Rollup of 8 pull requests

RELEASES.md

@@ -1,3 +1,126 @@
+Version 1.86.0 (2025-04-03)
+==========================
+
+<a id="1.86.0-Language"></a>
+
+Language
+--------
+- [Stabilize upcasting trait objects to supertraits.](https://github.com/rust-lang/rust/pull/134367)
+- [Allow safe functions to be marked with the `#[target_feature]` attribute.](https://github.com/rust-lang/rust/pull/134090)
+- [The `missing_abi` lint now warns-by-default.](https://github.com/rust-lang/rust/pull/132397)
+- Rust now lints about double negations, to catch cases that might have intended to be a prefix decrement operator (`--x`) as written in other languages. This was previously a clippy lint, `clippy::double_neg`, and is [now available directly in Rust as `double_negations`.](https://github.com/rust-lang/rust/pull/126604)
+- [More pointers are now detected as definitely not-null based on their alignment in const eval.](https://github.com/rust-lang/rust/pull/133700)
+- [Empty `repr()` attribute applied to invalid items are now correctly rejected.](https://github.com/rust-lang/rust/pull/133925)
+- [Inner attributes `#![test]` and `#![rustfmt::skip]` are no longer accepted in more places than intended.](https://github.com/rust-lang/rust/pull/134276)
+
+<a id="1.86.0-Compiler"></a>
+
+Compiler
+--------
+- [Debug-assert that raw pointers are non-null on access.](https://github.com/rust-lang/rust/pull/134424)
+- [Change `-O` to mean `-C opt-level=3` instead of `-C opt-level=2` to match Cargo's defaults.](https://github.com/rust-lang/rust/pull/135439)
+- [Fix emission of `overflowing_literals` under certain macro environments.](https://github.com/rust-lang/rust/pull/136393)
+
+<a id="1.86.0-Platform-Support"></a>
+
+Platform Support
+----------------
+- [Replace `i686-unknown-redox` target with `i586-unknown-redox`.](https://github.com/rust-lang/rust/pull/136698)
+- [Increase baseline CPU of `i686-unknown-hurd-gnu` to Pentium 4.](https://github.com/rust-lang/rust/pull/136700)
+- New tier 3 targets:
+  - [`{aarch64-unknown,x86_64-pc}-nto-qnx710_iosock`](https://github.com/rust-lang/rust/pull/133631).
+    For supporting Neutrino QNX 7.1 with `io-socket` network stack.
+  - [`{aarch64-unknown,x86_64-pc}-nto-qnx800`](https://github.com/rust-lang/rust/pull/133631).
+    For supporting Neutrino QNX 8.0 (`no_std`-only).
+  - [`{x86_64,i686}-win7-windows-gnu`](https://github.com/rust-lang/rust/pull/134609).
+    Intended for backwards compatibility with Windows 7. `{x86_64,i686}-win7-windows-msvc` are the Windows MSVC counterparts that already exist as Tier 3 targets.
+  - [`amdgcn-amd-amdhsa`](https://github.com/rust-lang/rust/pull/134740).
+  - [`x86_64-pc-cygwin`](https://github.com/rust-lang/rust/pull/134999).
+  - [`{mips,mipsel}-mti-none-elf`](https://github.com/rust-lang/rust/pull/135074).
+    Initial bare-metal support.
+  - [`m68k-unknown-none-elf`](https://github.com/rust-lang/rust/pull/135085).
+  - [`armv7a-nuttx-{eabi,eabihf}`, `aarch64-unknown-nuttx`, and `thumbv7a-nuttx-{eabi,eabihf}`](https://github.com/rust-lang/rust/pull/135757).
+
+Refer to Rust's [platform support page][platform-support-doc]
+for more information on Rust's tiered platform support.
+
+<a id="1.86.0-Libraries"></a>
+
+Libraries
+---------
+- The type of `FromBytesWithNulError` in `CStr::from_bytes_with_nul(bytes: &[u8]) -> Result<&Self, FromBytesWithNulError>` was [changed from an opaque struct to an enum](https://github.com/rust-lang/rust/pull/134143), allowing users to examine why the conversion failed.
+- [Remove `RustcDecodable` and `RustcEncodable`.](https://github.com/rust-lang/rust/pull/134272)
+- [Deprecate libtest's `--logfile` option.](https://github.com/rust-lang/rust/pull/134283)
+- [On recent versions of Windows, `std::fs::remove_file` will now remove read-only files.](https://github.com/rust-lang/rust/pull/134679)
+
+<a id="1.86.0-Stabilized-APIs"></a>
+
+Stabilized APIs
+---------------
+
+- [`{float}::next_down`](https://doc.rust-lang.org/stable/std/primitive.f64.html#method.next_down)
+- [`{float}::next_up`](https://doc.rust-lang.org/stable/std/primitive.f64.html#method.next_up)
+- [`<[_]>::get_disjoint_mut`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.get_disjoint_mut)
+- [`<[_]>::get_disjoint_unchecked_mut`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.get_disjoint_unchecked_mut)
+- [`slice::GetDisjointMutError`](https://doc.rust-lang.org/stable/std/slice/enum.GetDisjointMutError.html)
+- [`HashMap::get_disjoint_mut`](https://doc.rust-lang.org/std/collections/hash_map/struct.HashMap.html#method.get_disjoint_mut)
+- [`HashMap::get_disjoint_unchecked_mut`](https://doc.rust-lang.org/std/collections/hash_map/struct.HashMap.html#method.get_disjoint_unchecked_mut)
+- [`NonZero::count_ones`](https://doc.rust-lang.org/stable/std/num/struct.NonZero.html#method.count_ones)
+- [`Vec::pop_if`](https://doc.rust-lang.org/std/vec/struct.Vec.html#method.pop_if)
+- [`sync::Once::wait`](https://doc.rust-lang.org/stable/std/sync/struct.Once.html#method.wait)
+- [`sync::Once::wait_force`](https://doc.rust-lang.org/stable/std/sync/struct.Once.html#method.wait_force)
+- [`sync::OnceLock::wait`](https://doc.rust-lang.org/stable/std/sync/struct.OnceLock.html#method.wait)
+
+These APIs are now stable in const contexts:
+
+- [`hint::black_box`](https://doc.rust-lang.org/stable/std/hint/fn.black_box.html)
+- [`io::Cursor::get_mut`](https://doc.rust-lang.org/stable/std/io/struct.Cursor.html#method.get_mut)
+- [`io::Cursor::set_position`](https://doc.rust-lang.org/stable/std/io/struct.Cursor.html#method.set_position)
+- [`str::is_char_boundary`](https://doc.rust-lang.org/stable/std/primitive.str.html#method.is_char_boundary)
+- [`str::split_at`](https://doc.rust-lang.org/stable/std/primitive.str.html#method.split_at)
+- [`str::split_at_checked`](https://doc.rust-lang.org/stable/std/primitive.str.html#method.split_at_checked)
+- [`str::split_at_mut`](https://doc.rust-lang.org/stable/std/primitive.str.html#method.split_at_mut)
+- [`str::split_at_mut_checked`](https://doc.rust-lang.org/stable/std/primitive.str.html#method.split_at_mut_checked)
+
+<a id="1.86.0-Cargo"></a>
+
+Cargo
+-----
+- [When merging, replace rather than combine configuration keys that refer to a program path and its arguments.](https://github.com/rust-lang/cargo/pull/15066/)
+- [Error if both `--package` and `--workspace` are passed but the requested package is missing.](https://github.com/rust-lang/cargo/pull/15071/) This was previously silently ignored, which was considered a bug since missing packages should be reported.
+- [Deprecate the token argument in `cargo login` to avoid shell history leaks.](https://github.com/rust-lang/cargo/pull/15057/)
+- [Simplify the implementation of `SourceID` comparisons.](https://github.com/rust-lang/cargo/pull/14980/) This may potentially change behavior if the canonicalized URL compares differently in alternative registries.
+
+<a id="1.86.0-Rustdoc"></a>
+
+Rustdoc
+-----
+- [Add a sans-serif font setting.](https://github.com/rust-lang/rust/pull/133636)
+
+<a id="1.86.0-Compatibility-Notes"></a>
+
+Compatibility Notes
+-------------------
+- [The `wasm_c_abi` future compatibility warning is now a hard error.](https://github.com/rust-lang/rust/pull/133951)
+  Users of `wasm-bindgen` should upgrade to at least version 0.2.89, otherwise compilation will fail.
+- [Remove long-deprecated no-op attributes `#![no_start]` and `#![crate_id]`.](https://github.com/rust-lang/rust/pull/134300)
+- [The future incompatibility lint `cenum_impl_drop_cast` has been made into a hard error.](https://github.com/rust-lang/rust/pull/135964) This means it is now an error to cast a field-less enum to an integer if the enum implements `Drop`.
+- [SSE2 is now required for "i686" 32-bit x86 hard-float targets; disabling it causes a warning that will become a hard error eventually.](https://github.com/rust-lang/rust/pull/137037)
+  To compile for pre-SSE2 32-bit x86, use a "i586" target instead.
+
+<a id="1.86.0-Internal-Changes"></a>
+
+Internal Changes
+----------------
+
+These changes do not affect any public interfaces of Rust, but they represent
+significant improvements to the performance or internals of rustc and related
+tools.
+
+- [Build the rustc on AArch64 Linux with ThinLTO + PGO.](https://github.com/rust-lang/rust/pull/133807)
+  The ARM 64-bit compiler (AArch64) on Linux is now optimized with ThinLTO and PGO, similar to the optimizations we have already performed for the x86-64 compiler on Linux. This should make it up to 30% faster.
+
+
 Version 1.85.1 (2025-03-18)
 ==========================
 

compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp

@@ -855,10 +855,15 @@ extern "C" LLVMRustResult LLVMRustOptimize(
   }
 
   if (LintIR) {
-    PipelineStartEPCallbacks.push_back(
-        [](ModulePassManager &MPM, OptimizationLevel Level) {
-          MPM.addPass(createModuleToFunctionPassAdaptor(LintPass()));
-        });
+    PipelineStartEPCallbacks.push_back([](ModulePassManager &MPM,
+                                          OptimizationLevel Level) {
+#if LLVM_VERSION_GE(21, 0)
+      MPM.addPass(
+          createModuleToFunctionPassAdaptor(LintPass(/*AbortOnError=*/true)));
+#else
+      MPM.addPass(createModuleToFunctionPassAdaptor(LintPass()));
+#endif
+    });
   }
 
   if (InstrumentCoverage) {

compiler/rustc_middle/src/ty/consts/valtree.rs

@@ -33,7 +33,7 @@ pub enum ValTreeKind<'tcx> {
     /// The fields of any kind of aggregate. Structs, tuples and arrays are represented by
     /// listing their fields' values in order.
     ///
-    /// Enums are represented by storing their discriminant as a field, followed by all
+    /// Enums are represented by storing their variant index as a u32 field, followed by all
     /// the fields of the variant.
     ///
     /// ZST types are represented as an empty slice.

