be even more precise about "cast" vs "coercion"

compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs

@@ -333,8 +333,10 @@ impl<'tcx> BorrowExplanation<'tcx> {
                     }
                 }
 
-                if let ConstraintCategory::Cast { is_coercion: true, unsize_to: Some(unsize_ty) } =
+                if let ConstraintCategory::Cast {
-                    category
+                    is_implicit_coercion: true,
+                    unsize_to: Some(unsize_ty),
+                } = category
                 {
                     self.add_object_lifetime_default_note(tcx, err, unsize_ty);
                 }
@@ -742,7 +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

@@ -47,8 +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 { is_coercion: false, .. } => "cast ",
+            ConstraintCategory::Cast { is_implicit_coercion: false, .. } => "cast ",
-            ConstraintCategory::Cast { is_coercion: true, .. } => "coercion ",
+            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 {
+                match *cast_kind {
-                    CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer) => {
+                    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
@@ -2007,7 +2008,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                             self.prove_predicate(
                                 ty::ClauseKind::WellFormed(src_ty.into()),
                                 location.to_locations(),
-                                ConstraintCategory::Cast { is_coercion: true, unsize_to: None },
+                                ConstraintCategory::Cast { is_implicit_coercion, unsize_to: None },
                             );
 
                             let src_ty = self.normalize(src_ty, location);
@@ -2015,7 +2016,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                                 src_ty,
                                 *ty,
                                 location.to_locations(),
-                                ConstraintCategory::Cast { is_coercion: true, 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 { is_coercion: true, 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 { is_coercion: true, 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 { is_coercion: true, 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 { is_coercion: true, unsize_to: None },
+                            ConstraintCategory::Cast { is_implicit_coercion, unsize_to: None },
                         ) {
                             span_mirbug!(
                                 self,
@@ -2116,7 +2125,7 @@ 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,
@@ -2124,23 +2133,21 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                             [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 {
-                                is_coercion: true,
+                                is_implicit_coercion,
-                                unsize_to: Some(tcx.fold_regions(ty, |r, _| {
+                                unsize_to: Some(unsize_to),
-                                    if let ty::ReVar(_) = r.kind() {
-                                        tcx.lifetimes.re_erased
-                                    } else {
-                                        r
-                                    }
-                                })),
                             },
                         );
                     }
 
-                    CastKind::PointerCoercion(PointerCoercion::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
@@ -2151,12 +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 { is_coercion: true, unsize_to: None },
+                            ConstraintCategory::Cast { is_implicit_coercion, unsize_to: None },
                         );
 
                         let outlives_predicate = tcx.mk_predicate(Binder::dummy(
@@ -2167,11 +2175,14 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                         self.prove_predicate(
                             outlives_predicate,
                             location.to_locations(),
-                            ConstraintCategory::Cast { is_coercion: true, 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,);
@@ -2181,11 +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 { is_coercion: true, unsize_to: None },
+                            ConstraintCategory::Cast { is_implicit_coercion, unsize_to: None },
                         ) {
                             span_mirbug!(
                                 self,
@@ -2198,7 +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() {
@@ -2243,11 +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 { is_coercion: true, unsize_to: None },
+                            ConstraintCategory::Cast { is_implicit_coercion, unsize_to: None },
                         ) {
                             span_mirbug!(
                                 self,
@@ -2429,7 +2442,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                                         dst_obj,
                                         location.to_locations(),
                                         ConstraintCategory::Cast {
-                                            is_coercion: false,
+                                            is_implicit_coercion: false,
                                             unsize_to: None,
                                         },
                                     )

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,
                 ) => {
@@ -763,7 +764,7 @@ fn codegen_stmt<'tcx>(
                     }
                 }
                 Rvalue::Cast(
-                    CastKind::PointerCoercion(PointerCoercion::Unsize),
+                    CastKind::PointerCoercion(PointerCoercion::Unsize, _),
                     ref operand,
                     _to_ty,
                 ) => {
@@ -771,7 +772,7 @@ fn codegen_stmt<'tcx>(
                     crate::unsize::coerce_unsized_into(fx, operand, lval);
                 }
                 Rvalue::Cast(
-                    CastKind::PointerCoercion(PointerCoercion::DynStar),
+                    CastKind::PointerCoercion(PointerCoercion::DynStar, _),
                     ref operand,
                     _,
                 ) => {

compiler/rustc_codegen_ssa/src/mir/rvalue.rs

@@ -34,7 +34,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             }
 
             mir::Rvalue::Cast(
-                mir::CastKind::PointerCoercion(PointerCoercion::Unsize),
+                mir::CastKind::PointerCoercion(PointerCoercion::Unsize, _),
                 ref source,
                 _,
             ) => {
@@ -465,7 +465,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                         let lladdr = bx.ptrtoint(llptr, llcast_ty);
                         OperandValue::Immediate(lladdr)
                     }
-                    mir::CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer) => {
+                    mir::CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer, _) => {
                         match *operand.layout.ty.kind() {
                             ty::FnDef(def_id, args) => {
                                 let instance = ty::Instance::resolve_for_fn_ptr(
@@ -481,7 +481,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                             _ => bug!("{} cannot be reified to a fn ptr", operand.layout.ty),
                         }
                     }
-                    mir::CastKind::PointerCoercion(PointerCoercion::ClosureFnPointer(_)) => {
+                    mir::CastKind::PointerCoercion(PointerCoercion::ClosureFnPointer(_), _) => {
                         match *operand.layout.ty.kind() {
                             ty::Closure(def_id, args) => {
                                 let instance = Instance::resolve_closure(
@@ -496,11 +496,11 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                             _ => bug!("{} cannot be cast to a fn ptr", operand.layout.ty),
                         }
                     }
-                    mir::CastKind::PointerCoercion(PointerCoercion::UnsafeFnPointer) => {
+                    mir::CastKind::PointerCoercion(PointerCoercion::UnsafeFnPointer, _) => {
                         // This is a no-op at the LLVM level.
                         operand.val
                     }
-                    mir::CastKind::PointerCoercion(PointerCoercion::Unsize) => {
+                    mir::CastKind::PointerCoercion(PointerCoercion::Unsize, _) => {
                         assert!(bx.cx().is_backend_scalar_pair(cast));
                         let (lldata, llextra) = operand.val.pointer_parts();
                         let (lldata, llextra) =
@@ -508,7 +508,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                         OperandValue::Pair(lldata, llextra)
                     }
                     mir::CastKind::PointerCoercion(
-                        PointerCoercion::MutToConstPointer | PointerCoercion::ArrayToPointer,
+                        PointerCoercion::MutToConstPointer | PointerCoercion::ArrayToPointer, _
                     ) => {
                         bug!("{kind:?} is for borrowck, and should never appear in codegen");
                     }
@@ -526,7 +526,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                             bug!("unexpected non-pair operand");
                         }
                     }
-                    mir::CastKind::PointerCoercion(PointerCoercion::DynStar) => {
+                    mir::CastKind::PointerCoercion(PointerCoercion::DynStar, _) => {
                         let (lldata, llextra) = operand.val.pointer_parts();
                         let (lldata, llextra) =
                             base::cast_to_dyn_star(bx, lldata, operand.layout, cast.ty, llextra);

compiler/rustc_const_eval/src/check_consts/check.rs

@@ -440,6 +440,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
                     | PointerCoercion::UnsafeFnPointer
                     | PointerCoercion::ClosureFnPointer(_)
                     | PointerCoercion::ReifyFnPointer,
+                    _,
                 ),
                 _,
                 _,
@@ -448,7 +449,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
             }
 
             Rvalue::Cast(
-                CastKind::PointerCoercion(PointerCoercion::Unsize | PointerCoercion::DynStar),
+                CastKind::PointerCoercion(PointerCoercion::Unsize | PointerCoercion::DynStar, _),
                 _,
                 _,
             ) => {

compiler/rustc_const_eval/src/interpret/cast.rs

@@ -32,7 +32,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
             if cast_ty == dest.layout.ty { dest.layout } else { self.layout_of(cast_ty)? };
         // FIXME: In which cases should we trigger UB when the source is uninit?
         match cast_kind {
-            CastKind::PointerCoercion(PointerCoercion::Unsize) => {
+            CastKind::PointerCoercion(PointerCoercion::Unsize, _) => {
                 self.unsize_into(src, cast_layout, dest)?;
             }
 
@@ -68,11 +68,12 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
 
             CastKind::PointerCoercion(
                 PointerCoercion::MutToConstPointer | PointerCoercion::ArrayToPointer,
+                _,
             ) => {
                 bug!("{cast_kind:?} casts are for borrowck only, not runtime MIR");
             }
 
-            CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer) => {
+            CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer, _) => {
                 // All reifications must be monomorphic, bail out otherwise.
                 ensure_monomorphic_enough(*self.tcx, src.layout.ty)?;
 
@@ -94,7 +95,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                 }
             }
 
-            CastKind::PointerCoercion(PointerCoercion::UnsafeFnPointer) => {
+            CastKind::PointerCoercion(PointerCoercion::UnsafeFnPointer, _) => {
                 let src = self.read_immediate(src)?;
                 match cast_ty.kind() {
                     ty::FnPtr(..) => {
@@ -105,7 +106,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                 }
             }
 
-            CastKind::PointerCoercion(PointerCoercion::ClosureFnPointer(_)) => {
+            CastKind::PointerCoercion(PointerCoercion::ClosureFnPointer(_), _) => {
                 // All reifications must be monomorphic, bail out otherwise.
                 ensure_monomorphic_enough(*self.tcx, src.layout.ty)?;
 
@@ -125,7 +126,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                 }
             }
 
-            CastKind::PointerCoercion(PointerCoercion::DynStar) => {
+            CastKind::PointerCoercion(PointerCoercion::DynStar, _) => {
                 if let ty::Dynamic(data, _, ty::DynStar) = cast_ty.kind() {
                     // Initial cast from sized to dyn trait
                     let vtable = self.get_vtable_ptr(src.layout.ty, data)?;

compiler/rustc_middle/src/mir/query.rs

@@ -234,8 +234,8 @@ pub enum ConstraintCategory<'tcx> {
     UseAsStatic,
     TypeAnnotation,
     Cast {
-        /// Whether this cast is a coercion.
+        /// Whether this cast is a coercion that was automatically inserted by the compiler.
-        is_coercion: bool,
+        is_implicit_coercion: bool,
         /// Whether this is an unsizing coercion and if yes, this contains the target type.
         /// Region variables are erased to ReErased.
         #[derive_where(skip)]

compiler/rustc_middle/src/mir/statement.rs

@@ -432,7 +432,7 @@ impl<'tcx> Rvalue<'tcx> {
                 | CastKind::IntToFloat
                 | CastKind::FnPtrToPtr
                 | CastKind::PtrToPtr
-                | CastKind::PointerCoercion(_)
+                | CastKind::PointerCoercion(_, _)
                 | CastKind::PointerWithExposedProvenance
                 | CastKind::Transmute,
                 _,

compiler/rustc_middle/src/mir/syntax.rs

@@ -579,7 +579,7 @@ pub struct CopyNonOverlapping<'tcx> {
     pub count: Operand<'tcx>,
 }
 
