Should std::unique_ptr be permitted

Question

This is a very simple question. Consider the following code:

#include 
#include 

typedef std::unique_ptr UniqueVo         


        

Answer 1

MSVC is right while GCC is wrong:

Standard(3.9/5):

Incompletely-defined object types and the void types are incomplete types

Standard(20.7.1.1.2/4):

If T is an incomplete type, the program is ill-formed