foo.cc: In function ‘bool hws(std::string)’:
foo.cc:6:16: error: cannot convert ‘std::string’ {aka ‘std::__cxx11::basic_string<char>’} to ‘int’ in initialization
    6 |         int hw=a;
      |                ^
      |                |
      |                std::string {aka std::__cxx11::basic_string<char>}
foo.cc:7:31: error: request for member ‘end’ in ‘hws’, which is of non-class type ‘bool(std::string)’ {aka ‘bool(std::__cxx11::basic_string<char>)’}
    7 |         reverse(a.begin(),hws.end());
      |                               ^~~
foo.cc:8:18: error: no match for ‘operator==’ (operand types are ‘int’ and ‘std::string’ {aka ‘std::__cxx11::basic_string<char>’})
    8 |         return hw==a;
      |                ~~^~~
      |                |   |
      |                int std::string {aka std::__cxx11::basic_string<char>}
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/regex:68,
                 from stdc++.h:181:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/regex.h:1103:5: note: candidate: ‘template<class _BiIter> bool std::__cxx11::operator==(const sub_match<_BiIter>&, const sub_match<_BiIter>&)’
 1103 |     operator==(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/regex.h:1103:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::__cxx11::sub_match<_BiIter>’ and ‘int’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/regex.h:1199:5: note: candidate: ‘template<class _Bi_iter, class _Ch_traits, class _Ch_alloc> bool std::__cxx11::operator==(__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>&, const sub_match<_BiIter>&)’
 1199 |     operator==(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/regex.h:1199:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘std::__cxx11::__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>’ and ‘int’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/regex.h:1274:5: note: candidate: ‘template<class _Bi_iter, class _Ch_traits, class _Ch_alloc> bool std::__cxx11::operator==(const sub_match<_BiIter>&, __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>&)’
 1274 |     operator==(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/regex.h:1274:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::__cxx11::sub_match<_BiIter>’ and ‘int’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/regex.h:1366:5: note: candidate: ‘template<class _Bi_iter> bool std::__cxx11::operator==(const typename std::iterator_traits<_Iter>::value_type*, const sub_match<_BiIter>&)’
 1366 |     operator==(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/regex.h:1366:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   ‘std::string’ {aka ‘std::__cxx11::basic_string<char>’} is not derived from ‘const std::__cxx11::sub_match<_BiIter>’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/regex.h:1441:5: note: candidate: ‘template<class _Bi_iter> bool std::__cxx11::operator==(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type*)’
 1441 |     operator==(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/regex.h:1441:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::__cxx11::sub_match<_BiIter>’ and ‘int’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/regex.h:1534:5: note: candidate: ‘template<class _Bi_iter> bool std::__cxx11::operator==(const typename std::iterator_traits<_Iter>::value_type&, const sub_match<_BiIter>&)’
 1534 |     operator==(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/regex.h:1534:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   ‘std::string’ {aka ‘std::__cxx11::basic_string<char>’} is not derived from ‘const std::__cxx11::sub_match<_BiIter>’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/regex.h:1613:5: note: candidate: ‘template<class _Bi_iter> bool std::__cxx11::operator==(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type&)’
 1613 |     operator==(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/regex.h:1613:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::__cxx11::sub_match<_BiIter>’ and ‘int’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/regex.h:2186:5: note: candidate: ‘template<class _Bi_iter, class _Alloc> bool std::__cxx11::operator==(const match_results<_BiIter, _Alloc>&, const match_results<_BiIter, _Alloc>&)’
 2186 |     operator==(const match_results<_Bi_iter, _Alloc>& __m1,
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/regex.h:2186:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::__cxx11::match_results<_BiIter, _Alloc>’ and ‘int’
    8 |         return hw==a;
      |                    ^
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_algobase.h:64,
                 from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/algorithm:60,
                 from stdc++.h:51:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_pair.h:1033:5: note: candidate: ‘template<class _T1, class _T2> constexpr bool std::operator==(const pair<_T1, _T2>&, const pair<_T1, _T2>&)’
 1033 |     operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_pair.h:1033:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::pair<_T1, _T2>’ and ‘int’
    8 |         return hw==a;
      |                    ^
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_algobase.h:67:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_iterator.h:441:5: note: candidate: ‘template<class _Iterator> bool std::operator==(const reverse_iterator<_Iterator>&, const reverse_iterator<_Iterator>&)’
  441 |     operator==(const reverse_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_iterator.h:441:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::reverse_iterator<_Iterator>’ and ‘int’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_iterator.h:486:5: note: candidate: ‘template<class _IteratorL, class _IteratorR> bool std::operator==(const reverse_iterator<_Iterator>&, const reverse_iterator<_IteratorR>&)’
  486 |     operator==(const reverse_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_iterator.h:486:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::reverse_iterator<_Iterator>’ and ‘int’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_iterator.h:1667:5: note: candidate: ‘template<class _IteratorL, class _IteratorR> bool std::operator==(const move_iterator<_IteratorL>&, const move_iterator<_IteratorR>&)’
