/in/foo.cc:4:13: warning: #pragma system_header ignored outside include file
 #pragma GCC system_header
             ^~~~~~~~~~~~~
/in/foo.cc:11:13: warning: #pragma system_header ignored outside include file
 #pragma GCC system_header
             ^~~~~~~~~~~~~
/in/foo.cc:48:13: warning: #pragma system_header ignored outside include file
 #pragma GCC system_header
             ^~~~~~~~~~~~~
/in/foo.cc:85:13: warning: #pragma system_header ignored outside include file
 #pragma GCC system_header
             ^~~~~~~~~~~~~
/in/foo.cc:124:13: warning: #pragma system_header ignored outside include file
 #pragma GCC system_header
             ^~~~~~~~~~~~~
/in/foo.cc:214:13: warning: #pragma system_header ignored outside include file
 #pragma GCC system_header
             ^~~~~~~~~~~~~
/in/foo.cc:621:13: warning: #pragma system_header ignored outside include file
 #pragma GCC system_header
             ^~~~~~~~~~~~~
/in/foo.cc:658:13: warning: #pragma system_header ignored outside include file
 #pragma GCC system_header
             ^~~~~~~~~~~~~
/in/foo.cc:1220:13: warning: #pragma system_header ignored outside include file
 #pragma GCC system_header
             ^~~~~~~~~~~~~
/in/foo.cc:2929:13: warning: #pragma system_header ignored outside include file
 #pragma GCC system_header
             ^~~~~~~~~~~~~
/in/foo.cc:3563:13: warning: #pragma system_header ignored outside include file
 #pragma GCC system_header
             ^~~~~~~~~~~~~
/in/foo.cc:3854:13: warning: #pragma system_header ignored outside include file
 #pragma GCC system_header
             ^~~~~~~~~~~~~
/in/foo.cc:4106:13: warning: #pragma system_header ignored outside include file
 #pragma GCC system_header
             ^~~~~~~~~~~~~
/in/foo.cc:4346:13: warning: #pragma system_header ignored outside include file
 #pragma GCC system_header
             ^~~~~~~~~~~~~
/in/foo.cc:4379:13: warning: #pragma system_header ignored outside include file
 #pragma GCC system_header
             ^~~~~~~~~~~~~
/in/foo.cc:4691:13: warning: #pragma system_header ignored outside include file
 #pragma GCC system_header
             ^~~~~~~~~~~~~
/in/foo.cc:6413:13: warning: #pragma system_header ignored outside include file
 #pragma GCC system_header
             ^~~~~~~~~~~~~
/in/foo.cc:7450:13: warning: #pragma system_header ignored outside include file
 #pragma GCC system_header
             ^~~~~~~~~~~~~
/in/foo.cc:7623:13: warning: #pragma system_header ignored outside include file
 #pragma GCC system_header
             ^~~~~~~~~~~~~
/in/foo.cc:8097:13: warning: #pragma system_header ignored outside include file
 #pragma GCC system_header
             ^~~~~~~~~~~~~
/in/foo.cc:8993:13: warning: #pragma system_header ignored outside include file
 #pragma GCC system_header
             ^~~~~~~~~~~~~
/in/foo.cc:9872:13: warning: #pragma system_header ignored outside include file
 #pragma GCC system_header
             ^~~~~~~~~~~~~
/in/foo.cc:1494:17: error: expected template-name before '<' token
     : _Iter_base<_Iterator, __is_normal_iterator<_Iterator>::__value>
                 ^
/in/foo.cc:1494:17: error: expected '{' before '<' token
/in/foo.cc:1505:17: error: expected template-name before '<' token
     : _Iter_base<_Iterator, __is_move_iterator<_Iterator>::__value>
                 ^
/in/foo.cc:1505:17: error: expected '{' before '<' token
In file included from /usr/include/c++/6/string:52:0,
                 from /in/foo.cc:4694:
/usr/include/c++/6/bits/basic_string.h:4943:5: error: reference to 'basic_string' is ambiguous
     basic_string<_CharT, _Traits, _Alloc>
     ^~~~~~~~~~~~
/in/foo.cc:144:11: note: candidates are: template<class _CharT, class _Traits, class _Alloc> class std::basic_string
     class basic_string;
           ^~~~~~~~~~~~
In file included from /usr/include/c++/6/string:52:0,
                 from /in/foo.cc:4694:
/usr/include/c++/6/bits/basic_string.h:72:11: note:                 template<class _CharT, class _Traits, class _Alloc> class std::__cxx11::basic_string
     class basic_string
           ^~~~~~~~~~~~