compiler/rustc_mir_transform/src/coroutine/by_move_body.rs

@@ -219,6 +219,8 @@ pub(crate) fn coroutine_by_move_body_def_id<'tcx>(
         mir::MirSource::from_instance(InstanceKind::Item(body_def.def_id().to_def_id()));
     dump_mir(tcx, false, "built", &"after", &by_move_body, |_, _| Ok(()));
 
+    // Feed HIR because we try to access this body's attrs in the inliner.
+    body_def.feed_hir();
     // Inherited from the by-ref coroutine.
     body_def.codegen_fn_attrs(tcx.codegen_fn_attrs(coroutine_def_id).clone());
     body_def.coverage_attr_on(tcx.coverage_attr_on(coroutine_def_id));

compiler/rustc_resolve/src/diagnostics.rs

@@ -1325,11 +1325,6 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             })
         }
 
-        // If only some candidates are accessible, take just them
-        if !candidates.iter().all(|v: &ImportSuggestion| !v.accessible) {
-            candidates.retain(|x| x.accessible)
-        }
-
         candidates
     }
 
@@ -1793,7 +1788,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                 &import_suggestions,
                 Instead::Yes,
                 FoundUse::Yes,
-                DiagMode::Import { append: single_nested },
+                DiagMode::Import { append: single_nested, unresolved_import: false },
                 vec![],
                 "",
             );
@@ -2750,6 +2745,8 @@ pub(crate) enum DiagMode {
     Pattern,
     /// The binding is part of a use statement
     Import {
+        /// `true` means diagnostics is for unresolved import
+        unresolved_import: bool,
         /// `true` mean add the tips afterward for case `use a::{b,c}`,
         /// rather than replacing within.
         append: bool,
@@ -2800,6 +2797,7 @@ fn show_candidates(
         return false;
     }
 
+    let mut showed = false;
     let mut accessible_path_strings: Vec<PathString<'_>> = Vec::new();
     let mut inaccessible_path_strings: Vec<PathString<'_>> = Vec::new();
 
@@ -2958,8 +2956,11 @@ fn show_candidates(
             append_candidates(&mut msg, accessible_path_strings);
             err.help(msg);
         }
-        true
-    } else if !(inaccessible_path_strings.is_empty() || matches!(mode, DiagMode::Import { .. })) {
+        showed = true;
+    }
+    if !inaccessible_path_strings.is_empty()
+        && (!matches!(mode, DiagMode::Import { unresolved_import: false, .. }))
+    {
         let prefix =
             if let DiagMode::Pattern = mode { "you might have meant to match on " } else { "" };
         if let [(name, descr, source_span, note, _)] = &inaccessible_path_strings[..] {
@@ -3022,10 +3023,9 @@ fn show_candidates(
 
             err.span_note(multi_span, msg);
         }
-        true
-    } else {
-        false
+        showed = true;
     }
+    showed
 }
 
 #[derive(Debug)]

compiler/rustc_resolve/src/imports.rs

@@ -734,7 +734,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                         &mut diag,
                         Some(err.span),
                         candidates,
-                        DiagMode::Import { append: false },
+                        DiagMode::Import { append: false, unresolved_import: true },
                         (source != target)
                             .then(|| format!(" as {target}"))
                             .as_deref()

compiler/rustc_trait_selection/src/traits/effects.rs

@@ -106,10 +106,6 @@ fn match_candidate<'tcx>(
 
     more_nested(selcx, &mut nested);
 
-    for nested in &mut nested {
-        nested.set_depth_from_parent(obligation.recursion_depth);
-    }
-
     Ok(nested)
 }
 
@@ -378,10 +374,6 @@ fn evaluate_host_effect_from_selection_candiate<'tcx>(
                             }),
                     );
 
-                    for nested in &mut nested {
-                        nested.set_depth_from_parent(obligation.recursion_depth);
-                    }
-
                     Ok(nested)
                 }
                 _ => Err(EvaluationFailure::NoSolution),

compiler/rustc_trait_selection/src/traits/fulfill.rs

@@ -225,9 +225,15 @@ struct FulfillProcessor<'a, 'tcx> {
     selcx: SelectionContext<'a, 'tcx>,
 }
 
-fn mk_pending<'tcx>(os: PredicateObligations<'tcx>) -> PendingPredicateObligations<'tcx> {
+fn mk_pending<'tcx>(
+    parent: &PredicateObligation<'tcx>,
+    os: PredicateObligations<'tcx>,
+) -> PendingPredicateObligations<'tcx> {
     os.into_iter()
-        .map(|o| PendingPredicateObligation { obligation: o, stalled_on: vec![] })
+        .map(|mut o| {
+            o.set_depth_from_parent(parent.recursion_depth);
+            PendingPredicateObligation { obligation: o, stalled_on: vec![] }
+        })
         .collect()
 }
 
@@ -341,7 +347,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
             );
             if predicate != obligation.predicate {
                 obligations.push(obligation.with(infcx.tcx, predicate));
-                return ProcessResult::Changed(mk_pending(obligations));
+                return ProcessResult::Changed(mk_pending(obligation, obligations));
             }
         }
         let binder = obligation.predicate.kind();
@@ -385,7 +391,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                     let mut obligations = PredicateObligations::with_capacity(1);
                     obligations.push(obligation.with(infcx.tcx, pred));
 
