stabilize gai

66 files changed, 116 insertions, 377 deletions

diff --git a/compiler/rustc_ast_lowering/messages.ftl b/compiler/rustc_ast_lowering/messages.ftl
index 5ef76fb64aa..a8498d771da 100644
--- a/compiler/rustc_ast_lowering/messages.ftl
+++ b/compiler/rustc_ast_lowering/messages.ftl
@@ -172,9 +172,6 @@ ast_lowering_template_modifier = template modifier
 
 ast_lowering_this_not_async = this is not `async`
 
-ast_lowering_underscore_array_length_unstable =
-    using `_` for array lengths is unstable
-
 ast_lowering_underscore_expr_lhs_assign =
     in expressions, `_` can only be used on the left-hand side of an assignment
     .label = `_` not allowed here
diff --git a/compiler/rustc_ast_lowering/src/lib.rs b/compiler/rustc_ast_lowering/src/lib.rs
index b99df8bd7e5..f070759ca81 100644
--- a/compiler/rustc_ast_lowering/src/lib.rs
+++ b/compiler/rustc_ast_lowering/src/lib.rs
@@ -48,7 +48,7 @@ use rustc_data_structures::sorted_map::SortedMap;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_data_structures::sync::spawn;
 use rustc_data_structures::tagged_ptr::TaggedRef;
-use rustc_errors::{DiagArgFromDisplay, DiagCtxtHandle, StashKey};
+use rustc_errors::{DiagArgFromDisplay, DiagCtxtHandle};
 use rustc_hir::def::{DefKind, LifetimeRes, Namespace, PartialRes, PerNS, Res};
 use rustc_hir::def_id::{CRATE_DEF_ID, LOCAL_CRATE, LocalDefId};
 use rustc_hir::{
@@ -59,7 +59,7 @@ use rustc_index::{Idx, IndexSlice, IndexVec};
 use rustc_macros::extension;
 use rustc_middle::span_bug;
 use rustc_middle::ty::{ResolverAstLowering, TyCtxt};
-use rustc_session::parse::{add_feature_diagnostics, feature_err};
+use rustc_session::parse::add_feature_diagnostics;
 use rustc_span::symbol::{Ident, Symbol, kw, sym};
 use rustc_span::{DUMMY_SP, DesugaringKind, Span};
 use smallvec::SmallVec;
@@ -2068,15 +2068,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         // `ExprKind::Paren(ExprKind::Underscore)` and should also be lowered to `GenericArg::Infer`
         match c.value.peel_parens().kind {
             ExprKind::Underscore => {
-                if !self.tcx.features().generic_arg_infer() {
-                    feature_err(
-                        &self.tcx.sess,
-                        sym::generic_arg_infer,
-                        c.value.span,
-                        fluent_generated::ast_lowering_underscore_array_length_unstable,
-                    )
-                    .stash(c.value.span, StashKey::UnderscoreForArrayLengths);
-                }
                 let ct_kind = hir::ConstArgKind::Infer(self.lower_span(c.value.span), ());
                 self.arena.alloc(hir::ConstArg { hir_id: self.lower_node_id(c.id), kind: ct_kind })
             }
diff --git a/compiler/rustc_feature/src/accepted.rs b/compiler/rustc_feature/src/accepted.rs
index b1c185220f4..cfe0f4e5d6c 100644
--- a/compiler/rustc_feature/src/accepted.rs
+++ b/compiler/rustc_feature/src/accepted.rs
@@ -220,6 +220,8 @@ declare_features! (
     (accepted, fn_must_use, "1.27.0", Some(43302)),
     /// Allows capturing variables in scope using format_args!
     (accepted, format_args_capture, "1.58.0", Some(67984)),
+    /// Infer generic args for both consts and types.
+    (accepted, generic_arg_infer, "CURRENT_RUSTC_VERSION", Some(85077)),
     /// Allows associated types to be generic, e.g., `type Foo<T>;` (RFC 1598).
     (accepted, generic_associated_types, "1.65.0", Some(44265)),
     /// Allows attributes on lifetime/type formal parameters in generics (RFC 1327).
diff --git a/compiler/rustc_feature/src/unstable.rs b/compiler/rustc_feature/src/unstable.rs
index 594021d78d2..8c6411342f2 100644
--- a/compiler/rustc_feature/src/unstable.rs
+++ b/compiler/rustc_feature/src/unstable.rs
@@ -516,8 +516,6 @@ declare_features! (
     (unstable, frontmatter, "1.88.0", Some(136889)),
     /// Allows defining gen blocks and `gen fn`.
     (unstable, gen_blocks, "1.75.0", Some(117078)),
-    /// Infer generic args for both consts and types.
-    (unstable, generic_arg_infer, "1.55.0", Some(85077)),
     /// Allows non-trivial generic constants which have to have wfness manually propagated to callers
     (incomplete, generic_const_exprs, "1.56.0", Some(76560)),
     /// Allows generic parameters and where-clauses on free & associated const items.
diff --git a/compiler/rustc_hir_analysis/src/collect/type_of.rs b/compiler/rustc_hir_analysis/src/collect/type_of.rs
index 141d96b57e5..902a2e15dff 100644
--- a/compiler/rustc_hir_analysis/src/collect/type_of.rs
+++ b/compiler/rustc_hir_analysis/src/collect/type_of.rs
@@ -452,13 +452,6 @@ fn infer_placeholder_type<'tcx>(
             if let Some(ty) = node.ty() {
                 visitor.visit_ty_unambig(ty);
             }
-            // If we have just one span, let's try to steal a const `_` feature error.
-            let try_steal_span = if !tcx.features().generic_arg_infer() && visitor.spans.len() == 1
-            {
-                visitor.spans.first().copied()
-            } else {
-                None
-            };
             // If we didn't find any infer tys, then just fallback to `span`.
             if visitor.spans.is_empty() {
                 visitor.spans.push(span);
@@ -489,15 +482,7 @@ fn infer_placeholder_type<'tcx>(
                 }
             }
 
-            if let Some(try_steal_span) = try_steal_span {
-                cx.dcx().try_steal_replace_and_emit_err(
-                    try_steal_span,
-                    StashKey::UnderscoreForArrayLengths,
-                    diag,
-                )
-            } else {
-                diag.emit()
-            }
+            diag.emit()
         });
     Ty::new_error(tcx, guar)
 }
diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/generics.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/generics.rs
index 3a26b8331f8..8c7c3750865 100644
--- a/compiler/rustc_hir_analysis/src/hir_ty_lowering/generics.rs
+++ b/compiler/rustc_hir_analysis/src/hir_ty_lowering/generics.rs
@@ -8,7 +8,7 @@ use rustc_middle::ty::{
     self, GenericArgsRef, GenericParamDef, GenericParamDefKind, IsSuggestable, Ty,
 };
 use rustc_session::lint::builtin::LATE_BOUND_LIFETIME_ARGUMENTS;
-use rustc_span::{kw, sym};
+use rustc_span::kw;
 use smallvec::SmallVec;
 use tracing::{debug, instrument};
 
@@ -258,19 +258,6 @@ pub fn lower_generic_args<'tcx: 'a, 'a>(
                             GenericParamDefKind::Const { .. },
                             _,
                         ) => {
-                            if let GenericParamDefKind::Const { .. } = param.kind
-                                && let GenericArg::Infer(inf) = arg
-                                && !tcx.features().generic_arg_infer()
-                            {
-                                rustc_session::parse::feature_err(
-                                    tcx.sess,
-                                    sym::generic_arg_infer,
-                                    inf.span,
-                                    "const arguments cannot yet be inferred with `_`",
-                                )
-                                .emit();
-                            }
-
                             // We lower to an infer even when the feature gate is not enabled
                             // as it is useful for diagnostics to be able to see a `ConstKind::Infer`
                             args.push(ctx.provided_kind(&args, param, arg));
diff --git a/library/core/src/lib.rs b/library/core/src/lib.rs
index 88855831788..6231c3425c8 100644
--- a/library/core/src/lib.rs
+++ b/library/core/src/lib.rs
@@ -153,7 +153,6 @@
 #![feature(f16)]
 #![feature(freeze_impls)]
 #![feature(fundamental)]
-#![feature(generic_arg_infer)]
 #![feature(if_let_guard)]
 #![feature(intra_doc_pointers)]
 #![feature(intrinsics)]
diff --git a/src/tools/clippy/tests/ui/single_range_in_vec_init.rs b/src/tools/clippy/tests/ui/single_range_in_vec_init.rs
index 25884450b08..0888019e101 100644
--- a/src/tools/clippy/tests/ui/single_range_in_vec_init.rs
+++ b/src/tools/clippy/tests/ui/single_range_in_vec_init.rs
@@ -2,7 +2,6 @@
 //@no-rustfix: overlapping suggestions
 #![allow(clippy::no_effect, clippy::unnecessary_operation, clippy::useless_vec, unused)]
 #![warn(clippy::single_range_in_vec_init)]
-#![feature(generic_arg_infer)]
 