-/// Represents how a `TerminatorKind::Call` was constructed, used for diagnostics
+/// Represents how a [`TerminatorKind::Call`] was constructed, used for diagnostics.
 #[derive(Clone, Copy, TyEncodable, TyDecodable, Debug, PartialEq, Hash, HashStable)]
 #[derive(TypeFoldable, TypeVisitable)]
 pub enum CallSource {
@@ -1403,7 +1403,7 @@ pub enum CastKind {
     /// * [`PointerCoercion::MutToConstPointer`]
     ///
     /// Both are runtime nops, so should be [`CastKind::PtrToPtr`] instead in runtime MIR.
-    PointerCoercion(PointerCoercion),
+    PointerCoercion(PointerCoercion, CoercionSource),
     IntToInt,
     FloatToInt,
     FloatToFloat,
@@ -1419,6 +1419,15 @@ pub enum CastKind {
     Transmute,
 }
 
+/// Represents how a [`CastKind::PointerCoercion`] was constructed, used for diagnostics.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, TyEncodable, TyDecodable, Hash, HashStable)]
+pub enum CoercionSource {
+    /// The coercion was manually written by the user with an `as` cast.
+    AsCast,
+    /// The coercion was automatically inserted by the compiler.
+    Implicit,
+}
+
 #[derive(Clone, Debug, PartialEq, Eq, TyEncodable, TyDecodable, Hash, HashStable)]
 #[derive(TypeFoldable, TypeVisitable)]
 pub enum AggregateKind<'tcx> {

compiler/rustc_middle/src/thir.rs

@@ -338,6 +338,8 @@ pub enum ExprKind<'tcx> {
     PointerCoercion {
         cast: PointerCoercion,
         source: ExprId,
+        /// Whether this coercion is written with an `as` cast in the source code.
+        is_from_as_cast: bool,
     },
     /// A `loop` expression.
     Loop {

compiler/rustc_middle/src/thir/visit.rs

@@ -68,7 +68,9 @@ pub fn walk_expr<'thir, 'tcx: 'thir, V: Visitor<'thir, 'tcx>>(
         Cast { source } => visitor.visit_expr(&visitor.thir()[source]),
         Use { source } => visitor.visit_expr(&visitor.thir()[source]),
         NeverToAny { source } => visitor.visit_expr(&visitor.thir()[source]),
-        PointerCoercion { source, cast: _ } => visitor.visit_expr(&visitor.thir()[source]),
+        PointerCoercion { source, cast: _, is_from_as_cast: _ } => {
+            visitor.visit_expr(&visitor.thir()[source])
+        }
         Let { expr, ref pat } => {
             visitor.visit_expr(&visitor.thir()[expr]);
             visitor.visit_pat(pat);

compiler/rustc_mir_build/src/build/expr/as_rvalue.rs

@@ -292,7 +292,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 let cast_kind = mir_cast_kind(ty, expr.ty);
                 block.and(Rvalue::Cast(cast_kind, source, expr.ty))
             }
-            ExprKind::PointerCoercion { cast, source } => {
+            ExprKind::PointerCoercion { cast, source, is_from_as_cast } => {
                 let source = unpack!(
                     block = this.as_operand(
                         block,
@@ -302,7 +302,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                         NeedsTemporary::No
                     )
                 );
-                block.and(Rvalue::Cast(CastKind::PointerCoercion(cast), source, expr.ty))
+                let origin =
+                    if is_from_as_cast { CoercionSource::AsCast } else { CoercionSource::Implicit };
+                block.and(Rvalue::Cast(CastKind::PointerCoercion(cast, origin), source, expr.ty))
             }
             ExprKind::Array { ref fields } => {
                 // (*) We would (maybe) be closer to codegen if we

compiler/rustc_mir_build/src/build/matches/test.rs

@@ -407,7 +407,10 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                         source_info,
                         temp,
                         Rvalue::Cast(
-                            CastKind::PointerCoercion(PointerCoercion::Unsize),
+                            CastKind::PointerCoercion(
+                                PointerCoercion::Unsize,
+                                CoercionSource::Implicit,
+                            ),
                             Operand::Copy(val),
                             ty,
                         ),
@@ -421,7 +424,10 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                         source_info,
                         slice,
                         Rvalue::Cast(
-                            CastKind::PointerCoercion(PointerCoercion::Unsize),
+                            CastKind::PointerCoercion(
+                                PointerCoercion::Unsize,
+                                CoercionSource::Implicit,
+                            ),
                             expect,
                             ty,
                         ),

compiler/rustc_mir_build/src/thir/cx/expr.rs

@@ -104,15 +104,28 @@ impl<'tcx> Cx<'tcx> {
         };
 
         let kind = match adjustment.kind {
-            Adjust::Pointer(PointerCoercion::Unsize) => {
-                adjust_span(&mut expr);
-                ExprKind::PointerCoercion {
-                    cast: PointerCoercion::Unsize,
-                    source: self.thir.exprs.push(expr),
-                }
-            }
             Adjust::Pointer(cast) => {
-                ExprKind::PointerCoercion { cast, source: self.thir.exprs.push(expr) }
+                if cast == PointerCoercion::Unsize {
+                    adjust_span(&mut expr);
+                }
+
+                let is_from_as_cast = if let hir::Node::Expr(hir::Expr {
+                    kind: hir::ExprKind::Cast(..),
+                    span: cast_span,
+                    ..
+                }) = self.tcx.parent_hir_node(hir_expr.hir_id)
+                {
+                    // Use the whole span of the `x as T` expression for the coercion.
+                    span = *cast_span;
+                    true
+                } else {
+                    false
+                };
+                ExprKind::PointerCoercion {
+                    cast,
+                    source: self.thir.exprs.push(expr),
+                    is_from_as_cast,
+                }
             }
             Adjust::NeverToAny if adjustment.target.is_never() => return expr,
             Adjust::NeverToAny => ExprKind::NeverToAny { source: self.thir.exprs.push(expr) },
@@ -235,6 +248,7 @@ impl<'tcx> Cx<'tcx> {
             ExprKind::PointerCoercion {
                 source: self.mirror_expr(source),
                 cast: PointerCoercion::ArrayToPointer,
+                is_from_as_cast: true,
             }
         } else if let hir::ExprKind::Path(ref qpath) = source.kind
             && let res = self.typeck_results().qpath_res(qpath, source.hir_id)

compiler/rustc_mir_build/src/thir/print.rs

@@ -292,9 +292,14 @@ impl<'a, 'tcx> ThirPrinter<'a, 'tcx> {
                 self.print_expr(*source, depth_lvl + 2);
                 print_indented!(self, "}", depth_lvl);
             }
-            PointerCoercion { cast, source } => {
+            PointerCoercion { cast, is_from_as_cast, source } => {
                 print_indented!(self, "Pointer {", depth_lvl);
                 print_indented!(self, format!("cast: {:?}", cast), depth_lvl + 1);
+                print_indented!(
+                    self,
+                    format!("is_from_as_cast: {:?}", is_from_as_cast),
+                    depth_lvl + 1
+                );
                 print_indented!(self, "source:", depth_lvl + 1);
                 self.print_expr(*source, depth_lvl + 2);
                 print_indented!(self, "}", depth_lvl);

compiler/rustc_mir_transform/src/cleanup_post_borrowck.rs

@@ -42,6 +42,7 @@ impl<'tcx> crate::MirPass<'tcx> for CleanupPostBorrowck {
                             ref mut cast_kind @ CastKind::PointerCoercion(
                                 PointerCoercion::ArrayToPointer
                                 | PointerCoercion::MutToConstPointer,
+                                _,
                             ),
                             ..,
                         ),

compiler/rustc_mir_transform/src/dataflow_const_prop.rs

@@ -189,7 +189,7 @@ impl<'tcx> ValueAnalysis<'tcx> for ConstAnalysis<'_, 'tcx> {
                 }
             }
             Rvalue::Cast(
-                CastKind::PointerCoercion(ty::adjustment::PointerCoercion::Unsize),
+                CastKind::PointerCoercion(ty::adjustment::PointerCoercion::Unsize, _),
                 operand,
                 _,
             ) => {

compiler/rustc_mir_transform/src/gvn.rs

@@ -576,7 +576,7 @@ impl<'body, 'tcx> VnState<'body, 'tcx> {
                     }
                     value.offset(Size::ZERO, to, &self.ecx).ok()?
                 }
-                CastKind::PointerCoercion(ty::adjustment::PointerCoercion::Unsize) => {
+                CastKind::PointerCoercion(ty::adjustment::PointerCoercion::Unsize, _) => {
                     let src = self.evaluated[value].as_ref()?;
                     let to = self.ecx.layout_of(to).ok()?;
                     let dest = self.ecx.allocate(to, MemoryKind::Stack).ok()?;
@@ -593,7 +593,7 @@ impl<'body, 'tcx> VnState<'body, 'tcx> {
                     let ret = self.ecx.ptr_to_ptr(&src, to).ok()?;
                     ret.into()
                 }
-                CastKind::PointerCoercion(ty::adjustment::PointerCoercion::UnsafeFnPointer) => {
+                CastKind::PointerCoercion(ty::adjustment::PointerCoercion::UnsafeFnPointer, _) => {
                     let src = self.evaluated[value].as_ref()?;
                     let src = self.ecx.read_immediate(src).ok()?;
                     let to = self.ecx.layout_of(to).ok()?;
@@ -1138,7 +1138,7 @@ impl<'body, 'tcx> VnState<'body, 'tcx> {
             (
                 UnOp::PtrMetadata,
                 Value::Cast {
-                    kind: CastKind::PointerCoercion(ty::adjustment::PointerCoercion::Unsize),
+                    kind: CastKind::PointerCoercion(ty::adjustment::PointerCoercion::Unsize, _),
                     from,
                     to,
                     ..
@@ -1342,7 +1342,7 @@ impl<'body, 'tcx> VnState<'body, 'tcx> {
             return Some(value);
         }
 
-        if let CastKind::PointerCoercion(ReifyFnPointer | ClosureFnPointer(_)) = kind {
+        if let CastKind::PointerCoercion(ReifyFnPointer | ClosureFnPointer(_), _) = kind {
             // Each reification of a generic fn may get a different pointer.
             // Do not try to merge them.
             return self.new_opaque();
@@ -1429,7 +1429,7 @@ impl<'body, 'tcx> VnState<'body, 'tcx> {
 
