Add an early-exit to QueryNormalizer::fold_ty

Author: jonas-schievink

src/librustc/traits/query/normalize.rs

@@ -81,6 +81,10 @@ impl<'cx, 'tcx> TypeFolder<'tcx> for QueryNormalizer<'cx, 'tcx> {
     }
 
     fn fold_ty(&mut self, ty: Ty<'tcx>) -> Ty<'tcx> {
+        if !ty.has_projections() {
+            return ty;
+        }
+
         let ty = ty.super_fold_with(self);
         match ty.kind {
             ty::Opaque(def_id, substs) if !substs.has_escaping_bound_vars() => {