-                    ProcessResult::Changed(mk_pending(obligations))
+                    ProcessResult::Changed(mk_pending(obligation, obligations))
                 }
                 ty::PredicateKind::Ambiguous => ProcessResult::Unchanged,
                 ty::PredicateKind::NormalizesTo(..) => {
@@ -410,6 +416,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                     let host_obligation = obligation.with(infcx.tcx, data);
 
                     self.process_host_obligation(
+                        obligation,
                         host_obligation,
                         &mut pending_obligation.stalled_on,
                     )
@@ -486,7 +493,10 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                         // `<lhs_ty as Add<rhs_ty>>::Output` when this is an `Expr` representing
                         // `lhs + rhs`.
                         ty::ConstKind::Expr(_) => {
-                            return ProcessResult::Changed(mk_pending(PredicateObligations::new()));
+                            return ProcessResult::Changed(mk_pending(
+                                obligation,
+                                PredicateObligations::new(),
+                            ));
                         }
                         ty::ConstKind::Placeholder(_) => {
                             bug!("placeholder const {:?} in old solver", ct)
@@ -503,7 +513,10 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                         ct_ty,
                         ty,
                     ) {
-                        Ok(inf_ok) => ProcessResult::Changed(mk_pending(inf_ok.into_obligations())),
+                        Ok(inf_ok) => ProcessResult::Changed(mk_pending(
+                            obligation,
+                            inf_ok.into_obligations(),
+                        )),
                         Err(_) => ProcessResult::Error(FulfillmentErrorCode::Select(
                             SelectionError::ConstArgHasWrongType { ct, ct_ty, expected_ty: ty },
                         )),
@@ -537,7 +550,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                                 vec![TyOrConstInferVar::maybe_from_generic_arg(arg).unwrap()];
                             ProcessResult::Unchanged
                         }
-                        Some(os) => ProcessResult::Changed(mk_pending(os)),
+                        Some(os) => ProcessResult::Changed(mk_pending(obligation, os)),
                     }
                 }
 
@@ -553,11 +566,8 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                                 vec![TyOrConstInferVar::Ty(a), TyOrConstInferVar::Ty(b)];
                             ProcessResult::Unchanged
                         }
-                        Ok(Ok(mut ok)) => {
-                            for subobligation in &mut ok.obligations {
-                                subobligation.set_depth_from_parent(obligation.recursion_depth);
-                            }
-                            ProcessResult::Changed(mk_pending(ok.obligations))
+                        Ok(Ok(ok)) => {
+                            ProcessResult::Changed(mk_pending(obligation, ok.obligations))
                         }
                         Ok(Err(err)) => {
                             let expected_found = if subtype.a_is_expected {
@@ -582,7 +592,9 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                                 vec![TyOrConstInferVar::Ty(a), TyOrConstInferVar::Ty(b)];
                             ProcessResult::Unchanged
                         }
-                        Ok(Ok(ok)) => ProcessResult::Changed(mk_pending(ok.obligations)),
+                        Ok(Ok(ok)) => {
+                            ProcessResult::Changed(mk_pending(obligation, ok.obligations))
+                        }
                         Ok(Err(err)) => {
                             let expected_found = ExpectedFound::new(coerce.b, coerce.a);
                             ProcessResult::Error(FulfillmentErrorCode::Subtype(expected_found, err))
@@ -645,6 +657,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                                     )
                                 {
                                     return ProcessResult::Changed(mk_pending(
+                                        obligation,
                                         new_obligations.into_obligations(),
                                     ));
                                 }
@@ -659,6 +672,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                                     .eq(DefineOpaqueTypes::Yes, c1, c2)
                                 {
                                     return ProcessResult::Changed(mk_pending(
+                                        obligation,
                                         new_obligations.into_obligations(),
                                     ));
                                 }
@@ -704,9 +718,10 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                                 c1,
                                 c2,
                             ) {
-                                Ok(inf_ok) => {
-                                    ProcessResult::Changed(mk_pending(inf_ok.into_obligations()))
-                                }
+                                Ok(inf_ok) => ProcessResult::Changed(mk_pending(
+                                    obligation,
+                                    inf_ok.into_obligations(),
+                                )),
                                 Err(err) => {
                                     ProcessResult::Error(FulfillmentErrorCode::ConstEquate(
                                         ExpectedFound::new(c1, c2),
@@ -790,7 +805,7 @@ impl<'a, 'tcx> FulfillProcessor<'a, 'tcx> {
         match self.selcx.poly_select(&trait_obligation) {
             Ok(Some(impl_source)) => {
                 debug!("selecting trait at depth {} yielded Ok(Some)", obligation.recursion_depth);
-                ProcessResult::Changed(mk_pending(impl_source.nested_obligations()))
+                ProcessResult::Changed(mk_pending(obligation, impl_source.nested_obligations()))
             }
             Ok(None) => {
                 debug!("selecting trait at depth {} yielded Ok(None)", obligation.recursion_depth);
@@ -854,7 +869,7 @@ impl<'a, 'tcx> FulfillProcessor<'a, 'tcx> {
         }
 
         match project::poly_project_and_unify_term(&mut self.selcx, &project_obligation) {
-            ProjectAndUnifyResult::Holds(os) => ProcessResult::Changed(mk_pending(os)),
+            ProjectAndUnifyResult::Holds(os) => ProcessResult::Changed(mk_pending(obligation, os)),
             ProjectAndUnifyResult::FailedNormalization => {
                 stalled_on.clear();
                 stalled_on.extend(args_infer_vars(
@@ -868,7 +883,7 @@ impl<'a, 'tcx> FulfillProcessor<'a, 'tcx> {
                 let mut obligations = PredicateObligations::with_capacity(1);
                 obligations.push(project_obligation.with(tcx, project_obligation.predicate));
 