         // We have an unsizing cast, which assigns the length to fat pointer metadata.
         if let Value::Cast { kind, from, to, .. } = self.get(inner)
-            && let CastKind::PointerCoercion(ty::adjustment::PointerCoercion::Unsize) = kind
+            && let CastKind::PointerCoercion(ty::adjustment::PointerCoercion::Unsize, _) = kind
             && let Some(from) = from.builtin_deref(true)
             && let ty::Array(_, len) = from.kind()
             && let Some(to) = to.builtin_deref(true)

compiler/rustc_mir_transform/src/mentioned_items.rs

@@ -70,8 +70,8 @@ impl<'tcx> Visitor<'tcx> for MentionedItemsVisitor<'_, 'tcx> {
         match *rvalue {
             // We need to detect unsizing casts that required vtables.
             mir::Rvalue::Cast(
-                mir::CastKind::PointerCoercion(PointerCoercion::Unsize)
+                mir::CastKind::PointerCoercion(PointerCoercion::Unsize, _)
-                | mir::CastKind::PointerCoercion(PointerCoercion::DynStar),
+                | mir::CastKind::PointerCoercion(PointerCoercion::DynStar, _),
                 ref operand,
                 target_ty,
             ) => {
@@ -96,7 +96,7 @@ impl<'tcx> Visitor<'tcx> for MentionedItemsVisitor<'_, 'tcx> {
             }
             // Similarly, record closures that are turned into function pointers.
             mir::Rvalue::Cast(
-                mir::CastKind::PointerCoercion(PointerCoercion::ClosureFnPointer(_)),
+                mir::CastKind::PointerCoercion(PointerCoercion::ClosureFnPointer(_), _),
                 ref operand,
                 _,
             ) => {
@@ -106,7 +106,7 @@ impl<'tcx> Visitor<'tcx> for MentionedItemsVisitor<'_, 'tcx> {
             }
             // And finally, function pointer reification casts.
             mir::Rvalue::Cast(
-                mir::CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer),
+                mir::CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer, _),
                 ref operand,
                 _,
             ) => {

compiler/rustc_mir_transform/src/shim/async_destructor_ctor.rs

@@ -7,9 +7,10 @@ use rustc_hir::def_id::DefId;
 use rustc_hir::lang_items::LangItem;
 use rustc_index::{Idx, IndexVec};
 use rustc_middle::mir::{
-    BasicBlock, BasicBlockData, Body, CallSource, CastKind, Const, ConstOperand, ConstValue, Local,
+    BasicBlock, BasicBlockData, Body, CallSource, CastKind, CoercionSource, Const, ConstOperand,
-    LocalDecl, MirSource, Operand, Place, PlaceElem, RETURN_PLACE, Rvalue, SourceInfo, Statement,
+    ConstValue, Local, LocalDecl, MirSource, Operand, Place, PlaceElem, RETURN_PLACE, Rvalue,
-    StatementKind, Terminator, TerminatorKind, UnwindAction, UnwindTerminateReason,
+    SourceInfo, Statement, StatementKind, Terminator, TerminatorKind, UnwindAction,
+    UnwindTerminateReason,
 };
 use rustc_middle::ty::adjustment::PointerCoercion;
 use rustc_middle::ty::util::{AsyncDropGlueMorphology, Discr};
@@ -329,7 +330,7 @@ impl<'tcx> AsyncDestructorCtorShimBuilder<'tcx> {
     fn put_array_as_slice(&mut self, elem_ty: Ty<'tcx>) {
         let slice_ptr_ty = Ty::new_mut_ptr(self.tcx, Ty::new_slice(self.tcx, elem_ty));
         self.put_temp_rvalue(Rvalue::Cast(
-            CastKind::PointerCoercion(PointerCoercion::Unsize),
+            CastKind::PointerCoercion(PointerCoercion::Unsize, CoercionSource::Implicit),
             Operand::Copy(Self::SELF_PTR.into()),
             slice_ptr_ty,
         ))

compiler/rustc_mir_transform/src/validate.rs

@@ -1130,7 +1130,7 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
                 match kind {
                     // FIXME: Add Checks for these
                     CastKind::PointerWithExposedProvenance | CastKind::PointerExposeProvenance => {}
-                    CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer) => {
+                    CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer, _) => {
                         // FIXME: check signature compatibility.
                         check_kinds!(
                             op_ty,
@@ -1143,7 +1143,7 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
                             ty::FnPtr(..)
                         );
                     }
-                    CastKind::PointerCoercion(PointerCoercion::UnsafeFnPointer) => {
+                    CastKind::PointerCoercion(PointerCoercion::UnsafeFnPointer, _) => {
                         // FIXME: check safety and signature compatibility.
                         check_kinds!(
                             op_ty,
@@ -1156,7 +1156,7 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
                             ty::FnPtr(..)
                         );
                     }
-                    CastKind::PointerCoercion(PointerCoercion::ClosureFnPointer(..)) => {
+                    CastKind::PointerCoercion(PointerCoercion::ClosureFnPointer(..), _) => {
                         // FIXME: check safety, captures, and signature compatibility.
                         check_kinds!(
                             op_ty,
@@ -1169,7 +1169,7 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
                             ty::FnPtr(..)
                         );
                     }
-                    CastKind::PointerCoercion(PointerCoercion::MutToConstPointer) => {
+                    CastKind::PointerCoercion(PointerCoercion::MutToConstPointer, _) => {
                         // FIXME: check same pointee?
                         check_kinds!(
                             op_ty,
@@ -1185,7 +1185,7 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
                             self.fail(location, format!("After borrowck, MIR disallows {kind:?}"));
                         }
                     }
-                    CastKind::PointerCoercion(PointerCoercion::ArrayToPointer) => {
+                    CastKind::PointerCoercion(PointerCoercion::ArrayToPointer, _) => {
                         // FIXME: Check pointee types
                         check_kinds!(
                             op_ty,
@@ -1201,11 +1201,11 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
                             self.fail(location, format!("After borrowck, MIR disallows {kind:?}"));
                         }
                     }
-                    CastKind::PointerCoercion(PointerCoercion::Unsize) => {
+                    CastKind::PointerCoercion(PointerCoercion::Unsize, _) => {
                         // This is used for all `CoerceUnsized` types,
                         // not just pointers/references, so is hard to check.
                     }
-                    CastKind::PointerCoercion(PointerCoercion::DynStar) => {
+                    CastKind::PointerCoercion(PointerCoercion::DynStar, _) => {
                         // FIXME(dyn-star): make sure nothing needs to be done here.
                     }
                     CastKind::IntToInt | CastKind::IntToFloat => {

compiler/rustc_monomorphize/src/collector.rs

@@ -665,8 +665,8 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirUsedCollector<'a, 'tcx> {
             // have to instantiate all methods of the trait being cast to, so we
             // can build the appropriate vtable.
             mir::Rvalue::Cast(
-                mir::CastKind::PointerCoercion(PointerCoercion::Unsize)
+                mir::CastKind::PointerCoercion(PointerCoercion::Unsize, _)
-                | mir::CastKind::PointerCoercion(PointerCoercion::DynStar),
+                | mir::CastKind::PointerCoercion(PointerCoercion::DynStar, _),
                 ref operand,
                 target_ty,
             ) => {
@@ -694,7 +694,7 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirUsedCollector<'a, 'tcx> {
                 }
             }
             mir::Rvalue::Cast(
-                mir::CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer),
+                mir::CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer, _),
                 ref operand,
                 _,
             ) => {
@@ -705,7 +705,7 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirUsedCollector<'a, 'tcx> {
                 visit_fn_use(self.tcx, fn_ty, false, span, self.used_items);
             }
             mir::Rvalue::Cast(
-                mir::CastKind::PointerCoercion(PointerCoercion::ClosureFnPointer(_)),
+                mir::CastKind::PointerCoercion(PointerCoercion::ClosureFnPointer(_), _),
                 ref operand,
                 _,
             ) => {

compiler/rustc_smir/src/rustc_smir/convert/mir.rs

@@ -286,8 +286,8 @@ impl<'tcx> Stable<'tcx> for mir::CastKind {
         match self {
             PointerExposeProvenance => stable_mir::mir::CastKind::PointerExposeAddress,
             PointerWithExposedProvenance => stable_mir::mir::CastKind::PointerWithExposedProvenance,
-            PointerCoercion(PointerCoercion::DynStar) => stable_mir::mir::CastKind::DynStar,
+            PointerCoercion(PointerCoercion::DynStar, _) => stable_mir::mir::CastKind::DynStar,
-            PointerCoercion(c) => stable_mir::mir::CastKind::PointerCoercion(c.stable(tables)),
+            PointerCoercion(c, _) => stable_mir::mir::CastKind::PointerCoercion(c.stable(tables)),
             IntToInt => stable_mir::mir::CastKind::IntToInt,
             FloatToInt => stable_mir::mir::CastKind::FloatToInt,
             FloatToFloat => stable_mir::mir::CastKind::FloatToFloat,

src/tools/clippy/clippy_utils/src/qualify_min_const_fn.rs

@@ -123,7 +123,7 @@ fn check_rvalue<'tcx>(
             | CastKind::FloatToFloat
             | CastKind::FnPtrToPtr
             | CastKind::PtrToPtr
-            | CastKind::PointerCoercion(PointerCoercion::MutToConstPointer | PointerCoercion::ArrayToPointer),
+            | CastKind::PointerCoercion(PointerCoercion::MutToConstPointer | PointerCoercion::ArrayToPointer, _),
             operand,
             _,
         ) => check_operand(tcx, operand, span, body, msrv),
@@ -131,12 +131,12 @@ fn check_rvalue<'tcx>(
             CastKind::PointerCoercion(
                 PointerCoercion::UnsafeFnPointer
                 | PointerCoercion::ClosureFnPointer(_)
-                | PointerCoercion::ReifyFnPointer,
+                | PointerCoercion::ReifyFnPointer, _
             ),
             _,
             _,
         ) => Err((span, "function pointer casts are not allowed in const fn".into())),
-        Rvalue::Cast(CastKind::PointerCoercion(PointerCoercion::Unsize), op, cast_ty) => {
+        Rvalue::Cast(CastKind::PointerCoercion(PointerCoercion::Unsize, _), op, cast_ty) => {
             let Some(pointee_ty) = cast_ty.builtin_deref(true) else {
                 // We cannot allow this for now.
                 return Err((span, "unsizing casts are only allowed for references right now".into()));
@@ -154,7 +154,7 @@ fn check_rvalue<'tcx>(
         Rvalue::Cast(CastKind::PointerExposeProvenance, _, _) => {
             Err((span, "casting pointers to ints is unstable in const fn".into()))
         },
-        Rvalue::Cast(CastKind::PointerCoercion(PointerCoercion::DynStar), _, _) => {
+        Rvalue::Cast(CastKind::PointerCoercion(PointerCoercion::DynStar, _), _, _) => {
             // FIXME(dyn-star)
             unimplemented!()
         },

src/tools/miri/tests/fail/dyn-upcast-trait-mismatch.stderr

@@ -2,7 +2,7 @@ error: Undefined Behavior: using vtable for `Baz` but `Bar` was expected
   --> tests/fail/dyn-upcast-trait-mismatch.rs:LL:CC
    |
 LL |         let _err = baz_fake as *const dyn Foo;
-   |                    ^^^^^^^^ using vtable for `Baz` but `Bar` was expected
+   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^ using vtable for `Baz` but `Bar` was expected
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

