Rollup merge of #98688 - RalfJung:from-mplace, r=oli-obk

interpret: add From<&MplaceTy> for PlaceTy

We have a similar instance for `&MPlaceTy` to `OpTy`. Also add the same for `&mut`.

This avoids having to write `&(*place).into()`, which we have a few times here and at least twice in Miri (and it comes up again in my current patch).

r? ```@oli-obk```

4 files changed, 24 insertions, 3 deletions

diff --git a/compiler/rustc_const_eval/src/interpret/intern.rs b/compiler/rustc_const_eval/src/interpret/intern.rs
index 1fda60c021e..c1d42c9ae7c 100644
--- a/compiler/rustc_const_eval/src/interpret/intern.rs
+++ b/compiler/rustc_const_eval/src/interpret/intern.rs
@@ -195,7 +195,7 @@ impl<'rt, 'mir, 'tcx: 'mir, M: CompileTimeMachine<'mir, 'tcx, const_eval::Memory
         let tcx = self.ecx.tcx;
         let ty = mplace.layout.ty;
         if let ty::Ref(_, referenced_ty, ref_mutability) = *ty.kind() {
-            let value = self.ecx.read_immediate(&(*mplace).into())?;
+            let value = self.ecx.read_immediate(&mplace.into())?;
             let mplace = self.ecx.ref_to_mplace(&value)?;
             assert_eq!(mplace.layout.ty, referenced_ty);
             // Handle trait object vtables.
diff --git a/compiler/rustc_const_eval/src/interpret/operand.rs b/compiler/rustc_const_eval/src/interpret/operand.rs
index 6b05a49575f..e7a08e05275 100644
--- a/compiler/rustc_const_eval/src/interpret/operand.rs
+++ b/compiler/rustc_const_eval/src/interpret/operand.rs
@@ -204,6 +204,13 @@ impl<'tcx, Tag: Provenance> From<&'_ MPlaceTy<'tcx, Tag>> for OpTy<'tcx, Tag> {
     }
 }
 
+impl<'tcx, Tag: Provenance> From<&'_ mut MPlaceTy<'tcx, Tag>> for OpTy<'tcx, Tag> {
+    #[inline(always)]
+    fn from(mplace: &mut MPlaceTy<'tcx, Tag>) -> Self {
+        OpTy { op: Operand::Indirect(**mplace), layout: mplace.layout }
+    }
+}
+
 impl<'tcx, Tag: Provenance> From<ImmTy<'tcx, Tag>> for OpTy<'tcx, Tag> {
     #[inline(always)]
     fn from(val: ImmTy<'tcx, Tag>) -> Self {
diff --git a/compiler/rustc_const_eval/src/interpret/place.rs b/compiler/rustc_const_eval/src/interpret/place.rs
index 3dbcba72baf..337fcd28c66 100644
--- a/compiler/rustc_const_eval/src/interpret/place.rs
+++ b/compiler/rustc_const_eval/src/interpret/place.rs
@@ -118,7 +118,21 @@ impl<'tcx, Tag: Provenance> std::ops::Deref for MPlaceTy<'tcx, Tag> {
 impl<'tcx, Tag: Provenance> From<MPlaceTy<'tcx, Tag>> for PlaceTy<'tcx, Tag> {
     #[inline(always)]
     fn from(mplace: MPlaceTy<'tcx, Tag>) -> Self {
-        PlaceTy { place: Place::Ptr(mplace.mplace), layout: mplace.layout }
+        PlaceTy { place: Place::Ptr(*mplace), layout: mplace.layout }
+    }
+}
+
+impl<'tcx, Tag: Provenance> From<&'_ MPlaceTy<'tcx, Tag>> for PlaceTy<'tcx, Tag> {
+    #[inline(always)]
+    fn from(mplace: &MPlaceTy<'tcx, Tag>) -> Self {
+        PlaceTy { place: Place::Ptr(**mplace), layout: mplace.layout }
+    }
+}
+
+impl<'tcx, Tag: Provenance> From<&'_ mut MPlaceTy<'tcx, Tag>> for PlaceTy<'tcx, Tag> {
+    #[inline(always)]
+    fn from(mplace: &mut MPlaceTy<'tcx, Tag>) -> Self {
+        PlaceTy { place: Place::Ptr(**mplace), layout: mplace.layout }
     }
 }
 
diff --git a/compiler/rustc_const_eval/src/interpret/visitor.rs b/compiler/rustc_const_eval/src/interpret/visitor.rs
index 679d30227f1..2b77ed89893 100644
--- a/compiler/rustc_const_eval/src/interpret/visitor.rs
+++ b/compiler/rustc_const_eval/src/interpret/visitor.rs
@@ -92,7 +92,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> Value<'mir, 'tcx, M>
         &self,
         _ecx: &InterpCx<'mir, 'tcx, M>,
     ) -> InterpResult<'tcx, OpTy<'tcx, M::PointerTag>> {
-        Ok((*self).into())
+        Ok(self.into())
     }
 
     #[inline(always)]