 1667 |     operator==(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_iterator.h:1667:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::move_iterator<_IteratorL>’ and ‘int’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_iterator.h:1737:5: note: candidate: ‘template<class _Iterator> bool std::operator==(const move_iterator<_IteratorL>&, const move_iterator<_IteratorL>&)’
 1737 |     operator==(const move_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_iterator.h:1737:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::move_iterator<_IteratorL>’ and ‘int’
    8 |         return hw==a;
      |                    ^
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/char_traits.h:42,
                 from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/string:42,
                 from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bitset:52,
                 from stdc++.h:52:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/postypes.h:192:5: note: candidate: ‘template<class _StateT> bool std::operator==(const fpos<_StateT>&, const fpos<_StateT>&)’
  192 |     operator==(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs)
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/postypes.h:192:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::fpos<_StateT>’ and ‘int’
    8 |         return hw==a;
      |                    ^
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/string:43:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/allocator.h:235:5: note: candidate: ‘template<class _T1, class _T2> bool std::operator==(const allocator<_CharT>&, const allocator<_T2>&)’
  235 |     operator==(const allocator<_T1>&, const allocator<_T2>&)
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/allocator.h:235:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::allocator<_CharT>’ and ‘int’
    8 |         return hw==a;
      |                    ^
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/string:54:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/basic_string.h:3755:5: note: candidate: ‘template<class _CharT, class _Traits, class _Alloc> bool std::operator==(const __cxx11::basic_string<_CharT, _Traits, _Alloc>&, const __cxx11::basic_string<_CharT, _Traits, _Alloc>&)’
 3755 |     operator==(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/basic_string.h:3755:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>’ and ‘int’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/basic_string.h:3772:5: note: candidate: ‘template<class _CharT, class _Traits, class _Alloc> bool std::operator==(const __cxx11::basic_string<_CharT, _Traits, _Alloc>&, const _CharT*)’
 3772 |     operator==(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/basic_string.h:3772:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>’ and ‘int’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/basic_string.h:3819:5: note: candidate: ‘template<class _CharT, class _Traits, class _Alloc> bool std::operator==(const _CharT*, const __cxx11::basic_string<_CharT, _Traits, _Alloc>&)’
 3819 |     operator==(const _CharT* __lhs,
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/basic_string.h:3819:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const _CharT*’ and ‘int’
    8 |         return hw==a;
      |                    ^
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/functional:53,
                 from stdc++.h:53:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/tuple:2558:5: note: candidate: ‘template<class ... _TElements, class ... _UElements> constexpr bool std::operator==(const tuple<_Elements ...>&, const tuple<_Elements ...>&)’
 2558 |     operator==(const tuple<_TElements...>& __t,
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/tuple:2558:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::tuple<_Elements ...>’ and ‘int’
    8 |         return hw==a;
      |                    ^
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/functional:59:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/std_function.h:743:5: note: candidate: ‘template<class _Res, class ... _Args> bool std::operator==(const function<_Res(_ArgTypes ...)>&, nullptr_t)’
  743 |     operator==(const function<_Res(_Args...)>& __f, nullptr_t) noexcept
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/std_function.h:743:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::function<_Res(_ArgTypes ...)>’ and ‘int’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/std_function.h:750:5: note: candidate: ‘template<class _Res, class ... _Args> bool std::operator==(nullptr_t, const function<_Res(_ArgTypes ...)>&)’
  750 |     operator==(nullptr_t, const function<_Res(_Args...)>& __f) noexcept
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/std_function.h:750:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   ‘std::string’ {aka ‘std::__cxx11::basic_string<char>’} is not derived from ‘const std::function<_Res(_ArgTypes ...)>’
    8 |         return hw==a;
      |                    ^
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/iterator:66,
                 from stdc++.h:54:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/streambuf_iterator.h:234:5: note: candidate: ‘template<class _CharT, class _Traits> bool std::operator==(const istreambuf_iterator<_CharT, _Traits>&, const istreambuf_iterator<_CharT, _Traits>&)’
  234 |     operator==(const istreambuf_iterator<_CharT, _Traits>& __a,
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/streambuf_iterator.h:234:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::istreambuf_iterator<_CharT, _Traits>’ and ‘int’
    8 |         return hw==a;
      |                    ^
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/memory:78,
                 from stdc++.h:56:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/unique_ptr.h:838:5: note: candidate: ‘template<class _Tp, class _Dp, class _Up, class _Ep> bool std::operator==(const unique_ptr<_Tp, _Dp>&, const unique_ptr<_Up, _Ep>&)’
  838 |     operator==(const unique_ptr<_Tp, _Dp>& __x,
