diff --git a/src/librustc/ty/layout.rs b/src/librustc/ty/layout.rs
index 71cdec0f83eca..d03b038d6edd7 100644
--- a/src/librustc/ty/layout.rs
+++ b/src/librustc/ty/layout.rs
@@ -779,7 +779,8 @@ impl<'a, 'tcx> LayoutCx<'tcx, TyCtxt<'a, 'tcx, 'tcx>> {
                                 scalar.valid_range = *scalar.valid_range.start()..=end;
                             }
                         }
-                        _ => bug!(
+                        _ => assert!(
+                            start == Bound::Unbounded && end == Bound::Unbounded,
                             "nonscalar layout for layout_scalar_valid_range type {:?}: {:#?}",
                             def,
                             st,