foo.cpp:2:1: error: expected unqualified-id before '?' token
 ??? 2017/1/26 21:48:10
 ^
In file included from C:/MinGW32/lib/gcc/i686-w64-mingw32/6.3.0/include/c++/cmath:43:0,
                 from foo.cpp:5:
C:/MinGW32/lib/gcc/i686-w64-mingw32/6.3.0/include/c++/ext/type_traits.h:162:35: error: '__gnu_cxx::__is_null_pointer' declared as an 'inline' variable
   __is_null_pointer(std::nullptr_t)
                                   ^
C:/MinGW32/lib/gcc/i686-w64-mingw32/6.3.0/include/c++/ext/type_traits.h:162:35: error: 'bool __gnu_cxx::__is_null_pointer' redeclared as different kind of symbol
C:/MinGW32/lib/gcc/i686-w64-mingw32/6.3.0/include/c++/ext/type_traits.h:157:5: note: previous declaration 'template<class _Type> bool __gnu_cxx::__is_null_pointer(_Type)'
     __is_null_pointer(_Type)
     ^~~~~~~~~~~~~~~~~
C:/MinGW32/lib/gcc/i686-w64-mingw32/6.3.0/include/c++/ext/type_traits.h:162:21: error: 'nullptr_t' is not a member of 'std'
   __is_null_pointer(std::nullptr_t)
                     ^~~
In file included from C:/MinGW32/lib/gcc/i686-w64-mingw32/6.3.0/include/c++/bits/move.h:57:0,
                 from C:/MinGW32/lib/gcc/i686-w64-mingw32/6.3.0/include/c++/bits/stl_pair.h:59,
                 from C:/MinGW32/lib/gcc/i686-w64-mingw32/6.3.0/include/c++/utility:70,
                 from C:/MinGW32/lib/gcc/i686-w64-mingw32/6.3.0/include/c++/algorithm:60,
                 from foo.cpp:7:
C:/MinGW32/lib/gcc/i686-w64-mingw32/6.3.0/include/c++/type_traits:359:31: error: 'std::size_t' has not been declared
   template<typename _Tp, std::size_t _Size>
                               ^~~~~~
C:/MinGW32/lib/gcc/i686-w64-mingw32/6.3.0/include/c++/type_traits:360:25: error: '_Size' was not declared in this scope
     struct is_array<_Tp[_Size]>
                         ^~~~~
C:/MinGW32/lib/gcc/i686-w64-mingw32/6.3.0/include/c++/type_traits:360:31: error: template argument 1 is invalid
     struct is_array<_Tp[_Size]>
                               ^
C:/MinGW32/lib/gcc/i686-w64-mingw32/6.3.0/include/c++/type_traits:558:37: error: 'nullptr_t' is not a member of 'std'
     struct __is_null_pointer_helper<std::nullptr_t>
                                     ^~~
C:/MinGW32/lib/gcc/i686-w64-mingw32/6.3.0/include/c++/type_traits:558:37: error: 'nullptr_t' is not a member of 'std'
C:/MinGW32/lib/gcc/i686-w64-mingw32/6.3.0/include/c++/type_traits:558:51: error: template argument 1 is invalid
     struct __is_null_pointer_helper<std::nullptr_t>
                                                   ^
C:/MinGW32/lib/gcc/i686-w64-mingw32/6.3.0/include/c++/type_traits:1478:32: error: 'size_t' is not a member of 'std'
     : public integral_constant<std::size_t, __alignof__(_Tp)> { };
                                ^~~
C:/MinGW32/lib/gcc/i686-w64-mingw32/6.3.0/include/c++/type_traits:1478:32: note: suggested alternative:
In file included from C:/MinGW32/i686-w64-mingw32/include/stdio.h:9:0,
                 from C:/MinGW32/lib/gcc/i686-w64-mingw32/6.3.0/include/c++/cstdio:42,
                 from foo.cpp:3:
C:/MinGW32/i686-w64-mingw32/include/crtdefs.h:37:22: note:   'size_t'
 typedef unsigned int size_t;
                      ^~~~~~
In file included from C:/MinGW32/lib/gcc/i686-w64-mingw32/6.3.0/include/c++/bits/move.h:57:0,
                 from C:/MinGW32/lib/gcc/i686-w64-mingw32/6.3.0/include/c++/bits/stl_pair.h:59,
                 from C:/MinGW32/lib/gcc/i686-w64-mingw32/6.3.0/include/c++/utility:70,
                 from C:/MinGW32/lib/gcc/i686-w64-mingw32/6.3.0/include/c++/algorithm:60,
                 from foo.cpp:7:
C:/MinGW32/lib/gcc/i686-w64-mingw32/6.3.0/include/c++/type_traits:1478:32: error: 'size_t' is not a member of 'std'
     : public integral_constant<std::size_t, __alignof__(_Tp)> { };
                                ^~~
C:/MinGW32/lib/gcc/i686-w64-mingw32/6.3.0/include/c++/type_traits:1478:32: note: suggested alternative:
In file included from C:/MinGW32/i686-w64-mingw32/include/stdio.h:9:0,
                 from C:/MinGW32/lib/gcc/i686-w64-mingw32/6.3.0/include/c++/cstdio: