diff --git a/src/stacked_borrows.rs b/src/stacked_borrows.rs
index a90be317705a..41b5cc2a239d 100644
--- a/src/stacked_borrows.rs
+++ b/src/stacked_borrows.rs
@@ -322,9 +322,7 @@ impl<'tcx> Stack {
             }
             return;
         }
-        if self.frozen_since.is_some() {
-            bug!("Trying to create non-frozen reference to frozen location");
-        }
+        assert!(self.frozen_since.is_none(), "Trying to create non-frozen reference to frozen location");
 
         // Push new item to the stack.
         let itm = match bor {