-                ProcessResult::Changed(mk_pending(obligations))
+                ProcessResult::Changed(mk_pending(obligation, obligations))
             }
             ProjectAndUnifyResult::MismatchedProjectionTypes(e) => {
                 ProcessResult::Error(FulfillmentErrorCode::Project(e))
@@ -878,11 +893,12 @@ impl<'a, 'tcx> FulfillProcessor<'a, 'tcx> {
 
     fn process_host_obligation(
         &mut self,
+        obligation: &PredicateObligation<'tcx>,
         host_obligation: HostEffectObligation<'tcx>,
         stalled_on: &mut Vec<TyOrConstInferVar>,
     ) -> ProcessResult<PendingPredicateObligation<'tcx>, FulfillmentErrorCode<'tcx>> {
         match effects::evaluate_host_effect_obligation(&mut self.selcx, &host_obligation) {
-            Ok(nested) => ProcessResult::Changed(mk_pending(nested)),
+            Ok(nested) => ProcessResult::Changed(mk_pending(obligation, nested)),
             Err(effects::EvaluationFailure::Ambiguous) => {
                 stalled_on.clear();
                 stalled_on.extend(args_infer_vars(

compiler/rustc_trait_selection/src/traits/select/confirmation.rs

@@ -39,7 +39,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         obligation: &PolyTraitObligation<'tcx>,
         candidate: SelectionCandidate<'tcx>,
     ) -> Result<Selection<'tcx>, SelectionError<'tcx>> {
-        let mut impl_src = match candidate {
+        Ok(match candidate {
             SizedCandidate { has_nested } => {
                 let data = self.confirm_builtin_candidate(obligation, has_nested);
                 ImplSource::Builtin(BuiltinImplSource::Misc, data)
@@ -139,15 +139,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             BikeshedGuaranteedNoDropCandidate => {
                 self.confirm_bikeshed_guaranteed_no_drop_candidate(obligation)
             }
-        };
-
-        // The obligations returned by confirmation are recursively evaluated
-        // so we need to make sure they have the correct depth.
-        for subobligation in impl_src.borrow_nested_obligations_mut() {
-            subobligation.set_depth_from_parent(obligation.recursion_depth);
-        }
-
-        Ok(impl_src)
+        })
     }
 
     fn confirm_projection_candidate(

tests/codegen/cast-target-abi.rs

@@ -2,7 +2,7 @@
 //@ add-core-stubs
 //@ revisions:aarch64 loongarch64 powerpc64 sparc64 x86_64
 //@ min-llvm-version: 19
-//@ compile-flags: -Copt-level=3 -Cno-prepopulate-passes -Zlint-llvm-ir -Cllvm-args=-lint-abort-on-error
+//@ compile-flags: -Copt-level=3 -Cno-prepopulate-passes -Zlint-llvm-ir
 
 //@[aarch64] compile-flags: --target aarch64-unknown-linux-gnu
 //@[aarch64] needs-llvm-components: arm

tests/codegen/cffi/ffi-out-of-bounds-loads.rs

@@ -1,7 +1,7 @@
 //@ add-core-stubs
 //@ revisions: linux apple
 //@ min-llvm-version: 19
-//@ compile-flags: -Copt-level=0 -Cno-prepopulate-passes -Zlint-llvm-ir -Cllvm-args=-lint-abort-on-error
+//@ compile-flags: -Copt-level=0 -Cno-prepopulate-passes -Zlint-llvm-ir
 
 //@[linux] compile-flags: --target x86_64-unknown-linux-gnu
 //@[linux] needs-llvm-components: x86

tests/codegen/slice-last-elements-optimization.rs

@@ -0,0 +1,37 @@
+//@ compile-flags: -Copt-level=3
+//@ only-x86_64
+//@ min-llvm-version: 20
+#![crate_type = "lib"]
+
+// This test verifies that LLVM 20 properly optimizes the bounds check
+// when accessing the last few elements of a slice with proper conditions.
+// Previously, this would generate an unreachable branch to
+// slice_start_index_len_fail even when the bounds check was provably safe.
+
+// CHECK-LABEL: @last_four_initial(
+#[no_mangle]
+pub fn last_four_initial(s: &[u8]) -> &[u8] {
+    // Previously this would generate a branch to slice_start_index_len_fail
+    // that is unreachable. The LLVM 20 fix should eliminate this branch.
+    // CHECK-NOT: slice_start_index_len_fail
+    // CHECK-NOT: unreachable
+    let start = if s.len() <= 4 { 0 } else { s.len() - 4 };
+    &s[start..]
+}
+
+// CHECK-LABEL: @last_four_optimized(
+#[no_mangle]
+pub fn last_four_optimized(s: &[u8]) -> &[u8] {
+    // This version was already correctly optimized before the fix in LLVM 20.
+    // CHECK-NOT: slice_start_index_len_fail
+    // CHECK-NOT: unreachable
+    if s.len() <= 4 { &s[0..] } else { &s[s.len() - 4..] }
+}
+
+// Just to verify we're correctly checking for the right thing
+// CHECK-LABEL: @test_bounds_check_happens(
+#[no_mangle]
+pub fn test_bounds_check_happens(s: &[u8], i: usize) -> &[u8] {
+    // CHECK: slice_start_index_len_fail
+    &s[i..]
+}

tests/rustdoc-json/attrs/automatically_derived.rs

@@ -0,0 +1,13 @@
+#[derive(Default)]
+pub struct Derive;
+
+pub struct Manual;
+
+impl Default for Manual {
+    fn default() -> Self {
+        Self
+    }
+}
+
+//@ is '$.index[?(@.inner.impl.for.resolved_path.path == "Derive" && @.inner.impl.trait.path == "Default")].attrs' '["#[automatically_derived]"]'
+//@ is '$.index[?(@.inner.impl.for.resolved_path.path == "Manual" && @.inner.impl.trait.path == "Default")].attrs' '[]'