 #[macro_use]
 extern crate proc_macros;
diff --git a/src/tools/clippy/tests/ui/single_range_in_vec_init.stderr b/src/tools/clippy/tests/ui/single_range_in_vec_init.stderr
index a99127a7606..b21338e38a3 100644
--- a/src/tools/clippy/tests/ui/single_range_in_vec_init.stderr
+++ b/src/tools/clippy/tests/ui/single_range_in_vec_init.stderr
@@ -1,5 +1,5 @@
 error: an array of `Range` that is only one element
-  --> tests/ui/single_range_in_vec_init.rs:26:5
+  --> tests/ui/single_range_in_vec_init.rs:25:5
    |
 LL |     [0..200];
    |     ^^^^^^^^
@@ -18,7 +18,7 @@ LL +     [0; 200];
    |
 
 error: a `Vec` of `Range` that is only one element
-  --> tests/ui/single_range_in_vec_init.rs:28:5
+  --> tests/ui/single_range_in_vec_init.rs:27:5
    |
 LL |     vec![0..200];
    |     ^^^^^^^^^^^^
@@ -35,7 +35,7 @@ LL +     vec![0; 200];
    |
 
 error: an array of `Range` that is only one element
-  --> tests/ui/single_range_in_vec_init.rs:30:5
+  --> tests/ui/single_range_in_vec_init.rs:29:5
    |
 LL |     [0u8..200];
    |     ^^^^^^^^^^
@@ -52,7 +52,7 @@ LL +     [0u8; 200];
    |
 
 error: an array of `Range` that is only one element
-  --> tests/ui/single_range_in_vec_init.rs:32:5
+  --> tests/ui/single_range_in_vec_init.rs:31:5
    |
 LL |     [0usize..200];
    |     ^^^^^^^^^^^^^
@@ -69,7 +69,7 @@ LL +     [0usize; 200];
    |
 
 error: an array of `Range` that is only one element
-  --> tests/ui/single_range_in_vec_init.rs:34:5
+  --> tests/ui/single_range_in_vec_init.rs:33:5
    |
 LL |     [0..200usize];
    |     ^^^^^^^^^^^^^
@@ -86,7 +86,7 @@ LL +     [0; 200usize];
    |
 
 error: a `Vec` of `Range` that is only one element
-  --> tests/ui/single_range_in_vec_init.rs:36:5
+  --> tests/ui/single_range_in_vec_init.rs:35:5
    |
 LL |     vec![0u8..200];
    |     ^^^^^^^^^^^^^^
@@ -103,7 +103,7 @@ LL +     vec![0u8; 200];
    |
 
 error: a `Vec` of `Range` that is only one element
-  --> tests/ui/single_range_in_vec_init.rs:38:5
+  --> tests/ui/single_range_in_vec_init.rs:37:5
    |
 LL |     vec![0usize..200];
    |     ^^^^^^^^^^^^^^^^^
@@ -120,7 +120,7 @@ LL +     vec![0usize; 200];
    |
 
 error: a `Vec` of `Range` that is only one element
-  --> tests/ui/single_range_in_vec_init.rs:40:5
+  --> tests/ui/single_range_in_vec_init.rs:39:5
    |
 LL |     vec![0..200usize];
    |     ^^^^^^^^^^^^^^^^^
@@ -137,7 +137,7 @@ LL +     vec![0; 200usize];
    |
 
 error: an array of `Range` that is only one element
-  --> tests/ui/single_range_in_vec_init.rs:43:5
+  --> tests/ui/single_range_in_vec_init.rs:42:5
    |
 LL |     [0..200isize];
    |     ^^^^^^^^^^^^^
@@ -149,7 +149,7 @@ LL +     (0..200isize).collect::<std::vec::Vec<isize>>();
    |
 
 error: a `Vec` of `Range` that is only one element
-  --> tests/ui/single_range_in_vec_init.rs:45:5
+  --> tests/ui/single_range_in_vec_init.rs:44:5
    |
 LL |     vec![0..200isize];
    |     ^^^^^^^^^^^^^^^^^
diff --git a/tests/crashes/111419.rs b/tests/crashes/111419.rs
index 3a1a13df198..36f15e1d0a2 100644
--- a/tests/crashes/111419.rs
+++ b/tests/crashes/111419.rs
@@ -1,6 +1,6 @@
 //@ known-bug: #111419
 #![allow(incomplete_features)]
-#![feature(generic_const_exprs, generic_arg_infer)]
+#![feature(generic_const_exprs)]
 
 pub trait Example<const X: usize, const Y: usize, const Z: usize = { X + Y }>
 where
diff --git a/tests/ui/array-slice-vec/suggest-array-length.fixed b/tests/ui/array-slice-vec/suggest-array-length.fixed
index 2eacc2517d3..ae1c6583c23 100644
--- a/tests/ui/array-slice-vec/suggest-array-length.fixed
+++ b/tests/ui/array-slice-vec/suggest-array-length.fixed
@@ -10,14 +10,9 @@ fn main() {
     //~^ ERROR the placeholder `_` is not allowed within types on item signatures for static variables
     static REF_STATIK: &[u8; 1] = &[1];
     //~^ ERROR the placeholder `_` is not allowed within types on item signatures for static variables
-    let foo: [i32; 3] = [1, 2, 3];
-    //~^ ERROR using `_` for array lengths is unstable
-    let bar: [i32; 3] = [0; 3];
-    //~^ ERROR using `_` for array lengths is unstable
-    let ref_foo: &[i32; 3] = &[1, 2, 3];
-    //~^ ERROR using `_` for array lengths is unstable
-    let ref_bar: &[i32; 3] = &[0; 3];
-    //~^ ERROR using `_` for array lengths is unstable
-    let multiple_ref_foo: &&[i32; 3] = &&[1, 2, 3];
-    //~^ ERROR using `_` for array lengths is unstable
+    let foo: [i32; _] = [1, 2, 3];
+    let bar: [i32; _] = [0; 3];
+    let ref_foo: &[i32; _] = &[1, 2, 3];
+    let ref_bar: &[i32; _] = &[0; 3];
+    let multiple_ref_foo: &&[i32; _] = &&[1, 2, 3];
 }
diff --git a/tests/ui/array-slice-vec/suggest-array-length.rs b/tests/ui/array-slice-vec/suggest-array-length.rs
index fb4424cfed9..e53118014b2 100644
--- a/tests/ui/array-slice-vec/suggest-array-length.rs
+++ b/tests/ui/array-slice-vec/suggest-array-length.rs
@@ -11,13 +11,8 @@ fn main() {
     static REF_STATIK: &[u8; _] = &[1];
     //~^ ERROR the placeholder `_` is not allowed within types on item signatures for static variables
     let foo: [i32; _] = [1, 2, 3];
-    //~^ ERROR using `_` for array lengths is unstable
     let bar: [i32; _] = [0; 3];
-    //~^ ERROR using `_` for array lengths is unstable
     let ref_foo: &[i32; _] = &[1, 2, 3];
-    //~^ ERROR using `_` for array lengths is unstable
     let ref_bar: &[i32; _] = &[0; 3];
-    //~^ ERROR using `_` for array lengths is unstable
     let multiple_ref_foo: &&[i32; _] = &&[1, 2, 3];
-    //~^ ERROR using `_` for array lengths is unstable
 }
diff --git a/tests/ui/array-slice-vec/suggest-array-length.stderr b/tests/ui/array-slice-vec/suggest-array-length.stderr
index 14d10832e36..e498f2ca4f5 100644
--- a/tests/ui/array-slice-vec/suggest-array-length.stderr
+++ b/tests/ui/array-slice-vec/suggest-array-length.stderr
@@ -46,57 +46,6 @@ LL -     static REF_STATIK: &[u8; _] = &[1];
 LL +     static REF_STATIK: &[u8; 1] = &[1];
    |
 
