK-NEXT: insertvalue { i32, i32 }
     // CHECK-NEXT: insertvalue { i32, i32 }
     // CHECK-NEXT: ret { i32, i32 }
@@ -96,13 +89,9 @@ pub fn option_nop_match_64(x: Option<u64>) -> Option<u64> {
     // CHECK: start:
     // CHECK-NEXT: [[TRUNC:%.*]] = trunc nuw i64 %0 to i1
 
-    // NINETEEN-NEXT: [[SELECT:%.*]] = select i1 [[TRUNC]], i64 %0, i64 0
-    // NINETEEN-NEXT: [[REG2:%.*]] = insertvalue { i64, i64 } poison, i64 [[SELECT]], 0
-    // NINETEEN-NEXT: [[REG3:%.*]] = insertvalue { i64, i64 } [[REG2]], i64 %1, 1
-
-    // TWENTY-NEXT: [[SELECT:%.*]] = select i1 [[TRUNC]], i64 %1, i64 undef
-    // TWENTY-NEXT: [[REG2:%.*]] = insertvalue { i64, i64 } poison, i64 %0, 0
-    // TWENTY-NEXT: [[REG3:%.*]] = insertvalue { i64, i64 } [[REG2]], i64 [[SELECT]], 1
+    // CHECK-NEXT: [[SELECT:%.*]] = select i1 [[TRUNC]], i64 %1, i64 undef
+    // CHECK-NEXT: [[REG2:%.*]] = insertvalue { i64, i64 } poison, i64 %0, 0
+    // CHECK-NEXT: [[REG3:%.*]] = insertvalue { i64, i64 } [[REG2]], i64 [[SELECT]], 1
 
     // CHECK-NEXT: ret { i64, i64 } [[REG3]]
     match x {
@@ -115,8 +104,8 @@ pub fn option_nop_match_64(x: Option<u64>) -> Option<u64> {
 #[no_mangle]
 pub fn option_nop_traits_64(x: Option<u64>) -> Option<u64> {
     // CHECK: start:
-    // TWENTY-NEXT: %[[TRUNC:[0-9]+]] = trunc nuw i64 %0 to i1
-    // TWENTY-NEXT: %[[SEL:\.[0-9]+]] = select i1 %[[TRUNC]], i64 %1, i64 undef
+    // CHECK-NEXT: %[[TRUNC:[0-9]+]] = trunc nuw i64 %0 to i1
+    // CHECK-NEXT: %[[SEL:\.[0-9]+]] = select i1 %[[TRUNC]], i64 %1, i64 undef
     // CHECK-NEXT: insertvalue { i64, i64 }
     // CHECK-NEXT: insertvalue { i64, i64 }
     // CHECK-NEXT: ret { i64, i64 }
diff --git a/tests/codegen-llvm/union-aggregate.rs b/tests/codegen-llvm/union-aggregate.rs
index aac66c5dcdd..7faa66804fe 100644
--- a/tests/codegen-llvm/union-aggregate.rs
+++ b/tests/codegen-llvm/union-aggregate.rs
@@ -1,5 +1,4 @@
 //@ compile-flags: -Copt-level=0 -Cno-prepopulate-passes
-//@ min-llvm-version: 19
 //@ only-64bit
 
 #![crate_type = "lib"]
diff --git a/tests/mir-opt/dest-prop/aggregate.rewrap.DestinationPropagation.panic-abort.diff b/tests/mir-opt/dest-prop/aggregate.rewrap.DestinationPropagation.panic-abort.diff
new file mode 100644
index 00000000000..e80660f176b
--- /dev/null
+++ b/tests/mir-opt/dest-prop/aggregate.rewrap.DestinationPropagation.panic-abort.diff
@@ -0,0 +1,19 @@
+- // MIR for `rewrap` before DestinationPropagation
++ // MIR for `rewrap` after DestinationPropagation
+  
+  fn rewrap() -> (u8,) {
+      let mut _0: (u8,);
+      let mut _1: (u8,);
+      let mut _2: (u8,);
+  
+      bb0: {
+-         (_1.0: u8) = const 0_u8;
+-         _0 = copy _1;
++         (_0.0: u8) = const 0_u8;
++         nop;
+          _2 = (copy (_0.0: u8),);
+          _0 = copy _2;
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/dest-prop/aggregate.rewrap.DestinationPropagation.panic-unwind.diff b/tests/mir-opt/dest-prop/aggregate.rewrap.DestinationPropagation.panic-unwind.diff
new file mode 100644
index 00000000000..e80660f176b
--- /dev/null
+++ b/tests/mir-opt/dest-prop/aggregate.rewrap.DestinationPropagation.panic-unwind.diff
@@ -0,0 +1,19 @@
+- // MIR for `rewrap` before DestinationPropagation
++ // MIR for `rewrap` after DestinationPropagation
+  
+  fn rewrap() -> (u8,) {
+      let mut _0: (u8,);
+      let mut _1: (u8,);
+      let mut _2: (u8,);
+  
+      bb0: {
+-         (_1.0: u8) = const 0_u8;
+-         _0 = copy _1;
++         (_0.0: u8) = const 0_u8;
++         nop;
+          _2 = (copy (_0.0: u8),);
+          _0 = copy _2;
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/dest-prop/aggregate.rs b/tests/mir-opt/dest-prop/aggregate.rs
new file mode 100644
index 00000000000..636852159eb
--- /dev/null
+++ b/tests/mir-opt/dest-prop/aggregate.rs
@@ -0,0 +1,51 @@
+//@ test-mir-pass: DestinationPropagation
+// EMIT_MIR_FOR_EACH_PANIC_STRATEGY
+
+#![feature(custom_mir, core_intrinsics)]
+#![allow(internal_features)]
+
+use std::intrinsics::mir::*;
+use std::mem::MaybeUninit;
+
+fn dump_var<T>(_: T) {}
+
+// EMIT_MIR aggregate.rewrap.DestinationPropagation.diff
+#[custom_mir(dialect = "runtime")]
+fn rewrap() -> (u8,) {
+    // CHECK-LABEL: fn rewrap(
+    // CHECK: (_0.0: u8) = const 0_u8;
+    // CHECK: _2 = (copy (_0.0: u8),);
+    // CHECK: _0 = copy _2;
+    mir! {
+        let _1: (u8,);
+        let _2: (u8,);
+        {
+            _1.0 = 0;
+            RET = _1;
+            _2 = (RET.0, );
+            RET = _2;
+            Return()
+        }
+    }
+}
+
+// EMIT_MIR aggregate.swap.DestinationPropagation.diff
+#[custom_mir(dialect = "runtime")]
+fn swap() -> (MaybeUninit<[u8; 10]>, MaybeUninit<[u8; 10]>) {
+    // CHECK-LABEL: fn swap(
+    // CHECK: _0 = const
+    // CHECK: _2 = copy _0;
+    // CHECK: _0 = (copy (_2.1: {{.*}}), copy (_2.0: {{.*}}));
+    mir! {
+        let _1: (MaybeUninit<[u8; 10]>, MaybeUninit<[u8; 10]>);
+        let _2: (MaybeUninit<[u8; 10]>, MaybeUninit<[u8; 10]>);
+        let _3: ();
+        {
+            _1 = const { (MaybeUninit::new([0; 10]), MaybeUninit::new([1; 10])) };
+            _2 = _1;
+            _1 = (_2.1, _2.0);
+            RET = _1;
+            Return()
+        }
+    }
+}
diff --git a/tests/mir-opt/dest-prop/aggregate.swap.DestinationPropagation.panic-abort.diff b/tests/mir-opt/dest-prop/aggregate.swap.DestinationPropagation.panic-abort.diff
new file mode 100644
index 00000000000..3aaad3aaf69
--- /dev/null
+++ b/tests/mir-opt/dest-prop/aggregate.swap.DestinationPropagation.panic-abort.diff
@@ -0,0 +1,22 @@
+- // MIR for `swap` before DestinationPropagation
++ // MIR for `swap` after DestinationPropagation
+  
+  fn swap() -> (MaybeUninit<[u8; 10]>, MaybeUninit<[u8; 10]>) {
+      let mut _0: (std::mem::MaybeUninit<[u8; 10]>, std::mem::MaybeUninit<[u8; 10]>);
+      let mut _1: (std::mem::MaybeUninit<[u8; 10]>, std::mem::MaybeUninit<[u8; 10]>);
+      let mut _2: (std::mem::MaybeUninit<[u8; 10]>, std::mem::MaybeUninit<[u8; 10]>);
+      let mut _3: ();
+  
+      bb0: {
+-         _1 = const swap::{constant#6};
+-         _2 = copy _1;
+-         _1 = (copy (_2.1: std::mem::MaybeUninit<[u8; 10]>), copy (_2.0: std::mem::MaybeUninit<[u8; 10]>));
+-         _0 = copy _1;
++         _0 = const swap::{constant#6};
++         _2 = copy _0;
++         _0 = (copy (_2.1: std::mem::MaybeUninit<[u8; 10]>), copy (_2.0: std::mem::MaybeUninit<[u8; 10]>));
++         nop;
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/dest-prop/aggregate.swap.DestinationPropagation.panic-unwind.diff b/tests/mir-opt/dest-prop/aggregate.swap.DestinationPropagation.panic-unwind.diff
new file mode 100644
index 00000000000..3aaad3aaf69
--- /dev/null
+++ b/tests/mir-opt/dest-prop/aggregate.swap.DestinationPropagation.panic-unwind.diff
@@ -0,0 +1,22 @@
+- // MIR for `swap` before DestinationPropagation
++ // MIR for `swap` after DestinationPropagation
+  
+  fn swap() -> (MaybeUninit<[u8; 10]>, MaybeUninit<[u8; 10]>) {
+      let mut _0: (std::mem::MaybeUninit<[u8; 10]>, std::mem::MaybeUninit<[u8; 10]>);
+      let mut _1: (std::mem::MaybeUninit<[u8; 10]>, std::mem::MaybeUninit<[u8; 10]>);
+      let mut _2: (std::mem::MaybeUninit<[u8; 10]>, std::mem::MaybeUninit<[u8; 10]>);
+      let mut _3: ();
+  
+      bb0: {
+-         _1 = const swap::{constant#6};
+-         _2 = copy _1;
+-         _1 = (copy (_2.1: std::mem::MaybeUninit<[u8; 10]>), copy (_2.0: std::mem::MaybeUninit<[u8; 10]>));
+-         _0 = copy _1;
++         _0 = const swap::{constant#6};
++         _2 = copy _0;
++         _0 = (copy (_2.1: std::mem::MaybeUninit<[u8; 10]>), copy (_2.0: std::mem::MaybeUninit<[u8; 10]>));
++         nop;
+          return;
+      }
+  }
+  
diff --git a/tests/ui/README.md b/tests/ui/README.md
index 66c1bb905a7..3b28ef694dd 100644
--- a/tests/ui/README.md
+++ b/tests/ui/README.md
@@ -350,6 +350,12 @@ Tests for FFI with C varargs (`va_list`).
 
 Tests for detection and handling of cyclic trait dependencies.
 
+## `tests/ui/darwin-objc/`: Darwin Objective-C
+
+Tests exercising `#![feature(darwin_objc)]`.
+
+See [Tracking Issue for `darwin_objc` #145496](https://github.com/rust-lang/rust/issues/145496).
+
 ## `tests/ui/dataflow_const_prop/`
 
 Contains a single regression test for const prop in `SwitchInt` pass crashing when `ptr2int` transmute is involved.
diff --git a/tests/ui/abi/sparcv8plus-llvm19.rs b/tests/ui/abi/sparcv8plus-llvm19.rs
deleted file mode 100644
index 3d6d8568b6e..00000000000
--- a/tests/ui/abi/sparcv8plus-llvm19.rs
+++ /dev/null
@@ -1,42 +0,0 @@
-//@ add-core-stubs
-//@ revisions: sparc sparcv8plus sparc_cpu_v9 sparc_feature_v8plus sparc_cpu_v9_feature_v8plus
-//@[sparc] compile-flags: --target sparc-unknown-none-elf
-//@[sparc] needs-llvm-components: sparc
-//@[sparcv8plus] compile-flags: --target sparc-unknown-linux-gnu
-//@[sparcv8plus] needs-llvm-components: sparc
-//@[sparc_cpu_v9] compile-flags: --target sparc-unknown-none-elf -C target-cpu=v9
-//@[sparc_cpu_v9] needs-llvm-components: sparc
-//@[sparc_feature_v8plus] compile-flags: --target sparc-unknown-none-elf -C target-feature=+v8plus
-//@[sparc_feature_v8plus] needs-llvm-components: sparc
-//@[sparc_cpu_v9_feature_v8plus] compile-flags: --target sparc-unknown-none-elf -C target-cpu=v9 -C target-feature=+v8plus
-//@[sparc_cpu_v9_feature_v8plus] needs-llvm-components: sparc
-//@ exact-llvm-major-version: 19
-
-#![crate_type = "rlib"]
-#![feature(no_core, rustc_attrs, lang_items)]
-#![no_core]
-
-extern crate minicore;
-use minicore::*;
-
-#[rustc_builtin_macro]
-macro_rules! compile_error {
-    () => {};
-}
-
-#[cfg(all(not(target_feature = "v8plus"), not(target_feature = "v9")))]
-compile_error!("-v8plus,-v9");
-//[sparc]~^ ERROR -v8plus,-v9
-
-// FIXME: sparc_cpu_v9 should be in "-v8plus,+v9" group (fixed in LLVM 20)
-#[cfg(all(target_feature = "v8plus", target_feature = "v9"))]
-compile_error!("+v8plus,+v9");
-//[sparcv8plus,sparc_cpu_v9_feature_v8plus,sparc_cpu_v9]~^ ERROR +v8plus,+v9
-
-// FIXME: should be rejected
-#[cfg(all(target_feature = "v8plus", not(target_feature = "v9")))]
-compile_error!("+v8plus,-v9 (FIXME)");
-//[sparc_feature_v8plus]~^ ERROR +v8plus,-v9 (FIXME)
-
-#[cfg(all(not(target_feature = "v8plus"), target_feature = "v9"))]
-compile_error!("-v8plus,+v9");
diff --git a/tests/ui/abi/sparcv8plus-llvm19.sparc.stderr b/tests/ui/abi/sparcv8plus-llvm19.sparc.stderr
deleted file mode 100644
index d3462ae87d3..00000000000
--- a/tests/ui/abi/sparcv8plus-llvm19.sparc.stderr
+++ /dev/null
@@ -1,8 +0,0 @@
-error: -v8plus,-v9
-  --> $DIR/sparcv8plus-llvm19.rs:28:1
-   |
-LL | compile_error!("-v8plus,-v9");
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-error: aborting due to 1 previous error
-
diff --git a/tests/ui/abi/sparcv8plus-llvm19.sparc_cpu_v9.stderr b/tests/ui/abi/sparcv8plus-llvm19.sparc_cpu_v9.stderr
deleted file mode 100644
index 9891aec94b8..00000000000
--- a/tests/ui/abi/sparcv8plus-llvm19.sparc_cpu_v9.stderr
+++ /dev/null
@@ -1,8 +0,0 @@
-error: +v8plus,+v9
-  --> $DIR/sparcv8plus-llvm19.rs:33:1
-   |
-LL | compile_error!("+v8plus,+v9");
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-error: aborting due to 1 previous error
-
diff --git a/tests/ui/abi/sparcv8plus-llvm19.sparc_cpu_v9_feature_v8plus.stderr b/tests/ui/abi/sparcv8plus-llvm19.sparc_cpu_v9_feature_v8plus.stderr
deleted file mode 100644
index 9891aec94b8..00000000000
--- a/tests/ui/abi/sparcv8plus-llvm19.sparc_cpu_v9_feature_v8plus.stderr
+++ /dev/null
@@ -1,8 +0,0 @@
-error: +v8plus,+v9
-  --> $DIR/sparcv8plus-llvm19.rs:33:1
-   |
-LL | compile_error!("+v8plus,+v9");
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-error: aborting due to 1 previous error
-
diff --git a/tests/ui/abi/sparcv8plus-llvm19.sparc_feature_v8plus.stderr b/tests/ui/abi/sparcv8plus-llvm19.sparc_feature_v8plus.stderr
deleted file mode 100644
index dbcdb8ed121..00000000000
--- a/tests/ui/abi/sparcv8plus-llvm19.sparc_feature_v8plus.stderr
+++ /dev/null
@@ -1,8 +0,0 @@
-error: +v8plus,-v9 (FIXME)
-  --> $DIR/sparcv8plus-llvm19.rs:38:1
-   |
-LL | compile_error!("+v8plus,-v9 (FIXME)");
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-error: aborting due to 1 previous error
-
diff --git a/tests/ui/abi/sparcv8plus-llvm19.sparcv8plus.stderr b/tests/ui/abi/sparcv8plus-llvm19.sparcv8plus.stderr
deleted file mode 100644
index 9891aec94b8..00000000000
--- a/tests/ui/abi/sparcv8plus-llvm19.sparcv8plus.stderr
+++ /dev/null
@@ -1,8 +0,0 @@
-error: +v8plus,+v9
-  --> $DIR/sparcv8plus-llvm19.rs:33:1
-   |
-LL | compile_error!("+v8plus,+v9");
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-error: aborting due to 1 previous error
-
diff --git a/tests/ui/abi/sparcv8plus.rs b/tests/ui/abi/sparcv8plus.rs
index 6c17f721838..ba4fb6f7108 100644
--- a/tests/ui/abi/sparcv8plus.rs
+++ b/tests/ui/abi/sparcv8plus.rs
@@ -10,7 +10,6 @@
 //@[sparc_feature_v8plus] needs-llvm-components: sparc
 //@[sparc_cpu_v9_feature_v8plus] compile-flags: --target sparc-unknown-none-elf -C target-cpu=v9 -C target-feature=+v8plus
 //@[sparc_cpu_v9_feature_v8plus] needs-llvm-components: sparc
-//@ min-llvm-version: 20
 
