Auto merge of #136158 - cuviper:stable-next, r=cuviper 1.84.1

[stable] Prepare Rust 1.84.1 point release

- [Fix ICE 132920 in duplicate-crate diagnostics.](https://github.com/rust-lang/rust/pull/133304/)
- [Fix errors for overlapping impls in incremental rebuilds.](https://github.com/rust-lang/rust/pull/133828/)
- [Fix slow compilation related to the next-generation trait solver.](https://github.com/rust-lang/rust/pull/135618/)
- [Fix debuginfo when LLVM's location discriminator value limit is exceeded.](https://github.com/rust-lang/rust/pull/135643/)
- Fixes for building Rust from source:
  - [Only try to distribute `llvm-objcopy` if llvm tools are enabled.](https://github.com/rust-lang/rust/pull/134240/)
  - [Add Profile Override for Non-Git Sources.](https://github.com/rust-lang/rust/pull/135433/)
  - [Resolve symlinks of LLVM tool binaries before copying them.](https://github.com/rust-lang/rust/pull/135585/)
  - [Make it possible to use ci-rustc on tarball sources.](https://github.com/rust-lang/rust/pull/135722/)

cc `@rust-lang/release`
r? ghost

32 files changed, 422 insertions, 134 deletions

diff --git a/RELEASES.md b/RELEASES.md
index fe557a08a9d..de2caa01cbe 100644
--- a/RELEASES.md
+++ b/RELEASES.md
@@ -1,3 +1,18 @@
+Version 1.84.1 (2025-01-30)
+==========================
+
+<a id="1.84.1"></a>
+
+- [Fix ICE 132920 in duplicate-crate diagnostics.](https://github.com/rust-lang/rust/pull/133304/)
+- [Fix errors for overlapping impls in incremental rebuilds.](https://github.com/rust-lang/rust/pull/133828/)
+- [Fix slow compilation related to the next-generation trait solver.](https://github.com/rust-lang/rust/pull/135618/)
+- [Fix debuginfo when LLVM's location discriminator value limit is exceeded.](https://github.com/rust-lang/rust/pull/135643/)
+- Fixes for building Rust from source:
+  - [Only try to distribute `llvm-objcopy` if llvm tools are enabled.](https://github.com/rust-lang/rust/pull/134240/)
+  - [Add Profile Override for Non-Git Sources.](https://github.com/rust-lang/rust/pull/135433/)
+  - [Resolve symlinks of LLVM tool binaries before copying them.](https://github.com/rust-lang/rust/pull/135585/)
+  - [Make it possible to use ci-rustc on tarball sources.](https://github.com/rust-lang/rust/pull/135722/)
+
 Version 1.84.0 (2025-01-09)
 ==========================
 
diff --git a/compiler/rustc_codegen_gcc/src/debuginfo.rs b/compiler/rustc_codegen_gcc/src/debuginfo.rs
index 6aeb656c1ab..5d8c5c199b1 100644
--- a/compiler/rustc_codegen_gcc/src/debuginfo.rs
+++ b/compiler/rustc_codegen_gcc/src/debuginfo.rs
@@ -113,15 +113,15 @@ fn make_mir_scope<'gcc, 'tcx>(
     let scope_data = &mir.source_scopes[scope];
     let parent_scope = if let Some(parent) = scope_data.parent_scope {
         make_mir_scope(cx, _instance, mir, variables, debug_context, instantiated, parent);
-        debug_context.scopes[parent].unwrap()
+        debug_context.scopes[parent]
     } else {
         // The root is the function itself.
         let file = cx.sess().source_map().lookup_source_file(mir.span.lo());
-        debug_context.scopes[scope] = Some(DebugScope {
+        debug_context.scopes[scope] = DebugScope {
             file_start_pos: file.start_pos,
             file_end_pos: file.end_position(),
-            ..debug_context.scopes[scope].unwrap()
-        });
+            ..debug_context.scopes[scope]
+        };
         instantiated.insert(scope);
         return;
     };
@@ -130,7 +130,7 @@ fn make_mir_scope<'gcc, 'tcx>(
         if !vars.contains(scope) && scope_data.inlined.is_none() {
             // Do not create a DIScope if there are no variables defined in this
             // MIR `SourceScope`, and it's not `inlined`, to avoid debuginfo bloat.
-            debug_context.scopes[scope] = Some(parent_scope);
+            debug_context.scopes[scope] = parent_scope;
             instantiated.insert(scope);
             return;
         }
@@ -157,12 +157,12 @@ fn make_mir_scope<'gcc, 'tcx>(
     // TODO(tempdragon): dbg_scope: Add support for scope extension here.
     inlined_at.or(p_inlined_at);
 
-    debug_context.scopes[scope] = Some(DebugScope {
+    debug_context.scopes[scope] = DebugScope {
         dbg_scope,
         inlined_at,
         file_start_pos: loc.file.start_pos,
         file_end_pos: loc.file.end_position(),
-    });
+    };
     instantiated.insert(scope);
 }
 
@@ -232,12 +232,12 @@ impl<'gcc, 'tcx> DebugInfoCodegenMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
         }
 