-error[E0658]: using `_` for array lengths is unstable
-  --> $DIR/suggest-array-length.rs:13:20
-   |
-LL |     let foo: [i32; _] = [1, 2, 3];
-   |                    ^ help: consider specifying the array length: `3`
-   |
-   = note: see issue #85077 <https://github.com/rust-lang/rust/issues/85077> for more information
-   = help: add `#![feature(generic_arg_infer)]` 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]: using `_` for array lengths is unstable
-  --> $DIR/suggest-array-length.rs:15:20
-   |
-LL |     let bar: [i32; _] = [0; 3];
-   |                    ^ help: consider specifying the array length: `3`
-   |
-   = note: see issue #85077 <https://github.com/rust-lang/rust/issues/85077> for more information
-   = help: add `#![feature(generic_arg_infer)]` 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]: using `_` for array lengths is unstable
-  --> $DIR/suggest-array-length.rs:17:25
-   |
-LL |     let ref_foo: &[i32; _] = &[1, 2, 3];
-   |                         ^ help: consider specifying the array length: `3`
-   |
-   = note: see issue #85077 <https://github.com/rust-lang/rust/issues/85077> for more information
-   = help: add `#![feature(generic_arg_infer)]` 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]: using `_` for array lengths is unstable
-  --> $DIR/suggest-array-length.rs:19:25
-   |
-LL |     let ref_bar: &[i32; _] = &[0; 3];
-   |                         ^ help: consider specifying the array length: `3`
-   |
-   = note: see issue #85077 <https://github.com/rust-lang/rust/issues/85077> for more information
-   = help: add `#![feature(generic_arg_infer)]` 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]: using `_` for array lengths is unstable
-  --> $DIR/suggest-array-length.rs:21:35
-   |
-LL |     let multiple_ref_foo: &&[i32; _] = &&[1, 2, 3];
-   |                                   ^ help: consider specifying the array length: `3`
-   |
-   = note: see issue #85077 <https://github.com/rust-lang/rust/issues/85077> for more information
-   = help: add `#![feature(generic_arg_infer)]` 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: aborting due to 9 previous errors
+error: aborting due to 4 previous errors
 
-Some errors have detailed explanations: E0121, E0658.
-For more information about an error, try `rustc --explain E0121`.
+For more information about this error, try `rustc --explain E0121`.
diff --git a/tests/ui/async-await/issues/issue-95307.rs b/tests/ui/async-await/issues/issue-95307.rs
index 27903a667fb..83df65612b4 100644
--- a/tests/ui/async-await/issues/issue-95307.rs
+++ b/tests/ui/async-await/issues/issue-95307.rs
@@ -6,7 +6,6 @@
 pub trait C {
     async fn new() -> [u8; _];
     //~^ ERROR: the placeholder `_` is not allowed within types on item signatures for functions
-    //~| ERROR using `_` for array lengths is unstable
 }
 
 fn main() {}
diff --git a/tests/ui/async-await/issues/issue-95307.stderr b/tests/ui/async-await/issues/issue-95307.stderr
index 90100f39163..c670686f7c9 100644
--- a/tests/ui/async-await/issues/issue-95307.stderr
+++ b/tests/ui/async-await/issues/issue-95307.stderr
@@ -4,17 +4,6 @@ error[E0121]: the placeholder `_` is not allowed within types on item signatures
 LL |     async fn new() -> [u8; _];
    |                            ^ not allowed in type signatures
 
-error[E0658]: using `_` for array lengths is unstable
-  --> $DIR/issue-95307.rs:7:28
-   |
-LL |     async fn new() -> [u8; _];
-   |                            ^
-   |
-   = note: see issue #85077 <https://github.com/rust-lang/rust/issues/85077> for more information
-   = help: add `#![feature(generic_arg_infer)]` 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: aborting due to 2 previous errors
+error: aborting due to 1 previous error
 
-Some errors have detailed explanations: E0121, E0658.
-For more information about an error, try `rustc --explain E0121`.
+For more information about this error, try `rustc --explain E0121`.
diff --git a/tests/ui/closures/binder/forbid_ambig_const_infers.rs b/tests/ui/closures/binder/forbid_ambig_const_infers.rs
index e9d783711ee..eb258e0ed9f 100644
--- a/tests/ui/closures/binder/forbid_ambig_const_infers.rs
+++ b/tests/ui/closures/binder/forbid_ambig_const_infers.rs
@@ -1,4 +1,4 @@
-#![feature(generic_arg_infer, closure_lifetime_binder)]
+#![feature(closure_lifetime_binder)]
 
 struct Foo<const N: usize>([u32; N]);
 
diff --git a/tests/ui/closures/binder/forbid_ambig_type_infers.rs b/tests/ui/closures/binder/forbid_ambig_type_infers.rs
index 4e717ef3a17..ca44a5db96d 100644
--- a/tests/ui/closures/binder/forbid_ambig_type_infers.rs
+++ b/tests/ui/closures/binder/forbid_ambig_type_infers.rs
@@ -1,4 +1,4 @@
-#![feature(generic_arg_infer, closure_lifetime_binder)]
+#![feature(closure_lifetime_binder)]
 
 struct Foo<T>(T);
 
diff --git a/tests/ui/closures/binder/forbid_const_infer.rs b/tests/ui/closures/binder/forbid_const_infer.rs
index f5b8bf188df..8c8f0456f50 100644
--- a/tests/ui/closures/binder/forbid_const_infer.rs
+++ b/tests/ui/closures/binder/forbid_const_infer.rs
@@ -1,4 +1,4 @@
-#![feature(generic_arg_infer, closure_lifetime_binder)]
+#![feature(closure_lifetime_binder)]
 
 fn main() {
     let c = for<'a> |b: &'a [u32; _]| -> u32 { b[0] };
diff --git a/tests/ui/const-generics/associated_const_equality/equality_bound_with_infer.rs b/tests/ui/const-generics/associated_const_equality/equality_bound_with_infer.rs
index f45b7c3268b..dc42e00c2e8 100644
--- a/tests/ui/const-generics/associated_const_equality/equality_bound_with_infer.rs
+++ b/tests/ui/const-generics/associated_const_equality/equality_bound_with_infer.rs
@@ -1,4 +1,4 @@
-#![feature(generic_arg_infer, associated_const_equality, generic_const_items)]
+#![feature(associated_const_equality, generic_const_items)]
 #![expect(incomplete_features)]
 
 // Regression test for #133066 where we would try to evaluate `<() as Foo>::ASSOC<_>` even
diff --git a/tests/ui/const-generics/generic_arg_infer/array-repeat-expr-lib.rs b/tests/ui/const-generics/generic_arg_infer/array-repeat-expr-lib.rs
index c1f725db126..c3a67670114 100644
--- a/tests/ui/const-generics/generic_arg_infer/array-repeat-expr-lib.rs
+++ b/tests/ui/const-generics/generic_arg_infer/array-repeat-expr-lib.rs
@@ -1,6 +1,5 @@
 //@ check-pass
 
-#![feature(generic_arg_infer)]
 #![crate_type = "lib"]
 
 // Test that encoding the hallucinated `DefId` for the `_` const argument doesn't
diff --git a/tests/ui/const-generics/generic_arg_infer/array-repeat-expr.rs b/tests/ui/const-generics/generic_arg_infer/array-repeat-expr.rs
index 34091badfa7..fff9f2cc94d 100644
--- a/tests/ui/const-generics/generic_arg_infer/array-repeat-expr.rs
+++ b/tests/ui/const-generics/generic_arg_infer/array-repeat-expr.rs
@@ -1,7 +1,6 @@
 //@ run-pass
 
 // To avoid having to `or` gate `_` as an expr.
-#![feature(generic_arg_infer)]
 
 fn foo() -> [u8; 3] {
     let x: [u8; _] = [0; _];
diff --git a/tests/ui/const-generics/generic_arg_infer/dont-use-defaults.rs b/tests/ui/const-generics/generic_arg_infer/dont-use-defaults.rs
index 613ea9da99d..d4a1468c049 100644
--- a/tests/ui/const-generics/generic_arg_infer/dont-use-defaults.rs
+++ b/tests/ui/const-generics/generic_arg_infer/dont-use-defaults.rs
@@ -1,7 +1,4 @@
 //@ run-pass
-#![feature(generic_arg_infer)]
-
-// test that we dont use defaults to aide in type inference
 
 struct Foo<const N: usize = 2>;
 impl<const N: usize> Foo<N> {
diff --git a/tests/ui/const-generics/generic_arg_infer/in-signature.rs b/tests/ui/const-generics/generic_arg_infer/in-signature.rs
index cd852a26943..cd0235bf45a 100644
--- a/tests/ui/const-generics/generic_arg_infer/in-signature.rs
+++ b/tests/ui/const-generics/generic_arg_infer/in-signature.rs
@@ -1,5 +1,4 @@
 #![crate_type = "rlib"]
-#![feature(generic_arg_infer)]
 