 #![crate_type = "rlib"]
 #![feature(no_core, rustc_attrs, lang_items)]
diff --git a/tests/ui/abi/sparcv8plus.sparc.stderr b/tests/ui/abi/sparcv8plus.sparc.stderr
index e2aa89a9273..e31dbd344d6 100644
--- a/tests/ui/abi/sparcv8plus.sparc.stderr
+++ b/tests/ui/abi/sparcv8plus.sparc.stderr
@@ -1,5 +1,5 @@
 error: -v8plus,-v9
-  --> $DIR/sparcv8plus.rs:28:1
+  --> $DIR/sparcv8plus.rs:27:1
    |
 LL | compile_error!("-v8plus,-v9");
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/abi/sparcv8plus.sparc_cpu_v9.stderr b/tests/ui/abi/sparcv8plus.sparc_cpu_v9.stderr
index 2c5699f2dec..a1a8383cbe7 100644
--- a/tests/ui/abi/sparcv8plus.sparc_cpu_v9.stderr
+++ b/tests/ui/abi/sparcv8plus.sparc_cpu_v9.stderr
@@ -1,5 +1,5 @@
 error: -v8plus,+v9
-  --> $DIR/sparcv8plus.rs:41:1
+  --> $DIR/sparcv8plus.rs:40:1
    |
 LL | compile_error!("-v8plus,+v9");
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/abi/sparcv8plus.sparc_cpu_v9_feature_v8plus.stderr b/tests/ui/abi/sparcv8plus.sparc_cpu_v9_feature_v8plus.stderr
index 4b96e4421f9..c633ee26c51 100644
--- a/tests/ui/abi/sparcv8plus.sparc_cpu_v9_feature_v8plus.stderr
+++ b/tests/ui/abi/sparcv8plus.sparc_cpu_v9_feature_v8plus.stderr
@@ -1,5 +1,5 @@
 error: +v8plus,+v9
-  --> $DIR/sparcv8plus.rs:32:1
+  --> $DIR/sparcv8plus.rs:31:1
    |
 LL | compile_error!("+v8plus,+v9");
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/abi/sparcv8plus.sparc_feature_v8plus.stderr b/tests/ui/abi/sparcv8plus.sparc_feature_v8plus.stderr
index dfdec88961b..bad8adc1599 100644
--- a/tests/ui/abi/sparcv8plus.sparc_feature_v8plus.stderr
+++ b/tests/ui/abi/sparcv8plus.sparc_feature_v8plus.stderr
@@ -1,5 +1,5 @@
 error: +v8plus,-v9 (FIXME)
-  --> $DIR/sparcv8plus.rs:37:1
+  --> $DIR/sparcv8plus.rs:36:1
    |
 LL | compile_error!("+v8plus,-v9 (FIXME)");
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/abi/sparcv8plus.sparcv8plus.stderr b/tests/ui/abi/sparcv8plus.sparcv8plus.stderr
index 4b96e4421f9..c633ee26c51 100644
--- a/tests/ui/abi/sparcv8plus.sparcv8plus.stderr
+++ b/tests/ui/abi/sparcv8plus.sparcv8plus.stderr
@@ -1,5 +1,5 @@
 error: +v8plus,+v9
-  --> $DIR/sparcv8plus.rs:32:1
+  --> $DIR/sparcv8plus.rs:31:1
    |
 LL | compile_error!("+v8plus,+v9");
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/asm/loongarch/bad-reg.loongarch32_ilp32d.stderr b/tests/ui/asm/loongarch/bad-reg.loongarch32_ilp32d.stderr
index 8742d4bd82c..c67c913d2a6 100644
--- a/tests/ui/asm/loongarch/bad-reg.loongarch32_ilp32d.stderr
+++ b/tests/ui/asm/loongarch/bad-reg.loongarch32_ilp32d.stderr
@@ -1,35 +1,35 @@
 error: invalid register `$r0`: constant zero cannot be used as an operand for inline asm
-  --> $DIR/bad-reg.rs:27:18
+  --> $DIR/bad-reg.rs:26:18
    |
 LL |         asm!("", out("$r0") _);
    |                  ^^^^^^^^^^^^
 
 error: invalid register `$tp`: reserved for TLS
-  --> $DIR/bad-reg.rs:29:18
+  --> $DIR/bad-reg.rs:28:18
    |
 LL |         asm!("", out("$tp") _);
    |                  ^^^^^^^^^^^^
 
 error: invalid register `$sp`: the stack pointer cannot be used as an operand for inline asm
-  --> $DIR/bad-reg.rs:31:18
+  --> $DIR/bad-reg.rs:30:18
    |
 LL |         asm!("", out("$sp") _);
    |                  ^^^^^^^^^^^^
 
 error: invalid register `$r21`: reserved by the ABI
-  --> $DIR/bad-reg.rs:33:18
+  --> $DIR/bad-reg.rs:32:18
    |
 LL |         asm!("", out("$r21") _);
    |                  ^^^^^^^^^^^^^
 
 error: invalid register `$fp`: the frame pointer cannot be used as an operand for inline asm
-  --> $DIR/bad-reg.rs:35:18
+  --> $DIR/bad-reg.rs:34:18
    |
 LL |         asm!("", out("$fp") _);
    |                  ^^^^^^^^^^^^
 
 error: invalid register `$r31`: $r31 is used internally by LLVM and cannot be used as an operand for inline asm
-  --> $DIR/bad-reg.rs:37:18
+  --> $DIR/bad-reg.rs:36:18
    |
 LL |         asm!("", out("$r31") _);
    |                  ^^^^^^^^^^^^^
diff --git a/tests/ui/asm/loongarch/bad-reg.loongarch32_ilp32s.stderr b/tests/ui/asm/loongarch/bad-reg.loongarch32_ilp32s.stderr
index e6cb6e40c70..99c071919ac 100644
--- a/tests/ui/asm/loongarch/bad-reg.loongarch32_ilp32s.stderr
+++ b/tests/ui/asm/loongarch/bad-reg.loongarch32_ilp32s.stderr
@@ -1,59 +1,59 @@
 error: invalid register `$r0`: constant zero cannot be used as an operand for inline asm
-  --> $DIR/bad-reg.rs:27:18
+  --> $DIR/bad-reg.rs:26:18
    |
 LL |         asm!("", out("$r0") _);
    |                  ^^^^^^^^^^^^
 
 error: invalid register `$tp`: reserved for TLS
-  --> $DIR/bad-reg.rs:29:18
+  --> $DIR/bad-reg.rs:28:18
    |
 LL |         asm!("", out("$tp") _);
    |                  ^^^^^^^^^^^^
 
 error: invalid register `$sp`: the stack pointer cannot be used as an operand for inline asm
-  --> $DIR/bad-reg.rs:31:18
+  --> $DIR/bad-reg.rs:30:18
    |
 LL |         asm!("", out("$sp") _);
    |                  ^^^^^^^^^^^^
 
 error: invalid register `$r21`: reserved by the ABI
-  --> $DIR/bad-reg.rs:33:18
+  --> $DIR/bad-reg.rs:32:18
    |
 LL |         asm!("", out("$r21") _);
    |                  ^^^^^^^^^^^^^
 
 error: invalid register `$fp`: the frame pointer cannot be used as an operand for inline asm
-  --> $DIR/bad-reg.rs:35:18
+  --> $DIR/bad-reg.rs:34:18
    |
 LL |         asm!("", out("$fp") _);
    |                  ^^^^^^^^^^^^
 
 error: invalid register `$r31`: $r31 is used internally by LLVM and cannot be used as an operand for inline asm
-  --> $DIR/bad-reg.rs:37:18
+  --> $DIR/bad-reg.rs:36:18
    |
 LL |         asm!("", out("$r31") _);
    |                  ^^^^^^^^^^^^^
 
 error: register class `freg` requires at least one of the following target features: d, f
-  --> $DIR/bad-reg.rs:41:26
+  --> $DIR/bad-reg.rs:40:26
    |
 LL |         asm!("/* {} */", in(freg) f);
    |                          ^^^^^^^^^^
 
 error: register class `freg` requires at least one of the following target features: d, f
-  --> $DIR/bad-reg.rs:43:26
+  --> $DIR/bad-reg.rs:42:26
    |
 LL |         asm!("/* {} */", out(freg) _);
    |                          ^^^^^^^^^^^
 
 error: register class `freg` requires at least one of the following target features: d, f
-  --> $DIR/bad-reg.rs:45:26
+  --> $DIR/bad-reg.rs:44:26
    |
 LL |         asm!("/* {} */", in(freg) d);
    |                          ^^^^^^^^^^
 
 error: register class `freg` requires at least one of the following target features: d, f
-  --> $DIR/bad-reg.rs:47:26
+  --> $DIR/bad-reg.rs:46:26
    |
 LL |         asm!("/* {} */", out(freg) d);
    |                          ^^^^^^^^^^^
diff --git a/tests/ui/asm/loongarch/bad-reg.loongarch64_lp64d.stderr b/tests/ui/asm/loongarch/bad-reg.loongarch64_lp64d.stderr
index 8742d4bd82c..c67c913d2a6 100644
--- a/tests/ui/asm/loongarch/bad-reg.loongarch64_lp64d.stderr
+++ b/tests/ui/asm/loongarch/bad-reg.loongarch64_lp64d.stderr
@@ -1,35 +1,35 @@
 error: invalid register `$r0`: constant zero cannot be used as an operand for inline asm
-  --> $DIR/bad-reg.rs:27:18
+  --> $DIR/bad-reg.rs:26:18
    |
 LL |         asm!("", out("$r0") _);
    |                  ^^^^^^^^^^^^
 
 error: invalid register `$tp`: reserved for TLS
-  --> $DIR/bad-reg.rs:29:18
+  --> $DIR/bad-reg.rs:28:18
    |
 LL |         asm!("", out("$tp") _);
    |                  ^^^^^^^^^^^^
 
 error: invalid register `$sp`: the stack pointer cannot be used as an operand for inline asm
-  --> $DIR/bad-reg.rs:31:18
+  --> $DIR/bad-reg.rs:30:18
    |
 LL |         asm!("", out("$sp") _);
    |                  ^^^^^^^^^^^^
 
 error: invalid register `$r21`: reserved by the ABI
-  --> $DIR/bad-reg.rs:33:18
+  --> $DIR/bad-reg.rs:32:18
    |
 LL |         asm!("", out("$r21") _);
    |                  ^^^^^^^^^^^^^
 
 error: invalid register `$fp`: the frame pointer cannot be used as an operand for inline asm
-  --> $DIR/bad-reg.rs:35:18
+  --> $DIR/bad-reg.rs:34:18
    |
 LL |         asm!("", out("$fp") _);
    |                  ^^^^^^^^^^^^
 
 error: invalid register `$r31`: $r31 is used internally by LLVM and cannot be used as an operand for inline asm
-  --> $DIR/bad-reg.rs:37:18
+  --> $DIR/bad-reg.rs:36:18
    |
 LL |         asm!("", out("$r31") _);
    |                  ^^^^^^^^^^^^^
diff --git a/tests/ui/asm/loongarch/bad-reg.loongarch64_lp64s.stderr b/tests/ui/asm/loongarch/bad-reg.loongarch64_lp64s.stderr
index e6cb6e40c70..99c071919ac 100644
--- a/tests/ui/asm/loongarch/bad-reg.loongarch64_lp64s.stderr
+++ b/tests/ui/asm/loongarch/bad-reg.loongarch64_lp64s.stderr
@@ -1,59 +1,59 @@
 error: invalid register `$r0`: constant zero cannot be used as an operand for inline asm
-  --> $DIR/bad-reg.rs:27:18
+  --> $DIR/bad-reg.rs:26:18
    |
 LL |         asm!("", out("$r0") _);
    |                  ^^^^^^^^^^^^
 
 error: invalid register `$tp`: reserved for TLS
-  --> $DIR/bad-reg.rs:29:18
+  --> $DIR/bad-reg.rs:28:18
    |
 LL |         asm!("", out("$tp") _);
    |                  ^^^^^^^^^^^^
 
 error: invalid register `$sp`: the stack pointer cannot be used as an operand for inline asm
-  --> $DIR/bad-reg.rs:31:18
+  --> $DIR/bad-reg.rs:30:18
    |
 LL |         asm!("", out("$sp") _);
    |                  ^^^^^^^^^^^^
 
 error: invalid register `$r21`: reserved by the ABI
-  --> $DIR/bad-reg.rs:33:18
+  --> $DIR/bad-reg.rs:32:18
    |
 LL |         asm!("", out("$r21") _);
    |                  ^^^^^^^^^^^^^
 
 error: invalid register `$fp`: the frame pointer cannot be used as an operand for inline asm
-  --> $DIR/bad-reg.rs:35:18
+  --> $DIR/bad-reg.rs:34:18
    |
 LL |         asm!("", out("$fp") _);
    |                  ^^^^^^^^^^^^
 
 error: invalid register `$r31`: $r31 is used internally by LLVM and cannot be used as an operand for inline asm
-  --> $DIR/bad-reg.rs:37:18
+  --> $DIR/bad-reg.rs:36:18
    |
 LL |         asm!("", out("$r31") _);
    |                  ^^^^^^^^^^^^^
 
 error: register class `freg` requires at least one of the following target features: d, f
-  --> $DIR/bad-reg.rs:41:26
+  --> $DIR/bad-reg.rs:40:26
    |
 LL |         asm!("/* {} */", in(freg) f);
    |                          ^^^^^^^^^^
 
 error: register class `freg` requires at least one of the following target features: d, f
-  --> $DIR/bad-reg.rs:43:26
+  --> $DIR/bad-reg.rs:42:26
    |
 LL |         asm!("/* {} */", out(freg) _);
    |                          ^^^^^^^^^^^
 
 error: register class `freg` requires at least one of the following target features: d, f
-  --> $DIR/bad-reg.rs:45:26
+  --> $DIR/bad-reg.rs:44:26
    |
 LL |         asm!("/* {} */", in(freg) d);
    |                          ^^^^^^^^^^
 
 error: register class `freg` requires at least one of the following target features: d, f
-  --> $DIR/bad-reg.rs:47:26
+  --> $DIR/bad-reg.rs:46:26
    |
 LL |         asm!("/* {} */", out(freg) d);
    |                          ^^^^^^^^^^^
diff --git a/tests/ui/asm/loongarch/bad-reg.rs b/tests/ui/asm/loongarch/bad-reg.rs
index 0d3eba07f14..cca37dd2e8e 100644
--- a/tests/ui/asm/loongarch/bad-reg.rs
+++ b/tests/ui/asm/loongarch/bad-reg.rs
@@ -1,7 +1,6 @@
 //@ add-core-stubs
 //@ needs-asm-support
 //@ revisions: loongarch32_ilp32d loongarch32_ilp32s loongarch64_lp64d loongarch64_lp64s
-//@ min-llvm-version: 20
 //@[loongarch32_ilp32d] compile-flags: --target loongarch32-unknown-none
 //@[loongarch32_ilp32d] needs-llvm-components: loongarch
 //@[loongarch32_ilp32s] compile-flags: --target loongarch32-unknown-none-softfloat
diff --git a/tests/ui/associated-types/associated-types-for-unimpl-trait.fixed b/tests/ui/associated-types/associated-types-for-unimpl-trait.fixed
index bce6148f9e1..ae4d0107aee 100644
--- a/tests/ui/associated-types/associated-types-for-unimpl-trait.fixed
+++ b/tests/ui/associated-types/associated-types-for-unimpl-trait.fixed
@@ -8,7 +8,7 @@ trait Get {
 }
 
 trait Other {
-    fn uhoh<U: Get>(&self, foo: U, bar: <Self as Get>::Value) where Self: Sized, Self: Get, Self: Get {}
+    fn uhoh<U: Get>(&self, foo: U, bar: <Self as Get>::Value) where Self: Sized, Self: Get {}
     //~^ ERROR the trait bound `Self: Get` is not satisfied
     //~| ERROR the trait bound `Self: Get` is not satisfied
 }
diff --git a/tests/ui/borrowck/format-args-temporary-scopes.e2024.stderr b/tests/ui/borrowck/format-args-temporary-scopes.e2024.stderr
new file mode 100644
index 00000000000..506fc6e0965
--- /dev/null
+++ b/tests/ui/borrowck/format-args-temporary-scopes.e2024.stderr
@@ -0,0 +1,27 @@
+error[E0716]: temporary value dropped while borrowed
+  --> $DIR/format-args-temporary-scopes.rs:13:25
+   |
+LL |     println!("{:?}", { &temp() });
+   |                      ---^^^^^---
+   |                      |  |    |
+   |                      |  |    temporary value is freed at the end of this statement
+   |                      |  creates a temporary value which is freed while still in use
+   |                      borrow later used here
+   |
+   = note: consider using a `let` binding to create a longer lived value
+
+error[E0716]: temporary value dropped while borrowed
+  --> $DIR/format-args-temporary-scopes.rs:19:29
+   |
+LL |     println!("{:?}{:?}", { &temp() }, ());
+   |                          ---^^^^^---
+   |                          |  |    |
+   |                          |  |    temporary value is freed at the end of this statement
+   |                          |  creates a temporary value which is freed while still in use
+   |                          borrow later used here
+   |
+   = note: consider using a `let` binding to create a longer lived value
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0716`.
diff --git a/tests/ui/borrowck/format-args-temporary-scopes.rs b/tests/ui/borrowck/format-args-temporary-scopes.rs
new file mode 100644
index 00000000000..2641058accb
--- /dev/null
+++ b/tests/ui/borrowck/format-args-temporary-scopes.rs
@@ -0,0 +1,21 @@
+//! Test for #145784 as it relates to format arguments: arguments to macros such as `println!`
+//! should obey normal temporary scoping rules.
+//@ revisions: e2021 e2024
+//@ [e2021] check-pass
+//@ [e2021] edition: 2021
+//@ [e2024] edition: 2024
+
+fn temp() {}
+
+fn main() {
+    // In Rust 2024, block tail expressions are temporary scopes, so the result of `temp()` is
+    // dropped after evaluating `&temp()`.
+    println!("{:?}", { &temp() });
+    //[e2024]~^ ERROR: temporary value dropped while borrowed [E0716]
+
+    // In Rust 1.89, `format_args!` extended the lifetime of all extending expressions in its
+    // arguments when provided with two or more arguments. This caused the result of `temp()` to
+    // outlive the result of the block, making this compile.
+    println!("{:?}{:?}", { &temp() }, ());
+    //[e2024]~^ ERROR: temporary value dropped while borrowed [E0716]
+}
diff --git a/tests/ui/coercion/coerce-block-tail.stderr b/tests/ui/coercion/coerce-block-tail.stderr
index 1301f3b7813..b358401b706 100644
--- a/tests/ui/coercion/coerce-block-tail.stderr
+++ b/tests/ui/coercion/coerce-block-tail.stderr
@@ -6,10 +6,11 @@ LL |     let _: &i32 = & { Box::new(1i32) };
    |
    = note: expected type `i32`
             found struct `Box<i32>`
-help: consider unboxing the value
+help: consider removing the Box
+   |
+LL -     let _: &i32 = & { Box::new(1i32) };
+LL +     let _: &i32 = & { 1i32 };
    |
-LL |     let _: &i32 = & { *Box::new(1i32) };
-   |                       +
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/coercion/coerce-box-new-to-unboxed.rs b/tests/ui/coercion/coerce-box-new-to-unboxed.rs
new file mode 100644
index 00000000000..63ff0fc4e23
--- /dev/null
+++ b/tests/ui/coercion/coerce-box-new-to-unboxed.rs
@@ -0,0 +1,4 @@
+fn main() {
+    let _: String = Box::new(String::new());
+    //~^ ERROR mismatched types
+}
diff --git a/tests/ui/coercion/coerce-box-new-to-unboxed.stderr b/tests/ui/coercion/coerce-box-new-to-unboxed.stderr
new file mode 100644
index 00000000000..bdd962686e4
--- /dev/null
+++ b/tests/ui/coercion/coerce-box-new-to-unboxed.stderr
@@ -0,0 +1,19 @@
+error[E0308]: mismatched types
+  --> $DIR/coerce-box-new-to-unboxed.rs:2:21
+   |
+LL |     let _: String = Box::new(String::new());
+   |            ------   ^^^^^^^^^^^^^^^^^^^^^^^ expected `String`, found `Box<String>`
+   |            |
+   |            expected due to this
+   |
+   = note: expected struct `String`
+              found struct `Box<String>`
+help: consider removing the Box
+   |
+LL -     let _: String = Box::new(String::new());
+LL +     let _: String = String::new();
+   |
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/tests/ui/const-generics/adt_const_params/auxiliary/unsized_const_param.rs b/tests/ui/const-generics/adt_const_params/auxiliary/unsized_const_param.rs
index e2ba459f8dd..1bfd7c34656 100644
--- a/tests/ui/const-generics/adt_const_params/auxiliary/unsized_const_param.rs
+++ b/tests/ui/const-generics/adt_const_params/auxiliary/unsized_const_param.rs
@@ -1,6 +1,6 @@
 #![feature(adt_const_params, unsized_const_params)]
 