         // Initialize fn debug context (including scopes).
-        let empty_scope = Some(DebugScope {
+        let empty_scope = DebugScope {
             dbg_scope: self.dbg_scope_fn(instance, fn_abi, Some(llfn)),
             inlined_at: None,
             file_start_pos: BytePos(0),
             file_end_pos: BytePos(0),
-        });
+        };
         let mut fn_debug_context = FunctionDebugContext {
             scopes: IndexVec::from_elem(empty_scope, mir.source_scopes.as_slice()),
             inlined_function_scopes: Default::default(),
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/create_scope_map.rs b/compiler/rustc_codegen_llvm/src/debuginfo/create_scope_map.rs
index 07bd0f4d1c1..11c1f9d39f7 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/create_scope_map.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/create_scope_map.rs
@@ -9,7 +9,7 @@ use rustc_middle::mir::{Body, SourceScope};
 use rustc_middle::ty::layout::{FnAbiOf, HasTypingEnv};
 use rustc_middle::ty::{self, Instance};
 use rustc_session::config::DebugInfo;
-use rustc_span::{BytePos, hygiene};
+use rustc_span::{BytePos, DUMMY_SP, hygiene};
 
 use super::metadata::file_metadata;
 use super::utils::DIB;
@@ -85,23 +85,15 @@ fn make_mir_scope<'ll, 'tcx>(
             discriminators,
             parent,
         );
-        if let Some(parent_scope) = debug_context.scopes[parent] {
-            parent_scope
-        } else {
-            // If the parent scope could not be represented then no children
-            // can be either.
-            debug_context.scopes[scope] = None;
-            instantiated.insert(scope);
-            return;
-        }
+        debug_context.scopes[parent]
     } else {
         // The root is the function itself.
         let file = cx.sess().source_map().lookup_source_file(mir.span.lo());
-        debug_context.scopes[scope] = Some(DebugScope {
+        debug_context.scopes[scope] = DebugScope {
             file_start_pos: file.start_pos,
             file_end_pos: file.end_position(),
-            ..debug_context.scopes[scope].unwrap()
-        });
+            ..debug_context.scopes[scope]
+        };
         instantiated.insert(scope);
         return;
     };
@@ -112,7 +104,7 @@ fn make_mir_scope<'ll, 'tcx>(
     {
         // Do not create a DIScope if there are no variables defined in this
         // MIR `SourceScope`, and it's not `inlined`, to avoid debuginfo bloat.
-        debug_context.scopes[scope] = Some(parent_scope);
+        debug_context.scopes[scope] = parent_scope;
         instantiated.insert(scope);
         return;
     }
@@ -145,14 +137,7 @@ fn make_mir_scope<'ll, 'tcx>(
         },
     };
 
-    let mut debug_scope = Some(DebugScope {
-        dbg_scope,
-        inlined_at: parent_scope.inlined_at,
-        file_start_pos: loc.file.start_pos,
-        file_end_pos: loc.file.end_position(),
-    });
-
-    if let Some((_, callsite_span)) = scope_data.inlined {
+    let inlined_at = scope_data.inlined.map(|(_, callsite_span)| {
         let callsite_span = hygiene::walk_chain_collapsed(callsite_span, mir.span);
         let callsite_scope = parent_scope.adjust_dbg_scope_for_span(cx, callsite_span);
         let loc = cx.dbg_loc(callsite_scope, parent_scope.inlined_at, callsite_span);
@@ -175,29 +160,29 @@ fn make_mir_scope<'ll, 'tcx>(
         // Note further that we can't key this hashtable on the span itself,
         // because these spans could have distinct SyntaxContexts. We have
         // to key on exactly what we're giving to LLVM.
-        let inlined_at = match discriminators.entry(callsite_span.lo()) {
+        match discriminators.entry(callsite_span.lo()) {
             Entry::Occupied(mut o) => {
                 *o.get_mut() += 1;
+                // NB: We have to emit *something* here or we'll fail LLVM IR verification
+                // in at least some circumstances (see issue #135322) so if the required
+                // discriminant cannot be encoded fall back to the dummy location.
                 unsafe { llvm::LLVMRustDILocationCloneWithBaseDiscriminator(loc, *o.get()) }
+                    .unwrap_or_else(|| {
+                        cx.dbg_loc(callsite_scope, parent_scope.inlined_at, DUMMY_SP)
+                    })
             }
             Entry::Vacant(v) => {
                 v.insert(0);
-                Some(loc)
-            }
-        };
-        match inlined_at {
-            Some(inlined_at) => {
-                debug_scope.as_mut().unwrap().inlined_at = Some(inlined_at);
-            }
-            None => {
-                // LLVM has a maximum discriminator that it can encode (currently
-                // it uses 12 bits for 4096 possible values). If we exceed that
-                // there is little we can do but drop the debug info.
-                debug_scope = None;
+                loc
             }
         }
-    }
+    });
 
-    debug_context.scopes[scope] = debug_scope;
+    debug_context.scopes[scope] = DebugScope {
+        dbg_scope,
+        inlined_at: inlined_at.or(parent_scope.inlined_at),
+        file_start_pos: loc.file.start_pos,
+        file_end_pos: loc.file.end_position(),
+    };
     instantiated.insert(scope);
 }
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs b/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs
index a8fdfbed592..4b650b00bee 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs
@@ -294,12 +294,12 @@ impl<'ll, 'tcx> DebugInfoCodegenMethods<'tcx> for CodegenCx<'ll, 'tcx> {
         }
 
         // Initialize fn debug context (including scopes).
-        let empty_scope = Some(DebugScope {
+        let empty_scope = DebugScope {
             dbg_scope: self.dbg_scope_fn(instance, fn_abi, Some(llfn)),
             inlined_at: None,
             file_start_pos: BytePos(0),
             file_end_pos: BytePos(0),
-        });
+        };
         let mut fn_debug_context = FunctionDebugContext {
             scopes: IndexVec::from_elem(empty_scope, &mir.source_scopes),
             inlined_function_scopes: Default::default(),
diff --git a/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs b/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
index d4d7f16db55..21d20475408 100644
--- a/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
@@ -20,9 +20,7 @@ use crate::traits::*;
 
 pub struct FunctionDebugContext<'tcx, S, L> {
     /// Maps from source code to the corresponding debug info scope.
-    /// May be None if the backend is not capable of representing the scope for
-    /// some reason.
-    pub scopes: IndexVec<mir::SourceScope, Option<DebugScope<S, L>>>,
+    pub scopes: IndexVec<mir::SourceScope, DebugScope<S, L>>,
 
