Rollup merge of #144123 - oli-obk:ctfe-unsize, r=RalfJung

Generalize `unsize` and `unsize_into` destinations

Just something that I noticed during other work. We do this for most such functions, so let's do it here, too.

r? ``@RalfJung``

1 files changed, 4 insertions, 3 deletions

diff --git a/compiler/rustc_const_eval/src/interpret/cast.rs b/compiler/rustc_const_eval/src/interpret/cast.rs
index 7a73d70fc85..de4fbc7b475 100644
--- a/compiler/rustc_const_eval/src/interpret/cast.rs
+++ b/compiler/rustc_const_eval/src/interpret/cast.rs
@@ -17,6 +17,7 @@ use super::{
     throw_ub_custom,
 };
 use crate::fluent_generated as fluent;
+use crate::interpret::Writeable;
 
 impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
     pub fn cast(
@@ -358,7 +359,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
     fn unsize_into_ptr(
         &mut self,
         src: &OpTy<'tcx, M::Provenance>,
-        dest: &PlaceTy<'tcx, M::Provenance>,
+        dest: &impl Writeable<'tcx, M::Provenance>,
         // The pointee types
         source_ty: Ty<'tcx>,
         cast_ty: Ty<'tcx>,
@@ -455,7 +456,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         &mut self,
         src: &OpTy<'tcx, M::Provenance>,
         cast_ty: TyAndLayout<'tcx>,
-        dest: &PlaceTy<'tcx, M::Provenance>,
+        dest: &impl Writeable<'tcx, M::Provenance>,
     ) -> InterpResult<'tcx> {
         trace!("Unsizing {:?} of type {} into {}", *src, src.layout.ty, cast_ty.ty);
         match (src.layout.ty.kind(), cast_ty.ty.kind()) {
@@ -496,7 +497,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                     self.cur_span(),
                     "unsize_into: invalid conversion: {:?} -> {:?}",
                     src.layout,
-                    dest.layout
+                    dest.layout()
                 )
             }
         }