diff --git a/src/taggedlen.rs b/src/taggedlen.rs
index 7e76ca8..c357165 100644
--- a/src/taggedlen.rs
+++ b/src/taggedlen.rs
@@ -66,8 +66,13 @@ impl<T> TaggedLen<T> {
             panic!("smallvec length overflow")
         }
         #[cfg(any(debug_assertions, not(target_pointer_width = "64")))]
-        if self.len().saturating_add(n) > Self::MAX_LEN {
-            assert_failed();
+        match self.len().checked_add(n) {
+            Some(value) => {
+                if value > Self::MAX_LEN {
+                    assert_failed()
+                }
+            }
+            None => assert_failed()
         }
         self.0 += n << Self::SHIFT;
     }