     /// Maps from an inlined function to its debug info declaration.
     pub inlined_function_scopes: FxHashMap<Instance<'tcx>, S>,
@@ -233,7 +231,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         &self,
         source_info: mir::SourceInfo,
     ) -> Option<(Bx::DIScope, Option<Bx::DILocation>, Span)> {
-        let scope = &self.debug_context.as_ref()?.scopes[source_info.scope]?;
+        let scope = &self.debug_context.as_ref()?.scopes[source_info.scope];
         let span = hygiene::walk_chain_collapsed(source_info.span, self.mir.span);
         Some((scope.adjust_dbg_scope_for_span(self.cx, span), scope.inlined_at, span))
     }
diff --git a/compiler/rustc_query_system/src/dep_graph/graph.rs b/compiler/rustc_query_system/src/dep_graph/graph.rs
index 9b26a5bbcc6..4b47ce8389c 100644
--- a/compiler/rustc_query_system/src/dep_graph/graph.rs
+++ b/compiler/rustc_query_system/src/dep_graph/graph.rs
@@ -302,7 +302,11 @@ impl<D: Deps> DepGraph<D> {
         OP: FnOnce() -> R,
     {
         match self.data() {
-            Some(data) => data.with_anon_task(cx, dep_kind, op),
+            Some(data) => {
+                let (result, index) = data.with_anon_task_inner(cx, dep_kind, op);
+                self.read_index(index);
+                (result, index)
+            }
             None => (op(), self.next_virtual_depnode_index()),
         }
     }
@@ -397,7 +401,16 @@ impl<D: Deps> DepGraphData<D> {
 
     /// Executes something within an "anonymous" task, that is, a task the
     /// `DepNode` of which is determined by the list of inputs it read from.
-    pub(crate) fn with_anon_task<Tcx: DepContext<Deps = D>, OP, R>(
+    ///
+    /// NOTE: this does not actually count as a read of the DepNode here.
+    /// Using the result of this task without reading the DepNode will result
+    /// in untracked dependencies which may lead to ICEs as nodes are
+    /// incorrectly marked green.
+    ///
+    /// FIXME: This could perhaps return a `WithDepNode` to ensure that the
+    /// user of this function actually performs the read; we'll have to see
+    /// how to make that work with `anon` in `execute_job_incr`, though.
+    pub(crate) fn with_anon_task_inner<Tcx: DepContext<Deps = D>, OP, R>(
         &self,
         cx: Tcx,
         dep_kind: DepKind,
diff --git a/compiler/rustc_query_system/src/query/plumbing.rs b/compiler/rustc_query_system/src/query/plumbing.rs
index aac8ab87c64..6fb5e37d2d0 100644
--- a/compiler/rustc_query_system/src/query/plumbing.rs
+++ b/compiler/rustc_query_system/src/query/plumbing.rs
@@ -520,9 +520,11 @@ where
     let (result, dep_node_index) =
         qcx.start_query(job_id, query.depth_limit(), Some(&diagnostics), || {
             if query.anon() {
-                return dep_graph_data.with_anon_task(*qcx.dep_context(), query.dep_kind(), || {
-                    query.compute(qcx, key)
-                });
+                return dep_graph_data.with_anon_task_inner(
+                    *qcx.dep_context(),
+                    query.dep_kind(),
+                    || query.compute(qcx, key),
+                );
             }
 
             // `to_dep_node` is expensive for some `DepKind`s.
diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs
index 20cef5e06a4..307c1af41cc 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs
@@ -1808,24 +1808,6 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                 StringPart::highlighted("cargo tree".to_string()),
                 StringPart::normal("` to explore your dependency tree".to_string()),
             ]);
-
-            // FIXME: this is a giant hack for the benefit of this specific diagnostic. Because
-            // we're so nested in method calls before the error gets emitted, bubbling a single bit
-            // flag informing the top level caller to stop adding extra detail to the diagnostic,
-            // would actually be harder to follow. So we do something naughty here: we consume the
-            // diagnostic, emit it and leave in its place a "delayed bug" that will continue being
-            // modified but won't actually be printed to end users. This *is not ideal*, but allows
-            // us to reduce the verbosity of an error that is already quite verbose and increase its
-            // specificity. Below we modify the main message as well, in a way that *could* break if
-            // the implementation of Diagnostics change significantly, but that would be caught with
-            // a make test failure when this diagnostic is tested.
-            err.primary_message(format!(
-                "{} because the trait comes from a different crate version",
-                err.messages[0].0.as_str().unwrap(),
-            ));
-            let diag = err.clone();
-            err.downgrade_to_delayed_bug();
-            self.tcx.dcx().emit_diagnostic(diag);
             return true;
         }
 
diff --git a/compiler/rustc_trait_selection/src/traits/coherence.rs b/compiler/rustc_trait_selection/src/traits/coherence.rs
index a98871b2d60..d59f408b806 100644
--- a/compiler/rustc_trait_selection/src/traits/coherence.rs
+++ b/compiler/rustc_trait_selection/src/traits/coherence.rs
@@ -6,7 +6,7 @@
 
 use std::fmt::Debug;
 
-use rustc_data_structures::fx::FxIndexSet;
+use rustc_data_structures::fx::{FxHashSet, FxIndexSet};
 use rustc_errors::{Diag, EmissionGuarantee};
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::DefId;
@@ -117,28 +117,39 @@ pub fn overlapping_impls(
         return None;
     }
 