/usr/include/c++/6/bits/basic_string.h:4959:5: error: reference to 'basic_string' is ambiguous
     basic_string<_CharT,_Traits,_Alloc>
     ^~~~~~~~~~~~
/in/foo.cc:144:11: note: candidates are: template<class _CharT, class _Traits, class _Alloc> class std::basic_string
     class basic_string;
           ^~~~~~~~~~~~
In file included from /usr/include/c++/6/string:52:0,
                 from /in/foo.cc:4694:
/usr/include/c++/6/bits/basic_string.h:72:11: note:                 template<class _CharT, class _Traits, class _Alloc> class std::__cxx11::basic_string
     class basic_string
           ^~~~~~~~~~~~
/usr/include/c++/6/bits/basic_string.h:4970:5: error: reference to 'basic_string' is ambiguous
     basic_string<_CharT,_Traits,_Alloc>
     ^~~~~~~~~~~~
/in/foo.cc:144:11: note: candidates are: template<class _CharT, class _Traits, class _Alloc> class std::basic_string
     class basic_string;
           ^~~~~~~~~~~~
In file included from /usr/include/c++/6/string:52:0,
                 from /in/foo.cc:4694:
/usr/include/c++/6/bits/basic_string.h:72:11: note:                 template<class _CharT, class _Traits, class _Alloc> class std::__cxx11::basic_string
     class basic_string
           ^~~~~~~~~~~~
/usr/include/c++/6/bits/basic_string.h:4980:12: error: reference to 'basic_string' is ambiguous
     inline basic_string<_CharT, _Traits, _Alloc>
            ^~~~~~~~~~~~
/in/foo.cc:144:11: note: candidates are: template<class _CharT, class _Traits, class _Alloc> class std::basic_string
     class basic_string;
           ^~~~~~~~~~~~
In file included from /usr/include/c++/6/string:52:0,
                 from /in/foo.cc:4694:
/usr/include/c++/6/bits/basic_string.h:72:11: note:                 template<class _CharT, class _Traits, class _Alloc> class std::__cxx11::basic_string
     class basic_string
           ^~~~~~~~~~~~
/usr/include/c++/6/bits/basic_string.h:4996:12: error: reference to 'basic_string' is ambiguous
     inline basic_string<_CharT, _Traits, _Alloc>
            ^~~~~~~~~~~~
/in/foo.cc:144:11: note: candidates are: template<class _CharT, class _Traits, class _Alloc> class std::basic_string
     class basic_string;
           ^~~~~~~~~~~~
In file included from /usr/include/c++/6/string:52:0,
                 from /in/foo.cc:4694:
/usr/include/c++/6/bits/basic_string.h:72:11: note:                 template<class _CharT, class _Traits, class _Alloc> class std::__cxx11::basic_string
     class basic_string
           ^~~~~~~~~~~~
/usr/include/c++/6/bits/basic_string.h:5008:12: error: reference to 'basic_string' is ambiguous
     inline basic_string<_CharT, _Traits, _Alloc>
            ^~~~~~~~~~~~
/in/foo.cc:144:11: note: candidates are: template<class _CharT, class _Traits, class _Alloc> class std::basic_string
     class basic_string;
           ^~~~~~~~~~~~
In file included from /usr/include/c++/6/string:52:0,
                 from /in/foo.cc:4694:
/usr/include/c++/6/bits/basic_string.h:72:11: note:                 template<class _CharT, class _Traits, class _Alloc> class std::__cxx11::basic_string
     class basic_string
           ^~~~~~~~~~~~
/usr/include/c++/6/bits/basic_string.h:5014:12: error: reference to 'basic_string' is ambiguous
     inline basic_string<_CharT, _Traits, _Alloc>
            ^~~~~~~~~~~~
/in/foo.cc:144:11: note: candidates are: template<class _CharT, class _Traits, class _Alloc> class std::basic_string
     class basic_string;
           ^~~~~~~~~~~~
In file included from /usr/include/c++/6/string:52:0,
                 from /in/foo.cc:4694:
/usr/include/c++/6/bits/basic_string.h:72:11: note:                 template<class _CharT, class _Traits, class _Alloc> class std::__cxx11::basic_string
     class basic_string
           ^~~~~~~~~~~~
/usr/include/c++/6/bits/basic_string.h:5020:12: error: reference to 'basic_string' is ambiguous
     inline basic_string<_CharT, _Traits, _Alloc>
            ^~~~~~~~~~~~
/in/foo.cc:144:11: note: candidates are: template<class _CharT, class _Traits, class _Alloc> class std::basic_string
     class basic_string;
           ^~~~~~~~~~~~
I