Add a mir validation check to prevent OpaqueCast after analysis passes finish

1 files changed, 8 insertions, 0 deletions

diff --git a/compiler/rustc_const_eval/src/transform/validate.rs b/compiler/rustc_const_eval/src/transform/validate.rs
index 0d8733070a4..18b22882e7d 100644
--- a/compiler/rustc_const_eval/src/transform/validate.rs
+++ b/compiler/rustc_const_eval/src/transform/validate.rs
@@ -633,6 +633,14 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
         location: Location,
     ) {
         match elem {
+            ProjectionElem::OpaqueCast(ty)
+                if self.mir_phase >= MirPhase::Runtime(RuntimePhase::Initial) =>
+            {
+                self.fail(
+                    location,
+                    format!("explicit opaque type cast to `{ty}` after `RevealAll`"),
+                )
+            }
             ProjectionElem::Index(index) => {
                 let index_ty = self.body.local_decls[index].ty;
                 if index_ty != self.tcx.types.usize {