tests/ui/async-await/async-closures/by-move-body-inlined-attrs.rs

@@ -0,0 +1,28 @@
+//@ check-pass
+//@ compile-flags: -Zinline-mir -Zvalidate-mir
+//@ edition: 2024
+
+// See comment below.
+
+use std::future::Future;
+use std::pin::pin;
+use std::task::{Context, Waker};
+
+fn call_once<T>(f: impl FnOnce() -> T) -> T { f() }
+
+fn main() {
+    let x = async || {};
+    // We first inline `call_once<{async closure}>`.
+    //
+    // This gives us a future whose type is the "FnOnce" flavor of the async closure's
+    // child coroutine. The body of this coroutine is synthetic, which we synthesize in
+    // the by-move body query.
+    let fut = pin!(call_once(x));
+    // We then try to inline that body in this poll call.
+    //
+    // The inliner does some inlinability checks; one of these checks involves checking
+    // the body for the `#[rustc_no_mir_inline]` attribute. Since the synthetic body had
+    // no HIR synthesized, but it's still a local def id, we end up ICEing in the
+    // `local_def_id_to_hir_id` call when trying to read its attrs.
+    fut.poll(&mut Context::from_waker(Waker::noop()));
+}

tests/ui/imports/glob-resolve1.stderr

@@ -58,6 +58,11 @@ error[E0425]: cannot find function `import` in this scope
 LL |     import();
    |     ^^^^^^ not found in this scope
    |
+note: function `bar::import` exists but is inaccessible
+  --> $DIR/glob-resolve1.rs:7:5
+   |
+LL |     fn fpriv() {}
+   |     ^^^^^^^^^^ not accessible
 help: consider importing this function
    |
 LL + use other::import;

tests/ui/imports/issue-4366-2.stderr

@@ -16,6 +16,11 @@ error[E0423]: expected function, found module `foo`
 LL |     foo();
    |     ^^^ not a function
    |
+note: function `m1::foo` exists but is inaccessible
+  --> $DIR/issue-4366-2.rs:21:5
+   |
+LL |     fn foo() {}
+   |     ^^^^^^^^ not accessible
 help: consider importing this function instead
    |
 LL + use foo::foo;

tests/ui/imports/issue-4366.stderr

@@ -4,6 +4,11 @@ error[E0425]: cannot find function `foo` in this scope
 LL |         fn sub() -> isize { foo(); 1 }
    |                             ^^^ not found in this scope
    |
+note: function `m1::foo` exists but is inaccessible
+  --> $DIR/issue-4366.rs:23:5
+   |
+LL |     fn foo() {}
+   |     ^^^^^^^^ not accessible
 help: consider importing this function
    |
 LL +         use foo::foo;

tests/ui/imports/show-private-items-issue-138626.rs

@@ -0,0 +1,19 @@
+pub mod one {
+    mod foo {
+        pub struct Foo;
+    }
+
+    pub use self::foo::Foo;
+}
+
+pub mod two {
+    mod foo {
+        mod bar {
+            pub struct Foo;
+        }
+    }
+
+    pub use crate::two::foo::Foo; //~ ERROR unresolved import `crate::two::foo::Foo` [E0432]
+}
+
+fn main() {}

tests/ui/imports/show-private-items-issue-138626.stderr

@@ -0,0 +1,20 @@
+error[E0432]: unresolved import `crate::two::foo::Foo`
+  --> $DIR/show-private-items-issue-138626.rs:16:13
+   |
+LL |     pub use crate::two::foo::Foo;
+   |             ^^^^^^^^^^^^^^^^^^^^ no `Foo` in `two::foo`
+   |
+note: struct `two::foo::bar::Foo` exists but is inaccessible
+  --> $DIR/show-private-items-issue-138626.rs:12:13
+   |
+LL |             pub struct Foo;
+   |             ^^^^^^^^^^^^^^^ not accessible
+help: consider importing this struct through its public re-export instead
+   |
+LL -     pub use crate::two::foo::Foo;
+LL +     pub use one::Foo;
+   |
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0432`.

tests/ui/infinite/infinite-autoderef.stderr

@@ -1,8 +1,8 @@
 error[E0275]: overflow assigning `Box<_>` to `_`
-  --> $DIR/infinite-autoderef.rs:16:13
+  --> $DIR/infinite-autoderef.rs:16:22
    |
 LL |         x = Box::new(x);
-   |             ^^^^^^^^^^^
+   |                      ^
 
 error: aborting due to 1 previous error
 

tests/ui/occurs-check-2.rs

@@ -4,6 +4,6 @@ fn main() {
     let g;
 
     g = f;
-    f = Box::new(g);
     //~^ ERROR overflow assigning `Box<_>` to `_`
+    f = Box::new(g);
 }

tests/ui/occurs-check-2.stderr

@@ -1,8 +1,8 @@
 error[E0275]: overflow assigning `Box<_>` to `_`
-  --> $DIR/occurs-check-2.rs:7:9
+  --> $DIR/occurs-check-2.rs:6:9
    |
-LL |     f = Box::new(g);
-   |         ^^^^^^^^^^^
+LL |     g = f;
+   |         ^
 