 struct Foo<const N: usize>;
 struct Bar<T, const N: usize>(T);
diff --git a/tests/ui/const-generics/generic_arg_infer/in-signature.stderr b/tests/ui/const-generics/generic_arg_infer/in-signature.stderr
index 12d84268f95..f964fc8d2f2 100644
--- a/tests/ui/const-generics/generic_arg_infer/in-signature.stderr
+++ b/tests/ui/const-generics/generic_arg_infer/in-signature.stderr
@@ -1,5 +1,5 @@
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for return types
-  --> $DIR/in-signature.rs:7:21
+  --> $DIR/in-signature.rs:6:21
    |
 LL | fn arr_fn() -> [u8; _] {
    |                -----^-
@@ -8,7 +8,7 @@ LL | fn arr_fn() -> [u8; _] {
    |                help: replace with the correct return type: `[u8; 3]`
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for return types
-  --> $DIR/in-signature.rs:12:24
+  --> $DIR/in-signature.rs:11:24
    |
 LL | fn ty_fn() -> Bar<i32, _> {
    |               ---------^-
@@ -17,7 +17,7 @@ LL | fn ty_fn() -> Bar<i32, _> {
    |               help: replace with the correct return type: `Bar<i32, 3>`
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for return types
-  --> $DIR/in-signature.rs:17:25
+  --> $DIR/in-signature.rs:16:25
    |
 LL | fn ty_fn_mixed() -> Bar<_, _> {
    |                     ----^--^-
@@ -27,7 +27,7 @@ LL | fn ty_fn_mixed() -> Bar<_, _> {
    |                     help: replace with the correct return type: `Bar<i32, 3>`
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for constants
-  --> $DIR/in-signature.rs:22:20
+  --> $DIR/in-signature.rs:21:20
    |
 LL | const ARR_CT: [u8; _] = [0; 3];
    |                    ^ not allowed in type signatures
@@ -39,7 +39,7 @@ LL + const ARR_CT: [u8; 3] = [0; 3];
    |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for static variables
-  --> $DIR/in-signature.rs:24:25
+  --> $DIR/in-signature.rs:23:25
    |
 LL | static ARR_STATIC: [u8; _] = [0; 3];
    |                         ^ not allowed in type signatures
@@ -51,7 +51,7 @@ LL + static ARR_STATIC: [u8; 3] = [0; 3];
    |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for constants
-  --> $DIR/in-signature.rs:26:23
+  --> $DIR/in-signature.rs:25:23
    |
 LL | const TY_CT: Bar<i32, _> = Bar::<i32, 3>(0);
    |                       ^ not allowed in type signatures
@@ -63,7 +63,7 @@ LL + const TY_CT: Bar<i32, 3> = Bar::<i32, 3>(0);
    |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for static variables
-  --> $DIR/in-signature.rs:28:28
+  --> $DIR/in-signature.rs:27:28
    |
 LL | static TY_STATIC: Bar<i32, _> = Bar::<i32, 3>(0);
    |                            ^ not allowed in type signatures
@@ -75,7 +75,7 @@ LL + static TY_STATIC: Bar<i32, 3> = Bar::<i32, 3>(0);
    |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for constants
-  --> $DIR/in-signature.rs:30:24
+  --> $DIR/in-signature.rs:29:24
    |
 LL | const TY_CT_MIXED: Bar<_, _> = Bar::<i32, 3>(0);
    |                        ^  ^ not allowed in type signatures
@@ -89,7 +89,7 @@ LL + const TY_CT_MIXED: Bar<i32, 3> = Bar::<i32, 3>(0);
    |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for static variables
-  --> $DIR/in-signature.rs:32:29
+  --> $DIR/in-signature.rs:31:29
    |
 LL | static TY_STATIC_MIXED: Bar<_, _> = Bar::<i32, 3>(0);
    |                             ^  ^ not allowed in type signatures
@@ -103,19 +103,19 @@ LL + static TY_STATIC_MIXED: Bar<i32, 3> = Bar::<i32, 3>(0);
    |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for associated types
-  --> $DIR/in-signature.rs:51:23
+  --> $DIR/in-signature.rs:50:23
    |
 LL |     type Assoc = [u8; _];
    |                       ^ not allowed in type signatures
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for associated types
-  --> $DIR/in-signature.rs:55:27
+  --> $DIR/in-signature.rs:54:27
    |
 LL |     type Assoc = Bar<i32, _>;
    |                           ^ not allowed in type signatures
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for associated types
-  --> $DIR/in-signature.rs:59:22
+  --> $DIR/in-signature.rs:58:22
    |
 LL |     type Assoc = Bar<_, _>;
    |                      ^  ^ not allowed in type signatures
@@ -123,19 +123,19 @@ LL |     type Assoc = Bar<_, _>;
    |                      not allowed in type signatures
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for associated constants
-  --> $DIR/in-signature.rs:35:21
+  --> $DIR/in-signature.rs:34:21
    |
 LL |     const ARR: [u8; _];
    |                     ^ not allowed in type signatures
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for associated constants
-  --> $DIR/in-signature.rs:39:25
+  --> $DIR/in-signature.rs:38:25
    |
 LL |     const ARR: Bar<i32, _>;
    |                         ^ not allowed in type signatures
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for associated constants
-  --> $DIR/in-signature.rs:43:20
+  --> $DIR/in-signature.rs:42:20
    |
 LL |     const ARR: Bar<_, _>;
    |                    ^  ^ not allowed in type signatures
diff --git a/tests/ui/const-generics/generic_arg_infer/infer-arg-test.rs b/tests/ui/const-generics/generic_arg_infer/infer-arg-test.rs
index c254b4ee09d..dcdcd250ea9 100644
--- a/tests/ui/const-generics/generic_arg_infer/infer-arg-test.rs
+++ b/tests/ui/const-generics/generic_arg_infer/infer-arg-test.rs
@@ -1,5 +1,3 @@
-#![feature(generic_arg_infer)]
-
 struct All<'a, T, const N: usize> {
   v: &'a T,
 }
diff --git a/tests/ui/const-generics/generic_arg_infer/infer-arg-test.stderr b/tests/ui/const-generics/generic_arg_infer/infer-arg-test.stderr
index a9c57dbf26a..88645f839fc 100644
--- a/tests/ui/const-generics/generic_arg_infer/infer-arg-test.stderr
+++ b/tests/ui/const-generics/generic_arg_infer/infer-arg-test.stderr
@@ -1,17 +1,17 @@
 error: expected identifier, found reserved identifier `_`
-  --> $DIR/infer-arg-test.rs:7:17
+  --> $DIR/infer-arg-test.rs:5:17
    |
 LL | struct BadInfer<_>;
    |                 ^ expected identifier, found reserved identifier
 
 error: expected identifier, found reserved identifier `_`
-  --> $DIR/infer-arg-test.rs:13:17
+  --> $DIR/infer-arg-test.rs:11:17
    |
 LL | fn bad_infer_fn<_>() {}
    |                 ^ expected identifier, found reserved identifier
 
 error[E0392]: type parameter `_` is never used
-  --> $DIR/infer-arg-test.rs:7:17
+  --> $DIR/infer-arg-test.rs:5:17
    |
 LL | struct BadInfer<_>;
    |                 ^ unused type parameter
@@ -20,7 +20,7 @@ LL | struct BadInfer<_>;
    = help: if you intended `_` to be a const parameter, use `const _: /* Type */` instead
 
 error[E0107]: struct takes 2 generic arguments but 3 generic arguments were supplied
-  --> $DIR/infer-arg-test.rs:18:10
+  --> $DIR/infer-arg-test.rs:16:10
    |
 LL |   let a: All<_, _, _>;
    |          ^^^     --- help: remove the unnecessary generic argument
@@ -28,7 +28,7 @@ LL |   let a: All<_, _, _>;
    |          expected 2 generic arguments
    |
 note: struct defined here, with 2 generic parameters: `T`, `N`
-  --> $DIR/infer-arg-test.rs:3:8
+  --> $DIR/infer-arg-test.rs:1:8
    |
 LL | struct All<'a, T, const N: usize> {
    |        ^^^     -  --------------
diff --git a/tests/ui/const-generics/generic_arg_infer/infer_arg_and_const_arg.rs b/tests/ui/const-generics/generic_arg_infer/infer_arg_and_const_arg.rs
index 35b3fe4f435..e82250444d9 100644
--- a/tests/ui/const-generics/generic_arg_infer/infer_arg_and_const_arg.rs
+++ b/tests/ui/const-generics/generic_arg_infer/infer_arg_and_const_arg.rs
@@ -1,5 +1,4 @@
 //@ check-pass
-#![feature(generic_arg_infer)]
 
 struct Foo<const N: bool, const M: u8>;
 struct Bar<const N: u8, const M: u32>;
diff --git a/tests/ui/const-generics/generic_arg_infer/issue-91614.rs b/tests/ui/const-generics/generic_arg_infer/issue-91614.rs
index a386b1e5c2b..4a3d85499da 100644
--- a/tests/ui/const-generics/generic_arg_infer/issue-91614.rs
+++ b/tests/ui/const-generics/generic_arg_infer/issue-91614.rs
@@ -1,5 +1,4 @@
 #![feature(portable_simd)]
-#![feature(generic_arg_infer)]
 use std::simd::Mask;
 
 fn main() {
diff --git a/tests/ui/const-generics/generic_arg_infer/issue-91614.stderr b/tests/ui/const-generics/generic_arg_infer/issue-91614.stderr
index b07e1f29d0d..164bcc7111c 100644
--- a/tests/ui/const-generics/generic_arg_infer/issue-91614.stderr
+++ b/tests/ui/const-generics/generic_arg_infer/issue-91614.stderr
@@ -1,5 +1,5 @@
 error[E0284]: type annotations needed for `Mask<_, _>`
-  --> $DIR/issue-91614.rs:6:9
+  --> $DIR/issue-91614.rs:5:9
    |
 LL |     let y = Mask::<_, _>::splat(false);
    |         ^   ------------ type must be known at this point
@@ -12,7 +12,7 @@ LL |     let y: Mask<_, N> = Mask::<_, _>::splat(false);
    |          ++++++++++++
 