tests/mir-opt/address_of.address_of_reborrow.SimplifyCfg-initial.after.mir

@@ -150,7 +150,7 @@ fn address_of_reborrow() -> () {
         StorageLive(_9);
         StorageLive(_10);
         _10 = &raw const (*_1);
-        _9 = move _10 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+        _9 = move _10 as *const dyn std::marker::Send (PointerCoercion(Unsize, AsCast));
         StorageDead(_10);
         AscribeUserType(_9, o, UserTypeProjection { base: UserType(1), projs: [] });
         _8 = copy _9;
@@ -159,13 +159,13 @@ fn address_of_reborrow() -> () {
         StorageLive(_11);
         StorageLive(_12);
         _12 = &raw const (*_1);
-        _11 = move _12 as *const [i32] (PointerCoercion(Unsize));
+        _11 = move _12 as *const [i32] (PointerCoercion(Unsize, AsCast));
         StorageDead(_12);
         StorageDead(_11);
         StorageLive(_13);
         StorageLive(_14);
         _14 = &raw const (*_1);
-        _13 = move _14 as *const i32 (PointerCoercion(ArrayToPointer));
+        _13 = move _14 as *const i32 (PointerCoercion(ArrayToPointer, AsCast));
         StorageDead(_14);
         StorageDead(_13);
         StorageLive(_15);
@@ -179,14 +179,14 @@ fn address_of_reborrow() -> () {
         StorageLive(_17);
         StorageLive(_18);
         _18 = &raw const (*_1);
-        _17 = move _18 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+        _17 = move _18 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
         StorageDead(_18);
         FakeRead(ForLet(None), _17);
         AscribeUserType(_17, o, UserTypeProjection { base: UserType(7), projs: [] });
         StorageLive(_19);
         StorageLive(_20);
         _20 = &raw const (*_1);
-        _19 = move _20 as *const [i32] (PointerCoercion(Unsize));
+        _19 = move _20 as *const [i32] (PointerCoercion(Unsize, Implicit));
         StorageDead(_20);
         FakeRead(ForLet(None), _19);
         AscribeUserType(_19, o, UserTypeProjection { base: UserType(9), projs: [] });
@@ -204,7 +204,7 @@ fn address_of_reborrow() -> () {
         StorageLive(_25);
         StorageLive(_26);
         _26 = &raw const (*_3);
-        _25 = move _26 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+        _25 = move _26 as *const dyn std::marker::Send (PointerCoercion(Unsize, AsCast));
         StorageDead(_26);
         AscribeUserType(_25, o, UserTypeProjection { base: UserType(11), projs: [] });
         _24 = copy _25;
@@ -213,7 +213,7 @@ fn address_of_reborrow() -> () {
         StorageLive(_27);
         StorageLive(_28);
         _28 = &raw const (*_3);
-        _27 = move _28 as *const [i32] (PointerCoercion(Unsize));
+        _27 = move _28 as *const [i32] (PointerCoercion(Unsize, AsCast));
         StorageDead(_28);
         StorageDead(_27);
         StorageLive(_29);
@@ -227,14 +227,14 @@ fn address_of_reborrow() -> () {
         StorageLive(_31);
         StorageLive(_32);
         _32 = &raw const (*_3);
-        _31 = move _32 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+        _31 = move _32 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
         StorageDead(_32);
         FakeRead(ForLet(None), _31);
         AscribeUserType(_31, o, UserTypeProjection { base: UserType(17), projs: [] });
         StorageLive(_33);
         StorageLive(_34);
         _34 = &raw const (*_3);
-        _33 = move _34 as *const [i32] (PointerCoercion(Unsize));
+        _33 = move _34 as *const [i32] (PointerCoercion(Unsize, Implicit));
         StorageDead(_34);
         FakeRead(ForLet(None), _33);
         AscribeUserType(_33, o, UserTypeProjection { base: UserType(19), projs: [] });
@@ -252,7 +252,7 @@ fn address_of_reborrow() -> () {
         StorageLive(_39);
         StorageLive(_40);
         _40 = &raw mut (*_3);
-        _39 = move _40 as *mut dyn std::marker::Send (PointerCoercion(Unsize));
+        _39 = move _40 as *mut dyn std::marker::Send (PointerCoercion(Unsize, AsCast));
         StorageDead(_40);
         AscribeUserType(_39, o, UserTypeProjection { base: UserType(21), projs: [] });
         _38 = copy _39;
@@ -261,7 +261,7 @@ fn address_of_reborrow() -> () {
         StorageLive(_41);
         StorageLive(_42);
         _42 = &raw mut (*_3);
-        _41 = move _42 as *mut [i32] (PointerCoercion(Unsize));
+        _41 = move _42 as *mut [i32] (PointerCoercion(Unsize, AsCast));
         StorageDead(_42);
         StorageDead(_41);
         StorageLive(_43);
@@ -275,14 +275,14 @@ fn address_of_reborrow() -> () {
         StorageLive(_45);
         StorageLive(_46);
         _46 = &raw mut (*_3);
-        _45 = move _46 as *mut dyn std::marker::Send (PointerCoercion(Unsize));
+        _45 = move _46 as *mut dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
         StorageDead(_46);
         FakeRead(ForLet(None), _45);
         AscribeUserType(_45, o, UserTypeProjection { base: UserType(27), projs: [] });
         StorageLive(_47);
         StorageLive(_48);
         _48 = &raw mut (*_3);
-        _47 = move _48 as *mut [i32] (PointerCoercion(Unsize));
+        _47 = move _48 as *mut [i32] (PointerCoercion(Unsize, Implicit));
         StorageDead(_48);
         FakeRead(ForLet(None), _47);
         AscribeUserType(_47, o, UserTypeProjection { base: UserType(29), projs: [] });

tests/mir-opt/build_correct_coerce.main.built.after.mir

@@ -9,7 +9,7 @@ fn main() -> () {
 
     bb0: {
         StorageLive(_1);
-        _1 = foo as for<'a> fn(&'a (), &'a ()) (PointerCoercion(ReifyFnPointer));
+        _1 = foo as for<'a> fn(&'a (), &'a ()) (PointerCoercion(ReifyFnPointer, AsCast));
         FakeRead(ForLet(None), _1);
         _0 = const ();
         StorageDead(_1);

tests/mir-opt/building/receiver_ptr_mutability.main.built.after.mir

@@ -39,7 +39,7 @@ fn main() -> () {
         StorageLive(_3);
         StorageLive(_4);
         _4 = copy _1;
-        _3 = move _4 as *const Test (PointerCoercion(MutToConstPointer));
+        _3 = move _4 as *const Test (PointerCoercion(MutToConstPointer, Implicit));
         StorageDead(_4);
         _2 = Test::x(move _3) -> [return: bb2, unwind: bb4];
     }
@@ -64,7 +64,7 @@ fn main() -> () {
         StorageLive(_11);
         StorageLive(_12);
         _12 = copy (*(*(*(*_5))));
-        _11 = move _12 as *const Test (PointerCoercion(MutToConstPointer));
+        _11 = move _12 as *const Test (PointerCoercion(MutToConstPointer, Implicit));
         StorageDead(_12);
         _10 = Test::x(move _11) -> [return: bb3, unwind: bb4];
     }

tests/mir-opt/building/storage_live_dead_in_statics.XXX.built.after.mir

@@ -187,7 +187,7 @@ static XXX: &Foo = {
         StorageDead(_7);
         _5 = &_6;
         _4 = &(*_5);
-        _3 = move _4 as &[(u32, u32)] (PointerCoercion(Unsize));
+        _3 = move _4 as &[(u32, u32)] (PointerCoercion(Unsize, Implicit));
         StorageDead(_4);
         _2 = Foo { tup: const "hi", data: move _3 };
         StorageDead(_3);

tests/mir-opt/const_promotion_extern_static.BAR.PromoteTemps.diff

@@ -22,7 +22,7 @@
 -         _2 = &_3;
 +         _6 = const BAR::promoted[0];
 +         _2 = &(*_6);
-          _1 = move _2 as &[&i32] (PointerCoercion(Unsize));
+          _1 = move _2 as &[&i32] (PointerCoercion(Unsize, Implicit));
 -         StorageDead(_4);
           StorageDead(_2);
           _0 = core::slice::<impl [&i32]>::as_ptr(move _1) -> [return: bb1, unwind: bb2];

tests/mir-opt/const_promotion_extern_static.FOO.PromoteTemps.diff

@@ -22,7 +22,7 @@
 -         _2 = &_3;
 +         _6 = const FOO::promoted[0];
 +         _2 = &(*_6);
-          _1 = move _2 as &[&i32] (PointerCoercion(Unsize));
+          _1 = move _2 as &[&i32] (PointerCoercion(Unsize, Implicit));
 -         StorageDead(_4);
           StorageDead(_2);
           _0 = core::slice::<impl [&i32]>::as_ptr(move _1) -> [return: bb1, unwind: bb2];

tests/mir-opt/const_prop/bad_op_unsafe_oob_for_slices.main.GVN.32bit.panic-abort.diff

@@ -26,7 +26,7 @@
           _9 = const main::promoted[0];
           _3 = &(*_9);
           _2 = &raw const (*_3);
-          _1 = move _2 as *const [i32] (PointerCoercion(Unsize));
+          _1 = move _2 as *const [i32] (PointerCoercion(Unsize, Implicit));
           StorageDead(_2);
           StorageDead(_3);
           StorageLive(_5);

tests/mir-opt/const_prop/bad_op_unsafe_oob_for_slices.main.GVN.32bit.panic-unwind.diff

@@ -26,7 +26,7 @@
           _9 = const main::promoted[0];
           _3 = &(*_9);
           _2 = &raw const (*_3);
-          _1 = move _2 as *const [i32] (PointerCoercion(Unsize));
+          _1 = move _2 as *const [i32] (PointerCoercion(Unsize, Implicit));
           StorageDead(_2);
           StorageDead(_3);
           StorageLive(_5);

tests/mir-opt/const_prop/bad_op_unsafe_oob_for_slices.main.GVN.64bit.panic-abort.diff

@@ -26,7 +26,7 @@
           _9 = const main::promoted[0];
           _3 = &(*_9);
           _2 = &raw const (*_3);
-          _1 = move _2 as *const [i32] (PointerCoercion(Unsize));
+          _1 = move _2 as *const [i32] (PointerCoercion(Unsize, Implicit));
           StorageDead(_2);
           StorageDead(_3);
           StorageLive(_5);

tests/mir-opt/const_prop/bad_op_unsafe_oob_for_slices.main.GVN.64bit.panic-unwind.diff

@@ -26,7 +26,7 @@
           _9 = const main::promoted[0];
           _3 = &(*_9);
           _2 = &raw const (*_3);
-          _1 = move _2 as *const [i32] (PointerCoercion(Unsize));
+          _1 = move _2 as *const [i32] (PointerCoercion(Unsize, Implicit));
           StorageDead(_2);
           StorageDead(_3);
           StorageLive(_5);

tests/mir-opt/const_prop/reify_fn_ptr.main.GVN.diff

@@ -13,7 +13,7 @@
           StorageLive(_1);
           StorageLive(_2);
           StorageLive(_3);
-          _3 = main as fn() (PointerCoercion(ReifyFnPointer));
+          _3 = main as fn() (PointerCoercion(ReifyFnPointer, AsCast));
           _2 = move _3 as usize (PointerExposeProvenance);
           StorageDead(_3);
           _1 = move _2 as *const fn() (PointerWithExposedProvenance);

tests/mir-opt/const_prop/reify_fn_ptr.rs

@@ -3,7 +3,7 @@
 
 fn main() {
     // CHECK-LABEL: fn main(
-    // CHECK: [[ptr:_.*]] = main as fn() (PointerCoercion(ReifyFnPointer));
+    // CHECK: [[ptr:_.*]] = main as fn() (PointerCoercion(ReifyFnPointer, AsCast));
     // CHECK: [[addr:_.*]] = move [[ptr]] as usize (PointerExposeProvenance);
     // CHECK: [[back:_.*]] = move [[addr]] as *const fn() (PointerWithExposedProvenance);
     let _ = main as usize as *const fn();

