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, 14 insertions, 11 deletions

diff --git a/compiler/rustc_mir_build/src/builder/matches/match_pair.rs b/compiler/rustc_mir_build/src/builder/matches/match_pair.rs
index 9670c1716f5..d66b38c5b00 100644
--- a/compiler/rustc_mir_build/src/builder/matches/match_pair.rs
+++ b/compiler/rustc_mir_build/src/builder/matches/match_pair.rs
@@ -101,18 +101,21 @@ impl<'tcx> MatchPairTree<'tcx> {
             place_builder = resolved;
         }
 
-        // Only add the OpaqueCast projection if the given place is an opaque type and the
-        // expected type from the pattern is not.
-        let may_need_cast = match place_builder.base() {
-            PlaceBase::Local(local) => {
-                let ty =
-                    Place::ty_from(local, place_builder.projection(), &cx.local_decls, cx.tcx).ty;
-                ty != pattern.ty && ty.has_opaque_types()
+        if !cx.tcx.next_trait_solver_globally() {
+            // Only add the OpaqueCast projection if the given place is an opaque type and the
+            // expected type from the pattern is not.
+            let may_need_cast = match place_builder.base() {
+                PlaceBase::Local(local) => {
+                    let ty =
+                        Place::ty_from(local, place_builder.projection(), &cx.local_decls, cx.tcx)
+                            .ty;
+                    ty != pattern.ty && ty.has_opaque_types()
+                }
+                _ => true,
+            };
+            if may_need_cast {
+                place_builder = place_builder.project(ProjectionElem::OpaqueCast(pattern.ty));
             }
-            _ => true,
-        };
-        if may_need_cast {
-            place_builder = place_builder.project(ProjectionElem::OpaqueCast(pattern.ty));
         }
 
         let place = place_builder.try_to_place(cx);