-#[derive(std::marker::UnsizedConstParamTy, Eq, PartialEq)]
+#[derive(std::marker::ConstParamTy, Eq, PartialEq)]
 pub struct Foo([u8]);
 
 #[derive(std::marker::ConstParamTy, Eq, PartialEq)]
diff --git a/tests/ui/const-generics/adt_const_params/const_param_ty_bad.rs b/tests/ui/const-generics/adt_const_params/const_param_ty_bad.rs
index 35539193a27..d482e7fad06 100644
--- a/tests/ui/const-generics/adt_const_params/const_param_ty_bad.rs
+++ b/tests/ui/const-generics/adt_const_params/const_param_ty_bad.rs
@@ -1,7 +1,7 @@
 #![allow(incomplete_features)]
 #![feature(adt_const_params, unsized_const_params)]
 
-fn check(_: impl std::marker::UnsizedConstParamTy) {}
+fn check(_: impl std::marker::ConstParamTy_) {}
 
 fn main() {
     check(main); //~ error: `fn() {main}` can't be used as a const parameter type
diff --git a/tests/ui/const-generics/adt_const_params/const_param_ty_bad.stderr b/tests/ui/const-generics/adt_const_params/const_param_ty_bad.stderr
index c05584ef909..ff514f5608f 100644
--- a/tests/ui/const-generics/adt_const_params/const_param_ty_bad.stderr
+++ b/tests/ui/const-generics/adt_const_params/const_param_ty_bad.stderr
@@ -2,15 +2,15 @@ error[E0277]: `fn() {main}` can't be used as a const parameter type
   --> $DIR/const_param_ty_bad.rs:7:11
    |
 LL |     check(main);
-   |     ----- ^^^^ the trait `UnsizedConstParamTy` is not implemented for fn item `fn() {main}`
+   |     ----- ^^^^ the trait `ConstParamTy_` is not implemented for fn item `fn() {main}`
    |     |
    |     required by a bound introduced by this call
    |
 note: required by a bound in `check`
   --> $DIR/const_param_ty_bad.rs:4:18
    |
-LL | fn check(_: impl std::marker::UnsizedConstParamTy) {}
-   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `check`
+LL | fn check(_: impl std::marker::ConstParamTy_) {}
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `check`
 help: use parentheses to call this function
    |
 LL |     check(main());
@@ -24,12 +24,12 @@ LL |     check(|| {});
    |     |
    |     required by a bound introduced by this call
    |
-   = help: the trait `UnsizedConstParamTy` is not implemented for closure `{closure@$DIR/const_param_ty_bad.rs:8:11: 8:13}`
+   = help: the trait `ConstParamTy_` is not implemented for closure `{closure@$DIR/const_param_ty_bad.rs:8:11: 8:13}`
 note: required by a bound in `check`
   --> $DIR/const_param_ty_bad.rs:4:18
    |
-LL | fn check(_: impl std::marker::UnsizedConstParamTy) {}
-   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `check`
+LL | fn check(_: impl std::marker::ConstParamTy_) {}
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `check`
 help: use parentheses to call this closure
    |
 LL -     check(|| {});
@@ -40,15 +40,15 @@ error[E0277]: `fn()` can't be used as a const parameter type
   --> $DIR/const_param_ty_bad.rs:9:11
    |
 LL |     check(main as fn());
-   |     ----- ^^^^^^^^^^^^ the trait `UnsizedConstParamTy` is not implemented for `fn()`
+   |     ----- ^^^^^^^^^^^^ the trait `ConstParamTy_` is not implemented for `fn()`
    |     |
    |     required by a bound introduced by this call
    |
 note: required by a bound in `check`
   --> $DIR/const_param_ty_bad.rs:4:18
    |
-LL | fn check(_: impl std::marker::UnsizedConstParamTy) {}
-   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `check`
+LL | fn check(_: impl std::marker::ConstParamTy_) {}
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `check`
 help: use parentheses to call this function pointer
    |
 LL |     check(main as fn()());
@@ -58,16 +58,16 @@ error[E0277]: `&mut ()` can't be used as a const parameter type
   --> $DIR/const_param_ty_bad.rs:10:11
    |
 LL |     check(&mut ());
-   |     ----- ^^^^^^^ the trait `UnsizedConstParamTy` is not implemented for `&mut ()`
+   |     ----- ^^^^^^^ the trait `ConstParamTy_` is not implemented for `&mut ()`
    |     |
    |     required by a bound introduced by this call
    |
-   = note: `UnsizedConstParamTy` is implemented for `&()`, but not for `&mut ()`
+   = note: `ConstParamTy_` is implemented for `&()`, but not for `&mut ()`
 note: required by a bound in `check`
   --> $DIR/const_param_ty_bad.rs:4:18
    |
-LL | fn check(_: impl std::marker::UnsizedConstParamTy) {}
-   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `check`
+LL | fn check(_: impl std::marker::ConstParamTy_) {}
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `check`
 help: consider removing the leading `&`-reference
    |
 LL -     check(&mut ());
@@ -78,31 +78,31 @@ error[E0277]: `*mut ()` can't be used as a const parameter type
   --> $DIR/const_param_ty_bad.rs:11:11
    |
 LL |     check(&mut () as *mut ());
-   |     ----- ^^^^^^^^^^^^^^^^^^ the trait `UnsizedConstParamTy` is not implemented for `*mut ()`
+   |     ----- ^^^^^^^^^^^^^^^^^^ the trait `ConstParamTy_` is not implemented for `*mut ()`
    |     |
    |     required by a bound introduced by this call
    |
-   = help: the trait `UnsizedConstParamTy` is implemented for `()`
+   = help: the trait `ConstParamTy_` is implemented for `()`
 note: required by a bound in `check`
   --> $DIR/const_param_ty_bad.rs:4:18
    |
-LL | fn check(_: impl std::marker::UnsizedConstParamTy) {}
-   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `check`
+LL | fn check(_: impl std::marker::ConstParamTy_) {}
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `check`
 
 error[E0277]: `*const ()` can't be used as a const parameter type
   --> $DIR/const_param_ty_bad.rs:12:11
    |
 LL |     check(&() as *const ());
-   |     ----- ^^^^^^^^^^^^^^^^ the trait `UnsizedConstParamTy` is not implemented for `*const ()`
+   |     ----- ^^^^^^^^^^^^^^^^ the trait `ConstParamTy_` is not implemented for `*const ()`
    |     |
    |     required by a bound introduced by this call
    |
-   = help: the trait `UnsizedConstParamTy` is implemented for `()`
+   = help: the trait `ConstParamTy_` is implemented for `()`
 note: required by a bound in `check`
   --> $DIR/const_param_ty_bad.rs:4:18
    |
-LL | fn check(_: impl std::marker::UnsizedConstParamTy) {}
-   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `check`
+LL | fn check(_: impl std::marker::ConstParamTy_) {}
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `check`
 
 error: aborting due to 6 previous errors
 
diff --git a/tests/ui/const-generics/adt_const_params/const_param_ty_dyn_compatibility.rs b/tests/ui/const-generics/adt_const_params/const_param_ty_dyn_compatibility.rs
index 6a553c2e085..2fcf872c99a 100644
--- a/tests/ui/const-generics/adt_const_params/const_param_ty_dyn_compatibility.rs
+++ b/tests/ui/const-generics/adt_const_params/const_param_ty_dyn_compatibility.rs
@@ -1,12 +1,9 @@
 #![feature(adt_const_params, unsized_const_params)]
 #![allow(incomplete_features)]
 
-use std::marker::{ConstParamTy_, UnsizedConstParamTy};
+use std::marker::ConstParamTy_;
 
 fn foo(a: &dyn ConstParamTy_) {}
 //~^ ERROR: the trait `ConstParamTy_`
 
-fn bar(a: &dyn UnsizedConstParamTy) {}
-//~^ ERROR: the trait `UnsizedConstParamTy`
-
 fn main() {}
diff --git a/tests/ui/const-generics/adt_const_params/const_param_ty_dyn_compatibility.stderr b/tests/ui/const-generics/adt_const_params/const_param_ty_dyn_compatibility.stderr
index c71ec24dda3..ce695ff66d5 100644
--- a/tests/ui/const-generics/adt_const_params/const_param_ty_dyn_compatibility.stderr
+++ b/tests/ui/const-generics/adt_const_params/const_param_ty_dyn_compatibility.stderr
@@ -15,23 +15,6 @@ LL - fn foo(a: &dyn ConstParamTy_) {}
 LL + fn foo(a: &impl ConstParamTy_) {}
    |
 
-error[E0038]: the trait `UnsizedConstParamTy` is not dyn compatible
-  --> $DIR/const_param_ty_dyn_compatibility.rs:9:16
-   |
-LL | fn bar(a: &dyn UnsizedConstParamTy) {}
-   |                ^^^^^^^^^^^^^^^^^^^ `UnsizedConstParamTy` is not dyn compatible
-   |
-note: for a trait to be dyn compatible it needs to allow building a vtable
-      for more information, visit <https://doc.rust-lang.org/reference/items/traits.html#dyn-compatibility>
-  --> $SRC_DIR/core/src/cmp.rs:LL:COL
-   |
-   = note: the trait is not dyn compatible because it uses `Self` as a type parameter
-help: consider using an opaque type instead
-   |
-LL - fn bar(a: &dyn UnsizedConstParamTy) {}
-LL + fn bar(a: &impl UnsizedConstParamTy) {}
-   |
-
-error: aborting due to 2 previous errors
+error: aborting due to 1 previous error
 
 For more information about this error, try `rustc --explain E0038`.
diff --git a/tests/ui/const-generics/adt_const_params/const_param_ty_generic_bounds_do_not_hold.rs b/tests/ui/const-generics/adt_const_params/const_param_ty_generic_bounds_do_not_hold.rs
index 7ffdafa33e9..a86d74275de 100644
--- a/tests/ui/const-generics/adt_const_params/const_param_ty_generic_bounds_do_not_hold.rs
+++ b/tests/ui/const-generics/adt_const_params/const_param_ty_generic_bounds_do_not_hold.rs
@@ -4,7 +4,7 @@
 #[derive(PartialEq, Eq)]
 struct NotParam;
 
-fn check<T: std::marker::UnsizedConstParamTy + ?Sized>() {}
+fn check<T: std::marker::ConstParamTy_ + ?Sized>() {}
 
 fn main() {
     check::<&NotParam>(); //~ error: `NotParam` can't be used as a const parameter type
diff --git a/tests/ui/const-generics/adt_const_params/const_param_ty_generic_bounds_do_not_hold.stderr b/tests/ui/const-generics/adt_const_params/const_param_ty_generic_bounds_do_not_hold.stderr
index 158e76630f3..ca2aa3adcb7 100644
--- a/tests/ui/const-generics/adt_const_params/const_param_ty_generic_bounds_do_not_hold.stderr
+++ b/tests/ui/const-generics/adt_const_params/const_param_ty_generic_bounds_do_not_hold.stderr
@@ -4,17 +4,17 @@ error[E0277]: `NotParam` can't be used as a const parameter type
 LL |     check::<&NotParam>();
    |             ^^^^^^^^^ unsatisfied trait bound
    |
-help: the trait `UnsizedConstParamTy` is not implemented for `NotParam`
+help: the trait `ConstParamTy_` is not implemented for `NotParam`
   --> $DIR/const_param_ty_generic_bounds_do_not_hold.rs:5:1
    |
 LL | struct NotParam;
    | ^^^^^^^^^^^^^^^
-   = note: required for `&NotParam` to implement `UnsizedConstParamTy`
+   = note: required for `&NotParam` to implement `ConstParamTy_`
 note: required by a bound in `check`
   --> $DIR/const_param_ty_generic_bounds_do_not_hold.rs:7:13
    |
-LL | fn check<T: std::marker::UnsizedConstParamTy + ?Sized>() {}
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `check`
+LL | fn check<T: std::marker::ConstParamTy_ + ?Sized>() {}
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `check`
 
 error[E0277]: `NotParam` can't be used as a const parameter type
   --> $DIR/const_param_ty_generic_bounds_do_not_hold.rs:11:13
@@ -22,17 +22,17 @@ error[E0277]: `NotParam` can't be used as a const parameter type
 LL |     check::<[NotParam]>();
    |             ^^^^^^^^^^ unsatisfied trait bound
    |
-help: the trait `UnsizedConstParamTy` is not implemented for `NotParam`
+help: the trait `ConstParamTy_` is not implemented for `NotParam`
   --> $DIR/const_param_ty_generic_bounds_do_not_hold.rs:5:1
    |
 LL | struct NotParam;
    | ^^^^^^^^^^^^^^^
-   = note: required for `[NotParam]` to implement `UnsizedConstParamTy`
+   = note: required for `[NotParam]` to implement `ConstParamTy_`
 note: required by a bound in `check`
   --> $DIR/const_param_ty_generic_bounds_do_not_hold.rs:7:13
    |
-LL | fn check<T: std::marker::UnsizedConstParamTy + ?Sized>() {}
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `check`
+LL | fn check<T: std::marker::ConstParamTy_ + ?Sized>() {}
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `check`
 
 error[E0277]: `NotParam` can't be used as a const parameter type
   --> $DIR/const_param_ty_generic_bounds_do_not_hold.rs:12:13
@@ -40,17 +40,17 @@ error[E0277]: `NotParam` can't be used as a const parameter type
 LL |     check::<[NotParam; 17]>();
    |             ^^^^^^^^^^^^^^ unsatisfied trait bound
    |
-help: the trait `UnsizedConstParamTy` is not implemented for `NotParam`
+help: the trait `ConstParamTy_` is not implemented for `NotParam`
   --> $DIR/const_param_ty_generic_bounds_do_not_hold.rs:5:1
    |
 LL | struct NotParam;
    | ^^^^^^^^^^^^^^^
-   = note: required for `[NotParam; 17]` to implement `UnsizedConstParamTy`
+   = note: required for `[NotParam; 17]` to implement `ConstParamTy_`
 note: required by a bound in `check`
   --> $DIR/const_param_ty_generic_bounds_do_not_hold.rs:7:13
    |
-LL | fn check<T: std::marker::UnsizedConstParamTy + ?Sized>() {}
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `check`
+LL | fn check<T: std::marker::ConstParamTy_ + ?Sized>() {}
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `check`
 
 error: aborting due to 3 previous errors
 
diff --git a/tests/ui/const-generics/adt_const_params/const_param_ty_good.rs b/tests/ui/const-generics/adt_const_params/const_param_ty_good.rs
index 98a8eb6ee95..24bbc5a9a23 100644
--- a/tests/ui/const-generics/adt_const_params/const_param_ty_good.rs
+++ b/tests/ui/const-generics/adt_const_params/const_param_ty_good.rs
@@ -3,7 +3,7 @@
 #![feature(adt_const_params, unsized_const_params)]
 #![allow(incomplete_features)]
 
-use std::marker::UnsizedConstParamTy;
+use std::marker::{ConstParamTy, ConstParamTy_};
 
 #[derive(PartialEq, Eq)]
 struct S<T> {
@@ -11,15 +11,15 @@ struct S<T> {
     gen: T,
 }
 
-impl<T: UnsizedConstParamTy> UnsizedConstParamTy for S<T> {}
+impl<T: ConstParamTy_> ConstParamTy_ for S<T> {}
 
-#[derive(PartialEq, Eq, UnsizedConstParamTy)]
+#[derive(PartialEq, Eq, ConstParamTy)]
 struct D<T> {
     field: u8,
     gen: T,
 }
 
-fn check<T: UnsizedConstParamTy + ?Sized>() {}
+fn check<T: ConstParamTy_ + ?Sized>() {}
 
 fn main() {
     check::<u8>();
diff --git a/tests/ui/const-generics/adt_const_params/const_param_ty_impl_bad_field.rs b/tests/ui/const-generics/adt_const_params/const_param_ty_impl_bad_field.rs
index 8b3d0546010..0614ea97b1a 100644
--- a/tests/ui/const-generics/adt_const_params/const_param_ty_impl_bad_field.rs
+++ b/tests/ui/const-generics/adt_const_params/const_param_ty_impl_bad_field.rs
@@ -7,10 +7,10 @@ struct NotParam;
 #[derive(PartialEq, Eq)]
 struct CantParam(NotParam);
 
-impl std::marker::UnsizedConstParamTy for CantParam {}
+impl std::marker::ConstParamTy_ for CantParam {}
 //~^ error: the trait `ConstParamTy_` cannot be implemented for this type
 
