Rollup of 7 pull requests

Cargo.lock

@@ -2177,9 +2177,9 @@ dependencies = [
 
 [[package]]
 name = "memchr"
-version = "2.5.0"
+version = "2.7.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2dffe52ecf27772e601905b7522cb4ef790d2cc203488bbd0e2fe85fcb74566d"
+checksum = "78ca9ab1a0babb1e7d5695e3530886289c18cf2f87ec19a575a0abdce112e3a3"
 
 [[package]]
 name = "memmap2"

compiler/rustc_ast/Cargo.toml

@@ -4,10 +4,9 @@ version = "0.0.0"
 edition = "2021"
 
 [dependencies]
-# FIXME: bumping memchr to 2.7.1 causes linker errors in MSVC thin-lto
 # tidy-alphabetical-start
 bitflags = "2.4.1"
-memchr = "=2.5.0"
+memchr = "2.7.4"
 rustc_ast_ir = { path = "../rustc_ast_ir" }
 rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_index = { path = "../rustc_index" }

compiler/rustc_attr/src/builtin.rs

@@ -153,7 +153,7 @@ pub enum StabilityLevel {
 }
 
 /// Rust release in which a feature is stabilized.
-#[derive(Encodable, Decodable, PartialEq, Copy, Clone, Debug, Eq, Hash)]
+#[derive(Encodable, Decodable, PartialEq, Copy, Clone, Debug, Eq, PartialOrd, Ord, Hash)]
 #[derive(HashStable_Generic)]
 pub enum StableSince {
     Version(RustcVersion),

compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs

@@ -333,7 +333,11 @@ impl<'tcx> BorrowExplanation<'tcx> {
                     }
                 }
 
-                if let ConstraintCategory::Cast { unsize_to: Some(unsize_ty) } = category {
+                if let ConstraintCategory::Cast {
+                    is_implicit_coercion: true,
+                    unsize_to: Some(unsize_ty),
+                } = category
+                {
                     self.add_object_lifetime_default_note(tcx, err, unsize_ty);
                 }
                 self.add_lifetime_bound_suggestion_to_diagnostic(err, &category, span, region_name);
@@ -740,7 +744,7 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, 'tcx> {
                         // If we see an unsized cast, then if it is our data we should check
                         // whether it is being cast to a trait object.
                         Rvalue::Cast(
-                            CastKind::PointerCoercion(PointerCoercion::Unsize),
+                            CastKind::PointerCoercion(PointerCoercion::Unsize, _),
                             operand,
                             ty,
                         ) => {

compiler/rustc_borrowck/src/diagnostics/region_errors.rs

@@ -47,7 +47,8 @@ impl<'tcx> ConstraintDescription for ConstraintCategory<'tcx> {
             ConstraintCategory::Yield => "yielding this value ",
             ConstraintCategory::UseAsConst => "using this value as a constant ",
             ConstraintCategory::UseAsStatic => "using this value as a static ",
-            ConstraintCategory::Cast { .. } => "cast ",
+            ConstraintCategory::Cast { is_implicit_coercion: false, .. } => "cast ",
+            ConstraintCategory::Cast { is_implicit_coercion: true, .. } => "coercion ",
             ConstraintCategory::CallArgument(_) => "argument ",
             ConstraintCategory::TypeAnnotation => "type annotation ",
             ConstraintCategory::ClosureBounds => "closure body ",

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -1975,8 +1975,9 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
             Rvalue::Cast(cast_kind, op, ty) => {
                 self.check_operand(op, location);
 
-                match cast_kind {
-                    CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer) => {
+                match *cast_kind {
+                    CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer, coercion_source) => {
+                        let is_implicit_coercion = coercion_source == CoercionSource::Implicit;
                         let src_sig = op.ty(body, tcx).fn_sig(tcx);
 
                         // HACK: This shouldn't be necessary... We can remove this when we actually
@@ -2007,15 +2008,15 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                             self.prove_predicate(
                                 ty::ClauseKind::WellFormed(src_ty.into()),
                                 location.to_locations(),
-                                ConstraintCategory::Cast { unsize_to: None },
+                                ConstraintCategory::Cast { is_implicit_coercion, unsize_to: None },
                             );
 
                             let src_ty = self.normalize(src_ty, location);
                             if let Err(terr) = self.sub_types(
                                 src_ty,
                                 *ty,
                                 location.to_locations(),
-                                ConstraintCategory::Cast { unsize_to: None },
+                                ConstraintCategory::Cast { is_implicit_coercion, unsize_to: None },
                             ) {
                                 span_mirbug!(
                                     self,
@@ -2036,7 +2037,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                         self.prove_predicate(
                             ty::ClauseKind::WellFormed(src_ty.into()),
                             location.to_locations(),
-                            ConstraintCategory::Cast { unsize_to: None },
+                            ConstraintCategory::Cast { is_implicit_coercion, unsize_to: None },
                         );
 
