/in/foo.cc: In function 'int main()':
/in/foo.cc:50:3: error: reference to 'function' is ambiguous
   function();
   ^~~~~~~~
/in/foo.cc:5:6: note: candidates are: void function()
 void function(){
      ^~~~~~~~
In file included from /usr/include/x86_64-linux-gnu/c++/6/bits/stdc++.h:71:0,
                 from /in/foo.cc:2:
/usr/include/c++/6/functional:1526:11: note:                 template<class _Signature> class std::function
     class function;
           ^~~~~~~~