-#[derive(std::marker::UnsizedConstParamTy, Eq, PartialEq)]
+#[derive(std::marker::ConstParamTy, Eq, PartialEq)]
 //~^ error: the trait `ConstParamTy_` cannot be implemented for this type
 struct CantParamDerive(NotParam);
 
diff --git a/tests/ui/const-generics/adt_const_params/const_param_ty_impl_bad_field.stderr b/tests/ui/const-generics/adt_const_params/const_param_ty_impl_bad_field.stderr
index a4e5736d834..fd1836802c4 100644
--- a/tests/ui/const-generics/adt_const_params/const_param_ty_impl_bad_field.stderr
+++ b/tests/ui/const-generics/adt_const_params/const_param_ty_impl_bad_field.stderr
@@ -1,17 +1,17 @@
 error[E0204]: the trait `ConstParamTy_` cannot be implemented for this type
-  --> $DIR/const_param_ty_impl_bad_field.rs:10:43
+  --> $DIR/const_param_ty_impl_bad_field.rs:10:37
    |
 LL | struct CantParam(NotParam);
    |                  -------- this field does not implement `ConstParamTy_`
 LL |
-LL | impl std::marker::UnsizedConstParamTy for CantParam {}
-   |                                           ^^^^^^^^^
+LL | impl std::marker::ConstParamTy_ for CantParam {}
+   |                                     ^^^^^^^^^
 
 error[E0204]: the trait `ConstParamTy_` cannot be implemented for this type
   --> $DIR/const_param_ty_impl_bad_field.rs:13:10
    |
-LL | #[derive(std::marker::UnsizedConstParamTy, Eq, PartialEq)]
-   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | #[derive(std::marker::ConstParamTy, Eq, PartialEq)]
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^^
 LL |
 LL | struct CantParamDerive(NotParam);
    |                        -------- this field does not implement `ConstParamTy_`
diff --git a/tests/ui/const-generics/adt_const_params/const_param_ty_impl_no_structural_eq.rs b/tests/ui/const-generics/adt_const_params/const_param_ty_impl_no_structural_eq.rs
index e743b78fd13..a1c8eccfb09 100644
--- a/tests/ui/const-generics/adt_const_params/const_param_ty_impl_no_structural_eq.rs
+++ b/tests/ui/const-generics/adt_const_params/const_param_ty_impl_no_structural_eq.rs
@@ -3,20 +3,20 @@
 
 #[derive(PartialEq, Eq)]
 struct ImplementsConstParamTy;
-impl std::marker::UnsizedConstParamTy for ImplementsConstParamTy {}
+impl std::marker::ConstParamTy_ for ImplementsConstParamTy {}
 
 struct CantParam(ImplementsConstParamTy);
 
-impl std::marker::UnsizedConstParamTy for CantParam {}
+impl std::marker::ConstParamTy_ for CantParam {}
 //~^ error: the type `CantParam` does not `#[derive(PartialEq)]`
 //~| ERROR the trait bound `CantParam: Eq` is not satisfied
 
-#[derive(std::marker::UnsizedConstParamTy)]
+#[derive(std::marker::ConstParamTy)]
 //~^ error: the type `CantParamDerive` does not `#[derive(PartialEq)]`
 //~| ERROR the trait bound `CantParamDerive: Eq` is not satisfied
 struct CantParamDerive(ImplementsConstParamTy);
 
-fn check<T: std::marker::UnsizedConstParamTy>() {}
+fn check<T: std::marker::ConstParamTy_>() {}
 
 fn main() {
     check::<ImplementsConstParamTy>();
diff --git a/tests/ui/const-generics/adt_const_params/const_param_ty_impl_no_structural_eq.stderr b/tests/ui/const-generics/adt_const_params/const_param_ty_impl_no_structural_eq.stderr
index d3141381db8..c6b791ed967 100644
--- a/tests/ui/const-generics/adt_const_params/const_param_ty_impl_no_structural_eq.stderr
+++ b/tests/ui/const-generics/adt_const_params/const_param_ty_impl_no_structural_eq.stderr
@@ -1,10 +1,10 @@
 error[E0277]: the trait bound `CantParam: Eq` is not satisfied
-  --> $DIR/const_param_ty_impl_no_structural_eq.rs:10:43
+  --> $DIR/const_param_ty_impl_no_structural_eq.rs:10:37
    |
-LL | impl std::marker::UnsizedConstParamTy for CantParam {}
-   |                                           ^^^^^^^^^ the trait `Eq` is not implemented for `CantParam`
+LL | impl std::marker::ConstParamTy_ for CantParam {}
+   |                                     ^^^^^^^^^ the trait `Eq` is not implemented for `CantParam`
    |
-note: required by a bound in `UnsizedConstParamTy`
+note: required by a bound in `ConstParamTy_`
   --> $SRC_DIR/core/src/marker.rs:LL:COL
 help: consider annotating `CantParam` with `#[derive(Eq)]`
    |
@@ -13,26 +13,26 @@ LL | struct CantParam(ImplementsConstParamTy);
    |
 
 error[E0277]: the type `CantParam` does not `#[derive(PartialEq)]`
-  --> $DIR/const_param_ty_impl_no_structural_eq.rs:10:43
+  --> $DIR/const_param_ty_impl_no_structural_eq.rs:10:37
    |
-LL | impl std::marker::UnsizedConstParamTy for CantParam {}
-   |                                           ^^^^^^^^^ unsatisfied trait bound
+LL | impl std::marker::ConstParamTy_ for CantParam {}
+   |                                     ^^^^^^^^^ unsatisfied trait bound
    |
 help: the trait `StructuralPartialEq` is not implemented for `CantParam`
   --> $DIR/const_param_ty_impl_no_structural_eq.rs:8:1
    |
 LL | struct CantParam(ImplementsConstParamTy);
    | ^^^^^^^^^^^^^^^^
-note: required by a bound in `UnsizedConstParamTy`
+note: required by a bound in `ConstParamTy_`
   --> $SRC_DIR/core/src/marker.rs:LL:COL
 
 error[E0277]: the trait bound `CantParamDerive: Eq` is not satisfied
   --> $DIR/const_param_ty_impl_no_structural_eq.rs:14:10
    |
-LL | #[derive(std::marker::UnsizedConstParamTy)]
-   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Eq` is not implemented for `CantParamDerive`
+LL | #[derive(std::marker::ConstParamTy)]
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Eq` is not implemented for `CantParamDerive`
    |
-note: required by a bound in `UnsizedConstParamTy`
+note: required by a bound in `ConstParamTy_`
   --> $SRC_DIR/core/src/marker.rs:LL:COL
 help: consider annotating `CantParamDerive` with `#[derive(Eq)]`
    |
@@ -43,15 +43,15 @@ LL | struct CantParamDerive(ImplementsConstParamTy);
 error[E0277]: the type `CantParamDerive` does not `#[derive(PartialEq)]`
   --> $DIR/const_param_ty_impl_no_structural_eq.rs:14:10
    |
-LL | #[derive(std::marker::UnsizedConstParamTy)]
-   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unsatisfied trait bound
+LL | #[derive(std::marker::ConstParamTy)]
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^^ unsatisfied trait bound
    |
 help: the trait `StructuralPartialEq` is not implemented for `CantParamDerive`
   --> $DIR/const_param_ty_impl_no_structural_eq.rs:17:1
    |
 LL | struct CantParamDerive(ImplementsConstParamTy);
    | ^^^^^^^^^^^^^^^^^^^^^^
-note: required by a bound in `UnsizedConstParamTy`
+note: required by a bound in `ConstParamTy_`
   --> $SRC_DIR/core/src/marker.rs:LL:COL
 
 error: aborting due to 4 previous errors
diff --git a/tests/ui/const-generics/adt_const_params/const_param_ty_impl_union.rs b/tests/ui/const-generics/adt_const_params/const_param_ty_impl_union.rs
index 236b3bc162a..0c9b12805f7 100644
--- a/tests/ui/const-generics/adt_const_params/const_param_ty_impl_union.rs
+++ b/tests/ui/const-generics/adt_const_params/const_param_ty_impl_union.rs
@@ -12,10 +12,10 @@ impl PartialEq for Union {
 }
 impl Eq for Union {}
 
-impl std::marker::UnsizedConstParamTy for Union {}
+impl std::marker::ConstParamTy_ for Union {}
 //~^ ERROR the trait `ConstParamTy` may not be implemented for this type
 
-#[derive(std::marker::UnsizedConstParamTy)]
+#[derive(std::marker::ConstParamTy)]
 //~^ ERROR this trait cannot be derived for unions
 union UnionDerive {
     a: u8,
diff --git a/tests/ui/const-generics/adt_const_params/const_param_ty_impl_union.stderr b/tests/ui/const-generics/adt_const_params/const_param_ty_impl_union.stderr
index 837c289c924..cc2147b49ae 100644
--- a/tests/ui/const-generics/adt_const_params/const_param_ty_impl_union.stderr
+++ b/tests/ui/const-generics/adt_const_params/const_param_ty_impl_union.stderr
@@ -1,14 +1,14 @@
 error: this trait cannot be derived for unions
   --> $DIR/const_param_ty_impl_union.rs:18:10
    |
-LL | #[derive(std::marker::UnsizedConstParamTy)]
-   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | #[derive(std::marker::ConstParamTy)]
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: the trait `ConstParamTy` may not be implemented for this type
-  --> $DIR/const_param_ty_impl_union.rs:15:43
+  --> $DIR/const_param_ty_impl_union.rs:15:37
    |
-LL | impl std::marker::UnsizedConstParamTy for Union {}
-   |                                           ^^^^^ type is not a structure or enumeration
+LL | impl std::marker::ConstParamTy_ for Union {}
+   |                                     ^^^^^ type is not a structure or enumeration
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/const-generics/adt_const_params/nested_bad_const_param_ty.rs b/tests/ui/const-generics/adt_const_params/nested_bad_const_param_ty.rs
index 34ea143d254..d42ef90e1b1 100644
--- a/tests/ui/const-generics/adt_const_params/nested_bad_const_param_ty.rs
+++ b/tests/ui/const-generics/adt_const_params/nested_bad_const_param_ty.rs
@@ -5,17 +5,14 @@ use std::marker::ConstParamTy;
 
 #[derive(ConstParamTy)]
 //~^ ERROR the trait `ConstParamTy_` cannot be implemented for this ty
-//~| ERROR the trait `ConstParamTy_` cannot be implemented for this ty
 struct Foo([*const u8; 1]);
 
 #[derive(ConstParamTy)]
 //~^ ERROR the trait `ConstParamTy_` cannot be implemented for this ty
-//~| ERROR the trait `ConstParamTy_` cannot be implemented for this ty
 struct Foo2([*mut u8; 1]);
 
 #[derive(ConstParamTy)]
 //~^ ERROR the trait `ConstParamTy_` cannot be implemented for this ty
-//~| ERROR the trait `ConstParamTy_` cannot be implemented for this ty
 struct Foo3([fn(); 1]);
 
 fn main() {}
diff --git a/tests/ui/const-generics/adt_const_params/nested_bad_const_param_ty.stderr b/tests/ui/const-generics/adt_const_params/nested_bad_const_param_ty.stderr
index 6b8d2394a86..442ec6b96ce 100644
--- a/tests/ui/const-generics/adt_const_params/nested_bad_const_param_ty.stderr
+++ b/tests/ui/const-generics/adt_const_params/nested_bad_const_param_ty.stderr
@@ -3,91 +3,46 @@ error[E0204]: the trait `ConstParamTy_` cannot be implemented for this type
    |
 LL | #[derive(ConstParamTy)]
    |          ^^^^^^^^^^^^
-...
+LL |
 LL | struct Foo([*const u8; 1]);
    |            -------------- this field does not implement `ConstParamTy_`
    |
 note: the `ConstParamTy_` impl for `[*const u8; 1]` requires that `*const u8: ConstParamTy_`
-  --> $DIR/nested_bad_const_param_ty.rs:9:12
+  --> $DIR/nested_bad_const_param_ty.rs:8:12
    |
 LL | struct Foo([*const u8; 1]);
    |            ^^^^^^^^^^^^^^
 
 error[E0204]: the trait `ConstParamTy_` cannot be implemented for this type
-  --> $DIR/nested_bad_const_param_ty.rs:11:10
+  --> $DIR/nested_bad_const_param_ty.rs:10:10
    |
 LL | #[derive(ConstParamTy)]
    |          ^^^^^^^^^^^^
-...
+LL |
 LL | struct Foo2([*mut u8; 1]);
    |             ------------ this field does not implement `ConstParamTy_`
    |
 note: the `ConstParamTy_` impl for `[*mut u8; 1]` requires that `*mut u8: ConstParamTy_`
-  --> $DIR/nested_bad_const_param_ty.rs:14:13
+  --> $DIR/nested_bad_const_param_ty.rs:12:13
    |
 LL | struct Foo2([*mut u8; 1]);
    |             ^^^^^^^^^^^^
 
 error[E0204]: the trait `ConstParamTy_` cannot be implemented for this type
-  --> $DIR/nested_bad_const_param_ty.rs:16:10
+  --> $DIR/nested_bad_const_param_ty.rs:14:10
    |
 LL | #[derive(ConstParamTy)]
    |          ^^^^^^^^^^^^
-...
+LL |
 LL | struct Foo3([fn(); 1]);
    |             --------- this field does not implement `ConstParamTy_`
    |
 note: the `ConstParamTy_` impl for `[fn(); 1]` requires that `fn(): ConstParamTy_`
-  --> $DIR/nested_bad_const_param_ty.rs:19:13
+  --> $DIR/nested_bad_const_param_ty.rs:16:13
    |
 LL | struct Foo3([fn(); 1]);
    |             ^^^^^^^^^
 
-error[E0204]: the trait `ConstParamTy_` cannot be implemented for this type
-  --> $DIR/nested_bad_const_param_ty.rs:6:10
-   |
-LL | #[derive(ConstParamTy)]
-   |          ^^^^^^^^^^^^
-...
-LL | struct Foo([*const u8; 1]);
-   |            -------------- this field does not implement `ConstParamTy_`
-   |
-note: the `ConstParamTy_` impl for `[*const u8; 1]` requires that `*const u8: UnsizedConstParamTy`
-  --> $DIR/nested_bad_const_param_ty.rs:9:12
-   |
-LL | struct Foo([*const u8; 1]);
-   |            ^^^^^^^^^^^^^^
-
-error[E0204]: the trait `ConstParamTy_` cannot be implemented for this type
-  --> $DIR/nested_bad_const_param_ty.rs:11:10
-   |
-LL | #[derive(ConstParamTy)]
-   |          ^^^^^^^^^^^^
-...
-LL | struct Foo2([*mut u8; 1]);
-   |             ------------ this field does not implement `ConstParamTy_`
-   |
-note: the `ConstParamTy_` impl for `[*mut u8; 1]` requires that `*mut u8: UnsizedConstParamTy`
-  --> $DIR/nested_bad_const_param_ty.rs:14:13
-   |
-LL | struct Foo2([*mut u8; 1]);
-   |             ^^^^^^^^^^^^
-
-error[E0204]: the trait `ConstParamTy_` cannot be implemented for this type
-  --> $DIR/nested_bad_const_param_ty.rs:16:10
-   |
-LL | #[derive(ConstParamTy)]
-   |          ^^^^^^^^^^^^
-...
-LL | struct Foo3([fn(); 1]);
-   |             --------- this field does not implement `ConstParamTy_`
-   |
-note: the `ConstParamTy_` impl for `[fn(); 1]` requires that `fn(): UnsizedConstParamTy`
-  --> $DIR/nested_bad_const_param_ty.rs:19:13
-   |
-LL | struct Foo3([fn(); 1]);
-   |             ^^^^^^^^^
-
-error: aborting due to 6 previous errors
+error: aborting due to 3 previous errors
 
 For more information about this error, try `rustc --explain E0204`.
diff --git a/tests/ui/const-generics/adt_const_params/non_valtreeable_const_arg-2.stderr b/tests/ui/const-generics/adt_const_params/non_valtreeable_const_arg-2.stderr
index b13f76eabad..72dfda50ea5 100644
--- a/tests/ui/const-generics/adt_const_params/non_valtreeable_const_arg-2.stderr
+++ b/tests/ui/const-generics/adt_const_params/non_valtreeable_const_arg-2.stderr
@@ -9,11 +9,13 @@ help: you might be missing a const parameter
 LL | impl<const bar: /* Type */> Wrapper<{ bar() }> {
    |     +++++++++++++++++++++++
 
-error[E0741]: using function pointers as const generic parameters is forbidden
+error: using function pointers as const generic parameters is forbidden
   --> $DIR/non_valtreeable_const_arg-2.rs:8:25
    |
 LL | struct Wrapper<const F: fn()>;
    |                         ^^^^
+   |
+   = note: the only supported types are integers, `bool`, and `char`
 
 error[E0599]: the function or associated item `call` exists for struct `Wrapper<function>`, but its trait bounds were not satisfied
   --> $DIR/non_valtreeable_const_arg-2.rs:17:26
@@ -35,5 +37,5 @@ note: the trait `Fn` must be implemented
 
 error: aborting due to 3 previous errors
 
-Some errors have detailed explanations: E0425, E0599, E0741.
+Some errors have detailed explanations: E0425, E0599.
 For more information about an error, try `rustc --explain E0425`.
diff --git a/tests/ui/const-generics/adt_const_params/reference_pointee_is_const_param-1.rs b/tests/ui/const-generics/adt_const_params/reference_pointee_is_const_param-1.rs
index a1ee1c4cdd5..937acf2e6bb 100644
--- a/tests/ui/const-generics/adt_const_params/reference_pointee_is_const_param-1.rs
+++ b/tests/ui/const-generics/adt_const_params/reference_pointee_is_const_param-1.rs
@@ -1,11 +1,11 @@
 #![feature(adt_const_params, unsized_const_params)]
 #![allow(incomplete_features)]
 
-use std::marker::UnsizedConstParamTy;
+use std::marker::ConstParamTy_;
 
 struct Foo;
 
