Revert "Auto merge of #92007 - oli-obk:lazy_tait2, r=nikomatsakis"

This reverts commit e7cc3bddbe, reversing
changes made to 734368a200.

compiler/rustc_const_eval/src/transform/validate.rs

@@ -79,6 +79,7 @@ pub fn equal_up_to_regions<'tcx>(
     }
 
     // Normalize lifetimes away on both sides, then compare.
+    let param_env = param_env.with_reveal_all_normalized(tcx);
     let normalize = |ty: Ty<'tcx>| {
         tcx.normalize_erasing_regions(
             param_env,
@@ -170,7 +171,9 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
             return true;
         }
         // Normalize projections and things like that.
-        let param_env = self.param_env;
+        // FIXME: We need to reveal_all, as some optimizations change types in ways
+        // that require unfolding opaque types.
+        let param_env = self.param_env.with_reveal_all_normalized(self.tcx);
         let src = self.tcx.normalize_erasing_regions(param_env, src);
         let dest = self.tcx.normalize_erasing_regions(param_env, dest);