 error[E0284]: type annotations needed for `Mask<_, _>`
-  --> $DIR/issue-91614.rs:6:9
+  --> $DIR/issue-91614.rs:5:9
    |
 LL |     let y = Mask::<_, _>::splat(false);
    |         ^   -------------------------- type must be known at this point
diff --git a/tests/ui/const-generics/generic_arg_infer/parend_infer.nogate.stderr b/tests/ui/const-generics/generic_arg_infer/parend_infer.nogate.stderr
deleted file mode 100644
index d0a5da9676d..00000000000
--- a/tests/ui/const-generics/generic_arg_infer/parend_infer.nogate.stderr
+++ /dev/null
@@ -1,53 +0,0 @@
-error[E0658]: const arguments cannot yet be inferred with `_`
-  --> $DIR/parend_infer.rs:24:16
-   |
-LL |     let c: Foo<_> = Foo::<1>;
-   |                ^
-   |
-   = note: see issue #85077 <https://github.com/rust-lang/rust/issues/85077> for more information
-   = help: add `#![feature(generic_arg_infer)]` 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]: const arguments cannot yet be inferred with `_`
-  --> $DIR/parend_infer.rs:26:16
-   |
-LL |     let c: Foo<(_)> = Foo::<1>;
-   |                ^^^
-   |
-   = note: see issue #85077 <https://github.com/rust-lang/rust/issues/85077> for more information
-   = help: add `#![feature(generic_arg_infer)]` 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]: const arguments cannot yet be inferred with `_`
-  --> $DIR/parend_infer.rs:28:16
-   |
-LL |     let c: Foo<(((_)))> = Foo::<1>;
-   |                ^^^^^^^
-   |
-   = note: see issue #85077 <https://github.com/rust-lang/rust/issues/85077> for more information
-   = help: add `#![feature(generic_arg_infer)]` 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]: using `_` for array lengths is unstable
-  --> $DIR/parend_infer.rs:17:17
-   |
-LL |     let b: [u8; (_)] = [1; (((((_)))))];
-   |                 ^^^
-   |
-   = note: see issue #85077 <https://github.com/rust-lang/rust/issues/85077> for more information
-   = help: add `#![feature(generic_arg_infer)]` 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]: using `_` for array lengths is unstable
-  --> $DIR/parend_infer.rs:17:28
-   |
-LL |     let b: [u8; (_)] = [1; (((((_)))))];
-   |                            ^^^^^^^^^^^
-   |
-   = note: see issue #85077 <https://github.com/rust-lang/rust/issues/85077> for more information
-   = help: add `#![feature(generic_arg_infer)]` 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: aborting due to 5 previous errors
-
-For more information about this error, try `rustc --explain E0658`.
diff --git a/tests/ui/const-generics/generic_arg_infer/parend_infer.rs b/tests/ui/const-generics/generic_arg_infer/parend_infer.rs
index 3dc27a702de..9d7df8016cb 100644
--- a/tests/ui/const-generics/generic_arg_infer/parend_infer.rs
+++ b/tests/ui/const-generics/generic_arg_infer/parend_infer.rs
@@ -1,6 +1,4 @@
-//@[gate] check-pass
-//@ revisions: gate nogate
-#![cfg_attr(gate, feature(generic_arg_infer))]
+//@ check-pass
 
 struct Foo<const N: usize>;
 
@@ -15,16 +13,11 @@ fn main() {
     // AST Exprs similarly preserve parens for pretty printing reasons.
     #[rustfmt::skip]
     let b: [u8; (_)] = [1; (((((_)))))];
-    //[nogate]~^ error: using `_` for array lengths is unstable
-    //[nogate]~| error: using `_` for array lengths is unstable
     let b: [u8; 2] = b;
 
     // This is the same case as AST types as the parser doesn't distinguish between const
     // and type args when they share syntax
     let c: Foo<_> = Foo::<1>;
-    //[nogate]~^ error: const arguments cannot yet be inferred with `_`
     let c: Foo<(_)> = Foo::<1>;
-    //[nogate]~^ error: const arguments cannot yet be inferred with `_`
     let c: Foo<(((_)))> = Foo::<1>;
-    //[nogate]~^ error: const arguments cannot yet be inferred with `_`
 }
diff --git a/tests/ui/const-generics/generic_const_exprs/const_kind_expr/wf_obligation.rs b/tests/ui/const-generics/generic_const_exprs/const_kind_expr/wf_obligation.rs
index 6093fc70b16..a82ea45b123 100644
--- a/tests/ui/const-generics/generic_const_exprs/const_kind_expr/wf_obligation.rs
+++ b/tests/ui/const-generics/generic_const_exprs/const_kind_expr/wf_obligation.rs
@@ -1,4 +1,4 @@
-#![feature(generic_const_exprs, generic_arg_infer)]
+#![feature(generic_const_exprs)]
 #![allow(incomplete_features)]
 
 // minimized repro for #105205
diff --git a/tests/ui/const-generics/generic_const_exprs/poly-const-uneval-ice-106423.rs b/tests/ui/const-generics/generic_const_exprs/poly-const-uneval-ice-106423.rs
index ed5ba32b621..eca0404fcd0 100644
--- a/tests/ui/const-generics/generic_const_exprs/poly-const-uneval-ice-106423.rs
+++ b/tests/ui/const-generics/generic_const_exprs/poly-const-uneval-ice-106423.rs
@@ -3,7 +3,7 @@
 //@ edition:2021
 //@ check-pass
 
-#![feature(generic_const_exprs, generic_arg_infer)]
+#![feature(generic_const_exprs)]
 #![allow(incomplete_features)]
 #![allow(unused)]
 
@@ -41,17 +41,13 @@ where
     DigitalFilter::Ba(zpk)
 }
 
-pub fn zpk2tf_st<const N: usize>(
-    _z: &Arr<f32, N>,
-    _p: &Arr<f32, N>,
-) -> BaFormatFilter<{ N + 1 }>
+pub fn zpk2tf_st<const N: usize>(_z: &Arr<f32, N>, _p: &Arr<f32, N>) -> BaFormatFilter<{ N + 1 }>
 where
     [(); N + 1]: Sized,
 {
     BaFormatFilter {}
 }
 
-
 fn main() {
-    iirfilter_st_copy::<4, 2>([10., 50.,]);
+    iirfilter_st_copy::<4, 2>([10., 50.]);
 }
diff --git a/tests/ui/const-generics/generic_const_parameter_types/bad_inference.rs b/tests/ui/const-generics/generic_const_parameter_types/bad_inference.rs
index de2e687e870..9748c14d655 100644
--- a/tests/ui/const-generics/generic_const_parameter_types/bad_inference.rs
+++ b/tests/ui/const-generics/generic_const_parameter_types/bad_inference.rs
@@ -1,9 +1,4 @@
-#![feature(
-    adt_const_params,
-    unsized_const_params,
-    generic_const_parameter_types,
-    generic_arg_infer
-)]
+#![feature(adt_const_params, unsized_const_params, generic_const_parameter_types)]
 #![allow(incomplete_features)]
 
 use std::marker::ConstParamTy_;
diff --git a/tests/ui/const-generics/generic_const_parameter_types/bad_inference.stderr b/tests/ui/const-generics/generic_const_parameter_types/bad_inference.stderr
index 1ac67fe622b..4652187b9ce 100644
--- a/tests/ui/const-generics/generic_const_parameter_types/bad_inference.stderr
+++ b/tests/ui/const-generics/generic_const_parameter_types/bad_inference.stderr
@@ -1,11 +1,11 @@
 error: anonymous constants with inferred types are not yet supported
-  --> $DIR/bad_inference.rs:17:25
+  --> $DIR/bad_inference.rs:12:25
    |
 LL |     let a = foo::<_, _, { [12_u8; 2] }>();
    |                         ^^^^^^^^^^^^^^
 
 error: anonymous constants with inferred types are not yet supported
-  --> $DIR/bad_inference.rs:21:34
+  --> $DIR/bad_inference.rs:16:34
    |
 LL |     let b: [u8; 2] = foo::<_, _, { [12; _] }>();
    |                                  ^^^^^^^^^^^
diff --git a/tests/ui/const-generics/generic_const_parameter_types/evaluate_const_parameter_in_mir.rs b/tests/ui/const-generics/generic_const_parameter_types/evaluate_const_parameter_in_mir.rs
index 910deb6632d..9f3ab1be250 100644
--- a/tests/ui/const-generics/generic_const_parameter_types/evaluate_const_parameter_in_mir.rs
+++ b/tests/ui/const-generics/generic_const_parameter_types/evaluate_const_parameter_in_mir.rs
@@ -1,11 +1,6 @@
 //@ check-pass
 