 error: aborting due to 1 previous error
 

tests/ui/occurs-check-3.stderr

@@ -1,8 +1,8 @@
 error[E0275]: overflow assigning `Clam<_>` to `_`
-  --> $DIR/occurs-check-3.rs:6:9
+  --> $DIR/occurs-check-3.rs:6:17
    |
 LL |     c = Clam::A(c);
-   |         ^^^^^^^^^^
+   |                 ^
 
 error: aborting due to 1 previous error
 

tests/ui/occurs-check.stderr

@@ -1,8 +1,8 @@
 error[E0275]: overflow assigning `Box<_>` to `_`
-  --> $DIR/occurs-check.rs:3:9
+  --> $DIR/occurs-check.rs:3:18
    |
 LL |     f = Box::new(f);
-   |         ^^^^^^^^^^^
+   |                  ^
 
 error: aborting due to 1 previous error
 

tests/ui/privacy/privacy-ns1.stderr

@@ -7,6 +7,14 @@ LL |     pub struct Baz;
 LL |     Bar();
    |     ^^^
    |
+note: these functions exist but are inaccessible
+  --> $DIR/privacy-ns1.rs:14:5
+   |
+LL |     fn Bar() { }
+   |     ^^^^^^^^ `foo1::Bar`: not accessible
+...
+LL |     fn Bar() { }
+   |     ^^^^^^^^ `foo3::Bar`: not accessible
 help: a unit struct with a similar name exists
    |
 LL -     Bar();
@@ -26,6 +34,14 @@ LL |     pub struct Baz;
 LL |     Bar();
    |     ^^^
    |
+note: these functions exist but are inaccessible
+  --> $DIR/privacy-ns1.rs:14:5
+   |
+LL |     fn Bar() { }
+   |     ^^^^^^^^ `foo1::Bar`: not accessible
+...
+LL |     fn Bar() { }
+   |     ^^^^^^^^ `foo3::Bar`: not accessible
 help: a unit struct with a similar name exists
    |
 LL -     Bar();
@@ -45,6 +61,14 @@ LL |     pub struct Baz;
 LL |     let _x: Box<Bar>;
    |                 ^^^
    |
+note: these traits exist but are inaccessible
+  --> $DIR/privacy-ns1.rs:25:5
+   |
+LL |     trait Bar {
+   |     ^^^^^^^^^ `foo2::Bar`: not accessible
+...
+LL |     trait Bar {
+   |     ^^^^^^^^^ `foo3::Bar`: not accessible
 help: a struct with a similar name exists
    |
 LL -     let _x: Box<Bar>;

tests/ui/privacy/privacy-ns2.stderr

@@ -4,6 +4,14 @@ error[E0423]: expected function, tuple struct or tuple variant, found trait `Bar
 LL |     Bar();
    |     ^^^ not a function, tuple struct or tuple variant
    |
+note: these functions exist but are inaccessible
+  --> $DIR/privacy-ns2.rs:14:5
+   |
+LL |     fn Bar() { }
+   |     ^^^^^^^^ `foo1::Bar`: not accessible
+...
+LL |     fn Bar() { }
+   |     ^^^^^^^^ `foo3::Bar`: not accessible
 help: consider importing this function instead
    |
 LL + use foo2::Bar;
@@ -18,6 +26,14 @@ LL |     pub struct Baz;
 LL |     Bar();
    |     ^^^
    |
+note: these functions exist but are inaccessible
+  --> $DIR/privacy-ns2.rs:14:5
+   |
+LL |     fn Bar() { }
+   |     ^^^^^^^^ `foo1::Bar`: not accessible
+...
+LL |     fn Bar() { }
+   |     ^^^^^^^^ `foo3::Bar`: not accessible
 help: a unit struct with a similar name exists
    |
 LL -     Bar();
@@ -34,6 +50,14 @@ error[E0573]: expected type, found function `Bar`
 LL |     let _x : Bar();
    |              ^^^^^ not a type
    |
+note: these traits exist but are inaccessible
+  --> $DIR/privacy-ns2.rs:31:5
+   |
+LL |     trait Bar {
+   |     ^^^^^^^^^ `foo2::Bar`: not accessible
+...
+LL |     trait Bar {
+   |     ^^^^^^^^^ `foo3::Bar`: not accessible
 help: use `=` if you meant to assign
    |
 LL -     let _x : Bar();

tests/ui/resolve/issue-21221-1.stderr

@@ -19,6 +19,17 @@ error[E0412]: cannot find type `Mul` in this scope
 LL | fn getMul() -> Mul {
    |                ^^^ not found in this scope
    |
+note: these items exist but are inaccessible
+  --> $DIR/issue-21221-1.rs:10:5
+   |
+LL |     enum Mul {
+   |     ^^^^^^^^ `mul3::Mul`: not accessible
+...
+LL |     type Mul = String;
+   |     ^^^^^^^^^^^^^^^^^^ `mul4::Mul`: not accessible
+...
+LL |     struct Mul{
+   |     ^^^^^^^^^^ `mul5::Mul`: not accessible
 help: consider importing one of these traits
    |
 LL + use std::ops::Mul;

tests/ui/traits/mutual-recursion-issue-75860.stderr

@@ -2,7 +2,7 @@ error[E0275]: overflow assigning `_` to `Option<_>`
   --> $DIR/mutual-recursion-issue-75860.rs:9:33
    |
 LL |     let left = |o_a: Option<_>| o_a.unwrap();
-   |                                 ^^^
+   |                                 ^^^^^^^^^^^^
 
 error: aborting due to 1 previous error
 

tests/ui/type-alias-impl-trait/type-alias-impl-trait-with-cycle-error-1.rs

@@ -1,9 +1,10 @@
 #![feature(type_alias_impl_trait)]
-//@ known-bug: #109268
 
 type Foo = impl Fn() -> Foo;
 
