Index: include/string
===================================================================
--- include/string
+++ include/string
@@ -1993,7 +1993,7 @@
 
 template <class _CharT, class _Traits, class _Allocator>
 inline _LIBCPP_INLINE_VISIBILITY
-basic_string<_CharT, _Traits, _Allocator>::basic_string(const allocator_type& __a)
+basic_string<_CharT, _Traits, _Allocator>::basic_string(const allocator_type& __a) noexcept(is_nothrow_copy_constructible<allocator_type>::value)
 #if _LIBCPP_STD_VER <= 14
         _NOEXCEPT_(is_nothrow_copy_constructible<allocator_type>::value)
 #else