Fix transmute goal

3 files changed, 21 insertions, 5 deletions

diff --git a/compiler/rustc_trait_selection/src/traits/engine.rs b/compiler/rustc_trait_selection/src/traits/engine.rs
index a45ec8b3c44..5e270b62b00 100644
--- a/compiler/rustc_trait_selection/src/traits/engine.rs
+++ b/compiler/rustc_trait_selection/src/traits/engine.rs
@@ -329,4 +329,15 @@ where
             .at(cause, param_env)
             .structurally_normalize(value, &mut **self.engine.borrow_mut())
     }
+
+    pub fn structurally_normalize_const(
+        &self,
+        cause: &ObligationCause<'tcx>,
+        param_env: ty::ParamEnv<'tcx>,
+        value: ty::Const<'tcx>,
+    ) -> Result<ty::Const<'tcx>, Vec<E>> {
+        self.infcx
+            .at(cause, param_env)
+            .structurally_normalize_const(value, &mut **self.engine.borrow_mut())
+    }
 }
diff --git a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
index 0ba3b4e6e55..f78cd6c1aa0 100644
--- a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
@@ -405,11 +405,14 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
 
         let predicate = obligation.predicate.skip_binder();
 
-        let Some(assume) = rustc_transmute::Assume::from_const(
-            self.infcx.tcx,
-            obligation.param_env,
-            predicate.trait_ref.args.const_at(2),
-        ) else {
+        let mut assume = predicate.trait_ref.args.const_at(2);
+        // FIXME(min_generic_const_exprs): We should shallowly normalize this.
+        if self.tcx().features().generic_const_exprs {
+            assume = assume.normalize_internal(self.tcx(), obligation.param_env);
+        }
+        let Some(assume) =
+            rustc_transmute::Assume::from_const(self.infcx.tcx, obligation.param_env, assume)
+        else {
             return Err(Unimplemented);
         };
 
diff --git a/compiler/rustc_trait_selection/src/traits/structural_normalize.rs b/compiler/rustc_trait_selection/src/traits/structural_normalize.rs
index 3814f8112e9..f8d98eb856e 100644
--- a/compiler/rustc_trait_selection/src/traits/structural_normalize.rs
+++ b/compiler/rustc_trait_selection/src/traits/structural_normalize.rs
@@ -82,6 +82,8 @@ impl<'tcx> At<'_, 'tcx> {
             }
 
             Ok(self.infcx.resolve_vars_if_possible(new_infer_ct))
+        } else if self.infcx.tcx.features().generic_const_exprs {
+            Ok(ct.normalize_internal(self.infcx.tcx, self.param_env))
         } else {
             Ok(self.normalize(ct).into_value_registering_obligations(self.infcx, fulfill_cx))
         }