-#![feature(
-    adt_const_params,
-    unsized_const_params,
-    generic_const_parameter_types,
-    generic_arg_infer
-)]
+#![feature(adt_const_params, unsized_const_params, generic_const_parameter_types)]
 #![allow(incomplete_features)]
 
 use std::marker::ConstParamTy_;
diff --git a/tests/ui/const-generics/generic_const_parameter_types/inferred_from_arg.rs b/tests/ui/const-generics/generic_const_parameter_types/inferred_from_arg.rs
index d655fc174ee..a4e9aa54c01 100644
--- a/tests/ui/const-generics/generic_const_parameter_types/inferred_from_arg.rs
+++ b/tests/ui/const-generics/generic_const_parameter_types/inferred_from_arg.rs
@@ -1,6 +1,6 @@
 //@ check-pass
 
-#![feature(adt_const_params, generic_arg_infer, generic_const_parameter_types)]
+#![feature(adt_const_params, generic_const_parameter_types)]
 #![expect(incomplete_features)]
 
 struct Bar<const N: usize, const M: [u8; N]>;
diff --git a/tests/ui/const-generics/generic_const_parameter_types/unrelated_inferred_arg.rs b/tests/ui/const-generics/generic_const_parameter_types/unrelated_inferred_arg.rs
index b389e12884e..80117a27a23 100644
--- a/tests/ui/const-generics/generic_const_parameter_types/unrelated_inferred_arg.rs
+++ b/tests/ui/const-generics/generic_const_parameter_types/unrelated_inferred_arg.rs
@@ -1,11 +1,6 @@
 //@ check-pass
 
-#![feature(
-    adt_const_params,
-    unsized_const_params,
-    generic_const_parameter_types,
-    generic_arg_infer
-)]
+#![feature(adt_const_params, unsized_const_params, generic_const_parameter_types)]
 #![allow(incomplete_features)]
 
 use std::marker::ConstParamTy_;
diff --git a/tests/ui/const-generics/issues/issue-62878.min.stderr b/tests/ui/const-generics/issues/issue-62878.min.stderr
index d3d4fa43871..d7ca0e1e2db 100644
--- a/tests/ui/const-generics/issues/issue-62878.min.stderr
+++ b/tests/ui/const-generics/issues/issue-62878.min.stderr
@@ -16,17 +16,6 @@ help: add `#![feature(adt_const_params)]` to the crate attributes to enable more
 LL + #![feature(adt_const_params)]
    |
 
-error[E0658]: const arguments cannot yet be inferred with `_`
-  --> $DIR/issue-62878.rs:10:11
-   |
-LL |     foo::<_, { [1] }>();
-   |           ^
-   |
-   = note: see issue #85077 <https://github.com/rust-lang/rust/issues/85077> for more information
-   = help: add `#![feature(generic_arg_infer)]` 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: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0658, E0770.
-For more information about an error, try `rustc --explain E0658`.
+For more information about this error, try `rustc --explain E0770`.
diff --git a/tests/ui/const-generics/issues/issue-62878.rs b/tests/ui/const-generics/issues/issue-62878.rs
index c80b46ddbc4..0c143b34ce9 100644
--- a/tests/ui/const-generics/issues/issue-62878.rs
+++ b/tests/ui/const-generics/issues/issue-62878.rs
@@ -1,5 +1,5 @@
 //@ revisions: full min
-#![cfg_attr(full, feature(adt_const_params, generic_arg_infer))]
+#![cfg_attr(full, feature(adt_const_params))]
 #![cfg_attr(full, allow(incomplete_features))]
 
 fn foo<const N: usize, const A: [u8; N]>() {}
@@ -8,5 +8,4 @@ fn foo<const N: usize, const A: [u8; N]>() {}
 
 fn main() {
     foo::<_, { [1] }>();
-    //[min]~^ ERROR: const arguments cannot yet be inferred with `_`
 }
diff --git a/tests/ui/const-generics/min_const_generics/inferred_const.rs b/tests/ui/const-generics/min_const_generics/inferred_const.rs
index 0256ef732a3..4a4fb417ab1 100644
--- a/tests/ui/const-generics/min_const_generics/inferred_const.rs
+++ b/tests/ui/const-generics/min_const_generics/inferred_const.rs
@@ -1,4 +1,3 @@
-#![feature(generic_arg_infer)]
 //@ run-pass
 
 fn foo<const N: usize, const K: usize>(_data: [u32; N]) -> [u32; K] {
diff --git a/tests/ui/feature-gates/feature-gate-generic_arg_infer.normal.stderr b/tests/ui/feature-gates/feature-gate-generic_arg_infer.normal.stderr
deleted file mode 100644
index 73e6988b09c..00000000000
--- a/tests/ui/feature-gates/feature-gate-generic_arg_infer.normal.stderr
+++ /dev/null
@@ -1,33 +0,0 @@
-error[E0658]: using `_` for array lengths is unstable
-  --> $DIR/feature-gate-generic_arg_infer.rs:13:18
-   |
-LL |     let _y: [u8; _] = [0; 3];
-   |                  ^ help: consider specifying the array length: `3`
-   |
-   = note: see issue #85077 <https://github.com/rust-lang/rust/issues/85077> for more information
-   = help: add `#![feature(generic_arg_infer)]` 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]: const arguments cannot yet be inferred with `_`
-  --> $DIR/feature-gate-generic_arg_infer.rs:18:20
-   |
-LL |     let _x = foo::<_>([1, 2]);
-   |                    ^
-   |
-   = note: see issue #85077 <https://github.com/rust-lang/rust/issues/85077> for more information
-   = help: add `#![feature(generic_arg_infer)]` 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]: using `_` for array lengths is unstable
-  --> $DIR/feature-gate-generic_arg_infer.rs:11:27
-   |
-LL |     let _x: [u8; 3] = [0; _];
-   |                           ^
-   |
-   = note: see issue #85077 <https://github.com/rust-lang/rust/issues/85077> for more information
-   = help: add `#![feature(generic_arg_infer)]` 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: aborting due to 3 previous errors
-
-For more information about this error, try `rustc --explain E0658`.
diff --git a/tests/ui/feature-gates/feature-gate-generic_arg_infer.rs b/tests/ui/feature-gates/feature-gate-generic_arg_infer.rs
deleted file mode 100644
index 147978b0557..00000000000
--- a/tests/ui/feature-gates/feature-gate-generic_arg_infer.rs
+++ /dev/null
@@ -1,21 +0,0 @@
-//@ [feature] run-pass
-//@ revisions: normal feature
-
-#![cfg_attr(feature, feature(generic_arg_infer))]
-
-fn foo<const N: usize>(_: [u8; N]) -> [u8; N] {
-    [0; N]
-}
-
-fn bar() {
-    let _x: [u8; 3] = [0; _];
-    //[normal]~^ ERROR: using `_` for array lengths is unstable
-    let _y: [u8; _] = [0; 3];
-    //[normal]~^ ERROR: using `_` for array lengths is unstable
-}
-
-fn main() {
-    let _x = foo::<_>([1, 2]);
-    //[normal]~^ ERROR: const arguments cannot yet be inferred with `_`
-    bar();
-}
diff --git a/tests/ui/lang-items/lang-item-generic-requirements.rs b/tests/ui/lang-items/lang-item-generic-requirements.rs
index 25a4ff283ba..602c7f53428 100644
--- a/tests/ui/lang-items/lang-item-generic-requirements.rs
+++ b/tests/ui/lang-items/lang-item-generic-requirements.rs
@@ -50,14 +50,14 @@ fn ice() {
     let arr = [0; 5];
     //~^ ERROR requires `copy` lang_item
     let _ = arr[2];
-    //~^ ERROR cannot index into a value of type `[{integer}; 5]`
+    //~^ ERROR: cannot index into a value of type `[{integer}; 5]`
 
     // Use phantomdata
     let _ = MyPhantomData::<(), i32>;
 
     // Use Foo
     let _: () = Foo;
-    //~^ ERROR mismatched types
+    //~^ ERROR: mismatched types
 }
 
 // use `start`
diff --git a/tests/ui/object-lifetime/object-lifetime-default-inferred.rs b/tests/ui/object-lifetime/object-lifetime-default-inferred.rs
index 5abe09e2729..1ab821764de 100644
--- a/tests/ui/object-lifetime/object-lifetime-default-inferred.rs
+++ b/tests/ui/object-lifetime/object-lifetime-default-inferred.rs
@@ -4,7 +4,6 @@
 
