/in/foo.cc: In function 'int main()':
/in/foo.cc:50:3: error: reference to 'hash' is ambiguous
   hash=q[h].h;
   ^~~~
/in/foo.cc:36:9: note: candidates are: int hash
 int h,t,hash;
         ^~~~
In file included from /usr/include/c++/6/bits/basic_string.h:5643:0,
                 from /usr/include/c++/6/string:52,
                 from /usr/include/c++/6/bits/locale_classes.h:40,
                 from /usr/include/c++/6/bits/ios_base.h:41,
                 from /usr/include/c++/6/ios:42,
                 from /usr/include/c++/6/istream:38,
                 from /usr/include/c++/6/sstream:38,
                 from /usr/include/c++/6/complex:45,
                 from /usr/include/c++/6/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/6/bits/stdc++.h:52,
                 from /in/foo.cc:1:
/usr/include/c++/6/bits/functional_hash.h:58:12: note:                 template<class _Tp> struct std::hash
     struct hash;
            ^~~~
/in/foo.cc:51:6: error: reference to 'hash' is ambiguous
   if(hash==to.h){
      ^~~~
/in/foo.cc:36:9: note: candidates are: int hash
 int h,t,hash;
         ^~~~
In file included from /usr/include/c++/6/bits/basic_string.h:5643:0,
                 from /usr/include/c++/6/string:52,
                 from /usr/include/c++/6/bits/locale_classes.h:40,
                 from /usr/include/c++/6/bits/ios_base.h:41,
                 from /usr/include/c++/6/ios:42,
                 from /usr/include/c++/6/istream:38,
                 from /usr/include/c++/6/sstream:38,
                 from /usr/include/c++/6/complex:45,
                 from /usr/include/c++/6/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/6/bits/stdc++.h:52,
                 from /in/foo.cc:1:
/usr/include/c++/6/bits/functional_hash.h:58:12: note:                 template<class _Tp> struct std::hash
     struct hash;
            ^~~~
/in/foo.cc:55:7: error: reference to 'hash' is ambiguous
   vis[hash]=1;
       ^~~~
/in/foo.cc:36:9: note: candidates are: int hash
 int h,t,hash;
         ^~~~
In file included from /usr/include/c++/6/bits/basic_string.h:5643:0,
                 from /usr/include/c++/6/string:52,
                 from /usr/include/c++/6/bits/locale_classes.h:40,
                 from /usr/include/c++/6/bits/ios_base.h:41,
                 from /usr/include/c++/6/ios:42,
                 from /usr/include/c++/6/istream:38,
                 from /usr/include/c++/6/sstream:38,
                 from /usr/include/c++/6/complex:45,
                 from /usr/include/c++/6/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/6/bits/stdc++.h:52,
                 from /in/foo.cc:1:
/usr/include/c++/6/bits/functional_hash.h:58:12: note:                 template<class _Tp> struct std::hash
     struct hash;
            ^~~~