tests/mir-opt/const_prop/slice_len.main.GVN.32bit.panic-abort.diff

@@ -24,9 +24,9 @@
           _9 = const main::promoted[0];
           _4 = copy _9;
 -         _3 = copy _4;
--         _2 = move _3 as &[u32] (PointerCoercion(Unsize));
+-         _2 = move _3 as &[u32] (PointerCoercion(Unsize, AsCast));
 +         _3 = copy _9;
-+         _2 = copy _9 as &[u32] (PointerCoercion(Unsize));
++         _2 = copy _9 as &[u32] (PointerCoercion(Unsize, AsCast));
           StorageDead(_3);
           StorageLive(_6);
           _6 = const 1_usize;

tests/mir-opt/const_prop/slice_len.main.GVN.32bit.panic-unwind.diff

@@ -24,9 +24,9 @@
           _9 = const main::promoted[0];
           _4 = copy _9;
 -         _3 = copy _4;
--         _2 = move _3 as &[u32] (PointerCoercion(Unsize));
+-         _2 = move _3 as &[u32] (PointerCoercion(Unsize, AsCast));
 +         _3 = copy _9;
-+         _2 = copy _9 as &[u32] (PointerCoercion(Unsize));
++         _2 = copy _9 as &[u32] (PointerCoercion(Unsize, AsCast));
           StorageDead(_3);
           StorageLive(_6);
           _6 = const 1_usize;

tests/mir-opt/const_prop/slice_len.main.GVN.64bit.panic-abort.diff

@@ -24,9 +24,9 @@
           _9 = const main::promoted[0];
           _4 = copy _9;
 -         _3 = copy _4;
--         _2 = move _3 as &[u32] (PointerCoercion(Unsize));
+-         _2 = move _3 as &[u32] (PointerCoercion(Unsize, AsCast));
 +         _3 = copy _9;
-+         _2 = copy _9 as &[u32] (PointerCoercion(Unsize));
++         _2 = copy _9 as &[u32] (PointerCoercion(Unsize, AsCast));
           StorageDead(_3);
           StorageLive(_6);
           _6 = const 1_usize;

tests/mir-opt/const_prop/slice_len.main.GVN.64bit.panic-unwind.diff

@@ -24,9 +24,9 @@
           _9 = const main::promoted[0];
           _4 = copy _9;
 -         _3 = copy _4;
--         _2 = move _3 as &[u32] (PointerCoercion(Unsize));
+-         _2 = move _3 as &[u32] (PointerCoercion(Unsize, AsCast));
 +         _3 = copy _9;
-+         _2 = copy _9 as &[u32] (PointerCoercion(Unsize));
++         _2 = copy _9 as &[u32] (PointerCoercion(Unsize, AsCast));
           StorageDead(_3);
           StorageLive(_6);
           _6 = const 1_usize;

tests/mir-opt/const_prop/slice_len.rs

@@ -7,7 +7,7 @@
 fn main() {
     // CHECK-LABEL: fn main(
     // CHECK: debug a => [[a:_.*]];
-    // CHECK: [[slice:_.*]] = copy {{.*}} as &[u32] (PointerCoercion(Unsize));
+    // CHECK: [[slice:_.*]] = copy {{.*}} as &[u32] (PointerCoercion(Unsize, AsCast));
     // CHECK: assert(const true,
     // CHECK: [[a]] = const 2_u32;
     let a = (&[1u32, 2, 3] as &[u32])[1];

tests/mir-opt/copy-prop/issue_107511.main.CopyProp.panic-abort.diff

@@ -47,7 +47,7 @@
           StorageLive(_6);
           StorageLive(_7);
           _7 = &_2;
-          _6 = move _7 as &[i32] (PointerCoercion(Unsize));
+          _6 = move _7 as &[i32] (PointerCoercion(Unsize, Implicit));
           StorageDead(_7);
           _5 = core::slice::<impl [i32]>::len(move _6) -> [return: bb1, unwind unreachable];
       }

tests/mir-opt/copy-prop/issue_107511.main.CopyProp.panic-unwind.diff

@@ -47,7 +47,7 @@
           StorageLive(_6);
           StorageLive(_7);
           _7 = &_2;
-          _6 = move _7 as &[i32] (PointerCoercion(Unsize));
+          _6 = move _7 as &[i32] (PointerCoercion(Unsize, Implicit));
           StorageDead(_7);
           _5 = core::slice::<impl [i32]>::len(move _6) -> [return: bb1, unwind continue];
       }

tests/mir-opt/dataflow-const-prop/default_boxed_slice.main.GVN.32bit.panic-abort.diff

@@ -89,7 +89,7 @@
 -         _4 = Unique::<[bool; 0]> { pointer: move _5, _marker: const PhantomData::<[bool; 0]> };
 +         _4 = const Unique::<[bool; 0]> {{ pointer: NonNull::<[bool; 0]> {{ pointer: {0x1 as *const [bool; 0]} }}, _marker: PhantomData::<[bool; 0]> }};
           StorageDead(_5);
--         _3 = move _4 as std::ptr::Unique<[bool]> (PointerCoercion(Unsize));
+-         _3 = move _4 as std::ptr::Unique<[bool]> (PointerCoercion(Unsize, Implicit));
 +         _3 = const Unique::<[bool]> {{ pointer: NonNull::<[bool]> {{ pointer: Indirect { alloc_id: ALLOC0, offset: Size(0 bytes) }: *const [bool] }}, _marker: PhantomData::<[bool]> }};
           StorageDead(_4);
 -         _2 = Box::<[bool]>(copy _3, const std::alloc::Global);

tests/mir-opt/dataflow-const-prop/default_boxed_slice.main.GVN.32bit.panic-unwind.diff

@@ -93,7 +93,7 @@
 -         _4 = Unique::<[bool; 0]> { pointer: move _5, _marker: const PhantomData::<[bool; 0]> };
 +         _4 = const Unique::<[bool; 0]> {{ pointer: NonNull::<[bool; 0]> {{ pointer: {0x1 as *const [bool; 0]} }}, _marker: PhantomData::<[bool; 0]> }};
           StorageDead(_5);
--         _3 = move _4 as std::ptr::Unique<[bool]> (PointerCoercion(Unsize));
+-         _3 = move _4 as std::ptr::Unique<[bool]> (PointerCoercion(Unsize, Implicit));
 +         _3 = const Unique::<[bool]> {{ pointer: NonNull::<[bool]> {{ pointer: Indirect { alloc_id: ALLOC0, offset: Size(0 bytes) }: *const [bool] }}, _marker: PhantomData::<[bool]> }};
           StorageDead(_4);
 -         _2 = Box::<[bool]>(copy _3, const std::alloc::Global);

tests/mir-opt/dataflow-const-prop/default_boxed_slice.main.GVN.64bit.panic-abort.diff

@@ -89,7 +89,7 @@
 -         _4 = Unique::<[bool; 0]> { pointer: move _5, _marker: const PhantomData::<[bool; 0]> };
 +         _4 = const Unique::<[bool; 0]> {{ pointer: NonNull::<[bool; 0]> {{ pointer: {0x1 as *const [bool; 0]} }}, _marker: PhantomData::<[bool; 0]> }};
           StorageDead(_5);
--         _3 = move _4 as std::ptr::Unique<[bool]> (PointerCoercion(Unsize));
+-         _3 = move _4 as std::ptr::Unique<[bool]> (PointerCoercion(Unsize, Implicit));
 +         _3 = const Unique::<[bool]> {{ pointer: NonNull::<[bool]> {{ pointer: Indirect { alloc_id: ALLOC0, offset: Size(0 bytes) }: *const [bool] }}, _marker: PhantomData::<[bool]> }};
           StorageDead(_4);
 -         _2 = Box::<[bool]>(copy _3, const std::alloc::Global);

tests/mir-opt/dataflow-const-prop/default_boxed_slice.main.GVN.64bit.panic-unwind.diff

@@ -93,7 +93,7 @@
 -         _4 = Unique::<[bool; 0]> { pointer: move _5, _marker: const PhantomData::<[bool; 0]> };
 +         _4 = const Unique::<[bool; 0]> {{ pointer: NonNull::<[bool; 0]> {{ pointer: {0x1 as *const [bool; 0]} }}, _marker: PhantomData::<[bool; 0]> }};
           StorageDead(_5);
--         _3 = move _4 as std::ptr::Unique<[bool]> (PointerCoercion(Unsize));
+-         _3 = move _4 as std::ptr::Unique<[bool]> (PointerCoercion(Unsize, Implicit));
 +         _3 = const Unique::<[bool]> {{ pointer: NonNull::<[bool]> {{ pointer: Indirect { alloc_id: ALLOC0, offset: Size(0 bytes) }: *const [bool] }}, _marker: PhantomData::<[bool]> }};
           StorageDead(_4);
 -         _2 = Box::<[bool]>(copy _3, const std::alloc::Global);

tests/mir-opt/dataflow-const-prop/slice_len.main.DataflowConstProp.32bit.panic-abort.diff

@@ -32,7 +32,7 @@
           _14 = const main::promoted[0];
           _4 = copy _14;
           _3 = copy _4;
-          _2 = move _3 as &[u32] (PointerCoercion(Unsize));
+          _2 = move _3 as &[u32] (PointerCoercion(Unsize, AsCast));
           StorageDead(_3);
           StorageLive(_6);
           _6 = const 1_usize;

tests/mir-opt/dataflow-const-prop/slice_len.main.DataflowConstProp.32bit.panic-unwind.diff

@@ -32,7 +32,7 @@
           _14 = const main::promoted[0];
           _4 = copy _14;
           _3 = copy _4;
-          _2 = move _3 as &[u32] (PointerCoercion(Unsize));
+          _2 = move _3 as &[u32] (PointerCoercion(Unsize, AsCast));
           StorageDead(_3);
           StorageLive(_6);
           _6 = const 1_usize;

tests/mir-opt/dataflow-const-prop/slice_len.main.DataflowConstProp.64bit.panic-abort.diff

@@ -32,7 +32,7 @@
           _14 = const main::promoted[0];
           _4 = copy _14;
           _3 = copy _4;
-          _2 = move _3 as &[u32] (PointerCoercion(Unsize));
+          _2 = move _3 as &[u32] (PointerCoercion(Unsize, AsCast));
           StorageDead(_3);
           StorageLive(_6);
           _6 = const 1_usize;

tests/mir-opt/dataflow-const-prop/slice_len.main.DataflowConstProp.64bit.panic-unwind.diff

