diff --git a/libcxx/include/string b/libcxx/include/string
--- a/libcxx/include/string
+++ b/libcxx/include/string
@@ -1551,7 +1551,7 @@
 
     // Slow path for the (inlined) copy constructor for 'long' strings.
     // Always externally instantiated and not inlined.
-    // Asserts that __s is zero terminated.
+    // Requires that __s is zero terminated.
     // The main reason for this function to exist is because for unstable, we
     // want to allow inlining of the copy constructor. However, we don't want
     // to call the __init() functions as those are marked as inline which may