diff --git a/library/core/src/cell.rs b/library/core/src/cell.rs
index c1cc892eb86..b1b15e84dbf 100644
--- a/library/core/src/cell.rs
+++ b/library/core/src/cell.rs
@@ -1756,7 +1756,7 @@ impl<'b> BorrowRefMut<'b> {
         let borrow = self.borrow.get();
         debug_assert!(is_writing(borrow));
         // Prevent the borrow counter from underflowing.
-        assert!(borrow != isize::MIN);
+        assert!(borrow != BorrowFlag::MIN);
         self.borrow.set(borrow - 1);
         BorrowRefMut { borrow: self.borrow }
     }