-impl UnsizedConstParamTy for &'static Foo {}
+impl ConstParamTy_ for &'static Foo {}
 //~^ ERROR: the trait `ConstParamTy_` cannot be implemented for this type
 
 fn main() {}
diff --git a/tests/ui/const-generics/adt_const_params/reference_pointee_is_const_param-1.stderr b/tests/ui/const-generics/adt_const_params/reference_pointee_is_const_param-1.stderr
index 5ca8e6c7516..b977cf5d44e 100644
--- a/tests/ui/const-generics/adt_const_params/reference_pointee_is_const_param-1.stderr
+++ b/tests/ui/const-generics/adt_const_params/reference_pointee_is_const_param-1.stderr
@@ -1,8 +1,8 @@
 error[E0204]: the trait `ConstParamTy_` cannot be implemented for this type
-  --> $DIR/reference_pointee_is_const_param-1.rs:8:30
+  --> $DIR/reference_pointee_is_const_param-1.rs:8:24
    |
-LL | impl UnsizedConstParamTy for &'static Foo {}
-   |                              ^^^^^^^^^^^^ this field does not implement `ConstParamTy_`
+LL | impl ConstParamTy_ for &'static Foo {}
+   |                        ^^^^^^^^^^^^ this field does not implement `ConstParamTy_`
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/const-generics/adt_const_params/reference_pointee_is_const_param-2.rs b/tests/ui/const-generics/adt_const_params/reference_pointee_is_const_param-2.rs
index ac1b522f469..605fed26c9c 100644
--- a/tests/ui/const-generics/adt_const_params/reference_pointee_is_const_param-2.rs
+++ b/tests/ui/const-generics/adt_const_params/reference_pointee_is_const_param-2.rs
@@ -3,12 +3,12 @@
 
 // Regression test for #119299
 
-use std::marker::UnsizedConstParamTy;
+use std::marker::ConstParamTy_;
 
 #[derive(Eq, PartialEq)]
 struct ConstStrU(*const u8, usize);
 
-impl UnsizedConstParamTy for &'static ConstStrU {}
+impl ConstParamTy_ for &'static ConstStrU {}
 //~^ ERROR: the trait `ConstParamTy_` cannot be implemented for this type
 
 impl ConstStrU {
diff --git a/tests/ui/const-generics/adt_const_params/reference_pointee_is_const_param-2.stderr b/tests/ui/const-generics/adt_const_params/reference_pointee_is_const_param-2.stderr
index 5e5f6cc642d..0fe92f253a0 100644
--- a/tests/ui/const-generics/adt_const_params/reference_pointee_is_const_param-2.stderr
+++ b/tests/ui/const-generics/adt_const_params/reference_pointee_is_const_param-2.stderr
@@ -1,8 +1,8 @@
 error[E0204]: the trait `ConstParamTy_` cannot be implemented for this type
-  --> $DIR/reference_pointee_is_const_param-2.rs:11:30
+  --> $DIR/reference_pointee_is_const_param-2.rs:11:24
    |
-LL | impl UnsizedConstParamTy for &'static ConstStrU {}
-   |                              ^^^^^^^^^^^^^^^^^^ this field does not implement `ConstParamTy_`
+LL | impl ConstParamTy_ for &'static ConstStrU {}
+   |                        ^^^^^^^^^^^^^^^^^^ this field does not implement `ConstParamTy_`
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/const-generics/adt_const_params/trait_objects_as_a_const_generic.rs b/tests/ui/const-generics/adt_const_params/trait_objects_as_a_const_generic.rs
index b0934508399..0fe86adb291 100644
--- a/tests/ui/const-generics/adt_const_params/trait_objects_as_a_const_generic.rs
+++ b/tests/ui/const-generics/adt_const_params/trait_objects_as_a_const_generic.rs
@@ -1,11 +1,11 @@
 #![feature(adt_const_params, unsized_const_params)]
 #![allow(incomplete_features)]
 
-use std::marker::UnsizedConstParamTy;
+use std::marker::ConstParamTy_;
 
 trait Trait {}
 
-impl UnsizedConstParamTy for dyn Trait {}
+impl ConstParamTy_ for dyn Trait {}
 //~^ ERROR: the trait `ConstParamTy` may not be implemented for this type
 
 fn foo<const N: dyn Trait>() {}
diff --git a/tests/ui/const-generics/adt_const_params/trait_objects_as_a_const_generic.stderr b/tests/ui/const-generics/adt_const_params/trait_objects_as_a_const_generic.stderr
index 9933ba6e335..67c6314e297 100644
--- a/tests/ui/const-generics/adt_const_params/trait_objects_as_a_const_generic.stderr
+++ b/tests/ui/const-generics/adt_const_params/trait_objects_as_a_const_generic.stderr
@@ -1,8 +1,8 @@
 error: the trait `ConstParamTy` may not be implemented for this type
-  --> $DIR/trait_objects_as_a_const_generic.rs:8:30
+  --> $DIR/trait_objects_as_a_const_generic.rs:8:24
    |
-LL | impl UnsizedConstParamTy for dyn Trait {}
-   |                              ^^^^^^^^^ type is not a structure or enumeration
+LL | impl ConstParamTy_ for dyn Trait {}
+   |                        ^^^^^^^^^ type is not a structure or enumeration
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/const-generics/adt_const_params/unsized_field-1.rs b/tests/ui/const-generics/adt_const_params/unsized_field-1.rs
index f6e5bd6e355..5db031cb900 100644
--- a/tests/ui/const-generics/adt_const_params/unsized_field-1.rs
+++ b/tests/ui/const-generics/adt_const_params/unsized_field-1.rs
@@ -14,7 +14,10 @@ struct A([u8]);
 struct B(&'static [u8]);
 
 #[derive(ConstParamTy, Eq, PartialEq)]
-//~^ ERROR: the trait `ConstParamTy_` cannot be implemented for this type
 struct C(unsized_const_param::Foo);
 
+#[derive(std::marker::ConstParamTy, Eq, PartialEq)]
+//~^ ERROR: the trait `ConstParamTy_` cannot be implemented for this type
+struct D(unsized_const_param::GenericNotUnsizedParam<&'static [u8]>);
+
 fn main() {}
diff --git a/tests/ui/const-generics/adt_const_params/unsized_field-1.stderr b/tests/ui/const-generics/adt_const_params/unsized_field-1.stderr
index 3089b30bd76..a5ae5c726da 100644
--- a/tests/ui/const-generics/adt_const_params/unsized_field-1.stderr
+++ b/tests/ui/const-generics/adt_const_params/unsized_field-1.stderr
@@ -6,6 +6,12 @@ LL | #[derive(ConstParamTy, Eq, PartialEq)]
 LL |
 LL | struct A([u8]);
    |          ---- this field does not implement `ConstParamTy_`
+   |
+note: the `ConstParamTy_` impl for `[u8]` requires that `unstable feature: `unsized_const_params``
+  --> $DIR/unsized_field-1.rs:10:10
+   |
+LL | struct A([u8]);
+   |          ^^^^
 
 error[E0204]: the trait `ConstParamTy_` cannot be implemented for this type
   --> $DIR/unsized_field-1.rs:12:10
@@ -15,15 +21,27 @@ LL | #[derive(ConstParamTy, Eq, PartialEq)]
 LL |
 LL | struct B(&'static [u8]);
    |          ------------- this field does not implement `ConstParamTy_`
+   |
+note: the `ConstParamTy_` impl for `&'static [u8]` requires that `unstable feature: `unsized_const_params``
+  --> $DIR/unsized_field-1.rs:14:10
+   |
+LL | struct B(&'static [u8]);
+   |          ^^^^^^^^^^^^^
 
 error[E0204]: the trait `ConstParamTy_` cannot be implemented for this type
-  --> $DIR/unsized_field-1.rs:16:10
+  --> $DIR/unsized_field-1.rs:19:10
    |
-LL | #[derive(ConstParamTy, Eq, PartialEq)]
-   |          ^^^^^^^^^^^^
+LL | #[derive(std::marker::ConstParamTy, Eq, PartialEq)]
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^^
 LL |
-LL | struct C(unsized_const_param::Foo);
-   |          ------------------------ this field does not implement `ConstParamTy_`
+LL | struct D(unsized_const_param::GenericNotUnsizedParam<&'static [u8]>);
+   |          ---------------------------------------------------------- this field does not implement `ConstParamTy_`
+   |
+note: the `ConstParamTy_` impl for `GenericNotUnsizedParam<&'static [u8]>` requires that `unstable feature: `unsized_const_params``
+  --> $DIR/unsized_field-1.rs:21:10
+   |
+LL | struct D(unsized_const_param::GenericNotUnsizedParam<&'static [u8]>);
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 3 previous errors
 
diff --git a/tests/ui/const-generics/adt_const_params/unsized_field-2.rs b/tests/ui/const-generics/adt_const_params/unsized_field-2.rs
deleted file mode 100644
index e4a3a481b4e..00000000000
--- a/tests/ui/const-generics/adt_const_params/unsized_field-2.rs
+++ /dev/null
@@ -1,14 +0,0 @@
-//@ aux-build:unsized_const_param.rs
-#![feature(adt_const_params, unsized_const_params)]
-//~^ WARN: the feature `unsized_const_params` is incomplete
-
-extern crate unsized_const_param;
-
-#[derive(std::marker::ConstParamTy, Eq, PartialEq)]
-//~^ ERROR: the trait `ConstParamTy_` cannot be implemented for this type
-struct A(unsized_const_param::GenericNotUnsizedParam<&'static [u8]>);
-
-#[derive(std::marker::UnsizedConstParamTy, Eq, PartialEq)]
-struct B(unsized_const_param::GenericNotUnsizedParam<&'static [u8]>);
-
-fn main() {}
diff --git a/tests/ui/const-generics/adt_const_params/unsized_field-2.stderr b/tests/ui/const-generics/adt_const_params/unsized_field-2.stderr
deleted file mode 100644
index cef70ca0463..00000000000
--- a/tests/ui/const-generics/adt_const_params/unsized_field-2.stderr
+++ /dev/null
@@ -1,27 +0,0 @@
-warning: the feature `unsized_const_params` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/unsized_field-2.rs:2:30
-   |
-LL | #![feature(adt_const_params, unsized_const_params)]
-   |                              ^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: see issue #95174 <https://github.com/rust-lang/rust/issues/95174> for more information
-   = note: `#[warn(incomplete_features)]` on by default
-
-error[E0204]: the trait `ConstParamTy_` cannot be implemented for this type
-  --> $DIR/unsized_field-2.rs:7:10
-   |
-LL | #[derive(std::marker::ConstParamTy, Eq, PartialEq)]
-   |          ^^^^^^^^^^^^^^^^^^^^^^^^^
-LL |
-LL | struct A(unsized_const_param::GenericNotUnsizedParam<&'static [u8]>);
-   |          ---------------------------------------------------------- this field does not implement `ConstParamTy_`
-   |
-note: the `ConstParamTy_` impl for `GenericNotUnsizedParam<&'static [u8]>` requires that `&'static [u8]: ConstParamTy_`
-  --> $DIR/unsized_field-2.rs:9:10
-   |
-LL | struct A(unsized_const_param::GenericNotUnsizedParam<&'static [u8]>);
-   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-error: aborting due to 1 previous error; 1 warning emitted
-
-For more information about this error, try `rustc --explain E0204`.
diff --git a/tests/ui/const-generics/adt_const_params/unsizing-wfcheck-issue-126272.rs b/tests/ui/const-generics/adt_const_params/unsizing-wfcheck-issue-126272.rs
index 311f507d3c7..500e8e22b0e 100644
--- a/tests/ui/const-generics/adt_const_params/unsizing-wfcheck-issue-126272.rs
+++ b/tests/ui/const-generics/adt_const_params/unsizing-wfcheck-issue-126272.rs
@@ -7,7 +7,6 @@ use std::marker::ConstParamTy;
 
 #[derive(Debug, PartialEq, Eq, ConstParamTy)]
 //~^ ERROR the trait `ConstParamTy_`
-//~| ERROR the trait `ConstParamTy_`
 struct Foo {
     nested: &'static Bar<dyn std::fmt::Debug>,
     //~^ ERROR the size for values
diff --git a/tests/ui/const-generics/adt_const_params/unsizing-wfcheck-issue-126272.stderr b/tests/ui/const-generics/adt_const_params/unsizing-wfcheck-issue-126272.stderr
index 992a27c1c0e..d4aeb91999c 100644
--- a/tests/ui/const-generics/adt_const_params/unsizing-wfcheck-issue-126272.stderr
+++ b/tests/ui/const-generics/adt_const_params/unsizing-wfcheck-issue-126272.stderr
@@ -1,17 +1,17 @@
 error[E0277]: the size for values of type `(dyn Debug + 'static)` cannot be known at compilation time
-  --> $DIR/unsizing-wfcheck-issue-126272.rs:12:13
+  --> $DIR/unsizing-wfcheck-issue-126272.rs:11:13
    |
 LL |     nested: &'static Bar<dyn std::fmt::Debug>,
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
    |
    = help: the trait `Sized` is not implemented for `(dyn Debug + 'static)`
 note: required by an implicit `Sized` bound in `Bar`
-  --> $DIR/unsizing-wfcheck-issue-126272.rs:21:12
+  --> $DIR/unsizing-wfcheck-issue-126272.rs:20:12
    |
 LL | struct Bar<T>(T);
    |            ^ required by the implicit `Sized` requirement on this type parameter in `Bar`
 help: you could relax the implicit `Sized` bound on `T` if it were used through indirection like `&T` or `Box<T>`
-  --> $DIR/unsizing-wfcheck-issue-126272.rs:21:12
+  --> $DIR/unsizing-wfcheck-issue-126272.rs:20:12
    |
 LL | struct Bar<T>(T);
    |            ^  - ...if indirection were used here: `Box<T>`
@@ -26,34 +26,25 @@ LL | #[derive(Debug, PartialEq, Eq, ConstParamTy)]
 ...
 LL |     nested: &'static Bar<dyn std::fmt::Debug>,
    |     ----------------------------------------- this field does not implement `ConstParamTy_`
-
-error[E0204]: the trait `ConstParamTy_` cannot be implemented for this type
-  --> $DIR/unsizing-wfcheck-issue-126272.rs:8:32
    |
-LL | #[derive(Debug, PartialEq, Eq, ConstParamTy)]
-   |                                ^^^^^^^^^^^^
-...
-LL |     nested: &'static Bar<dyn std::fmt::Debug>,
-   |     ----------------------------------------- this field does not implement `ConstParamTy_`
-   |
-note: the `ConstParamTy_` impl for `&'static Bar<(dyn Debug + 'static)>` requires that `(dyn Debug + 'static): Eq`
-  --> $DIR/unsizing-wfcheck-issue-126272.rs:12:13
+note: the `ConstParamTy_` impl for `&'static Bar<(dyn Debug + 'static)>` requires that `(dyn Debug + 'static): ConstParamTy_`
+  --> $DIR/unsizing-wfcheck-issue-126272.rs:11:13
    |
 LL |     nested: &'static Bar<dyn std::fmt::Debug>,
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-note: the `ConstParamTy_` impl for `&'static Bar<(dyn Debug + 'static)>` requires that `(dyn Debug + 'static): Sized`
-  --> $DIR/unsizing-wfcheck-issue-126272.rs:12:13
+note: the `ConstParamTy_` impl for `&'static Bar<(dyn Debug + 'static)>` requires that `(dyn Debug + 'static): Eq`
+  --> $DIR/unsizing-wfcheck-issue-126272.rs:11:13
    |
 LL |     nested: &'static Bar<dyn std::fmt::Debug>,
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-note: the `ConstParamTy_` impl for `&'static Bar<(dyn Debug + 'static)>` requires that `(dyn Debug + 'static): UnsizedConstParamTy`
-  --> $DIR/unsizing-wfcheck-issue-126272.rs:12:13
+note: the `ConstParamTy_` impl for `&'static Bar<(dyn Debug + 'static)>` requires that `(dyn Debug + 'static): Sized`
+  --> $DIR/unsizing-wfcheck-issue-126272.rs:11:13
    |
 LL |     nested: &'static Bar<dyn std::fmt::Debug>,
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0277]: the size for values of type `(dyn Debug + 'static)` cannot be known at compilation time
-  --> $DIR/unsizing-wfcheck-issue-126272.rs:12:5
+  --> $DIR/unsizing-wfcheck-issue-126272.rs:11:5
    |
 LL | #[derive(Debug, PartialEq, Eq, ConstParamTy)]
    |          ----- in this derive macro expansion
@@ -64,7 +55,7 @@ LL |     nested: &'static Bar<dyn std::fmt::Debug>,
    = help: the trait `Sized` is not implemented for `(dyn Debug + 'static)`
    = help: the trait `Debug` is implemented for `Bar<T>`
 note: required for `Bar<(dyn Debug + 'static)>` to implement `Debug`
-  --> $DIR/unsizing-wfcheck-issue-126272.rs:20:10
+  --> $DIR/unsizing-wfcheck-issue-126272.rs:19:10
    |
 LL | #[derive(Debug, PartialEq, Eq, ConstParamTy)]
    |          ^^^^^
@@ -75,7 +66,7 @@ LL | struct Bar<T>(T);
    = note: required for the cast from `&&&'static Bar<(dyn Debug + 'static)>` to `&dyn Debug`
 
 error[E0369]: binary operation `==` cannot be applied to type `&Bar<dyn Debug>`
-  --> $DIR/unsizing-wfcheck-issue-126272.rs:12:5
+  --> $DIR/unsizing-wfcheck-issue-126272.rs:11:5
    |
 LL | #[derive(Debug, PartialEq, Eq, ConstParamTy)]
    |                 --------- in this derive macro expansion
@@ -84,7 +75,7 @@ LL |     nested: &'static Bar<dyn std::fmt::Debug>,
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0277]: the trait bound `dyn Debug: Eq` is not satisfied
-  --> $DIR/unsizing-wfcheck-issue-126272.rs:12:5
+  --> $DIR/unsizing-wfcheck-issue-126272.rs:11:5
    |
 LL | #[derive(Debug, PartialEq, Eq, ConstParamTy)]
    |                            -- in this derive macro expansion
@@ -94,7 +85,7 @@ LL |     nested: &'static Bar<dyn std::fmt::Debug>,
    |
    = help: the trait `Eq` is implemented for `Bar<T>`
 note: required for `Bar<dyn Debug>` to implement `Eq`
-  --> $DIR/unsizing-wfcheck-issue-126272.rs:20:28
+  --> $DIR/unsizing-wfcheck-issue-126272.rs:19:28
    |
 LL | #[derive(Debug, PartialEq, Eq, ConstParamTy)]
    |                            ^^ unsatisfied trait bound introduced in this `derive` macro
@@ -104,7 +95,7 @@ note: required by a bound in `AssertParamIsEq`
   --> $SRC_DIR/core/src/cmp.rs:LL:COL
 
 error[E0277]: the size for values of type `dyn Debug` cannot be known at compilation time
-  --> $DIR/unsizing-wfcheck-issue-126272.rs:12:5
+  --> $DIR/unsizing-wfcheck-issue-126272.rs:11:5
    |
 LL | #[derive(Debug, PartialEq, Eq, ConstParamTy)]
    |                            -- in this derive macro expansion
@@ -114,12 +105,12 @@ LL |     nested: &'static Bar<dyn std::fmt::Debug>,
    |
    = help: the trait `Sized` is not implemented for `dyn Debug`
 note: required by an implicit `Sized` bound in `Bar`
-  --> $DIR/unsizing-wfcheck-issue-126272.rs:21:12
+  --> $DIR/unsizing-wfcheck-issue-126272.rs:20:12
    |
 LL | struct Bar<T>(T);
    |            ^ required by the implicit `Sized` requirement on this type parameter in `Bar`
 help: you could relax the implicit `Sized` bound on `T` if it were used through indirection like `&T` or `Box<T>`
-  --> $DIR/unsizing-wfcheck-issue-126272.rs:21:12
+  --> $DIR/unsizing-wfcheck-issue-126272.rs:20:12
    |
 LL | struct Bar<T>(T);
    |            ^  - ...if indirection were used here: `Box<T>`
@@ -127,26 +118,26 @@ LL | struct Bar<T>(T);
    |            this could be changed to `T: ?Sized`...
 
 error[E0277]: the size for values of type `(dyn Debug + 'static)` cannot be known at compilation time
-  --> $DIR/unsizing-wfcheck-issue-126272.rs:26:33
+  --> $DIR/unsizing-wfcheck-issue-126272.rs:25:33
    |
 LL |     let x: Test<{ Foo { nested: &Bar(4) } }> = Test;
    |                                 ^^^^^^^ doesn't have a size known at compile-time
    |
    = help: the trait `Sized` is not implemented for `(dyn Debug + 'static)`
 note: required by an implicit `Sized` bound in `Bar`
-  --> $DIR/unsizing-wfcheck-issue-126272.rs:21:12
+  --> $DIR/unsizing-wfcheck-issue-126272.rs:20:12
    |
 LL | struct Bar<T>(T);
    |            ^ required by the implicit `Sized` requirement on this type parameter in `Bar`
 help: you could relax the implicit `Sized` bound on `T` if it were used through indirection like `&T` or `Box<T>`
-  --> $DIR/unsizing-wfcheck-issue-126272.rs:21:12
+  --> $DIR/unsizing-wfcheck-issue-126272.rs:20:12
    |
 LL | struct Bar<T>(T);
    |            ^  - ...if indirection were used here: `Box<T>`
    |            |
    |            this could be changed to `T: ?Sized`...
 