-    let _overlap_with_bad_diagnostics = overlap(
-        tcx,
-        TrackAmbiguityCauses::No,
-        skip_leak_check,
-        impl1_def_id,
-        impl2_def_id,
-        overlap_mode,
-    )?;
-
-    // In the case where we detect an error, run the check again, but
-    // this time tracking intercrate ambiguity causes for better
-    // diagnostics. (These take time and can lead to false errors.)
-    let overlap = overlap(
-        tcx,
-        TrackAmbiguityCauses::Yes,
-        skip_leak_check,
-        impl1_def_id,
-        impl2_def_id,
-        overlap_mode,
-    )
-    .unwrap();
-    Some(overlap)
+    if tcx.next_trait_solver_in_coherence() {
+        overlap(
+            tcx,
+            TrackAmbiguityCauses::Yes,
+            skip_leak_check,
+            impl1_def_id,
+            impl2_def_id,
+            overlap_mode,
+        )
+    } else {
+        let _overlap_with_bad_diagnostics = overlap(
+            tcx,
+            TrackAmbiguityCauses::No,
+            skip_leak_check,
+            impl1_def_id,
+            impl2_def_id,
+            overlap_mode,
+        )?;
+
+        // In the case where we detect an error, run the check again, but
+        // this time tracking intercrate ambiguity causes for better
+        // diagnostics. (These take time and can lead to false errors.)
+        let overlap = overlap(
+            tcx,
+            TrackAmbiguityCauses::Yes,
+            skip_leak_check,
+            impl1_def_id,
+            impl2_def_id,
+            overlap_mode,
+        )
+        .unwrap();
+        Some(overlap)
+    }
 }
 
 fn fresh_impl_header<'tcx>(infcx: &InferCtxt<'tcx>, impl_def_id: DefId) -> ty::ImplHeader<'tcx> {
@@ -616,6 +627,7 @@ fn compute_intercrate_ambiguity_causes<'tcx>(
 }
 
 struct AmbiguityCausesVisitor<'a, 'tcx> {
+    cache: FxHashSet<Goal<'tcx, ty::Predicate<'tcx>>>,
     causes: &'a mut FxIndexSet<IntercrateAmbiguityCause<'tcx>>,
 }
 
@@ -625,6 +637,10 @@ impl<'a, 'tcx> ProofTreeVisitor<'tcx> for AmbiguityCausesVisitor<'a, 'tcx> {
     }
 
     fn visit_goal(&mut self, goal: &InspectGoal<'_, 'tcx>) {
+        if !self.cache.insert(goal.goal()) {
+            return;
+        }
+
         let infcx = goal.infcx();
         for cand in goal.candidates() {
             cand.visit_nested_in_probe(self);
@@ -749,5 +765,10 @@ fn search_ambiguity_causes<'tcx>(
     goal: Goal<'tcx, ty::Predicate<'tcx>>,
     causes: &mut FxIndexSet<IntercrateAmbiguityCause<'tcx>>,
 ) {
-    infcx.probe(|_| infcx.visit_proof_tree(goal, &mut AmbiguityCausesVisitor { causes }));
+    infcx.probe(|_| {
+        infcx.visit_proof_tree(goal, &mut AmbiguityCausesVisitor {
+            cache: Default::default(),
+            causes,
+        })
+    });
 }
diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs
index 5b4e895189b..fcd195c8834 100644
--- a/compiler/rustc_trait_selection/src/traits/select/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs
@@ -1390,10 +1390,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
     where
         OP: FnOnce(&mut Self) -> R,
     {
-        let (result, dep_node) =
-            self.tcx().dep_graph.with_anon_task(self.tcx(), dep_kinds::TraitSelect, || op(self));
-        self.tcx().dep_graph.read_index(dep_node);
-        (result, dep_node)
+        self.tcx().dep_graph.with_anon_task(self.tcx(), dep_kinds::TraitSelect, || op(self))
     }
 
     /// filter_impls filters candidates that have a positive impl for a negative
diff --git a/compiler/rustc_type_ir/src/search_graph/mod.rs b/compiler/rustc_type_ir/src/search_graph/mod.rs
index 5010fc09adc..3cc2dcbaca6 100644
--- a/compiler/rustc_type_ir/src/search_graph/mod.rs
+++ b/compiler/rustc_type_ir/src/search_graph/mod.rs
@@ -511,7 +511,7 @@ impl<D: Delegate<Cx = X>, X: Cx> SearchGraph<D> {
 
         // This is for global caching, so we properly track query dependencies.
         // Everything that affects the `result` should be performed within this
-        // `with_anon_task` closure. If computing this goal depends on something
+        // `with_cached_task` closure. If computing this goal depends on something
         // not tracked by the cache key and from outside of this anon task, it
         // must not be added to the global cache. Notably, this is the case for
         // trait solver cycles participants.
diff --git a/src/bootstrap/bootstrap.py b/src/bootstrap/bootstrap.py
index d7ae0299dd6..baad163ca07 100644
--- a/src/bootstrap/bootstrap.py
+++ b/src/bootstrap/bootstrap.py
@@ -1145,7 +1145,12 @@ def bootstrap(args):
     else:
         config_toml = ''
 
-    profile = RustBuild.get_toml_static(config_toml, 'profile')
+    profile = RustBuild.get_toml_static(config_toml, "profile")
+    is_non_git_source = not os.path.exists(os.path.join(rust_root, ".git"))
+
+    if profile is None and is_non_git_source:
+        profile = "dist"
+
     if profile is not None:
         # Allows creating alias for profile names, allowing
         # profiles to be renamed while maintaining back compatibility
diff --git a/src/bootstrap/src/core/build_steps/compile.rs b/src/bootstrap/src/core/build_steps/compile.rs
index 8e088682f92..761220527b3 100644
--- a/src/bootstrap/src/core/build_steps/compile.rs
+++ b/src/bootstrap/src/core/build_steps/compile.rs
@@ -1800,7 +1800,13 @@ impl Step for Assemble {
                     // When using `download-ci-llvm`, some of the tools
                     // may not exist, so skip trying to copy them.
                     if src_path.exists() {
-                        builder.copy_link(&src_path, &libdir_bin.join(&tool_exe));
+                        // There is a chance that these tools are being installed from an external LLVM.
+                        // Use `Builder::resolve_symlink_and_copy` instead of `Builder::copy_link` to ensure
+                        // we are copying the original file not the symlinked path, which causes issues for
+                        // tarball distribution.
+                        //
+                        // See https://github.com/rust-lang/rust/issues/135554.
+                        builder.resolve_symlink_and_copy(&src_path, &libdir_bin.join(&tool_exe));
                     }
                 }
             }
diff --git a/src/bootstrap/src/core/build_steps/dist.rs b/src/bootstrap/src/core/build_steps/dist.rs
index 0cb8971634f..cb352e217f0 100644
--- a/src/bootstrap/src/core/build_steps/dist.rs
+++ b/src/bootstrap/src/core/build_steps/dist.rs
@@ -471,7 +471,7 @@ impl Step for Rustc {
                 }
             }
 