 
 #![allow(dead_code)]
-#![feature(generic_arg_infer)]
 
 trait Test {
     fn foo(&self) { }
diff --git a/tests/ui/parser/issues/issue-14303-fncall.rs b/tests/ui/parser/issues/issue-14303-fncall.rs
index 8f7fbec9470..1e8ef6af3fa 100644
--- a/tests/ui/parser/issues/issue-14303-fncall.rs
+++ b/tests/ui/parser/issues/issue-14303-fncall.rs
@@ -1,7 +1,5 @@
-//@ revisions: full generic_arg
 // can't run rustfix because it doesn't handle multipart suggestions correctly
 // we need the above to avoid ast borrowck failure in recovered code
-#![cfg_attr(generic_arg, feature(generic_arg_infer))]
 
 struct S<'a, T> {
     a: &'a T,
@@ -10,8 +8,7 @@ struct S<'a, T> {
 
 fn foo<'a, 'b>(start: &'a usize, end: &'a usize) {
     let _x = (*start..*end).map(|x| S { a: start, b: end }).collect::<Vec<S<_, 'a>>>();
-    //[generic_arg]~^ ERROR placeholder provided when a lifetime was expected
-    //[full]~^^ ERROR placeholder provided when a lifetime was expected
+    //~^ ERROR placeholder provided when a lifetime was expected
 }
 
 fn main() {}
diff --git a/tests/ui/parser/issues/issue-14303-fncall.stderr b/tests/ui/parser/issues/issue-14303-fncall.stderr
new file mode 100644
index 00000000000..c42a23fa9d3
--- /dev/null
+++ b/tests/ui/parser/issues/issue-14303-fncall.stderr
@@ -0,0 +1,9 @@
+error[E0747]: placeholder provided when a lifetime was expected
+  --> $DIR/issue-14303-fncall.rs:10:77
+   |
+LL |     let _x = (*start..*end).map(|x| S { a: start, b: end }).collect::<Vec<S<_, 'a>>>();
+   |                                                                             ^
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0747`.
diff --git a/tests/ui/pattern/slice-array-infer.rs b/tests/ui/pattern/slice-array-infer.rs
index fdead488ea1..8d471b31bea 100644
--- a/tests/ui/pattern/slice-array-infer.rs
+++ b/tests/ui/pattern/slice-array-infer.rs
@@ -1,7 +1,6 @@
 //@ check-pass
 
 #![allow(unused_variables)]
-#![feature(generic_arg_infer)]
 
 struct Zeroes;
 impl Into<&'static [usize; 3]> for Zeroes {
diff --git a/tests/ui/repeat-expr/copy-check-const-element-uninferred-count.rs b/tests/ui/repeat-expr/copy-check-const-element-uninferred-count.rs
index 6115146539c..722fdae6c99 100644
--- a/tests/ui/repeat-expr/copy-check-const-element-uninferred-count.rs
+++ b/tests/ui/repeat-expr/copy-check-const-element-uninferred-count.rs
@@ -1,5 +1,3 @@
-#![feature(generic_arg_infer)]
-
 // Test when deferring repeat expr copy checks to end of typechecking whether elements
 // that are const items allow for repeat counts to go uninferred without an error being
 // emitted if they would later wind up inferred by integer fallback.
diff --git a/tests/ui/repeat-expr/copy-check-const-element-uninferred-count.stderr b/tests/ui/repeat-expr/copy-check-const-element-uninferred-count.stderr
index 2f52537fa94..9c9cfefd663 100644
--- a/tests/ui/repeat-expr/copy-check-const-element-uninferred-count.stderr
+++ b/tests/ui/repeat-expr/copy-check-const-element-uninferred-count.stderr
@@ -1,5 +1,5 @@
 error[E0284]: type annotations needed for `[String; _]`
-  --> $DIR/copy-check-const-element-uninferred-count.rs:64:9
+  --> $DIR/copy-check-const-element-uninferred-count.rs:62:9
    |
 LL |     let a = [const { String::new() }; _];
    |         ^   ---------------------------- type must be known at this point
diff --git a/tests/ui/repeat-expr/copy-check-deferred-after-fallback.rs b/tests/ui/repeat-expr/copy-check-deferred-after-fallback.rs
index 3f310f07de0..a6bd5b299c9 100644
--- a/tests/ui/repeat-expr/copy-check-deferred-after-fallback.rs
+++ b/tests/ui/repeat-expr/copy-check-deferred-after-fallback.rs
@@ -1,5 +1,3 @@
-#![feature(generic_arg_infer)]
-
 // Test when deferring repeat expr copy checks to end of typechecking whether they're
 // checked before integer fallback occurs or not. We accomplish this by having a repeat
 // count that can only be inferred after integer fallback has occured. This test will
diff --git a/tests/ui/repeat-expr/copy-check-deferred-after-fallback.stderr b/tests/ui/repeat-expr/copy-check-deferred-after-fallback.stderr
index 103b074dda7..0cd7ebe7494 100644
--- a/tests/ui/repeat-expr/copy-check-deferred-after-fallback.stderr
+++ b/tests/ui/repeat-expr/copy-check-deferred-after-fallback.stderr
@@ -1,5 +1,5 @@
 error[E0282]: type annotations needed for `[Foo<{integer}>; _]`
-  --> $DIR/copy-check-deferred-after-fallback.rs:39:9
+  --> $DIR/copy-check-deferred-after-fallback.rs:37:9
    |
 LL |     let b = [Foo(PhantomData); _];
    |         ^    ---------------- type must be known at this point
diff --git a/tests/ui/repeat-expr/copy-check-deferred-before-fallback.rs b/tests/ui/repeat-expr/copy-check-deferred-before-fallback.rs
index 4fbb8f0a00c..23b13348f5a 100644
--- a/tests/ui/repeat-expr/copy-check-deferred-before-fallback.rs
+++ b/tests/ui/repeat-expr/copy-check-deferred-before-fallback.rs
@@ -1,5 +1,4 @@
 //@ check-pass
-#![feature(generic_arg_infer)]
 
 // Test when deferring repeat expr checks to end of typechecking whether they're
 // checked before integer fallback occurs. We accomplish this by having the repeat
diff --git a/tests/ui/repeat-expr/copy-check-inference-side-effects.rs b/tests/ui/repeat-expr/copy-check-inference-side-effects.rs
index 4e3bfdead26..8587f1f9ce9 100644
--- a/tests/ui/repeat-expr/copy-check-inference-side-effects.rs
+++ b/tests/ui/repeat-expr/copy-check-inference-side-effects.rs
@@ -1,5 +1,3 @@
-#![feature(generic_arg_infer)]
-
 struct Foo<const N: usize>;
 
 impl Clone for Foo<1> {
diff --git a/tests/ui/repeat-expr/copy-check-inference-side-effects.stderr b/tests/ui/repeat-expr/copy-check-inference-side-effects.stderr
index 505beff0f6b..bf4ae9b60bb 100644
--- a/tests/ui/repeat-expr/copy-check-inference-side-effects.stderr
+++ b/tests/ui/repeat-expr/copy-check-inference-side-effects.stderr
@@ -1,5 +1,5 @@
 error[E0282]: type annotations needed for `[Foo<_>; 2]`
-  --> $DIR/copy-check-inference-side-effects.rs:17:9
+  --> $DIR/copy-check-inference-side-effects.rs:15:9
    |
 LL |     let a /* : [Foo<?x>; 2] */ = [Foo::<_>; 2];
    |         ^
@@ -13,7 +13,7 @@ LL |     let a: [Foo<N>; 2] /* : [Foo<?x>; 2] */ = [Foo::<_>; 2];
    |          +++++++++++++
 
 error[E0282]: type annotations needed for `[String; _]`
-  --> $DIR/copy-check-inference-side-effects.rs:27:9
+  --> $DIR/copy-check-inference-side-effects.rs:25:9
    |
 LL |     let b /* : [String; ?x] */ = ["string".to_string(); _];
    |         ^                         -------------------- type must be known at this point
diff --git a/tests/ui/repeat-expr/copy-check-when-count-inferred-later.rs b/tests/ui/repeat-expr/copy-check-when-count-inferred-later.rs
index b9d123cbefa..72467e6f32e 100644
--- a/tests/ui/repeat-expr/copy-check-when-count-inferred-later.rs
+++ b/tests/ui/repeat-expr/copy-check-when-count-inferred-later.rs
@@ -1,5 +1,3 @@
-#![feature(generic_arg_infer)]
-
 // Test that we enforce repeat expr element types are `Copy` even
 // when the repeat count is only inferred at a later point in type
 // checking.
diff --git a/tests/ui/repeat-expr/copy-check-when-count-inferred-later.stderr b/tests/ui/repeat-expr/copy-check-when-count-inferred-later.stderr
index 1c862f2b606..6b8049e77cc 100644
--- a/tests/ui/repeat-expr/copy-check-when-count-inferred-later.stderr
+++ b/tests/ui/repeat-expr/copy-check-when-count-inferred-later.stderr
@@ -1,5 +1,5 @@
 error[E0277]: the trait bound `String: Copy` is not satisfied
-  --> $DIR/copy-check-when-count-inferred-later.rs:8:14
+  --> $DIR/copy-check-when-count-inferred-later.rs:6:14
    |
 LL |     let a = [String::new(); _];
    |              ^^^^^^^^^^^^^ the trait `Copy` is not implemented for `String`
diff --git a/tests/ui/repeat-expr/dont-require-copy-on-infer.rs b/tests/ui/repeat-expr/dont-require-copy-on-infer.rs
index e81bf1595be..ad0e4bd2be0 100644
--- a/tests/ui/repeat-expr/dont-require-copy-on-infer.rs
+++ b/tests/ui/repeat-expr/dont-require-copy-on-infer.rs
@@ -1,5 +1,4 @@
 //@ check-pass
-#![feature(generic_arg_infer)]
 