-error: aborting due to 8 previous errors
+error: aborting due to 7 previous errors
 
 Some errors have detailed explanations: E0204, E0277, E0369.
 For more information about an error, try `rustc --explain E0204`.
diff --git a/tests/ui/const-generics/const-param-with-additional-obligations.rs b/tests/ui/const-generics/const-param-with-additional-obligations.rs
index 98097e86c7d..5110f95d5bf 100644
--- a/tests/ui/const-generics/const-param-with-additional-obligations.rs
+++ b/tests/ui/const-generics/const-param-with-additional-obligations.rs
@@ -1,14 +1,14 @@
 #![feature(adt_const_params, unsized_const_params)]
 #![allow(incomplete_features)]
 
-use std::marker::UnsizedConstParamTy;
+use std::marker::ConstParamTy_;
 
 #[derive(Eq, PartialEq)]
 struct Foo<T>(T);
 
 trait Other {}
 
-impl<T> UnsizedConstParamTy for Foo<T> where T: Other + UnsizedConstParamTy {}
+impl<T> ConstParamTy_ for Foo<T> where T: Other + ConstParamTy_ {}
 
 fn foo<const N: Foo<u8>>() {}
 //~^ ERROR `Foo<u8>` must implement `ConstParamTy` to be used as the type of a const generic parameter
diff --git a/tests/ui/const-generics/generic_const_parameter_types/no_const_param_ty_bound.stderr b/tests/ui/const-generics/generic_const_parameter_types/no_const_param_ty_bound.stderr
index 4ea323f4a5c..1eacc28b262 100644
--- a/tests/ui/const-generics/generic_const_parameter_types/no_const_param_ty_bound.stderr
+++ b/tests/ui/const-generics/generic_const_parameter_types/no_const_param_ty_bound.stderr
@@ -4,7 +4,7 @@ error[E0741]: `[T; N]` can't be used as a const parameter type
 LL | struct UsesType<T, const N: usize, const M: [T; N]>(PhantomData<T>);
    |                                             ^^^^^^
    |
-   = note: `T` must implement `UnsizedConstParamTy`, but it does not
+   = note: `T` must implement `ConstParamTy_`, but it does not
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/const-generics/issue-66451.rs b/tests/ui/const-generics/issue-66451.rs
index 0b8693e0e67..9ce7658586a 100644
--- a/tests/ui/const-generics/issue-66451.rs
+++ b/tests/ui/const-generics/issue-66451.rs
@@ -1,15 +1,15 @@
 #![feature(adt_const_params, unsized_const_params)]
 #![allow(incomplete_features)]
 
-use std::marker::UnsizedConstParamTy;
+use std::marker::ConstParamTy;
 
-#[derive(Debug, PartialEq, Eq, UnsizedConstParamTy)]
+#[derive(Debug, PartialEq, Eq, ConstParamTy)]
 struct Foo {
     value: i32,
     nested: &'static Bar<i32>,
 }
 
-#[derive(Debug, PartialEq, Eq, UnsizedConstParamTy)]
+#[derive(Debug, PartialEq, Eq, ConstParamTy)]
 struct Bar<T>(T);
 
 struct Test<const F: Foo>;
diff --git a/tests/ui/const-generics/issues/issue-63322-forbid-dyn.full.stderr b/tests/ui/const-generics/issues/issue-63322-forbid-dyn.full.stderr
index 8ea96428deb..1301ca92f01 100644
--- a/tests/ui/const-generics/issues/issue-63322-forbid-dyn.full.stderr
+++ b/tests/ui/const-generics/issues/issue-63322-forbid-dyn.full.stderr
@@ -4,7 +4,7 @@ error[E0741]: `&'static (dyn A + 'static)` can't be used as a const parameter ty
 LL | fn test<const T: &'static dyn A>() {
    |                  ^^^^^^^^^^^^^^
    |
-   = note: `(dyn A + 'static)` must implement `UnsizedConstParamTy`, but it does not
+   = note: `(dyn A + 'static)` must implement `ConstParamTy_`, but it does not
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/const-generics/slice-const-param-mismatch.adt_const_params.stderr b/tests/ui/const-generics/slice-const-param-mismatch.adt_const_params.stderr
index bcb2bd255da..d970b12df6a 100644
--- a/tests/ui/const-generics/slice-const-param-mismatch.adt_const_params.stderr
+++ b/tests/ui/const-generics/slice-const-param-mismatch.adt_const_params.stderr
@@ -1,14 +1,22 @@
-error[E0741]: `&'static str` can't be used as a const parameter type
-  --> $DIR/slice-const-param-mismatch.rs:8:29
+error[E0658]: use of unstable library feature `unsized_const_params`
+  --> $DIR/slice-const-param-mismatch.rs:8:20
    |
 LL | struct ConstString<const T: &'static str>;
-   |                             ^^^^^^^^^^^^
+   |                    ^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add `#![feature(unsized_const_params)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+   = note: required for `&'static str` to implement `ConstParamTy_`
 
-error[E0741]: `&'static [u8]` can't be used as a const parameter type
-  --> $DIR/slice-const-param-mismatch.rs:11:28
+error[E0658]: use of unstable library feature `unsized_const_params`
+  --> $DIR/slice-const-param-mismatch.rs:11:19
    |
 LL | struct ConstBytes<const T: &'static [u8]>;
-   |                            ^^^^^^^^^^^^^
+   |                   ^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add `#![feature(unsized_const_params)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+   = note: required for `&'static [u8]` to implement `ConstParamTy_`
 
 error[E0308]: mismatched types
   --> $DIR/slice-const-param-mismatch.rs:17:35
@@ -45,5 +53,5 @@ LL |     let _: ConstBytes<b"AAA"> = ConstBytes::<b"BBB">;
 
 error: aborting due to 5 previous errors
 
-Some errors have detailed explanations: E0308, E0741.
+Some errors have detailed explanations: E0308, E0658.
 For more information about an error, try `rustc --explain E0308`.
diff --git a/tests/ui/const-generics/slice-const-param.rs b/tests/ui/const-generics/slice-const-param.rs
index 1c5088b5283..8b5e934149e 100644
--- a/tests/ui/const-generics/slice-const-param.rs
+++ b/tests/ui/const-generics/slice-const-param.rs
@@ -12,7 +12,7 @@ pub fn function_with_bytes<const BYTES: &'static [u8]>() -> &'static [u8] {
 }
 
 // Also check the codepaths for custom DST
-#[derive(std::marker::UnsizedConstParamTy, PartialEq, Eq)]
+#[derive(std::marker::ConstParamTy, PartialEq, Eq)]
 struct MyStr(str);
 
 fn function_with_my_str<const S: &'static MyStr>() -> &'static MyStr {
diff --git a/tests/ui/const-generics/transmute-const-param-static-reference.adt_const_params.stderr b/tests/ui/const-generics/transmute-const-param-static-reference.adt_const_params.stderr
index 7a936ced030..c2351c707d7 100644
--- a/tests/ui/const-generics/transmute-const-param-static-reference.adt_const_params.stderr
+++ b/tests/ui/const-generics/transmute-const-param-static-reference.adt_const_params.stderr
@@ -1,9 +1,13 @@
-error[E0741]: `&'static ()` can't be used as a const parameter type
-  --> $DIR/transmute-const-param-static-reference.rs:9:23
+error[E0658]: use of unstable library feature `unsized_const_params`
+  --> $DIR/transmute-const-param-static-reference.rs:9:14
    |
 LL | struct Const<const P: &'static ()>;
-   |                       ^^^^^^^^^^^
+   |              ^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add `#![feature(unsized_const_params)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+   = note: required for `&'static ()` to implement `ConstParamTy_`
 
 error: aborting due to 1 previous error
 
-For more information about this error, try `rustc --explain E0741`.
+For more information about this error, try `rustc --explain E0658`.
diff --git a/tests/ui/const-generics/transmute-const-param-static-reference.rs b/tests/ui/const-generics/transmute-const-param-static-reference.rs
index 0b47fd31eaf..bf164bdadb0 100644
--- a/tests/ui/const-generics/transmute-const-param-static-reference.rs
+++ b/tests/ui/const-generics/transmute-const-param-static-reference.rs
@@ -8,7 +8,7 @@
 
 struct Const<const P: &'static ()>;
 //[min]~^ ERROR `&'static ()` is forbidden as the type of a const generic parameter
-//[adt_const_params]~^^ ERROR `&'static ()` can't be used as a const parameter type
+//[adt_const_params]~^^ ERROR use of unstable library feature `unsized_const_params`
 
 fn main() {
     const A: &'static () = unsafe { std::mem::transmute(10 as *const ()) };
diff --git a/tests/ui/const-generics/unsized_const_params/symbol_mangling_v0_str.rs b/tests/ui/const-generics/unsized_const_params/symbol_mangling_v0_str.rs
index 359126f1251..429c401af1f 100644
--- a/tests/ui/const-generics/unsized_const_params/symbol_mangling_v0_str.rs
+++ b/tests/ui/const-generics/unsized_const_params/symbol_mangling_v0_str.rs
@@ -1,13 +1,13 @@
 //@ check-pass
 //@ compile-flags: -Csymbol-mangling-version=v0
 #![allow(incomplete_features)]
-#![feature(unsized_const_params)]
+#![feature(adt_const_params, unsized_const_params)]
 
 // Regression test for #116303
 
 #[derive(PartialEq, Eq)]
 struct MyStr(str);
-impl std::marker::UnsizedConstParamTy for MyStr {}
+impl std::marker::ConstParamTy_ for MyStr {}
 
 fn function_with_my_str<const S: &'static MyStr>() -> &'static MyStr {
     S
diff --git a/tests/ui/consts/const_refs_to_static_fail.stderr b/tests/ui/consts/const_refs_to_static_fail.stderr
index c567b3e0ce1..2bb6d2b8fef 100644
--- a/tests/ui/consts/const_refs_to_static_fail.stderr
+++ b/tests/ui/consts/const_refs_to_static_fail.stderr
@@ -16,7 +16,7 @@ error: constant BAD_PATTERN cannot be used as pattern
 LL |         BAD_PATTERN => {},
    |         ^^^^^^^^^^^
    |
-   = note: constants that reference mutable or external memory cannot be used as pattern
+   = note: constants that reference mutable or external memory cannot be used as patterns
 
 error: aborting due to 3 previous errors
 
diff --git a/tests/ui/consts/const_refs_to_static_fail_invalid.stderr b/tests/ui/consts/const_refs_to_static_fail_invalid.stderr
index f9088c318a6..226a9de285d 100644
--- a/tests/ui/consts/const_refs_to_static_fail_invalid.stderr
+++ b/tests/ui/consts/const_refs_to_static_fail_invalid.stderr
@@ -15,7 +15,7 @@ error: constant extern_::C cannot be used as pattern
 LL |         C => {}
    |         ^
    |
-   = note: constants that reference mutable or external memory cannot be used as pattern
+   = note: constants that reference mutable or external memory cannot be used as patterns
 
 error: constant mutable::C cannot be used as pattern
   --> $DIR/const_refs_to_static_fail_invalid.rs:42:9
@@ -23,7 +23,7 @@ error: constant mutable::C cannot be used as pattern
 LL |         C => {}
    |         ^
    |
-   = note: constants that reference mutable or external memory cannot be used as pattern
+   = note: constants that reference mutable or external memory cannot be used as patterns
 
 error: aborting due to 3 previous errors
 
diff --git a/tests/ui/consts/miri_unleashed/const_refers_to_static.stderr b/tests/ui/consts/miri_unleashed/const_refers_to_static.stderr
index 6b70a211a72..5b8797c5116 100644
--- a/tests/ui/consts/miri_unleashed/const_refers_to_static.stderr
+++ b/tests/ui/consts/miri_unleashed/const_refers_to_static.stderr
@@ -22,7 +22,7 @@ error: constant REF_INTERIOR_MUT cannot be used as pattern
 LL |         REF_INTERIOR_MUT => {},
    |         ^^^^^^^^^^^^^^^^
    |
-   = note: constants that reference mutable or external memory cannot be used as pattern
+   = note: constants that reference mutable or external memory cannot be used as patterns
 
 warning: skipping const checks
    |
diff --git a/tests/ui/consts/miri_unleashed/const_refers_to_static_cross_crate.stderr b/tests/ui/consts/miri_unleashed/const_refers_to_static_cross_crate.stderr
index d753506cc94..c2b730375f2 100644
--- a/tests/ui/consts/miri_unleashed/const_refers_to_static_cross_crate.stderr
+++ b/tests/ui/consts/miri_unleashed/const_refers_to_static_cross_crate.stderr
@@ -10,7 +10,7 @@ error: constant SLICE_MUT cannot be used as pattern
 LL |         SLICE_MUT => true,
    |         ^^^^^^^^^
    |
-   = note: constants that reference mutable or external memory cannot be used as pattern
+   = note: constants that reference mutable or external memory cannot be used as patterns
 
 error: constant U8_MUT cannot be used as pattern
   --> $DIR/const_refers_to_static_cross_crate.rs:44:9
@@ -18,7 +18,7 @@ error: constant U8_MUT cannot be used as pattern
 LL |         U8_MUT => true,
    |         ^^^^^^
    |
-   = note: constants that reference mutable or external memory cannot be used as pattern
+   = note: constants that reference mutable or external memory cannot be used as patterns
 
 error: constant U8_MUT2 cannot be used as pattern
   --> $DIR/const_refers_to_static_cross_crate.rs:53:9
@@ -26,7 +26,7 @@ error: constant U8_MUT2 cannot be used as pattern
 LL |         U8_MUT2 => true,
    |         ^^^^^^^
    |
-   = note: constants that reference mutable or external memory cannot be used as pattern
+   = note: constants that reference mutable or external memory cannot be used as patterns
 
