Rollup merge of #139902 - lcnr:no-opaque-cast-projection, r=oli-obk

do not emit `OpaqueCast` projections with `-Znext-solver`

We normalize opaque types in their defining scope if the new solver is enabled. This means projections do not contain any 'revealable' opaque types we need to worry about. We either have a type which has been normalized by writeback or we need to normalize it anyways.

r? ```@compiler-errors``` ```@oli-obk```

1 files changed, 15 insertions, 13 deletions

diff --git a/compiler/rustc_mir_transform/src/post_analysis_normalize.rs b/compiler/rustc_mir_transform/src/post_analysis_normalize.rs
index 76c2f082c0b..5599dee4cca 100644
--- a/compiler/rustc_mir_transform/src/post_analysis_normalize.rs
+++ b/compiler/rustc_mir_transform/src/post_analysis_normalize.rs
@@ -39,20 +39,22 @@ impl<'tcx> MutVisitor<'tcx> for PostAnalysisNormalizeVisitor<'tcx> {
         _context: PlaceContext,
         _location: Location,
     ) {
-        // Performance optimization: don't reintern if there is no `OpaqueCast` to remove.
-        if place.projection.iter().all(|elem| !matches!(elem, ProjectionElem::OpaqueCast(_))) {
-            return;
+        if !self.tcx.next_trait_solver_globally() {
+            // `OpaqueCast` projections are only needed if there are opaque types on which projections
+            // are performed. After the `PostAnalysisNormalize` pass, all opaque types are replaced with their
+            // hidden types, so we don't need these projections anymore.
+            //
+            // Performance optimization: don't reintern if there is no `OpaqueCast` to remove.
+            if place.projection.iter().any(|elem| matches!(elem, ProjectionElem::OpaqueCast(_))) {
+                place.projection = self.tcx.mk_place_elems(
+                    &place
+                        .projection
+                        .into_iter()
+                        .filter(|elem| !matches!(elem, ProjectionElem::OpaqueCast(_)))
+                        .collect::<Vec<_>>(),
+                );
+            };
         }
-        // `OpaqueCast` projections are only needed if there are opaque types on which projections
-        // are performed. After the `PostAnalysisNormalize` pass, all opaque types are replaced with their
-        // hidden types, so we don't need these projections anymore.
-        place.projection = self.tcx.mk_place_elems(
-            &place
-                .projection
-                .into_iter()
-                .filter(|elem| !matches!(elem, ProjectionElem::OpaqueCast(_)))
-                .collect::<Vec<_>>(),
-        );
         self.super_place(place, _context, _location);
     }