 fn main() {
     let a: [_; 1] = [String::new(); _];
diff --git a/tests/ui/repeat-expr/no-conservative-copy-impl-requirement.rs b/tests/ui/repeat-expr/no-conservative-copy-impl-requirement.rs
index eb70df62996..df79ad51b42 100644
--- a/tests/ui/repeat-expr/no-conservative-copy-impl-requirement.rs
+++ b/tests/ui/repeat-expr/no-conservative-copy-impl-requirement.rs
@@ -1,5 +1,3 @@
-#![feature(generic_arg_infer)]
-
 struct Foo<const N: usize>;
 
 impl Clone for Foo<1> {
diff --git a/tests/ui/repeat-expr/no-conservative-copy-impl-requirement.stderr b/tests/ui/repeat-expr/no-conservative-copy-impl-requirement.stderr
index 04f8ff33fda..bf1e46e4ef8 100644
--- a/tests/ui/repeat-expr/no-conservative-copy-impl-requirement.stderr
+++ b/tests/ui/repeat-expr/no-conservative-copy-impl-requirement.stderr
@@ -1,5 +1,5 @@
 error[E0282]: type annotations needed for `&[Foo<_>; _]`
-  --> $DIR/no-conservative-copy-impl-requirement.rs:17:9
+  --> $DIR/no-conservative-copy-impl-requirement.rs:15:9
    |
 LL |     let x = &[Foo::<_>; _];
    |         ^     -------- type must be known at this point
diff --git a/tests/ui/simd/const-err-trumps-simd-err.rs b/tests/ui/simd/const-err-trumps-simd-err.rs
index 8d9870855f8..33f0abb06f3 100644
--- a/tests/ui/simd/const-err-trumps-simd-err.rs
+++ b/tests/ui/simd/const-err-trumps-simd-err.rs
@@ -4,7 +4,6 @@
 //! Make sure that monomorphization-time const errors from `static_assert` take priority over the
 //! error from simd_extract. Basically this checks that if a const fails to evaluate in some
 //! function, we don't bother codegen'ing the function.
-#![feature(generic_arg_infer)]
 #![feature(core_intrinsics)]
 #![feature(repr_simd)]
 
diff --git a/tests/ui/simd/const-err-trumps-simd-err.stderr b/tests/ui/simd/const-err-trumps-simd-err.stderr
index d4ba54a28da..93d1fce637f 100644
--- a/tests/ui/simd/const-err-trumps-simd-err.stderr
+++ b/tests/ui/simd/const-err-trumps-simd-err.stderr
@@ -1,17 +1,17 @@
 error[E0080]: evaluation panicked: assertion failed: LANE < 4
-  --> $DIR/const-err-trumps-simd-err.rs:18:13
+  --> $DIR/const-err-trumps-simd-err.rs:17:13
    |
 LL |     const { assert!(LANE < 4); } // the error should be here...
    |             ^^^^^^^^^^^^^^^^^ evaluation of `get_elem::<4>::{constant#0}` failed here
 
 note: erroneous constant encountered
-  --> $DIR/const-err-trumps-simd-err.rs:18:5
+  --> $DIR/const-err-trumps-simd-err.rs:17:5
    |
 LL |     const { assert!(LANE < 4); } // the error should be here...
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 note: the above error was encountered while instantiating `fn get_elem::<4>`
-  --> $DIR/const-err-trumps-simd-err.rs:24:5
+  --> $DIR/const-err-trumps-simd-err.rs:23:5
    |
 LL |     get_elem::<4>(int8x4_t([0, 0, 0, 0]));
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/span/issue-42234-unknown-receiver-type.rs b/tests/ui/span/issue-42234-unknown-receiver-type.rs
index 53d1e3eed82..8f7bbf0fe5e 100644
--- a/tests/ui/span/issue-42234-unknown-receiver-type.rs
+++ b/tests/ui/span/issue-42234-unknown-receiver-type.rs
@@ -1,6 +1,3 @@
-//@ revisions: full generic_arg
-#![cfg_attr(generic_arg, feature(generic_arg_infer))]
-
 // When the type of a method call's receiver is unknown, the span should point
 // to the receiver (and not the entire call, as was previously the case before
 // the fix of which this tests).
diff --git a/tests/ui/span/issue-42234-unknown-receiver-type.stderr b/tests/ui/span/issue-42234-unknown-receiver-type.stderr
new file mode 100644
index 00000000000..10308ec07da
--- /dev/null
+++ b/tests/ui/span/issue-42234-unknown-receiver-type.stderr
@@ -0,0 +1,23 @@
+error[E0282]: type annotations needed
+  --> $DIR/issue-42234-unknown-receiver-type.rs:6:24
+   |
+LL |     let x: Option<_> = None;
+   |                        ^^^^ cannot infer type of the type parameter `T` declared on the enum `Option`
+LL |     x.unwrap().method_that_could_exist_on_some_type();
+   |     ---------- type must be known at this point
+   |
+help: consider specifying the generic argument
+   |
+LL |     let x: Option<_> = None::<T>;
+   |                            +++++
+
+error[E0282]: type annotations needed
+  --> $DIR/issue-42234-unknown-receiver-type.rs:12:10
+   |
+LL |         .sum::<_>()
+   |          ^^^ cannot infer type of the type parameter `S` declared on the method `sum`
+   |
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0282`.
diff --git a/tests/ui/traits/const-traits/tilde-const-and-const-params.rs b/tests/ui/traits/const-traits/tilde-const-and-const-params.rs
index 706c77b6200..428223d92c0 100644
--- a/tests/ui/traits/const-traits/tilde-const-and-const-params.rs
+++ b/tests/ui/traits/const-traits/tilde-const-and-const-params.rs
@@ -1,5 +1,4 @@
 #![feature(const_trait_impl)]
-#![feature(generic_arg_infer)]
 #![feature(generic_const_exprs)]
 #![allow(incomplete_features)]
 
diff --git a/tests/ui/traits/const-traits/tilde-const-and-const-params.stderr b/tests/ui/traits/const-traits/tilde-const-and-const-params.stderr
index f77d63db054..95e684bd0c4 100644
--- a/tests/ui/traits/const-traits/tilde-const-and-const-params.stderr
+++ b/tests/ui/traits/const-traits/tilde-const-and-const-params.stderr
@@ -1,35 +1,35 @@
 error: `~const` is not allowed here
-  --> $DIR/tilde-const-and-const-params.rs:9:15
+  --> $DIR/tilde-const-and-const-params.rs:8:15
    |
 LL |     fn add<A: ~const Add42>(self) -> Foo<{ A::add(N) }> {
    |               ^^^^^^
    |
 note: this function is not `const`, so it cannot have `~const` trait bounds
-  --> $DIR/tilde-const-and-const-params.rs:9:8
+  --> $DIR/tilde-const-and-const-params.rs:8:8
    |
 LL |     fn add<A: ~const Add42>(self) -> Foo<{ A::add(N) }> {
    |        ^^^
 
 error: `~const` is not allowed here
-  --> $DIR/tilde-const-and-const-params.rs:27:11
+  --> $DIR/tilde-const-and-const-params.rs:26:11
    |
 LL | fn bar<A: ~const Add42, const N: usize>(_: Foo<N>) -> Foo<{ A::add(N) }> {
    |           ^^^^^^
    |
 note: this function is not `const`, so it cannot have `~const` trait bounds
-  --> $DIR/tilde-const-and-const-params.rs:27:4
+  --> $DIR/tilde-const-and-const-params.rs:26:4
    |
 LL | fn bar<A: ~const Add42, const N: usize>(_: Foo<N>) -> Foo<{ A::add(N) }> {
    |    ^^^
 
 error[E0277]: the trait bound `A: const Add42` is not satisfied
-  --> $DIR/tilde-const-and-const-params.rs:27:61
+  --> $DIR/tilde-const-and-const-params.rs:26:61
    |
 LL | fn bar<A: ~const Add42, const N: usize>(_: Foo<N>) -> Foo<{ A::add(N) }> {
    |                                                             ^
 
 error[E0277]: the trait bound `A: const Add42` is not satisfied
-  --> $DIR/tilde-const-and-const-params.rs:9:44
+  --> $DIR/tilde-const-and-const-params.rs:8:44
    |
 LL |     fn add<A: ~const Add42>(self) -> Foo<{ A::add(N) }> {
    |                                            ^