In the following code, the 'alignas' attribute on the declaration of s1a is marked as a syntax error, even though the C++ 14 grammar explicitly allows it. namespace a_ {   struct alignas(0) s1 { int i; }; } int main() {   using s1a alignas(0) = a_::s1; } Furthermore, alignas will currently be ignored in relaxed mode or marked as an error in strict mode if used to specify the alignment of an enumeration type or a lambda object.