diff --git a/libcxx/include/string b/libcxx/include/string
--- a/libcxx/include/string
+++ b/libcxx/include/string
@@ -3941,7 +3941,7 @@
         return false;
     if (data() == 0)
         return false;
-    if (data()[size()] != value_type(0))
+    if (data()[size()] != value_type())
         return false;
     return true;
 }
@@ -3959,6 +3959,7 @@
         __alloc_traits::deallocate(__alloc(), __get_long_pointer(), capacity() + 1);
         __set_long_cap(0);
         __set_short_size(0);
+        traits_type::assign(*__get_short_pointer(), value_type());
     }
 }