                         // The type that we see in the fcx is like
@@ -2049,7 +2050,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                             src_ty,
                             *ty,
                             location.to_locations(),
-                            ConstraintCategory::Cast { unsize_to: None },
+                            ConstraintCategory::Cast { is_implicit_coercion, unsize_to: None },
                         ) {
                             span_mirbug!(
                                 self,
@@ -2062,19 +2063,23 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                         }
                     }
 
-                    CastKind::PointerCoercion(PointerCoercion::ClosureFnPointer(safety)) => {
+                    CastKind::PointerCoercion(
+                        PointerCoercion::ClosureFnPointer(safety),
+                        coercion_source,
+                    ) => {
                         let sig = match op.ty(body, tcx).kind() {
                             ty::Closure(_, args) => args.as_closure().sig(),
                             _ => bug!(),
                         };
                         let ty_fn_ptr_from =
-                            Ty::new_fn_ptr(tcx, tcx.signature_unclosure(sig, *safety));
+                            Ty::new_fn_ptr(tcx, tcx.signature_unclosure(sig, safety));
 
+                        let is_implicit_coercion = coercion_source == CoercionSource::Implicit;
                         if let Err(terr) = self.sub_types(
                             ty_fn_ptr_from,
                             *ty,
                             location.to_locations(),
-                            ConstraintCategory::Cast { unsize_to: None },
+                            ConstraintCategory::Cast { is_implicit_coercion, unsize_to: None },
                         ) {
                             span_mirbug!(
                                 self,
@@ -2087,7 +2092,10 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                         }
                     }
 
-                    CastKind::PointerCoercion(PointerCoercion::UnsafeFnPointer) => {
+                    CastKind::PointerCoercion(
+                        PointerCoercion::UnsafeFnPointer,
+                        coercion_source,
+                    ) => {
                         let fn_sig = op.ty(body, tcx).fn_sig(tcx);
 
                         // The type that we see in the fcx is like
@@ -2099,11 +2107,12 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
 
                         let ty_fn_ptr_from = tcx.safe_to_unsafe_fn_ty(fn_sig);
 
+                        let is_implicit_coercion = coercion_source == CoercionSource::Implicit;
                         if let Err(terr) = self.sub_types(
                             ty_fn_ptr_from,
                             *ty,
                             location.to_locations(),
-                            ConstraintCategory::Cast { unsize_to: None },
+                            ConstraintCategory::Cast { is_implicit_coercion, unsize_to: None },
                         ) {
                             span_mirbug!(
                                 self,
@@ -2116,30 +2125,29 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                         }
                     }
 
-                    CastKind::PointerCoercion(PointerCoercion::Unsize) => {
+                    CastKind::PointerCoercion(PointerCoercion::Unsize, coercion_source) => {
                         let &ty = ty;
                         let trait_ref = ty::TraitRef::new(
                             tcx,
                             tcx.require_lang_item(LangItem::CoerceUnsized, Some(span)),
                             [op.ty(body, tcx), ty],
                         );
 
+                        let is_implicit_coercion = coercion_source == CoercionSource::Implicit;
+                        let unsize_to = tcx.fold_regions(ty, |r, _| {
+                            if let ty::ReVar(_) = r.kind() { tcx.lifetimes.re_erased } else { r }
+                        });
                         self.prove_trait_ref(
                             trait_ref,
                             location.to_locations(),
                             ConstraintCategory::Cast {
-                                unsize_to: Some(tcx.fold_regions(ty, |r, _| {
-                                    if let ty::ReVar(_) = r.kind() {
-                                        tcx.lifetimes.re_erased
-                                    } else {
-                                        r
-                                    }
-                                })),
+                                is_implicit_coercion,
+                                unsize_to: Some(unsize_to),
                             },
                         );
                     }
 
-                    CastKind::DynStar => {
+                    CastKind::PointerCoercion(PointerCoercion::DynStar, coercion_source) => {
                         // get the constraints from the target type (`dyn* Clone`)
                         //
                         // apply them to prove that the source type `Foo` implements `Clone` etc
@@ -2150,12 +2158,13 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
 
                         let self_ty = op.ty(body, tcx);
 
+                        let is_implicit_coercion = coercion_source == CoercionSource::Implicit;
                         self.prove_predicates(
                             existential_predicates
                                 .iter()
                                 .map(|predicate| predicate.with_self_ty(tcx, self_ty)),
                             location.to_locations(),
-                            ConstraintCategory::Cast { unsize_to: None },
+                            ConstraintCategory::Cast { is_implicit_coercion, unsize_to: None },
                         );
 