+#[define_opaque(Foo)]
 fn crash(x: Foo) -> Foo {
+    //~^ ERROR overflow evaluating the requirement `<Foo as FnOnce<()>>::Output == Foo`
     x
 }
 

tests/ui/type-alias-impl-trait/type-alias-impl-trait-with-cycle-error-1.stderr

@@ -1,10 +1,9 @@
-error: unconstrained opaque type
-  --> $DIR/type-alias-impl-trait-with-cycle-error-1.rs:4:12
+error[E0275]: overflow evaluating the requirement `<Foo as FnOnce<()>>::Output == Foo`
+  --> $DIR/type-alias-impl-trait-with-cycle-error-1.rs:6:21
    |
-LL | type Foo = impl Fn() -> Foo;
-   |            ^^^^^^^^^^^^^^^^
-   |
-   = note: `Foo` must be used in combination with a concrete type within the same crate
+LL | fn crash(x: Foo) -> Foo {
+   |                     ^^^
 
 error: aborting due to 1 previous error
 
+For more information about this error, try `rustc --explain E0275`.

tests/ui/type-alias-impl-trait/type-alias-impl-trait-with-cycle-error-2.rs

@@ -1,13 +1,13 @@
 #![feature(type_alias_impl_trait)]
-//@ known-bug: #109268
 
 pub trait Bar<T> {
     type Item;
 }
 
 type Foo = impl Bar<Foo, Item = Foo>;
-
+#[define_opaque(Foo)]
 fn crash(x: Foo) -> Foo {
+    //~^ ERROR overflow evaluating the requirement `<Foo as Bar<Foo>>::Item == Foo`
     x
 }
 

tests/ui/type-alias-impl-trait/type-alias-impl-trait-with-cycle-error-2.stderr

@@ -1,10 +1,9 @@
-error: unconstrained opaque type
-  --> $DIR/type-alias-impl-trait-with-cycle-error-2.rs:8:12
+error[E0275]: overflow evaluating the requirement `<Foo as Bar<Foo>>::Item == Foo`
+  --> $DIR/type-alias-impl-trait-with-cycle-error-2.rs:9:21
    |
-LL | type Foo = impl Bar<Foo, Item = Foo>;
-   |            ^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: `Foo` must be used in combination with a concrete type within the same crate
+LL | fn crash(x: Foo) -> Foo {
+   |                     ^^^
 
 error: aborting due to 1 previous error
 
+For more information about this error, try `rustc --explain E0275`.

tests/ui/type-alias-impl-trait/type-alias-impl-trait-with-cycle-error-3.rs

@@ -1,9 +1,9 @@
 #![feature(type_alias_impl_trait)]
-//@ known-bug: #109268
 
 type Foo<'a> = impl Fn() -> Foo<'a>;
-
+#[define_opaque(Foo)]
 fn crash<'a>(_: &'a (), x: Foo<'a>) -> Foo<'a> {
+    //~^ ERROR overflow evaluating the requirement `<Foo<'_> as FnOnce<()>>::Output == Foo<'a>`
     x
 }
 

tests/ui/type-alias-impl-trait/type-alias-impl-trait-with-cycle-error-3.stderr

@@ -1,10 +1,9 @@
-error: unconstrained opaque type
-  --> $DIR/type-alias-impl-trait-with-cycle-error-3.rs:4:16
+error[E0275]: overflow evaluating the requirement `<Foo<'_> as FnOnce<()>>::Output == Foo<'a>`
+  --> $DIR/type-alias-impl-trait-with-cycle-error-3.rs:5:40
    |
-LL | type Foo<'a> = impl Fn() -> Foo<'a>;
-   |                ^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: `Foo` must be used in combination with a concrete type within the same crate
+LL | fn crash<'a>(_: &'a (), x: Foo<'a>) -> Foo<'a> {
+   |                                        ^^^^^^^
 
 error: aborting due to 1 previous error
 
+For more information about this error, try `rustc --explain E0275`.

tests/ui/unresolved/unresolved-import.rs

@@ -31,6 +31,8 @@ mod food {
 
     mod zug {
         pub mod baz {
+        //~^ NOTE module `food::zug::baz` exists but is inaccessible
+        //~| NOTE not accessible
             pub struct Foobar;
         }
     }

tests/ui/unresolved/unresolved-import.stderr

@@ -26,6 +26,12 @@ LL | use food::baz;
    |     |     |
    |     |     help: a similar name exists in the module: `bag`
    |     no `baz` in `food`
+   |
+note: module `food::zug::baz` exists but is inaccessible
+  --> $DIR/unresolved-import.rs:33:9
+   |
+LL |         pub mod baz {
+   |         ^^^^^^^^^^^ not accessible
 
 error[E0432]: unresolved import `food::beens`
   --> $DIR/unresolved-import.rs:19:12
@@ -37,13 +43,13 @@ LL | use food::{beens as Foo};
    |            help: a similar name exists in the module: `beans`
 
 error[E0432]: unresolved import `MyEnum`
-  --> $DIR/unresolved-import.rs:44:9
+  --> $DIR/unresolved-import.rs:46:9
    |
 LL |     use MyEnum::*;
    |         ^^^^^^ help: a similar path exists: `self::MyEnum`
 
 error[E0432]: unresolved import `Enum`
-  --> $DIR/unresolved-import.rs:55:9
+  --> $DIR/unresolved-import.rs:57:9
    |
 LL |     use Enum::*;
    |         ^^^^ help: a similar path exists: `self::Enum`