@@ -32,7 +32,7 @@
           _14 = const main::promoted[0];
           _4 = copy _14;
           _3 = copy _4;
-          _2 = move _3 as &[u32] (PointerCoercion(Unsize));
+          _2 = move _3 as &[u32] (PointerCoercion(Unsize, AsCast));
           StorageDead(_3);
           StorageLive(_6);
           _6 = const 1_usize;

tests/mir-opt/gvn.array_len.GVN.panic-abort.diff

@@ -16,7 +16,7 @@
 +         nop;
           StorageLive(_3);
           _3 = &(*_1);
-          _2 = move _3 as &[i32] (PointerCoercion(Unsize));
+          _2 = move _3 as &[i32] (PointerCoercion(Unsize, Implicit));
           StorageDead(_3);
           StorageLive(_4);
           _4 = &raw const (*_2);

tests/mir-opt/gvn.array_len.GVN.panic-unwind.diff

@@ -16,7 +16,7 @@
 +         nop;
           StorageLive(_3);
           _3 = &(*_1);
-          _2 = move _3 as &[i32] (PointerCoercion(Unsize));
+          _2 = move _3 as &[i32] (PointerCoercion(Unsize, Implicit));
           StorageDead(_3);
           StorageLive(_4);
           _4 = &raw const (*_2);

tests/mir-opt/gvn.fn_pointers.GVN.panic-abort.diff

@@ -37,7 +37,7 @@
       bb0: {
 -         StorageLive(_1);
 +         nop;
-          _1 = identity::<u8> as fn(u8) -> u8 (PointerCoercion(ReifyFnPointer));
+          _1 = identity::<u8> as fn(u8) -> u8 (PointerCoercion(ReifyFnPointer, AsCast));
           StorageLive(_2);
           StorageLive(_3);
           _3 = copy _1;
@@ -50,7 +50,7 @@
           StorageDead(_2);
 -         StorageLive(_4);
 +         nop;
-          _4 = identity::<u8> as fn(u8) -> u8 (PointerCoercion(ReifyFnPointer));
+          _4 = identity::<u8> as fn(u8) -> u8 (PointerCoercion(ReifyFnPointer, AsCast));
           StorageLive(_5);
           StorageLive(_6);
           _6 = copy _4;
@@ -69,9 +69,9 @@
 +         nop;
           StorageLive(_9);
 -         _9 = copy _7;
--         _8 = move _9 as fn() (PointerCoercion(ClosureFnPointer(Safe)));
+-         _8 = move _9 as fn() (PointerCoercion(ClosureFnPointer(Safe), AsCast));
 +         _9 = const ZeroSized: {closure@$DIR/gvn.rs:614:19: 614:21};
-+         _8 = const ZeroSized: {closure@$DIR/gvn.rs:614:19: 614:21} as fn() (PointerCoercion(ClosureFnPointer(Safe)));
++         _8 = const ZeroSized: {closure@$DIR/gvn.rs:614:19: 614:21} as fn() (PointerCoercion(ClosureFnPointer(Safe), AsCast));
           StorageDead(_9);
           StorageLive(_10);
           StorageLive(_11);
@@ -87,9 +87,9 @@
 +         nop;
           StorageLive(_13);
 -         _13 = copy _7;
--         _12 = move _13 as fn() (PointerCoercion(ClosureFnPointer(Safe)));
+-         _12 = move _13 as fn() (PointerCoercion(ClosureFnPointer(Safe), AsCast));
 +         _13 = const ZeroSized: {closure@$DIR/gvn.rs:614:19: 614:21};
-+         _12 = const ZeroSized: {closure@$DIR/gvn.rs:614:19: 614:21} as fn() (PointerCoercion(ClosureFnPointer(Safe)));
++         _12 = const ZeroSized: {closure@$DIR/gvn.rs:614:19: 614:21} as fn() (PointerCoercion(ClosureFnPointer(Safe), AsCast));
           StorageDead(_13);
           StorageLive(_14);
           StorageLive(_15);

tests/mir-opt/gvn.fn_pointers.GVN.panic-unwind.diff

@@ -37,7 +37,7 @@
       bb0: {
 -         StorageLive(_1);
 +         nop;
-          _1 = identity::<u8> as fn(u8) -> u8 (PointerCoercion(ReifyFnPointer));
+          _1 = identity::<u8> as fn(u8) -> u8 (PointerCoercion(ReifyFnPointer, AsCast));
           StorageLive(_2);
           StorageLive(_3);
           _3 = copy _1;
@@ -50,7 +50,7 @@
           StorageDead(_2);
 -         StorageLive(_4);
 +         nop;
-          _4 = identity::<u8> as fn(u8) -> u8 (PointerCoercion(ReifyFnPointer));
+          _4 = identity::<u8> as fn(u8) -> u8 (PointerCoercion(ReifyFnPointer, AsCast));
           StorageLive(_5);
           StorageLive(_6);
           _6 = copy _4;
@@ -69,9 +69,9 @@
 +         nop;
           StorageLive(_9);
 -         _9 = copy _7;
--         _8 = move _9 as fn() (PointerCoercion(ClosureFnPointer(Safe)));
+-         _8 = move _9 as fn() (PointerCoercion(ClosureFnPointer(Safe), AsCast));
 +         _9 = const ZeroSized: {closure@$DIR/gvn.rs:614:19: 614:21};
-+         _8 = const ZeroSized: {closure@$DIR/gvn.rs:614:19: 614:21} as fn() (PointerCoercion(ClosureFnPointer(Safe)));
++         _8 = const ZeroSized: {closure@$DIR/gvn.rs:614:19: 614:21} as fn() (PointerCoercion(ClosureFnPointer(Safe), AsCast));
           StorageDead(_9);
           StorageLive(_10);
           StorageLive(_11);
@@ -87,9 +87,9 @@
 +         nop;
           StorageLive(_13);
 -         _13 = copy _7;
--         _12 = move _13 as fn() (PointerCoercion(ClosureFnPointer(Safe)));
+-         _12 = move _13 as fn() (PointerCoercion(ClosureFnPointer(Safe), AsCast));
 +         _13 = const ZeroSized: {closure@$DIR/gvn.rs:614:19: 614:21};
-+         _12 = const ZeroSized: {closure@$DIR/gvn.rs:614:19: 614:21} as fn() (PointerCoercion(ClosureFnPointer(Safe)));
++         _12 = const ZeroSized: {closure@$DIR/gvn.rs:614:19: 614:21} as fn() (PointerCoercion(ClosureFnPointer(Safe), AsCast));
           StorageDead(_13);
           StorageLive(_14);
           StorageLive(_15);

tests/mir-opt/gvn.wide_ptr_provenance.GVN.panic-abort.diff

@@ -64,10 +64,10 @@
           _44 = const wide_ptr_provenance::promoted[1];
           _5 = &(*_44);
           _4 = &(*_5);
-          _3 = move _4 as &dyn std::marker::Send (PointerCoercion(Unsize));
+          _3 = move _4 as &dyn std::marker::Send (PointerCoercion(Unsize, AsCast));
           StorageDead(_4);
           _2 = &raw const (*_3);
--         _1 = move _2 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _1 = move _2 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 -         StorageDead(_2);
 +         _1 = copy _2;
 +         nop;
@@ -82,10 +82,10 @@
           _43 = const wide_ptr_provenance::promoted[0];
           _11 = &(*_43);
           _10 = &(*_11);
-          _9 = move _10 as &dyn std::marker::Send (PointerCoercion(Unsize));
+          _9 = move _10 as &dyn std::marker::Send (PointerCoercion(Unsize, AsCast));
           StorageDead(_10);
           _8 = &raw const (*_9);
--         _7 = move _8 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _7 = move _8 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 -         StorageDead(_8);
 +         _7 = copy _8;
 +         nop;
@@ -99,7 +99,7 @@
           StorageLive(_16);
           StorageLive(_17);
 -         _17 = copy _7;
--         _16 = move _17 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _16 = move _17 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 +         _17 = copy _8;
 +         _16 = copy _8;
           StorageDead(_17);
@@ -121,7 +121,7 @@
           StorageLive(_21);
           StorageLive(_22);
 -         _22 = copy _7;
--         _21 = move _22 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _21 = move _22 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 +         _22 = copy _8;
 +         _21 = copy _8;
           StorageDead(_22);
@@ -143,7 +143,7 @@
           StorageLive(_26);
           StorageLive(_27);
 -         _27 = copy _7;
--         _26 = move _27 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _26 = move _27 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 +         _27 = copy _8;
 +         _26 = copy _8;
           StorageDead(_27);
@@ -165,7 +165,7 @@
           StorageLive(_31);
           StorageLive(_32);
 -         _32 = copy _7;
--         _31 = move _32 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _31 = move _32 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 +         _32 = copy _8;
 +         _31 = copy _8;
           StorageDead(_32);
@@ -187,7 +187,7 @@
           StorageLive(_36);
           StorageLive(_37);
 -         _37 = copy _7;
--         _36 = move _37 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _36 = move _37 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 +         _37 = copy _8;
 +         _36 = copy _8;
           StorageDead(_37);
@@ -209,7 +209,7 @@
           StorageLive(_41);
           StorageLive(_42);
 -         _42 = copy _7;
--         _41 = move _42 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _41 = move _42 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 +         _42 = copy _8;
 +         _41 = copy _8;
           StorageDead(_42);

tests/mir-opt/gvn.wide_ptr_provenance.GVN.panic-unwind.diff

@@ -64,10 +64,10 @@
           _44 = const wide_ptr_provenance::promoted[1];
           _5 = &(*_44);
           _4 = &(*_5);
-          _3 = move _4 as &dyn std::marker::Send (PointerCoercion(Unsize));
+          _3 = move _4 as &dyn std::marker::Send (PointerCoercion(Unsize, AsCast));
           StorageDead(_4);
           _2 = &raw const (*_3);
--         _1 = move _2 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _1 = move _2 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 -         StorageDead(_2);
 +         _1 = copy _2;
 +         nop;
@@ -82,10 +82,10 @@
           _43 = const wide_ptr_provenance::promoted[0];
           _11 = &(*_43);
           _10 = &(*_11);
-          _9 = move _10 as &dyn std::marker::Send (PointerCoercion(Unsize));
+          _9 = move _10 as &dyn std::marker::Send (PointerCoercion(Unsize, AsCast));
           StorageDead(_10);
           _8 = &raw const (*_9);
--         _7 = move _8 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _7 = move _8 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 -         StorageDead(_8);
 +         _7 = copy _8;
 +         nop;
@@ -99,7 +99,7 @@
           StorageLive(_16);
           StorageLive(_17);
 -         _17 = copy _7;
--         _16 = move _17 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _16 = move _17 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 +         _17 = copy _8;
 +         _16 = copy _8;
           StorageDead(_17);
@@ -121,7 +121,7 @@
           StorageLive(_21);
           StorageLive(_22);
 -         _22 = copy _7;
--         _21 = move _22 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _21 = move _22 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 +         _22 = copy _8;
 +         _21 = copy _8;
           StorageDead(_22);
@@ -143,7 +143,7 @@
           StorageLive(_26);
           StorageLive(_27);
 -         _27 = copy _7;
--         _26 = move _27 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _26 = move _27 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 +         _27 = copy _8;
 +         _26 = copy _8;
           StorageDead(_27);
@@ -165,7 +165,7 @@
           StorageLive(_31);
           StorageLive(_32);
 -         _32 = copy _7;
--         _31 = move _32 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _31 = move _32 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 +         _32 = copy _8;
 +         _31 = copy _8;
           StorageDead(_32);
@@ -187,7 +187,7 @@
           StorageLive(_36);
           StorageLive(_37);
 -         _37 = copy _7;
--         _36 = move _37 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _36 = move _37 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 +         _37 = copy _8;
 +         _36 = copy _8;
           StorageDead(_37);
@@ -209,7 +209,7 @@
           StorageLive(_41);
           StorageLive(_42);
 -         _42 = copy _7;
--         _41 = move _42 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _41 = move _42 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 +         _42 = copy _8;
 +         _41 = copy _8;
           StorageDead(_42);