 error: aborting due to 4 previous errors
 
diff --git a/tests/ui/darwin-objc/darwin-objc-bad-arg.rs b/tests/ui/darwin-objc/darwin-objc-bad-arg.rs
new file mode 100644
index 00000000000..70eb83aa052
--- /dev/null
+++ b/tests/ui/darwin-objc/darwin-objc-bad-arg.rs
@@ -0,0 +1,36 @@
+// Test that `objc::class!` and `objc::selector!` only take string literals.
+
+//@ edition: 2024
+//@ only-apple
+
+#![feature(darwin_objc)]
+
+use std::os::darwin::objc;
+
+pub fn main() {
+    let s = "NSObject";
+    objc::class!(s);
+    //~^ ERROR attribute value must be a literal
+
+    objc::class!(NSObject);
+    //~^ ERROR attribute value must be a literal
+
+    objc::class!(123);
+    //~^ ERROR `objc::class!` expected a string literal
+
+    objc::class!("NSObject\0");
+    //~^ ERROR `objc::class!` may not contain null characters
+
+    let s = "alloc";
+    objc::selector!(s);
+    //~^ ERROR attribute value must be a literal
+
+    objc::selector!(alloc);
+    //~^ ERROR attribute value must be a literal
+
+    objc::selector!(123);
+    //~^ ERROR `objc::selector!` expected a string literal
+
+    objc::selector!("alloc\0");
+    //~^ ERROR `objc::selector!` may not contain null characters
+}
diff --git a/tests/ui/darwin-objc/darwin-objc-bad-arg.stderr b/tests/ui/darwin-objc/darwin-objc-bad-arg.stderr
new file mode 100644
index 00000000000..99eeb27e30c
--- /dev/null
+++ b/tests/ui/darwin-objc/darwin-objc-bad-arg.stderr
@@ -0,0 +1,50 @@
+error: attribute value must be a literal
+  --> $DIR/darwin-objc-bad-arg.rs:12:18
+   |
+LL |     objc::class!(s);
+   |                  ^
+
+error: attribute value must be a literal
+  --> $DIR/darwin-objc-bad-arg.rs:15:18
+   |
+LL |     objc::class!(NSObject);
+   |                  ^^^^^^^^
+
+error: `objc::class!` expected a string literal
+  --> $DIR/darwin-objc-bad-arg.rs:18:18
+   |
+LL |     objc::class!(123);
+   |                  ^^^
+
+error: `objc::class!` may not contain null characters
+  --> $DIR/darwin-objc-bad-arg.rs:21:18
+   |
+LL |     objc::class!("NSObject\0");
+   |                  ^^^^^^^^^^^^
+
+error: attribute value must be a literal
+  --> $DIR/darwin-objc-bad-arg.rs:25:21
+   |
+LL |     objc::selector!(s);
+   |                     ^
+
+error: attribute value must be a literal
+  --> $DIR/darwin-objc-bad-arg.rs:28:21
+   |
+LL |     objc::selector!(alloc);
+   |                     ^^^^^
+
+error: `objc::selector!` expected a string literal
+  --> $DIR/darwin-objc-bad-arg.rs:31:21
+   |
+LL |     objc::selector!(123);
+   |                     ^^^
+
+error: `objc::selector!` may not contain null characters
+  --> $DIR/darwin-objc-bad-arg.rs:34:21
+   |
+LL |     objc::selector!("alloc\0");
+   |                     ^^^^^^^^^
+
+error: aborting due to 8 previous errors
+
diff --git a/tests/ui/darwin-objc/darwin-objc-bad-const.rs b/tests/ui/darwin-objc/darwin-objc-bad-const.rs
new file mode 100644
index 00000000000..ccf28697b48
--- /dev/null
+++ b/tests/ui/darwin-objc/darwin-objc-bad-const.rs
@@ -0,0 +1,17 @@
+// Test that `objc::class!` and `objc::selector!` aren't `const` expressions.
+// The system gives them their final values at dynamic load time.
+
+//@ edition: 2024
+//@ only-apple
+
+#![feature(darwin_objc)]
+
+use std::os::darwin::objc;
+
+pub const CLASS: objc::Class = objc::class!("NSObject");
+//~^ ERROR cannot access extern static `CLASS::VAL` [E0080]
+
+pub const SELECTOR: objc::SEL = objc::selector!("alloc");
+//~^ ERROR cannot access extern static `SELECTOR::VAL` [E0080]
+
+pub fn main() {}
diff --git a/tests/ui/darwin-objc/darwin-objc-bad-const.stderr b/tests/ui/darwin-objc/darwin-objc-bad-const.stderr
new file mode 100644
index 00000000000..43d0b7d761f
--- /dev/null
+++ b/tests/ui/darwin-objc/darwin-objc-bad-const.stderr
@@ -0,0 +1,19 @@
+error[E0080]: cannot access extern static `CLASS::VAL`
+  --> $DIR/darwin-objc-bad-const.rs:11:32
+   |
+LL | pub const CLASS: objc::Class = objc::class!("NSObject");
+   |                                ^^^^^^^^^^^^^^^^^^^^^^^^ evaluation of `CLASS` failed here
+   |
+   = note: this error originates in the macro `objc::class` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0080]: cannot access extern static `SELECTOR::VAL`
+  --> $DIR/darwin-objc-bad-const.rs:14:33
+   |
+LL | pub const SELECTOR: objc::SEL = objc::selector!("alloc");
+   |                                 ^^^^^^^^^^^^^^^^^^^^^^^^ evaluation of `SELECTOR` failed here
+   |
+   = note: this error originates in the macro `objc::selector` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0080`.
diff --git a/tests/ui/darwin-objc/darwin-objc-bad-ref.rs b/tests/ui/darwin-objc/darwin-objc-bad-ref.rs
new file mode 100644
index 00000000000..fb1437366dd
--- /dev/null
+++ b/tests/ui/darwin-objc/darwin-objc-bad-ref.rs
@@ -0,0 +1,31 @@
+// Test that `objc::class!` and `objc::selector!` can't be returned by reference.
+// A single instance may have multiple addresses (e.g. across dylib boundaries).
+
+//@ edition: 2024
+//@ only-apple
+
+#![feature(darwin_objc)]
+
+use std::os::darwin::objc;
+
+pub fn class_ref<'a>() -> &'a objc::Class {
+    &objc::class!("NSObject")
+    //~^ ERROR cannot return reference to temporary value [E0515]
+}
+
+pub fn class_ref_static() -> &'static objc::Class {
+    &objc::class!("NSObject")
+    //~^ ERROR cannot return reference to temporary value [E0515]
+}
+
+pub fn selector_ref<'a>() -> &'a objc::SEL {
+    &objc::selector!("alloc")
+    //~^ ERROR cannot return reference to temporary value [E0515]
+}
+
+pub fn selector_ref_static() -> &'static objc::SEL {
+    &objc::selector!("alloc")
+    //~^ ERROR cannot return reference to temporary value [E0515]
+}
+
+pub fn main() {}
diff --git a/tests/ui/darwin-objc/darwin-objc-bad-ref.stderr b/tests/ui/darwin-objc/darwin-objc-bad-ref.stderr
new file mode 100644
index 00000000000..b09e6a75c84
--- /dev/null
+++ b/tests/ui/darwin-objc/darwin-objc-bad-ref.stderr
@@ -0,0 +1,39 @@
+error[E0515]: cannot return reference to temporary value
+  --> $DIR/darwin-objc-bad-ref.rs:12:5
+   |
+LL |     &objc::class!("NSObject")
+   |     ^------------------------
+   |     ||
+   |     |temporary value created here
+   |     returns a reference to data owned by the current function
+
+error[E0515]: cannot return reference to temporary value
+  --> $DIR/darwin-objc-bad-ref.rs:17:5
+   |
+LL |     &objc::class!("NSObject")
+   |     ^------------------------
+   |     ||
+   |     |temporary value created here
+   |     returns a reference to data owned by the current function
+
+error[E0515]: cannot return reference to temporary value
+  --> $DIR/darwin-objc-bad-ref.rs:22:5
+   |
+LL |     &objc::selector!("alloc")
+   |     ^------------------------
+   |     ||
+   |     |temporary value created here
+   |     returns a reference to data owned by the current function
+
+error[E0515]: cannot return reference to temporary value
+  --> $DIR/darwin-objc-bad-ref.rs:27:5
+   |
+LL |     &objc::selector!("alloc")
+   |     ^------------------------
+   |     ||
+   |     |temporary value created here
+   |     returns a reference to data owned by the current function
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0515`.
diff --git a/tests/ui/darwin-objc/darwin-objc-class-selector.rs b/tests/ui/darwin-objc/darwin-objc-class-selector.rs
new file mode 100644
index 00000000000..b9a2fc3634f
--- /dev/null
+++ b/tests/ui/darwin-objc/darwin-objc-class-selector.rs
@@ -0,0 +1,31 @@
+// Call `[NSObject class]` using `objc::class!` and `objc::selector!`.
+
+//@ edition: 2024
+//@ only-apple
+//@ run-pass
+
+#![feature(darwin_objc)]
+
+use std::mem::transmute;
+use std::os::darwin::objc;
+
+#[link(name = "Foundation", kind = "framework")]
+unsafe extern "C" {}
+
+#[link(name = "objc", kind = "dylib")]
+unsafe extern "C" {
+    unsafe fn objc_msgSend();
+}
+
+fn main() {
+    let msg_send_fn = unsafe {
+        transmute::<
+            unsafe extern "C" fn(),
+            unsafe extern "C" fn(objc::Class, objc::SEL) -> objc::Class,
+        >(objc_msgSend)
+    };
+    let static_sel = objc::selector!("class");
+    let static_class = objc::class!("NSObject");
+    let runtime_class = unsafe { msg_send_fn(static_class, static_sel) };
+    assert_eq!(static_class, runtime_class);
+}
diff --git a/tests/ui/darwin-objc/darwin-objc-class.rs b/tests/ui/darwin-objc/darwin-objc-class.rs
new file mode 100644
index 00000000000..851149d8726
--- /dev/null
+++ b/tests/ui/darwin-objc/darwin-objc-class.rs
@@ -0,0 +1,39 @@
+// Test that `objc::class!` returns the same thing as `objc_lookUpClass`.
+
+//@ edition: 2024
+//@ only-apple
+//@ run-pass
+
+#![feature(darwin_objc)]
+
+use std::ffi::c_char;
+use std::os::darwin::objc;
+
+#[link(name = "Foundation", kind = "framework")]
+unsafe extern "C" {}
+
+#[link(name = "objc")]
+unsafe extern "C" {
+    fn objc_lookUpClass(methname: *const c_char) -> objc::Class;
+}
+
+fn get_object_class() -> objc::Class {
+    objc::class!("NSObject")
+}
+
+fn lookup_object_class() -> objc::Class {
+    unsafe { objc_lookUpClass(c"NSObject".as_ptr()) }
+}
+
+fn get_string_class() -> objc::Class {
+    objc::class!("NSString")
+}
+
+fn lookup_string_class() -> objc::Class {
+    unsafe { objc_lookUpClass(c"NSString".as_ptr()) }
+}
+
+fn main() {
+    assert_eq!(get_object_class(), lookup_object_class());
+    assert_eq!(get_string_class(), lookup_string_class());
+}
diff --git a/tests/ui/darwin-objc/darwin-objc-selector.rs b/tests/ui/darwin-objc/darwin-objc-selector.rs
new file mode 100644
index 00000000000..008ae4c4ca4
--- /dev/null
+++ b/tests/ui/darwin-objc/darwin-objc-selector.rs
@@ -0,0 +1,36 @@
+// Test that `objc::selector!` returns the same thing as `sel_registerName`.
+
+//@ edition: 2024
+//@ only-apple
+//@ run-pass
+
+#![feature(darwin_objc)]
+
+use std::ffi::c_char;
+use std::os::darwin::objc;
+
+#[link(name = "objc")]
+unsafe extern "C" {
+    fn sel_registerName(methname: *const c_char) -> objc::SEL;
+}
+
+fn get_alloc_selector() -> objc::SEL {
+    objc::selector!("alloc")
+}
+
+fn register_alloc_selector() -> objc::SEL {
+    unsafe { sel_registerName(c"alloc".as_ptr()) }
+}
+
+fn get_init_selector() -> objc::SEL {
+    objc::selector!("initWithCString:encoding:")
+}
+
+fn register_init_selector() -> objc::SEL {
+    unsafe { sel_registerName(c"initWithCString:encoding:".as_ptr()) }
+}
+
+fn main() {
+    assert_eq!(get_alloc_selector(), register_alloc_selector());
+    assert_eq!(get_init_selector(), register_init_selector());
+}
diff --git a/tests/ui/dist/cranelift-x86_64-unknown-linux-gnu-dist.rs b/tests/ui/dist/cranelift-x86_64-unknown-linux-gnu-dist.rs
index 198f8d1bc10..6d12ab1e4cf 100644
--- a/tests/ui/dist/cranelift-x86_64-unknown-linux-gnu-dist.rs
+++ b/tests/ui/dist/cranelift-x86_64-unknown-linux-gnu-dist.rs
@@ -2,6 +2,7 @@
 // dist artifacts.
 
 //@ only-dist
+//@ only-nightly (cranelift is not stable yet)
 //@ only-x86_64-unknown-linux-gnu
 //@ compile-flags: -Z codegen-backend=cranelift
 //@ run-pass
diff --git a/tests/ui/drop/super-let-tail-expr-drop-order.rs b/tests/ui/drop/super-let-tail-expr-drop-order.rs
new file mode 100644
index 00000000000..5b2ecfbb320
--- /dev/null
+++ b/tests/ui/drop/super-let-tail-expr-drop-order.rs
@@ -0,0 +1,192 @@
+//! Test for #145784: the argument to `pin!` should be treated as an extending expression if and
+//! only if the whole `pin!` invocation is an extending expression. Likewise, since `pin!` is
+//! implemented in terms of `super let`, test the same for `super let` initializers. Since the
+//! argument to `pin!` and the initializer of `super let` are not temporary drop scopes, this only
+//! affects lifetimes in two cases:
+//!
+//! - Block tail expressions in Rust 2024, which are both extending expressions and temporary drop
+//! scopes; treating them as extending expressions within a non-extending `pin!` resulted in borrow
+//! expression operands living past the end of the block.
+//!
+//! - Nested `super let` statements, which can have their binding and temporary lifetimes extended
+//! when the block they're in is an extending expression.
+//!
+//! For more information on extending expressions, see
+//! https://doc.rust-lang.org/reference/destructors.html#extending-based-on-expressions
+//!
+//! For tests that `super let` initializers aren't temporary drop scopes, and tests for
+//! lifetime-extended `super let`, see tests/ui/borrowck/super-let-lifetime-and-drop.rs
+//@ run-pass
+//@ revisions: e2021 e2024
+//@ [e2021] edition: 2021
+//@ [e2024] edition: 2024
+
+#![feature(super_let)]
+#![allow(unused_braces)]
+
+use std::cell::RefCell;
+use std::pin::pin;
+
+fn f<T>(_: LogDrop<'_>, x: T) -> T { x }
+
+fn main() {
+    // Test block arguments to `pin!` in non-extending expressions.
+    // In Rust 2021, block tail expressions aren't temporary drop scopes, so their temporaries
+    // should outlive the `pin!` invocation.
+    // In Rust 2024, block tail expressions are temporary drop scopes, so their temporaries should
+    // be dropped after evaluating the tail expression within the `pin!` invocation.
+    // By nesting two `pin!` calls, this ensures non-extended `pin!` doesn't extend an inner `pin!`.
+    assert_drop_order(1..=3, |o| {
+        #[cfg(e2021)]
+        (
+            pin!((
+                pin!({ &o.log(3) as *const LogDrop<'_> }),
+                drop(o.log(1)),
+            )),
+            drop(o.log(2)),
+        );
+        #[cfg(e2024)]
+        (
+            pin!((
+                pin!({ &o.log(1) as *const LogDrop<'_> }),
+                drop(o.log(2)),
+            )),
+            drop(o.log(3)),
+        );
+    });
+
+    // The same holds for `super let` initializers in non-extending expressions.
+    assert_drop_order(1..=4, |o| {
+        #[cfg(e2021)]
+        (
+            {
+                super let _ = {
+                    super let _ = { &o.log(4) as *const LogDrop<'_> };
+                    drop(o.log(1))
+                };
+                drop(o.log(2))
+            },
+            drop(o.log(3)),
+        );
+        #[cfg(e2024)]
+        (
+            {
+                super let _ = {
+                    super let _ = { &o.log(1) as *const LogDrop<'_> };
+                    drop(o.log(2))
+                };
+                drop(o.log(3))
+            },
+            drop(o.log(4)),
+        );
+    });
+
+    // Within an extending expression, the argument to `pin!` is also an extending expression,
+    // allowing borrow operands in block tail expressions to have extended lifetimes.
+    assert_drop_order(1..=2, |o| {
+        let _ = pin!({ &o.log(2) as *const LogDrop<'_> });
+        drop(o.log(1));
+    });
+
+    // The same holds for `super let` initializers in extending expressions.
+    assert_drop_order(1..=2, |o| {
+        let _ =  { super let _ = { &o.log(2) as *const LogDrop<'_> }; };
+        drop(o.log(1));
+    });
+
+    // We have extending borrow expressions within an extending block
+    // expression (within an extending borrow expression) within a
+    // non-extending expresion within the initializer expression.
+    #[cfg(e2021)]
+    {
+        // These two should be the same.
+        assert_drop_order(1..=3, |e| {
+            let _v = f(e.log(1), &{ &raw const *&e.log(2) });
+            drop(e.log(3));
+        });
+        assert_drop_order(1..=3, |e| {
+            let _v = f(e.log(1), {
+                super let v = &{ &raw const *&e.log(2) };
+                v
+            });
+            drop(e.log(3));
+        });
+    }
+    #[cfg(e2024)]
+    {
+        // These two should be the same.
+        assert_drop_order(1..=3, |e| {
+            let _v = f(e.log(2), &{ &raw const *&e.log(1) });
+            drop(e.log(3));
+        });
+        assert_drop_order(1..=3, |e| {
+            let _v = f(e.log(2), {
+                super let v = &{ &raw const *&e.log(1) };
+                v
+            });
+            drop(e.log(3));
+        });
+    }
+
+    // We have extending borrow expressions within a non-extending
+    // expression within the initializer expression.
+    //
+    // These two should be the same.
+    assert_drop_order(1..=3, |e| {
+        let _v = f(e.log(1), &&raw const *&e.log(2));
+        drop(e.log(3));
+    });
+    assert_drop_order(1..=3, |e| {
+        let _v = f(e.log(1), {
+            super let v = &&raw const *&e.log(2);
+            v
+        });
+        drop(e.log(3));
+    });
+
+    // We have extending borrow expressions within an extending block
+    // expression (within an extending borrow expression) within the
+    // initializer expression.
+    //
+    // These two should be the same.
+    assert_drop_order(1..=2, |e| {
+        let _v = &{ &raw const *&e.log(2) };
+        drop(e.log(1));
+    });
+    assert_drop_order(1..=2, |e| {
+        let _v = {
+            super let v = &{ &raw const *&e.log(2) };
+            v
+        };
+        drop(e.log(1));
+    });
+}
+
+// # Test scaffolding...
+
+struct DropOrder(RefCell<Vec<u64>>);
+struct LogDrop<'o>(&'o DropOrder, u64);
+
+impl DropOrder {
+    fn log(&self, n: u64) -> LogDrop<'_> {
+        LogDrop(self, n)
+    }
+}
+
+impl<'o> Drop for LogDrop<'o> {
+    fn drop(&mut self) {
+        self.0.0.borrow_mut().push(self.1);
+    }
+}
+
+#[track_caller]
+fn assert_drop_order(
+    ex: impl IntoIterator<Item = u64>,
+    f: impl Fn(&DropOrder),
+) {
+    let order = DropOrder(RefCell::new(Vec::new()));
+    f(&order);
+    let order = order.0.into_inner();
+    let expected: Vec<u64> = ex.into_iter().collect();
+    assert_eq!(order, expected);
+}
diff --git a/tests/ui/feature-gates/feature-gate-adt_const_params.rs b/tests/ui/feature-gates/feature-gate-adt_const_params.rs
index 8a3bcf25963..7efa529c557 100644
--- a/tests/ui/feature-gates/feature-gate-adt_const_params.rs
+++ b/tests/ui/feature-gates/feature-gate-adt_const_params.rs
@@ -1,2 +1,6 @@
-struct Foo<const NAME: &'static str>; //~ ERROR `&'static str` is forbidden
+struct Bar(u8);
+
+struct Foo<const N: Bar>;
+//~^ ERROR: `Bar` is forbidden as the type of a const generic parameter
+
 fn main() {}
diff --git a/tests/ui/feature-gates/feature-gate-adt_const_params.stderr b/tests/ui/feature-gates/feature-gate-adt_const_params.stderr
index 18d514f8cb5..7ea91a8f4c2 100644
--- a/tests/ui/feature-gates/feature-gate-adt_const_params.stderr
+++ b/tests/ui/feature-gates/feature-gate-adt_const_params.stderr
@@ -1,18 +1,14 @@
-error: `&'static str` is forbidden as the type of a const generic parameter
-  --> $DIR/feature-gate-adt_const_params.rs:1:24
+error: `Bar` is forbidden as the type of a const generic parameter
+  --> $DIR/feature-gate-adt_const_params.rs:3:21
    |
-LL | struct Foo<const NAME: &'static str>;
-   |                        ^^^^^^^^^^^^
+LL | struct Foo<const N: Bar>;
+   |                     ^^^
    |
    = note: the only supported types are integers, `bool`, and `char`
 help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
    |
 LL + #![feature(adt_const_params)]
    |
-help: add `#![feature(unsized_const_params)]` to the crate attributes to enable references to implement the `ConstParamTy` trait
-   |
-LL + #![feature(unsized_const_params)]
-   |
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/layout/thaw-transmute-invalid-enum.rs b/tests/ui/layout/thaw-transmute-invalid-enum.rs
index a7c2e1a86de..20fc8d46359 100644
--- a/tests/ui/layout/thaw-transmute-invalid-enum.rs
+++ b/tests/ui/layout/thaw-transmute-invalid-enum.rs
@@ -9,6 +9,7 @@ mod assert {
     where
         Dst: TransmuteFrom<Src>,
         //~^ ERROR: use of unstable library feature `transmutability`
+        //~^^ ERROR: use of unstable library feature `transmutability`
     {
     }
 }
diff --git a/tests/ui/layout/thaw-transmute-invalid-enum.stderr b/tests/ui/layout/thaw-transmute-invalid-enum.stderr
index d12fc4694e0..2b89159c263 100644
--- a/tests/ui/layout/thaw-transmute-invalid-enum.stderr
+++ b/tests/ui/layout/thaw-transmute-invalid-enum.stderr
@@ -1,5 +1,5 @@
 error[E0412]: cannot find type `Subset` in this scope
-  --> $DIR/thaw-transmute-invalid-enum.rs:34:41
+  --> $DIR/thaw-transmute-invalid-enum.rs:35:41
    |
 LL |     assert::is_transmutable::<Superset, Subset>();
    |                                         ^^^^^^ not found in this scope
@@ -10,7 +10,7 @@ LL | fn test<Subset>() {
    |        ++++++++
 