-            {
+            if builder.config.llvm_enabled(compiler.host) && builder.config.llvm_tools_enabled {
                 let src_dir = builder.sysroot_target_bindir(compiler, host);
                 let llvm_objcopy = exe("llvm-objcopy", compiler.host);
                 let rust_objcopy = exe("rust-objcopy", compiler.host);
diff --git a/src/bootstrap/src/core/config/config.rs b/src/bootstrap/src/core/config/config.rs
index e706aba977b..1738bef2328 100644
--- a/src/bootstrap/src/core/config/config.rs
+++ b/src/bootstrap/src/core/config/config.rs
@@ -2815,21 +2815,26 @@ impl Config {
             allowed_paths.push(":!library");
         }
 
-        // Look for a version to compare to based on the current commit.
-        // Only commits merged by bors will have CI artifacts.
-        let commit = match self.last_modified_commit(&allowed_paths, "download-rustc", if_unchanged)
-        {
-            Some(commit) => commit,
-            None => {
-                if if_unchanged {
-                    return None;
+        let commit = if self.rust_info.is_managed_git_subrepository() {
+            // Look for a version to compare to based on the current commit.
+            // Only commits merged by bors will have CI artifacts.
+            match self.last_modified_commit(&allowed_paths, "download-rustc", if_unchanged) {
+                Some(commit) => commit,
+                None => {
+                    if if_unchanged {
+                        return None;
+                    }
+                    println!("ERROR: could not find commit hash for downloading rustc");
+                    println!("HELP: maybe your repository history is too shallow?");
+                    println!("HELP: consider setting `rust.download-rustc=false` in config.toml");
+                    println!("HELP: or fetch enough history to include one upstream commit");
+                    crate::exit!(1);
                 }
-                println!("ERROR: could not find commit hash for downloading rustc");
-                println!("HELP: maybe your repository history is too shallow?");
-                println!("HELP: consider setting `rust.download-rustc=false` in config.toml");
-                println!("HELP: or fetch enough history to include one upstream commit");
-                crate::exit!(1);
             }
+        } else {
+            channel::read_commit_info_file(&self.src)
+                .map(|info| info.sha.trim().to_owned())
+                .expect("git-commit-info is missing in the project root")
         };
 
         if CiEnv::is_ci() && {
@@ -2858,10 +2863,8 @@ impl Config {
         let if_unchanged = || {
             if self.rust_info.is_from_tarball() {
                 // Git is needed for running "if-unchanged" logic.
-                println!(
-                    "WARNING: 'if-unchanged' has no effect on tarball sources; ignoring `download-ci-llvm`."
-                );
-                return false;
+                println!("ERROR: 'if-unchanged' is only compatible with Git managed sources.");
+                crate::exit!(1);
             }
 
             // Fetching the LLVM submodule is unnecessary for self-tests.
@@ -2903,6 +2906,11 @@ impl Config {
         option_name: &str,
         if_unchanged: bool,
     ) -> Option<String> {
+        assert!(
+            self.rust_info.is_managed_git_subrepository(),
+            "Can't run `Config::last_modified_commit` on a non-git source."
+        );
+
         // Look for a version to compare to based on the current commit.
         // Only commits merged by bors will have CI artifacts.
         let commit = get_closest_merge_commit(Some(&self.src), &self.git_config(), &[]).unwrap();
diff --git a/src/bootstrap/src/lib.rs b/src/bootstrap/src/lib.rs
index c384fd6bf43..ac735f0f685 100644
--- a/src/bootstrap/src/lib.rs
+++ b/src/bootstrap/src/lib.rs
@@ -1681,6 +1681,14 @@ Executed at: {executed_at}"#,
         paths
     }
 
+    /// Copies a file from `src` to `dst`.
+    ///
+    /// If `src` is a symlink, `src` will be resolved to the actual path
+    /// and copied to `dst` instead of the symlink itself.
+    pub fn resolve_symlink_and_copy(&self, src: &Path, dst: &Path) {
+        self.copy_link_internal(src, dst, true);
+    }
+
     /// Links a file from `src` to `dst`.
     /// Attempts to use hard links if possible, falling back to copying.
     /// You can neither rely on this being a copy nor it being a link,
diff --git a/src/version b/src/version
index bd0f9e6c28f..1a17bdc1710 100644
--- a/src/version
+++ b/src/version
@@ -1 +1 @@
-1.84.0
+1.84.1
diff --git a/tests/incremental/track-deps-in-new-solver.rs b/tests/incremental/track-deps-in-new-solver.rs
new file mode 100644
index 00000000000..fb013b2b24a
--- /dev/null
+++ b/tests/incremental/track-deps-in-new-solver.rs
@@ -0,0 +1,25 @@
+//@ revisions: cfail1 cfail2
+
+//@ compile-flags: -Znext-solver
+//@ check-pass
+
+pub trait Future {
+    type Error;
+    fn poll() -> Self::Error;
+}
+
+struct S;
+impl Future for S {
+    type Error = Error;
+    fn poll() -> Self::Error {
+        todo!()
+    }
+}
+
+#[cfg(cfail1)]
+pub struct Error(());
+
+#[cfg(cfail2)]
+pub struct Error();
+
+fn main() {}
diff --git a/tests/run-make/crate-loading-crate-depends-on-itself/foo.stderr b/tests/run-make/crate-loading-crate-depends-on-itself/foo.stderr
index 9c2fcabe5ba..36379429530 100644
--- a/tests/run-make/crate-loading-crate-depends-on-itself/foo.stderr
+++ b/tests/run-make/crate-loading-crate-depends-on-itself/foo.stderr
@@ -1,4 +1,4 @@
-error[E0277]: the trait bound `foo::Struct: Trait` is not satisfied because the trait comes from a different crate version
+error[E0277]: the trait bound `foo::Struct: Trait` is not satisfied
   --> foo-current.rs:13:19
    |
 13 |     check_trait::<foo::Struct>();
@@ -23,6 +23,11 @@ note: there are multiple different versions of crate `foo` in the dependency gra
    | --------------- this is the found trait
    = note: two types coming from two different versions of the same crate are different types even if they look the same
    = help: you can use `cargo tree` to explore your dependency tree
+note: required by a bound in `check_trait`
+  --> foo-current.rs:10:19
+   |
+10 | fn check_trait<T: Trait>() {}
+   |                   ^^^^^ required by this bound in `check_trait`
 