tests/mir-opt/gvn.wide_ptr_same_provenance.GVN.panic-abort.diff

@@ -86,10 +86,10 @@
 -         _7 = &(*_1)[_8];
 +         _7 = &(*_1)[0 of 1];
           _6 = &(*_7);
-          _5 = move _6 as &dyn std::marker::Send (PointerCoercion(Unsize));
+          _5 = move _6 as &dyn std::marker::Send (PointerCoercion(Unsize, AsCast));
           StorageDead(_6);
           _4 = &raw const (*_5);
--         _3 = move _4 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _3 = move _4 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 -         StorageDead(_4);
 +         _3 = copy _4;
 +         nop;
@@ -115,10 +115,10 @@
 -         _15 = &(*_1)[_16];
 +         _15 = &(*_1)[1 of 2];
           _14 = &(*_15);
-          _13 = move _14 as &dyn std::marker::Send (PointerCoercion(Unsize));
+          _13 = move _14 as &dyn std::marker::Send (PointerCoercion(Unsize, AsCast));
           StorageDead(_14);
           _12 = &raw const (*_13);
--         _11 = move _12 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _11 = move _12 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 -         StorageDead(_12);
 +         _11 = copy _12;
 +         nop;
@@ -132,7 +132,7 @@
           StorageLive(_22);
           StorageLive(_23);
 -         _23 = copy _11;
--         _22 = move _23 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _22 = move _23 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 +         _23 = copy _12;
 +         _22 = copy _12;
           StorageDead(_23);
@@ -154,7 +154,7 @@
           StorageLive(_27);
           StorageLive(_28);
 -         _28 = copy _11;
--         _27 = move _28 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _27 = move _28 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 +         _28 = copy _12;
 +         _27 = copy _12;
           StorageDead(_28);
@@ -176,7 +176,7 @@
           StorageLive(_32);
           StorageLive(_33);
 -         _33 = copy _11;
--         _32 = move _33 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _32 = move _33 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 +         _33 = copy _12;
 +         _32 = copy _12;
           StorageDead(_33);
@@ -198,7 +198,7 @@
           StorageLive(_37);
           StorageLive(_38);
 -         _38 = copy _11;
--         _37 = move _38 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _37 = move _38 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 +         _38 = copy _12;
 +         _37 = copy _12;
           StorageDead(_38);
@@ -220,7 +220,7 @@
           StorageLive(_42);
           StorageLive(_43);
 -         _43 = copy _11;
--         _42 = move _43 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _42 = move _43 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 +         _43 = copy _12;
 +         _42 = copy _12;
           StorageDead(_43);
@@ -242,7 +242,7 @@
           StorageLive(_47);
           StorageLive(_48);
 -         _48 = copy _11;
--         _47 = move _48 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _47 = move _48 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 +         _48 = copy _12;
 +         _47 = copy _12;
           StorageDead(_48);

tests/mir-opt/gvn.wide_ptr_same_provenance.GVN.panic-unwind.diff

@@ -86,10 +86,10 @@
 -         _7 = &(*_1)[_8];
 +         _7 = &(*_1)[0 of 1];
           _6 = &(*_7);
-          _5 = move _6 as &dyn std::marker::Send (PointerCoercion(Unsize));
+          _5 = move _6 as &dyn std::marker::Send (PointerCoercion(Unsize, AsCast));
           StorageDead(_6);
           _4 = &raw const (*_5);
--         _3 = move _4 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _3 = move _4 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 -         StorageDead(_4);
 +         _3 = copy _4;
 +         nop;
@@ -115,10 +115,10 @@
 -         _15 = &(*_1)[_16];
 +         _15 = &(*_1)[1 of 2];
           _14 = &(*_15);
-          _13 = move _14 as &dyn std::marker::Send (PointerCoercion(Unsize));
+          _13 = move _14 as &dyn std::marker::Send (PointerCoercion(Unsize, AsCast));
           StorageDead(_14);
           _12 = &raw const (*_13);
--         _11 = move _12 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _11 = move _12 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 -         StorageDead(_12);
 +         _11 = copy _12;
 +         nop;
@@ -132,7 +132,7 @@
           StorageLive(_22);
           StorageLive(_23);
 -         _23 = copy _11;
--         _22 = move _23 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _22 = move _23 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 +         _23 = copy _12;
 +         _22 = copy _12;
           StorageDead(_23);
@@ -154,7 +154,7 @@
           StorageLive(_27);
           StorageLive(_28);
 -         _28 = copy _11;
--         _27 = move _28 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _27 = move _28 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 +         _28 = copy _12;
 +         _27 = copy _12;
           StorageDead(_28);
@@ -176,7 +176,7 @@
           StorageLive(_32);
           StorageLive(_33);
 -         _33 = copy _11;
--         _32 = move _33 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _32 = move _33 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 +         _33 = copy _12;
 +         _32 = copy _12;
           StorageDead(_33);
@@ -198,7 +198,7 @@
           StorageLive(_37);
           StorageLive(_38);
 -         _38 = copy _11;
--         _37 = move _38 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _37 = move _38 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 +         _38 = copy _12;
 +         _37 = copy _12;
           StorageDead(_38);
@@ -220,7 +220,7 @@
           StorageLive(_42);
           StorageLive(_43);
 -         _43 = copy _11;
--         _42 = move _43 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _42 = move _43 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 +         _43 = copy _12;
 +         _42 = copy _12;
           StorageDead(_43);
@@ -242,7 +242,7 @@
           StorageLive(_47);
           StorageLive(_48);
 -         _48 = copy _11;
--         _47 = move _48 as *const dyn std::marker::Send (PointerCoercion(Unsize));
+-         _47 = move _48 as *const dyn std::marker::Send (PointerCoercion(Unsize, Implicit));
 +         _48 = copy _12;
 +         _47 = copy _12;
           StorageDead(_48);

tests/mir-opt/inline/dyn_trait.get_query.Inline.panic-abort.diff

@@ -31,7 +31,7 @@
           _4 = copy _2;
 -         _0 = try_execute_query::<<Q as Query>::C>(move _4) -> [return: bb2, unwind unreachable];
 +         StorageLive(_5);
-+         _5 = copy _4 as &dyn Cache<V = <Q as Query>::V> (PointerCoercion(Unsize));
++         _5 = copy _4 as &dyn Cache<V = <Q as Query>::V> (PointerCoercion(Unsize, Implicit));
 +         _0 = <dyn Cache<V = <Q as Query>::V> as Cache>::store_nocache(move _5) -> [return: bb2, unwind unreachable];
       }
   

tests/mir-opt/inline/dyn_trait.get_query.Inline.panic-unwind.diff

@@ -31,7 +31,7 @@
           _4 = copy _2;
 -         _0 = try_execute_query::<<Q as Query>::C>(move _4) -> [return: bb2, unwind continue];
 +         StorageLive(_5);
-+         _5 = copy _4 as &dyn Cache<V = <Q as Query>::V> (PointerCoercion(Unsize));
++         _5 = copy _4 as &dyn Cache<V = <Q as Query>::V> (PointerCoercion(Unsize, Implicit));
 +         _0 = <dyn Cache<V = <Q as Query>::V> as Cache>::store_nocache(move _5) -> [return: bb2, unwind continue];
       }
   

tests/mir-opt/inline/dyn_trait.try_execute_query.Inline.panic-abort.diff

@@ -14,7 +14,7 @@
           StorageLive(_2);
           StorageLive(_3);
           _3 = copy _1;
-          _2 = move _3 as &dyn Cache<V = <C as Cache>::V> (PointerCoercion(Unsize));
+          _2 = move _3 as &dyn Cache<V = <C as Cache>::V> (PointerCoercion(Unsize, Implicit));
           StorageDead(_3);
 -         _0 = mk_cycle::<<C as Cache>::V>(move _2) -> [return: bb1, unwind unreachable];
 +         _0 = <dyn Cache<V = <C as Cache>::V> as Cache>::store_nocache(move _2) -> [return: bb1, unwind unreachable];

tests/mir-opt/inline/dyn_trait.try_execute_query.Inline.panic-unwind.diff

@@ -14,7 +14,7 @@
           StorageLive(_2);
           StorageLive(_3);
           _3 = copy _1;
-          _2 = move _3 as &dyn Cache<V = <C as Cache>::V> (PointerCoercion(Unsize));
+          _2 = move _3 as &dyn Cache<V = <C as Cache>::V> (PointerCoercion(Unsize, Implicit));
           StorageDead(_3);
 -         _0 = mk_cycle::<<C as Cache>::V>(move _2) -> [return: bb1, unwind continue];
 +         _0 = <dyn Cache<V = <C as Cache>::V> as Cache>::store_nocache(move _2) -> [return: bb1, unwind continue];

tests/mir-opt/issue_76432.test.SimplifyComparisonIntegral.panic-abort.diff

@@ -26,7 +26,7 @@
           StorageLive(_4);
           _4 = [copy _1, copy _1, copy _1];
           _3 = &_4;
-          _2 = copy _3 as &[T] (PointerCoercion(Unsize));
+          _2 = copy _3 as &[T] (PointerCoercion(Unsize, Implicit));
           nop;
           nop;
           goto -> bb2;

tests/mir-opt/issue_76432.test.SimplifyComparisonIntegral.panic-unwind.diff

@@ -26,7 +26,7 @@
           StorageLive(_4);
           _4 = [copy _1, copy _1, copy _1];
           _3 = &_4;
-          _2 = copy _3 as &[T] (PointerCoercion(Unsize));
+          _2 = copy _3 as &[T] (PointerCoercion(Unsize, Implicit));
           nop;
           nop;
           goto -> bb2;

tests/mir-opt/lower_array_len.array_bound.GVN.panic-abort.diff

@@ -24,7 +24,7 @@
           StorageLive(_6);
           StorageLive(_7);
           _7 = &(*_2);
-          _6 = move _7 as &[u8] (PointerCoercion(Unsize));
+          _6 = move _7 as &[u8] (PointerCoercion(Unsize, Implicit));
           StorageDead(_7);
 -         _5 = PtrMetadata(move _6);
 +         _5 = const N;

tests/mir-opt/lower_array_len.array_bound.GVN.panic-unwind.diff

@@ -24,7 +24,7 @@
           StorageLive(_6);
           StorageLive(_7);
           _7 = &(*_2);
-          _6 = move _7 as &[u8] (PointerCoercion(Unsize));
+          _6 = move _7 as &[u8] (PointerCoercion(Unsize, Implicit));
           StorageDead(_7);
 -         _5 = PtrMetadata(move _6);
 +         _5 = const N;

tests/mir-opt/lower_array_len.array_bound_mut.GVN.panic-abort.diff

@@ -27,7 +27,7 @@
           StorageLive(_6);
           StorageLive(_7);
           _7 = &(*_2);
-          _6 = move _7 as &[u8] (PointerCoercion(Unsize));
+          _6 = move _7 as &[u8] (PointerCoercion(Unsize, Implicit));
           StorageDead(_7);
 -         _5 = PtrMetadata(move _6);
 +         _5 = const N;

tests/mir-opt/lower_array_len.array_bound_mut.GVN.panic-unwind.diff

@@ -27,7 +27,7 @@
           StorageLive(_6);
           StorageLive(_7);
           _7 = &(*_2);
-          _6 = move _7 as &[u8] (PointerCoercion(Unsize));
+          _6 = move _7 as &[u8] (PointerCoercion(Unsize, Implicit));
           StorageDead(_7);
 -         _5 = PtrMetadata(move _6);
 +         _5 = const N;