 error[E0517]: attribute should be applied to a struct or union
-  --> $DIR/thaw-transmute-invalid-enum.rs:21:11
+  --> $DIR/thaw-transmute-invalid-enum.rs:22:11
    |
 LL |   #[repr(C, packed(2))]
    |             ^^^^^^^^^
@@ -50,8 +50,19 @@ LL |         Dst: TransmuteFrom<Src>,
    = help: add `#![feature(transmutability)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
+error[E0658]: use of unstable library feature `transmutability`
+  --> $DIR/thaw-transmute-invalid-enum.rs:10:14
+   |
+LL |         Dst: TransmuteFrom<Src>,
+   |              ^^^^^^^^^^^^^^^^^^
+   |
+   = help: add `#![feature(transmutability)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+note: required by a bound in `TransmuteFrom`
+  --> $SRC_DIR/core/src/mem/transmutability.rs:LL:COL
+
 error[E0740]: field must implement `Copy` or be wrapped in `ManuallyDrop<...>` to be used in a union
-  --> $DIR/thaw-transmute-invalid-enum.rs:29:9
+  --> $DIR/thaw-transmute-invalid-enum.rs:30:9
    |
 LL |         a: Ox00,
    |         ^^^^^^^
@@ -62,7 +73,7 @@ help: wrap the field type in `ManuallyDrop<...>`
 LL |         a: std::mem::ManuallyDrop<Ox00>,
    |            +++++++++++++++++++++++    +
 
-error: aborting due to 6 previous errors
+error: aborting due to 7 previous errors
 
 Some errors have detailed explanations: E0412, E0517, E0658, E0740.
 For more information about an error, try `rustc --explain E0412`.
diff --git a/tests/ui/lifetimes/issue-105507.fixed b/tests/ui/lifetimes/issue-105507.fixed
index 46d4f14a245..a3c4e5784b8 100644
--- a/tests/ui/lifetimes/issue-105507.fixed
+++ b/tests/ui/lifetimes/issue-105507.fixed
@@ -31,7 +31,7 @@ impl<T> ProjectedMyTrait for T
 
 fn require_trait<T: MyTrait>(_: T) {}
 
-fn foo<T : MyTrait + 'static + 'static, U : MyTrait + 'static + 'static>(wrap: Wrapper<'_, Option<T>>, wrap1: Wrapper<'_, Option<U>>) {
+fn foo<T : MyTrait + 'static, U : MyTrait + 'static>(wrap: Wrapper<'_, Option<T>>, wrap1: Wrapper<'_, Option<U>>) {
     //~^ HELP consider restricting the type parameter to the `'static` lifetime
     //~| HELP consider restricting the type parameter to the `'static` lifetime
     require_trait(wrap);
diff --git a/tests/ui/lint/unused_parens_follow_ident.fixed b/tests/ui/lint/unused_parens_follow_ident.fixed
new file mode 100644
index 00000000000..e61b287e5a6
--- /dev/null
+++ b/tests/ui/lint/unused_parens_follow_ident.fixed
@@ -0,0 +1,17 @@
+//@ run-rustfix
+
+#![deny(unused_parens)]
+
+macro_rules! wrap {
+    ($name:ident $arg:expr) => {
+        $name($arg);
+    };
+}
+
+fn main() {
+    wrap!(unary routine()); //~ ERROR unnecessary parentheses around function argument
+    wrap!(unary routine()); //~ ERROR unnecessary parentheses around function argument
+}
+
+fn unary(_: ()) {}
+fn routine() {}
diff --git a/tests/ui/lint/unused_parens_follow_ident.rs b/tests/ui/lint/unused_parens_follow_ident.rs
new file mode 100644
index 00000000000..32a163345b2
--- /dev/null
+++ b/tests/ui/lint/unused_parens_follow_ident.rs
@@ -0,0 +1,17 @@
+//@ run-rustfix
+
+#![deny(unused_parens)]
+
+macro_rules! wrap {
+    ($name:ident $arg:expr) => {
+        $name($arg);
+    };
+}
+
+fn main() {
+    wrap!(unary(routine())); //~ ERROR unnecessary parentheses around function argument
+    wrap!(unary (routine())); //~ ERROR unnecessary parentheses around function argument
+}
+
+fn unary(_: ()) {}
+fn routine() {}
diff --git a/tests/ui/lint/unused_parens_follow_ident.stderr b/tests/ui/lint/unused_parens_follow_ident.stderr
new file mode 100644
index 00000000000..ce7bb26778c
--- /dev/null
+++ b/tests/ui/lint/unused_parens_follow_ident.stderr
@@ -0,0 +1,31 @@
+error: unnecessary parentheses around function argument
+  --> $DIR/unused_parens_follow_ident.rs:12:16
+   |
+LL |     wrap!(unary(routine()));
+   |                ^         ^
+   |
+note: the lint level is defined here
+  --> $DIR/unused_parens_follow_ident.rs:3:9
+   |
+LL | #![deny(unused_parens)]
+   |         ^^^^^^^^^^^^^
+help: remove these parentheses
+   |
+LL -     wrap!(unary(routine()));
+LL +     wrap!(unary routine());
+   |
+
+error: unnecessary parentheses around function argument
+  --> $DIR/unused_parens_follow_ident.rs:13:17
+   |
+LL |     wrap!(unary (routine()));
+   |                 ^         ^
+   |
+help: remove these parentheses
+   |
+LL -     wrap!(unary (routine()));
+LL +     wrap!(unary routine());
+   |
+
+error: aborting due to 2 previous errors
+
diff --git a/tests/ui/parser/expr-as-stmt.fixed b/tests/ui/parser/expr-as-stmt.fixed
index bfae55047ed..b3a491200ed 100644
--- a/tests/ui/parser/expr-as-stmt.fixed
+++ b/tests/ui/parser/expr-as-stmt.fixed
@@ -66,7 +66,7 @@ fn asteroids() -> impl FnOnce() -> bool {
 
 // https://github.com/rust-lang/rust/issues/105179
 fn r#match() -> i32 {
-    ((match () { () => 1 })) + match () { () => 1 } //~ ERROR expected expression, found `+`
+    (match () { () => 1 }) + match () { () => 1 } //~ ERROR expected expression, found `+`
     //~^ ERROR mismatched types
 }
 
@@ -82,7 +82,7 @@ fn matches() -> bool {
     (match () { _ => true }) && match () { _ => true }; //~ ERROR mismatched types
     //~^ ERROR expected `;`, found keyword `match`
     (match () { _ => true }) && true; //~ ERROR mismatched types
-    ((match () { _ => true })) && true //~ ERROR mismatched types
+    (match () { _ => true }) && true //~ ERROR mismatched types
     //~^ ERROR mismatched types
 }
 fn main() {}
diff --git a/tests/ui/suggestions/apitit-unimplemented-method.rs b/tests/ui/suggestions/apitit-unimplemented-method.rs
index b182e1939b3..c0cd709e230 100644
--- a/tests/ui/suggestions/apitit-unimplemented-method.rs
+++ b/tests/ui/suggestions/apitit-unimplemented-method.rs
@@ -4,9 +4,12 @@ extern crate dep;
 use dep::*;
 
 struct Local;
+
 impl Trait for Local {}
 //~^ ERROR not all trait items implemented
 //~| HELP implement the missing item: `fn foo(_: impl Sized) { todo!() }`
-//~| HELP implement the missing item: `fn bar<T>(_: impl Sized) { todo!() }`
+//~| HELP implement the missing item: `fn bar<T>(_: impl Sized) where Foo<T>: MetaSized { todo!() }`
+//~| HELP implement the missing item: `fn baz<const N: usize>() { todo!() }`
+//~| HELP implement the missing item: `fn quux<'a: 'b, 'b, T>() where T: ?Sized { todo!() }`
 
 fn main() {}
diff --git a/tests/ui/suggestions/apitit-unimplemented-method.stderr b/tests/ui/suggestions/apitit-unimplemented-method.stderr
index b309a64e958..1f2e0ea2cad 100644
--- a/tests/ui/suggestions/apitit-unimplemented-method.stderr
+++ b/tests/ui/suggestions/apitit-unimplemented-method.stderr
@@ -1,11 +1,13 @@
-error[E0046]: not all trait items implemented, missing: `foo`, `bar`
-  --> $DIR/apitit-unimplemented-method.rs:7:1
+error[E0046]: not all trait items implemented, missing: `foo`, `bar`, `baz`, `quux`
+  --> $DIR/apitit-unimplemented-method.rs:8:1
    |
 LL | impl Trait for Local {}
-   | ^^^^^^^^^^^^^^^^^^^^ missing `foo`, `bar` in implementation
+   | ^^^^^^^^^^^^^^^^^^^^ missing `foo`, `bar`, `baz`, `quux` in implementation
    |
    = help: implement the missing item: `fn foo(_: impl Sized) { todo!() }`
-   = help: implement the missing item: `fn bar<T>(_: impl Sized) { todo!() }`
+   = help: implement the missing item: `fn bar<T>(_: impl Sized) where Foo<T>: MetaSized { todo!() }`
+   = help: implement the missing item: `fn baz<const N: usize>() { todo!() }`
+   = help: implement the missing item: `fn quux<'a: 'b, 'b, T>() where T: ?Sized { todo!() }`
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/suggestions/auxiliary/dep.rs b/tests/ui/suggestions/auxiliary/dep.rs
index ac0de418313..c28c8b8a52f 100644
--- a/tests/ui/suggestions/auxiliary/dep.rs
+++ b/tests/ui/suggestions/auxiliary/dep.rs
@@ -1,4 +1,16 @@
+#![feature(sized_hierarchy)]
+
+use std::marker::MetaSized;
+
+pub struct Foo<T> {
+    inner: T,
+}
+
 pub trait Trait {
     fn foo(_: impl Sized);
-    fn bar<T>(_: impl Sized);
+    fn bar<T>(_: impl Sized)
+    where
+        Foo<T>: MetaSized;
+    fn baz<'a, const N: usize>();
+    fn quux<'a: 'b, 'b, T: ?Sized>();
 }
diff --git a/tests/ui/suggestions/missing-bound-in-derive-copy-impl-2.fixed b/tests/ui/suggestions/missing-bound-in-derive-copy-impl-2.fixed
index 99433f73320..8a2be310e0d 100644
--- a/tests/ui/suggestions/missing-bound-in-derive-copy-impl-2.fixed
+++ b/tests/ui/suggestions/missing-bound-in-derive-copy-impl-2.fixed
@@ -8,7 +8,7 @@ pub struct Vector2<T: Debug + Copy + Clone> {
 }
 
 #[derive(Debug, Copy, Clone)]
-pub struct AABB<K: Debug + std::marker::Copy + std::marker::Copy + std::marker::Copy + std::marker::Copy> {
+pub struct AABB<K: Debug + std::marker::Copy> {
     pub loc: Vector2<K>, //~ ERROR the trait bound `K: Copy` is not satisfied
     //~^ ERROR the trait bound `K: Copy` is not satisfied
     //~| ERROR the trait bound `K: Copy` is not satisfied
diff --git a/tests/ui/suggestions/missing-bound-in-derive-copy-impl-3.fixed b/tests/ui/suggestions/missing-bound-in-derive-copy-impl-3.fixed
index 6da3e351ffb..74df1d7c7cf 100644
--- a/tests/ui/suggestions/missing-bound-in-derive-copy-impl-3.fixed
+++ b/tests/ui/suggestions/missing-bound-in-derive-copy-impl-3.fixed
@@ -8,7 +8,7 @@ pub struct Vector2<T: Debug + Copy + Clone>{
 }
 
 #[derive(Debug, Copy, Clone)] //~ ERROR the trait `Copy` cannot be implemented for this type
-pub struct AABB<K: Copy + Debug + std::fmt::Debug + std::fmt::Debug + std::fmt::Debug>{
+pub struct AABB<K: Copy + Debug + std::fmt::Debug>{
     pub loc: Vector2<K>, //~ ERROR `K` doesn't implement `Debug`
     //~^ ERROR `K` doesn't implement `Debug`
     pub size: Vector2<K> //~ ERROR `K` doesn't implement `Debug`
diff --git a/tests/ui/suggestions/trait-impl-bound-suggestions.fixed b/tests/ui/suggestions/trait-impl-bound-suggestions.fixed
index 9d3168f5acd..49793b4b6f4 100644
--- a/tests/ui/suggestions/trait-impl-bound-suggestions.fixed
+++ b/tests/ui/suggestions/trait-impl-bound-suggestions.fixed
@@ -10,7 +10,7 @@ struct ConstrainedStruct<X: Copy> {
 }
 
 #[allow(dead_code)]
-trait InsufficientlyConstrainedGeneric<X=()> where Self: Sized, X: std::marker::Copy, X: std::marker::Copy {
+trait InsufficientlyConstrainedGeneric<X=()> where Self: Sized, X: std::marker::Copy {
     fn return_the_constrained_type(&self, x: X) -> ConstrainedStruct<X> {
         //~^ ERROR the trait bound `X: Copy` is not satisfied
         ConstrainedStruct { x }
@@ -20,7 +20,7 @@ trait InsufficientlyConstrainedGeneric<X=()> where Self: Sized, X: std::marker::
 
 // Regression test for #120838
 #[allow(dead_code)]
-trait InsufficientlyConstrainedGenericWithEmptyWhere<X=()> where Self: Sized, X: std::marker::Copy, X: std::marker::Copy {
+trait InsufficientlyConstrainedGenericWithEmptyWhere<X=()> where Self: Sized, X: std::marker::Copy {
     fn return_the_constrained_type(&self, x: X) -> ConstrainedStruct<X> {
         //~^ ERROR the trait bound `X: Copy` is not satisfied
         ConstrainedStruct { x }
diff --git a/tests/ui/symbol-names/const-generics-structural-demangling.rs b/tests/ui/symbol-names/const-generics-structural-demangling.rs
index 06e3ce51fa6..0b4af61f991 100644
--- a/tests/ui/symbol-names/const-generics-structural-demangling.rs
+++ b/tests/ui/symbol-names/const-generics-structural-demangling.rs
@@ -6,7 +6,7 @@
 #![feature(adt_const_params, unsized_const_params, decl_macro, rustc_attrs)]
 #![allow(incomplete_features)]
 
-use std::marker::UnsizedConstParamTy;
+use std::marker::ConstParamTy;
 
 pub struct RefByte<const RB: &'static u8>;
 
@@ -42,7 +42,7 @@ pub struct TupleByteBool<const TBB: (u8, bool)>;
 //~| ERROR demangling-alt(<c::TupleByteBool<{(1, false)}>>)
 impl TupleByteBool<{ (1, false) }> {}
 
-#[derive(PartialEq, Eq, UnsizedConstParamTy)]
+#[derive(PartialEq, Eq, ConstParamTy)]
 pub enum MyOption<T> {
     Some(T),
     None,
@@ -66,7 +66,7 @@ impl OptionUsize<{ MyOption::None }> {}
 //~| ERROR demangling-alt(<c::OptionUsize<{c::MyOption::<usize>::Some(0)}>>)
 impl OptionUsize<{ MyOption::Some(0) }> {}
 
-#[derive(PartialEq, Eq, UnsizedConstParamTy)]
+#[derive(PartialEq, Eq, ConstParamTy)]
 pub struct Foo {
     s: &'static str,
     ch: char,
@@ -83,7 +83,7 @@ impl Foo_<{ Foo { s: "abc", ch: 'x', slice: &[1, 2, 3] } }> {}
 // NOTE(eddyb) this tests specifically the use of disambiguators in field names,
 // using macros 2.0 hygiene to create a `struct` with conflicting field names.
 macro duplicate_field_name_test($x:ident) {
-    #[derive(PartialEq, Eq, UnsizedConstParamTy)]
+    #[derive(PartialEq, Eq, ConstParamTy)]
     pub struct Bar {
         $x: u8,
         x: u16,
diff --git a/tests/ui/type-inference/has_sigdrop.rs b/tests/ui/type-inference/has_sigdrop.rs
new file mode 100644
index 00000000000..c3d835cfe16
--- /dev/null
+++ b/tests/ui/type-inference/has_sigdrop.rs
@@ -0,0 +1,18 @@
+//@ run-pass
+// Inference, canonicalization, and significant drops should work nicely together.
+// Related issue: #86868
+
+#[clippy::has_significant_drop]
+struct DropGuy {}
+
+fn creator() -> DropGuy {
+    DropGuy {}
+}
+
+fn dropper() {
+    let _ = creator();
+}
+
+fn main() {
+    dropper();
+}