Comment move->copy transform.

cjgillot · web-flow · commit 9c5add14e7c1 · 2023-02-06T18:14:24.000+01:00
diff --git a/compiler/rustc_mir_transform/src/copy_prop.rs b/compiler/rustc_mir_transform/src/copy_prop.rs
@@ -153,6 +153,7 @@ impl<'tcx> MutVisitor<'tcx> for Replacer<'_, 'tcx> {
 
     fn visit_operand(&mut self, operand: &mut Operand<'tcx>, loc: Location) {
         if let Operand::Move(place) = *operand
+            // A move out of a projection of a copy is equivalent to a copy of the original projection.
             && !place.has_deref()
             && !self.fully_moved.contains(place.local)
         {

Original file line number	Diff line number	Diff line change
`@@ -153,6 +153,7 @@ impl<'tcx> MutVisitor<'tcx> for Replacer<'_, 'tcx> {`
`153`	`153`
`154`	`154`	`fn visit_operand(&mut self, operand: &mut Operand<'tcx>, loc: Location) {`
`155`	`155`	`if let Operand::Move(place) = *operand`
	`156`	`+ // A move out of a projection of a copy is equivalent to a copy of the original projection.`
`156`	`157`	`&& !place.has_deref()`
`157`	`158`	`&& !self.fully_moved.contains(place.local)`
`158`	`159`	`{`