tests/mir-opt/lower_array_len.array_len.GVN.panic-abort.diff

@@ -11,7 +11,7 @@
           StorageLive(_2);
           StorageLive(_3);
           _3 = &(*_1);
-          _2 = move _3 as &[u8] (PointerCoercion(Unsize));
+          _2 = move _3 as &[u8] (PointerCoercion(Unsize, Implicit));
           StorageDead(_3);
 -         _0 = PtrMetadata(move _2);
 +         _0 = const N;

tests/mir-opt/lower_array_len.array_len.GVN.panic-unwind.diff

@@ -11,7 +11,7 @@
           StorageLive(_2);
           StorageLive(_3);
           _3 = &(*_1);
-          _2 = move _3 as &[u8] (PointerCoercion(Unsize));
+          _2 = move _3 as &[u8] (PointerCoercion(Unsize, Implicit));
           StorageDead(_3);
 -         _0 = PtrMetadata(move _2);
 +         _0 = const N;

tests/mir-opt/lower_array_len.array_len_by_value.GVN.panic-abort.diff

@@ -11,7 +11,7 @@
           StorageLive(_2);
           StorageLive(_3);
           _3 = &_1;
-          _2 = move _3 as &[u8] (PointerCoercion(Unsize));
+          _2 = move _3 as &[u8] (PointerCoercion(Unsize, Implicit));
           StorageDead(_3);
 -         _0 = PtrMetadata(move _2);
 +         _0 = const N;

tests/mir-opt/lower_array_len.array_len_by_value.GVN.panic-unwind.diff

@@ -11,7 +11,7 @@
           StorageLive(_2);
           StorageLive(_3);
           _3 = &_1;
-          _2 = move _3 as &[u8] (PointerCoercion(Unsize));
+          _2 = move _3 as &[u8] (PointerCoercion(Unsize, Implicit));
           StorageDead(_3);
 -         _0 = PtrMetadata(move _2);
 +         _0 = const N;

tests/mir-opt/lower_array_len.array_len_raw.GVN.panic-abort.diff

@@ -24,7 +24,7 @@
           StorageLive(_4);
           _4 = &_1;
           _3 = &(*_4);
-          _2 = move _3 as &[u8] (PointerCoercion(Unsize));
+          _2 = move _3 as &[u8] (PointerCoercion(Unsize, Implicit));
           StorageDead(_3);
           StorageDead(_4);
           StorageLive(_5);

tests/mir-opt/lower_array_len.array_len_raw.GVN.panic-unwind.diff

@@ -24,7 +24,7 @@
           StorageLive(_4);
           _4 = &_1;
           _3 = &(*_4);
-          _2 = move _3 as &[u8] (PointerCoercion(Unsize));
+          _2 = move _3 as &[u8] (PointerCoercion(Unsize, Implicit));
           StorageDead(_3);
           StorageDead(_4);
           StorageLive(_5);

tests/mir-opt/lower_array_len.array_len_reborrow.GVN.panic-abort.diff

@@ -23,7 +23,7 @@
           StorageLive(_4);
           _4 = &mut _1;
           _3 = &mut (*_4);
-          _2 = move _3 as &mut [u8] (PointerCoercion(Unsize));
+          _2 = move _3 as &mut [u8] (PointerCoercion(Unsize, Implicit));
           StorageDead(_3);
           StorageDead(_4);
           StorageLive(_5);

tests/mir-opt/lower_array_len.array_len_reborrow.GVN.panic-unwind.diff

@@ -23,7 +23,7 @@
           StorageLive(_4);
           _4 = &mut _1;
           _3 = &mut (*_4);
-          _2 = move _3 as &mut [u8] (PointerCoercion(Unsize));
+          _2 = move _3 as &mut [u8] (PointerCoercion(Unsize, Implicit));
           StorageDead(_3);
           StorageDead(_4);
           StorageLive(_5);

tests/mir-opt/pre-codegen/issue_117368_print_invalid_constant.main.GVN.32bit.panic-abort.diff

@@ -93,7 +93,7 @@
       bb5: {
           StorageLive(_15);
           _16 = &_13;
-          _15 = copy _16 as &dyn std::fmt::Debug (PointerCoercion(Unsize));
+          _15 = copy _16 as &dyn std::fmt::Debug (PointerCoercion(Unsize, Implicit));
           _14 = result::unwrap_failed(const "called `Result::unwrap()` on an `Err` value", move _15) -> unwind unreachable;
       }
   

tests/mir-opt/pre-codegen/issue_117368_print_invalid_constant.main.GVN.64bit.panic-abort.diff

@@ -93,7 +93,7 @@
       bb5: {
           StorageLive(_15);
           _16 = &_13;
-          _15 = copy _16 as &dyn std::fmt::Debug (PointerCoercion(Unsize));
+          _15 = copy _16 as &dyn std::fmt::Debug (PointerCoercion(Unsize, Implicit));
           _14 = result::unwrap_failed(const "called `Result::unwrap()` on an `Err` value", move _15) -> unwind unreachable;
       }
   

tests/mir-opt/retag.main.SimplifyCfg-pre-optimizations.after.panic-abort.mir

@@ -105,7 +105,7 @@ fn main() -> () {
         StorageLive(_14);
         _14 = {closure@main::{closure#0}};
         Retag(_14);
-        _13 = move _14 as for<'a> fn(&'a i32) -> &'a i32 (PointerCoercion(ClosureFnPointer(Safe)));
+        _13 = move _14 as for<'a> fn(&'a i32) -> &'a i32 (PointerCoercion(ClosureFnPointer(Safe), Implicit));
         StorageDead(_14);
         StorageLive(_15);
         StorageLive(_16);

tests/mir-opt/retag.main.SimplifyCfg-pre-optimizations.after.panic-unwind.mir

@@ -105,7 +105,7 @@ fn main() -> () {
         StorageLive(_14);
         _14 = {closure@main::{closure#0}};
         Retag(_14);
-        _13 = move _14 as for<'a> fn(&'a i32) -> &'a i32 (PointerCoercion(ClosureFnPointer(Safe)));
+        _13 = move _14 as for<'a> fn(&'a i32) -> &'a i32 (PointerCoercion(ClosureFnPointer(Safe), Implicit));
         StorageDead(_14);
         StorageLive(_15);
         StorageLive(_16);

tests/mir-opt/simplify_locals.c.SimplifyLocals-before-const-prop.diff

@@ -21,7 +21,7 @@
 -         StorageLive(_4);
 -         _4 = &_1;
 -         _3 = &(*_4);
--         _2 = move _3 as &[u8] (PointerCoercion(Unsize));
+-         _2 = move _3 as &[u8] (PointerCoercion(Unsize, Implicit));
 -         StorageDead(_3);
 -         StorageDead(_4);
 -         StorageDead(_2);

tests/mir-opt/sroa/lifetimes.foo.ScalarReplacementOfAggregates.diff

@@ -61,7 +61,7 @@
       }
   
       bb1: {
-          _3 = move _4 as std::boxed::Box<dyn std::fmt::Display> (PointerCoercion(Unsize));
+          _3 = move _4 as std::boxed::Box<dyn std::fmt::Display> (PointerCoercion(Unsize, Implicit));
           StorageDead(_4);
           _2 = Result::<Box<dyn std::fmt::Display>, <T as Err>::Err>::Ok(move _3);
           StorageDead(_3);

tests/ui/lifetimes/issue-90600-expected-return-static-indirect.stderr

@@ -7,7 +7,7 @@ LL |     let refcell = RefCell::new(&mut foo);
    |                                ^^^^^^^^ borrowed value does not live long enough
 LL |
 LL |     let read = &refcell as &RefCell<dyn Read>;
-   |                -------- coercion requires that `foo` is borrowed for `'static`
+   |                ------------------------------ cast requires that `foo` is borrowed for `'static`
 ...
 LL | }
    |  - `foo` dropped here while still borrowed
@@ -19,7 +19,7 @@ LL | fn inner(mut foo: &[u8]) {
    |                   - let's call the lifetime of this reference `'1`
 ...
 LL |     let read = &refcell as &RefCell<dyn Read>;
-   |                ^^^^^^^^ coercion requires that `'1` must outlive `'static`
+   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cast requires that `'1` must outlive `'static`
 
 error: aborting due to 2 previous errors
 

tests/ui/regions/regions-close-object-into-object-4.stderr

@@ -30,12 +30,11 @@ error[E0310]: the parameter type `U` may not live long enough
   --> $DIR/regions-close-object-into-object-4.rs:9:5
    |
 LL |     Box::new(B(&*v)) as Box<dyn X>
-   |     ^^^^^^^^^^^^^^^^
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |     |
    |     the parameter type `U` must be valid for the static lifetime...
    |     ...so that the type `U` will meet its required lifetime bounds
    |
-   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 help: consider adding an explicit lifetime bound
    |
 LL | fn i<'a, T, U: 'static>(v: Box<dyn A<U>+'a>) -> Box<dyn X + 'static> {

tests/ui/regions/regions-close-object-into-object-5.stderr

@@ -30,12 +30,11 @@ error[E0310]: the parameter type `T` may not live long enough
   --> $DIR/regions-close-object-into-object-5.rs:17:5
    |
 LL |     Box::new(B(&*v)) as Box<dyn X>
-   |     ^^^^^^^^^^^^^^^^
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |     |
    |     the parameter type `T` must be valid for the static lifetime...
    |     ...so that the type `T` will meet its required lifetime bounds
    |
-   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 help: consider adding an explicit lifetime bound
    |
 LL | fn f<'a, T: 'static, U>(v: Box<A<T> + 'static>) -> Box<X + 'static> {

tests/ui/regions/regions-close-over-type-parameter-1.stderr

@@ -2,7 +2,7 @@ error[E0310]: the parameter type `A` may not live long enough
   --> $DIR/regions-close-over-type-parameter-1.rs:11:5
    |
 LL |     Box::new(v) as Box<dyn SomeTrait + 'static>
-   |     ^^^^^^^^^^^
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |     |
    |     the parameter type `A` must be valid for the static lifetime...
    |     ...so that the type `A` will meet its required lifetime bounds
@@ -18,7 +18,7 @@ error[E0309]: the parameter type `A` may not live long enough
 LL | fn make_object3<'a, 'b, A: SomeTrait + 'a>(v: A) -> Box<dyn SomeTrait + 'b> {
    |                     -- the parameter type `A` must be valid for the lifetime `'b` as defined here...
 LL |     Box::new(v) as Box<dyn SomeTrait + 'b>
-   |     ^^^^^^^^^^^ ...so that the type `A` will meet its required lifetime bounds
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ...so that the type `A` will meet its required lifetime bounds
    |
 help: consider adding an explicit lifetime bound
    |

tests/ui/suggestions/lifetimes/suggest-using-tick-underscore-lifetime-in-return-trait-object.stderr

@@ -4,7 +4,7 @@ error: lifetime may not live long enough
 LL | fn foo<T: Any>(value: &T) -> Box<dyn Any> {
    |                       - let's call the lifetime of this reference `'1`
 LL |     Box::new(value) as Box<dyn Any>
-   |     ^^^^^^^^^^^^^^^ coercion requires that `'1` must outlive `'static`
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cast requires that `'1` must outlive `'static`
    |
 help: to declare that the trait object captures data from argument `value`, you can add an explicit `'_` lifetime bound
    |