                         let outlives_predicate = tcx.mk_predicate(Binder::dummy(
@@ -2166,11 +2175,14 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                         self.prove_predicate(
                             outlives_predicate,
                             location.to_locations(),
-                            ConstraintCategory::Cast { unsize_to: None },
+                            ConstraintCategory::Cast { is_implicit_coercion, unsize_to: None },
                         );
                     }
 
-                    CastKind::PointerCoercion(PointerCoercion::MutToConstPointer) => {
+                    CastKind::PointerCoercion(
+                        PointerCoercion::MutToConstPointer,
+                        coercion_source,
+                    ) => {
                         let ty::RawPtr(ty_from, hir::Mutability::Mut) = op.ty(body, tcx).kind()
                         else {
                             span_mirbug!(self, rvalue, "unexpected base type for cast {:?}", ty,);
@@ -2180,11 +2192,12 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                             span_mirbug!(self, rvalue, "unexpected target type for cast {:?}", ty,);
                             return;
                         };
+                        let is_implicit_coercion = coercion_source == CoercionSource::Implicit;
                         if let Err(terr) = self.sub_types(
                             *ty_from,
                             *ty_to,
                             location.to_locations(),
-                            ConstraintCategory::Cast { unsize_to: None },
+                            ConstraintCategory::Cast { is_implicit_coercion, unsize_to: None },
                         ) {
                             span_mirbug!(
                                 self,
@@ -2197,7 +2210,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                         }
                     }
 
-                    CastKind::PointerCoercion(PointerCoercion::ArrayToPointer) => {
+                    CastKind::PointerCoercion(PointerCoercion::ArrayToPointer, coercion_source) => {
                         let ty_from = op.ty(body, tcx);
 
                         let opt_ty_elem_mut = match ty_from.kind() {
@@ -2242,11 +2255,12 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                             return;
                         }
 
+                        let is_implicit_coercion = coercion_source == CoercionSource::Implicit;
                         if let Err(terr) = self.sub_types(
                             *ty_elem,
                             *ty_to,
                             location.to_locations(),
-                            ConstraintCategory::Cast { unsize_to: None },
+                            ConstraintCategory::Cast { is_implicit_coercion, unsize_to: None },
                         ) {
                             span_mirbug!(
                                 self,
@@ -2427,7 +2441,10 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                                         src_obj,
                                         dst_obj,
                                         location.to_locations(),
-                                        ConstraintCategory::Cast { unsize_to: None },
+                                        ConstraintCategory::Cast {
+                                            is_implicit_coercion: false,
+                                            unsize_to: None,
+                                        },
                                     )
                                     .unwrap();
                                 }

compiler/rustc_codegen_cranelift/src/base.rs

@@ -652,7 +652,7 @@ fn codegen_stmt<'tcx>(
                     lval.write_cvalue(fx, res);
                 }
                 Rvalue::Cast(
-                    CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer),
+                    CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer, _),
                     ref operand,
                     to_ty,
                 ) => {
@@ -677,7 +677,7 @@ fn codegen_stmt<'tcx>(
                     }
                 }
                 Rvalue::Cast(
-                    CastKind::PointerCoercion(PointerCoercion::UnsafeFnPointer),
+                    CastKind::PointerCoercion(PointerCoercion::UnsafeFnPointer, _),
                     ref operand,
                     to_ty,
                 ) => {
@@ -688,6 +688,7 @@ fn codegen_stmt<'tcx>(
                 Rvalue::Cast(
                     CastKind::PointerCoercion(
                         PointerCoercion::MutToConstPointer | PointerCoercion::ArrayToPointer,
+                        _,
                     ),
                     ..,
                 ) => {
@@ -741,7 +742,7 @@ fn codegen_stmt<'tcx>(
                     }
                 }
                 Rvalue::Cast(
-                    CastKind::PointerCoercion(PointerCoercion::ClosureFnPointer(_)),
+                    CastKind::PointerCoercion(PointerCoercion::ClosureFnPointer(_), _),
                     ref operand,
                     _to_ty,
                 ) => {
@@ -763,14 +764,18 @@ fn codegen_stmt<'tcx>(
                     }
                 }
                 Rvalue::Cast(
-                    CastKind::PointerCoercion(PointerCoercion::Unsize),
+                    CastKind::PointerCoercion(PointerCoercion::Unsize, _),
                     ref operand,
                     _to_ty,
                 ) => {
                     let operand = codegen_operand(fx, operand);
                     crate::unsize::coerce_unsized_into(fx, operand, lval);
                 }
-                Rvalue::Cast(CastKind::DynStar, ref operand, _) => {
+                Rvalue::Cast(
+                    CastKind::PointerCoercion(PointerCoercion::DynStar, _),
+                    ref operand,
+                    _,
+                ) => {
                     let operand = codegen_operand(fx, operand);
                     crate::unsize::coerce_dyn_star(fx, operand, lval);
                 }