 error: aborting due to 1 previous error
 
diff --git a/tests/run-make/crate-loading/multiple-dep-versions.stderr b/tests/run-make/crate-loading/multiple-dep-versions.stderr
index 7f04b2dd64a..5888aad8f37 100644
--- a/tests/run-make/crate-loading/multiple-dep-versions.stderr
+++ b/tests/run-make/crate-loading/multiple-dep-versions.stderr
@@ -1,8 +1,10 @@
-error[E0277]: the trait bound `dep_2_reexport::Type: Trait` is not satisfied because the trait comes from a different crate version
+error[E0277]: the trait bound `dep_2_reexport::Type: Trait` is not satisfied
   --> replaced
    |
 LL |     do_something(Type);
-   |                  ^^^^ the trait `Trait` is not implemented for `dep_2_reexport::Type`
+   |     ------------ ^^^^ the trait `Trait` is not implemented for `dep_2_reexport::Type`
+   |     |
+   |     required by a bound introduced by this call
    |
 note: there are multiple different versions of crate `dependency` in the dependency graph
   --> replaced
@@ -27,6 +29,11 @@ LL | pub trait Trait {
    | --------------- this is the found trait
    = note: two types coming from two different versions of the same crate are different types even if they look the same
    = help: you can use `cargo tree` to explore your dependency tree
+note: required by a bound in `do_something`
+  --> replaced
+   |
+LL | pub fn do_something<X: Trait>(_: X) {}
+   |                        ^^^^^ required by this bound in `do_something`
 
 error[E0599]: no method named `foo` found for struct `dep_2_reexport::Type` in the current scope
   --> replaced
@@ -77,11 +84,13 @@ LL | use dependency::{Trait, do_something};
 LL | pub trait Trait {
    | --------------- this is the trait that was imported
 
-error[E0277]: the trait bound `OtherType: Trait` is not satisfied because the trait comes from a different crate version
+error[E0277]: the trait bound `OtherType: Trait` is not satisfied
   --> replaced
    |
 LL |     do_something(OtherType);
-   |                  ^^^^^^^^^ the trait `Trait` is not implemented for `OtherType`
+   |     ------------ ^^^^^^^^^ the trait `Trait` is not implemented for `OtherType`
+   |     |
+   |     required by a bound introduced by this call
    |
 note: there are multiple different versions of crate `dependency` in the dependency graph
   --> replaced
@@ -106,6 +115,11 @@ LL | pub struct OtherType;
 LL | pub trait Trait {
    | --------------- this is the found trait
    = help: you can use `cargo tree` to explore your dependency tree
+note: required by a bound in `do_something`
+  --> replaced
+   |
+LL | pub fn do_something<X: Trait>(_: X) {}
+   |                        ^^^^^ required by this bound in `do_something`
 
 error: aborting due to 4 previous errors
 
diff --git a/tests/run-make/diagnostics-traits-from-duplicate-crates/minibevy.rs b/tests/run-make/diagnostics-traits-from-duplicate-crates/minibevy.rs
new file mode 100644
index 00000000000..1bc8473e08e
--- /dev/null
+++ b/tests/run-make/diagnostics-traits-from-duplicate-crates/minibevy.rs
@@ -0,0 +1,2 @@
+pub trait Resource {}
+pub struct Ray2d;
diff --git a/tests/run-make/diagnostics-traits-from-duplicate-crates/minirapier.rs b/tests/run-make/diagnostics-traits-from-duplicate-crates/minirapier.rs
new file mode 100644
index 00000000000..2b84332aa51
--- /dev/null
+++ b/tests/run-make/diagnostics-traits-from-duplicate-crates/minirapier.rs
@@ -0,0 +1 @@
+pub type Ray = minibevy::Ray2d;
diff --git a/tests/run-make/diagnostics-traits-from-duplicate-crates/repro.rs b/tests/run-make/diagnostics-traits-from-duplicate-crates/repro.rs
new file mode 100644
index 00000000000..90a6dfc2e15
--- /dev/null
+++ b/tests/run-make/diagnostics-traits-from-duplicate-crates/repro.rs
@@ -0,0 +1,14 @@
+extern crate minibevy;
+extern crate minirapier;
+
+use minibevy::Resource;
+use minirapier::Ray;
+
+fn insert_resource<R: Resource>(_resource: R) {}
+
+struct Res;
+impl Resource for Res {}
+
+fn main() {
+    insert_resource(Res.into());
+}
diff --git a/tests/run-make/diagnostics-traits-from-duplicate-crates/rmake.rs b/tests/run-make/diagnostics-traits-from-duplicate-crates/rmake.rs
new file mode 100644
index 00000000000..32c4cf33896
--- /dev/null
+++ b/tests/run-make/diagnostics-traits-from-duplicate-crates/rmake.rs
@@ -0,0 +1,45 @@
+// Non-regression test for issue #132920 where multiple versions of the same crate are present in
+// the dependency graph, and an unexpected error in a dependent crate caused an ICE in the
+// unsatisfied bounds diagnostics for traits present in multiple crate versions.
+//
+// Setup:
+// - two versions of the same crate: minibevy_a and minibevy_b
+// - minirapier: depends on minibevy_a
+// - repro: depends on minirapier and minibevy_b
+
+use run_make_support::rustc;
+
+fn main() {
+    // Prepare dependencies, mimicking a check build with cargo.
+    rustc()
+        .input("minibevy.rs")
+        .crate_name("minibevy")
+        .crate_type("lib")
+        .emit("metadata")
+        .metadata("a")
+        .extra_filename("-a")
+        .run();
+    rustc()
+        .input("minibevy.rs")
+        .crate_name("minibevy")
+        .crate_type("lib")
+        .emit("metadata")
+        .metadata("b")
+        .extra_filename("-b")
+        .run();
+    rustc()
+        .input("minirapier.rs")
+        .crate_name("minirapier")
+        .crate_type("lib")
+        .emit("metadata")
+        .extern_("minibevy", "libminibevy-a.rmeta")
+        .run();
+
+    // Building the main crate used to ICE here when printing the `type annotations needed` error.
+    rustc()
+        .input("repro.rs")
+        .extern_("minibevy", "libminibevy-b.rmeta")
+        .extern_("minirapier", "libminirapier.rmeta")
+        .run_fail()
+        .assert_stderr_not_contains("error: the compiler unexpectedly panicked. this is a bug");
+}
diff --git a/tests/run-make/llvm-location-discriminator-limit-dummy-span/main.rs b/tests/run-make/llvm-location-discriminator-limit-dummy-span/main.rs
new file mode 100644
index 00000000000..421eb4331b3
--- /dev/null
+++ b/tests/run-make/llvm-location-discriminator-limit-dummy-span/main.rs
@@ -0,0 +1,3 @@
+fn main() {
+    other::big_function();
+}
diff --git a/tests/run-make/llvm-location-discriminator-limit-dummy-span/other.rs b/tests/run-make/llvm-location-discriminator-limit-dummy-span/other.rs
new file mode 100644
index 00000000000..a3ff578ebe4
--- /dev/null
+++ b/tests/run-make/llvm-location-discriminator-limit-dummy-span/other.rs
@@ -0,0 +1 @@
+proc::declare_big_function!();
diff --git a/tests/run-make/llvm-location-discriminator-limit-dummy-span/proc.rs b/tests/run-make/llvm-location-discriminator-limit-dummy-span/proc.rs
new file mode 100644
index 00000000000..59d17a9be59
--- /dev/null
+++ b/tests/run-make/llvm-location-discriminator-limit-dummy-span/proc.rs
@@ -0,0 +1,7 @@
+extern crate proc_macro;
+use proc_macro::TokenStream;
+
+#[proc_macro]
+pub fn declare_big_function(_input: TokenStream) -> TokenStream {
+    include_str!("./generated.rs").parse().unwrap()
+}
diff --git a/tests/run-make/llvm-location-discriminator-limit-dummy-span/rmake.rs b/tests/run-make/llvm-location-discriminator-limit-dummy-span/rmake.rs
new file mode 100644
index 00000000000..2727effe818
--- /dev/null
+++ b/tests/run-make/llvm-location-discriminator-limit-dummy-span/rmake.rs
@@ -0,0 +1,65 @@
+//! Regression test for <https://github.com/rust-lang/rust/issues/135332>.
+//!
+//! We can't simply drop debuginfo location spans when LLVM's location discriminator value limit is
+//! reached. Otherwise, with `-Z verify-llvm-ir` and fat LTO, LLVM will report a broken module for
+//!
+//! ```text
+//! inlinable function call in a function with debug info must have a !dbg location
+//! ```
+
+//@ ignore-cross-compile
+//@ needs-dynamic-linking
+//@ only-nightly (requires unstable rustc flag)
+
+#![deny(warnings)]
+
+use run_make_support::{dynamic_lib_name, rfs, rust_lib_name, rustc};
+
+// Synthesize a function that will have a large (`n`) number of functions
+// MIR-inlined into it. When combined with a proc-macro, all of these inline
+// callsites will have the same span, forcing rustc to use the DWARF
+// discriminator to distinguish between them. LLVM's capacity to store that
+// discriminator is not infinite (currently it allocates 12 bits for a
+// maximum value of 4096) so if this function gets big enough rustc's error
+// handling path will be exercised.
+fn generate_program(n: u32) -> String {
+    let mut program = String::from("pub type BigType = Vec<Vec<String>>;\n\n");
+    program.push_str("pub fn big_function() -> BigType {\n");
+    program.push_str("    vec![\n");
+    for i in 1..=n {
+        program.push_str(&format!("vec![\"string{}\".to_owned()],\n", i));
+    }
+    program.push_str("    ]\n");
+    program.push_str("}\n");
+    program
+}
+
+fn main() {
+    // The reported threshold is around 1366 (4096/3), but let's bump it to
+    // around 1500 to be less sensitive.
+    rfs::write("generated.rs", generate_program(1500));
+
+    rustc()
+        .input("proc.rs")
+        .crate_type("proc-macro")
+        .edition("2021")
+        .arg("-Cdebuginfo=line-tables-only")
+        .run();
+    rustc()
+        .extern_("proc", dynamic_lib_name("proc"))
+        .input("other.rs")
+        .crate_type("rlib")
+        .edition("2021")
+        .opt_level("3")
+        .arg("-Cdebuginfo=line-tables-only")
+        .run();
+    rustc()
+        .extern_("other", rust_lib_name("other"))
+        .input("main.rs")
+        .edition("2021")
+        .opt_level("3")
+        .arg("-Cdebuginfo=line-tables-only")
+        .arg("-Clto=fat")
+        .arg("-Zverify-llvm-ir")
+        .run();
+}
diff --git a/tests/ui/coherence/occurs-check/associated-type.next.stderr b/tests/ui/coherence/occurs-check/associated-type.next.stderr
index 466b991471e..25f9523f4e4 100644
--- a/tests/ui/coherence/occurs-check/associated-type.next.stderr
+++ b/tests/ui/coherence/occurs-check/associated-type.next.stderr
@@ -1,7 +1,5 @@
  WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [*const ?1t, '^0.Named(DefId(0:27 ~ associated_type[f554]::{impl#3}::'a#1), "'a")], def_id: DefId(0:5 ~ associated_type[f554]::ToUnit::Unit), .. }
  WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [*const ?1t, '^0.Named(DefId(0:27 ~ associated_type[f554]::{impl#3}::'a#1), "'a")], def_id: DefId(0:5 ~ associated_type[f554]::ToUnit::Unit), .. }
- WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [*const ?1t, '^0.Named(DefId(0:27 ~ associated_type[f554]::{impl#3}::'a#1), "'a")], def_id: DefId(0:5 ~ associated_type[f554]::ToUnit::Unit), .. }
- WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [*const ?1t, '^0.Named(DefId(0:27 ~ associated_type[f554]::{impl#3}::'a#1), "'a")], def_id: DefId(0:5 ~ associated_type[f554]::ToUnit::Unit), .. }
 error[E0119]: conflicting implementations of trait `Overlap<for<'a> fn(&'a (), ())>` for type `for<'a> fn(&'a (), ())`
   --> $DIR/associated-type.rs:32:1
    |
diff --git a/tests/ui/coherence/occurs-check/associated-type.old.stderr b/tests/ui/coherence/occurs-check/associated-type.old.stderr
index 1e0345f4ec0..e091ddcacb2 100644
--- a/tests/ui/coherence/occurs-check/associated-type.old.stderr
+++ b/tests/ui/coherence/occurs-check/associated-type.old.stderr
@@ -1,7 +1,5 @@
  WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [*const ?1t, '^0.Named(DefId(0:27 ~ associated_type[f554]::{impl#3}::'a#1), "'a")], def_id: DefId(0:5 ~ associated_type[f554]::ToUnit::Unit), .. }
  WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [*const ?1t, '^0.Named(DefId(0:27 ~ associated_type[f554]::{impl#3}::'a#1), "'a")], def_id: DefId(0:5 ~ associated_type[f554]::ToUnit::Unit), .. }
- WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [*const ?1t, '^0.Named(DefId(0:27 ~ associated_type[f554]::{impl#3}::'a#1), "'a")], def_id: DefId(0:5 ~ associated_type[f554]::ToUnit::Unit), .. }
- WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [*const ?1t, '^0.Named(DefId(0:27 ~ associated_type[f554]::{impl#3}::'a#1), "'a")], def_id: DefId(0:5 ~ associated_type[f554]::ToUnit::Unit), .. }
 error[E0119]: conflicting implementations of trait `Overlap<for<'a> fn(&'a (), ())>` for type `for<'a> fn(&'a (), ())`
   --> $DIR/associated-type.rs:32:1
    |
diff --git a/tests/ui/traits/next-solver/coherence/ambiguity-causes-visitor-hang.rs b/tests/ui/traits/next-solver/coherence/ambiguity-causes-visitor-hang.rs
new file mode 100644
index 00000000000..54854b1b8a5
--- /dev/null
+++ b/tests/ui/traits/next-solver/coherence/ambiguity-causes-visitor-hang.rs
@@ -0,0 +1,56 @@
+// Computing the ambiguity causes for the overlap ended up
+// causing an exponential blowup when recursing into the normalization
+// goals for `<Box<?t> as RecursiveSuper>::Assoc`. This test
+// takes multiple minutes when doing so and less than a second
+// otherwise.
+
+//@ compile-flags: -Znext-solver=coherence
+
+trait RecursiveSuper:
+    Super<
+        A0 = Self::Assoc,
+        A1 = Self::Assoc,
+        A2 = Self::Assoc,
+        A3 = Self::Assoc,
+        A4 = Self::Assoc,
+        A5 = Self::Assoc,
+        A6 = Self::Assoc,
+        A7 = Self::Assoc,
+        A8 = Self::Assoc,
+        A9 = Self::Assoc,
+        A10 = Self::Assoc,
+        A11 = Self::Assoc,
+        A12 = Self::Assoc,
+        A13 = Self::Assoc,
+        A14 = Self::Assoc,
+        A15 = Self::Assoc,
+    >
+{
+    type Assoc;
+}
+
+trait Super {
+    type A0;
+    type A1;
+    type A2;
+    type A3;
+    type A4;
+    type A5;
+    type A6;
+    type A7;
+    type A8;
+    type A9;
+    type A10;
+    type A11;
+    type A12;
+    type A13;
+    type A14;
+    type A15;
+}
+
+trait Overlap {}
+impl<T: RecursiveSuper> Overlap for T {}
+impl<T> Overlap for Box<T> {}
+//~^ ERROR conflicting implementations of trait `Overlap` for type `Box<_>`
+
+fn main() {}
diff --git a/tests/ui/traits/next-solver/coherence/ambiguity-causes-visitor-hang.stderr b/tests/ui/traits/next-solver/coherence/ambiguity-causes-visitor-hang.stderr
new file mode 100644
index 00000000000..3731dc5b74e
--- /dev/null
+++ b/tests/ui/traits/next-solver/coherence/ambiguity-causes-visitor-hang.stderr
@@ -0,0 +1,14 @@
+error[E0119]: conflicting implementations of trait `Overlap` for type `Box<_>`
+  --> $DIR/ambiguity-causes-visitor-hang.rs:53:1
+   |
+LL | impl<T: RecursiveSuper> Overlap for T {}
+   | ------------------------------------- first implementation here
+LL | impl<T> Overlap for Box<T> {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `Box<_>`
+   |
+   = note: downstream crates may implement trait `Super` for type `std::boxed::Box<_>`
+   = note: downstream crates may implement trait `RecursiveSuper` for type `std::boxed::Box<_>`
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0119`.