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/unique_ptr.h:838:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::unique_ptr<_Tp, _Dp>’ and ‘int’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/unique_ptr.h:846:5: note: candidate: ‘template<class _Tp, class _Dp> bool std::operator==(const unique_ptr<_Tp, _Dp>&, nullptr_t)’
  846 |     operator==(const unique_ptr<_Tp, _Dp>& __x, nullptr_t) noexcept
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/unique_ptr.h:846:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::unique_ptr<_Tp, _Dp>’ and ‘int’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/unique_ptr.h:854:5: note: candidate: ‘template<class _Tp, class _Dp> bool std::operator==(nullptr_t, const unique_ptr<_Tp, _Dp>&)’
  854 |     operator==(nullptr_t, const unique_ptr<_Tp, _Dp>& __x) noexcept
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/unique_ptr.h:854:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   ‘std::string’ {aka ‘std::__cxx11::basic_string<char>’} is not derived from ‘const std::unique_ptr<_Tp, _Dp>’
    8 |         return hw==a;
      |                    ^
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/shared_ptr.h:53,
                 from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/memory:80:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/shared_ptr_base.h:1797:5: note: candidate: ‘template<class _Tp1, class _Tp2, __gnu_cxx::_Lock_policy _Lp> bool std::operator==(const __shared_ptr<_Tp1, _Lp>&, const __shared_ptr<_Tp2, _Lp>&)’
 1797 |     operator==(const __shared_ptr<_Tp1, _Lp>& __a,
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/shared_ptr_base.h:1797:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::__shared_ptr<_Tp1, _Lp>’ and ‘int’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/shared_ptr_base.h:1803:5: note: candidate: ‘template<class _Tp, __gnu_cxx::_Lock_policy _Lp> bool std::operator==(const __shared_ptr<_Tp, _Lp>&, nullptr_t)’
 1803 |     operator==(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/shared_ptr_base.h:1803:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::__shared_ptr<_Tp, _Lp>’ and ‘int’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/shared_ptr_base.h:1823:5: note: candidate: ‘template<class _Tp, __gnu_cxx::_Lock_policy _Lp> bool std::operator==(nullptr_t, const __shared_ptr<_Tp, _Lp>&)’
 1823 |     operator==(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/shared_ptr_base.h:1823:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   ‘std::string’ {aka ‘std::__cxx11::basic_string<char>’} is not derived from ‘const std::__shared_ptr<_Tp, _Lp>’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/shared_ptr.h:554:5: note: candidate: ‘template<class _Tp, class _Up> bool std::operator==(const shared_ptr<_Tp>&, const shared_ptr<_Tp>&)’
  554 |     operator==(const shared_ptr<_Tp>& __a, const shared_ptr<_Up>& __b) noexcept
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/shared_ptr.h:554:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::shared_ptr<_Tp>’ and ‘int’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/shared_ptr.h:560:5: note: candidate: ‘template<class _Tp> bool std::operator==(const shared_ptr<_Tp>&, nullptr_t)’
  560 |     operator==(const shared_ptr<_Tp>& __a, nullptr_t) noexcept
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/shared_ptr.h:560:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::shared_ptr<_Tp>’ and ‘int’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/shared_ptr.h:581:5: note: candidate: ‘template<class _Tp> bool std::operator==(nullptr_t, const shared_ptr<_Tp>&)’
  581 |     operator==(nullptr_t, const shared_ptr<_Tp>& __a) noexcept
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/shared_ptr.h:581:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   ‘std::string’ {aka ‘std::__cxx11::basic_string<char>’} is not derived from ‘const std::shared_ptr<_Tp>’
    8 |         return hw==a;
      |                    ^
In file included from stdc++.h:63:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/array:303:5: note: candidate: ‘template<class _Tp, long unsigned int _Nm> bool std::operator==(const array<_Tp, _Nm>&, const array<_Tp, _Nm>&)’
  303 |     operator==(const array<_Tp, _Nm>& __one, const array<_Tp, _Nm>& __two)
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/array:303:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::array<_Tp, _Nm>’ and ‘int’
    8 |         return hw==a;
      |                    ^
In file included from stdc++.h:67:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/scoped_allocator:508:5: note: candidate: ‘template<class _OutA1, class _OutA2, class ... _InA> bool std::operator==(const scoped_allocator_adaptor<_OutA1, _InA ...>&, const scoped_allocator_adaptor<_InnerHead, _InnerTail ...>&)’
  508 |     operator==(const scoped_allocator_adaptor<_OutA1, _InA...>& __a,
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/scoped_allocator:508:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::scoped_allocator_adaptor<_OutA1, _InA ...>’ and ‘int’
    8 |         return hw==a;
      |                    ^
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/ccomplex:39,
                 from stdc++.h:127:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/complex:472:5: note: candidate: ‘template<class _Tp> constexpr bool std::operator==(const complex<_Tp>&, const complex<_Tp>&)’
  472 |     operator==(const complex<_Tp>& __x, const complex<_Tp>& __y)
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/complex:472:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::complex<_Tp>’ and ‘int’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/complex:477:5: note: candidate: ‘template<class _Tp> constexpr bool std::operator==(const complex<_Tp>&, const _Tp&)’
  477 |     operator==(const complex<_Tp>& __x, const _Tp& __y)
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/complex:477:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::complex<_Tp>’ and ‘int’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/complex:483:5: note: candidate: ‘template<class _Tp> constexpr bool std::operator==(const _Tp&, const complex<_Tp>&)’
  483 |     operator==(const _Tp& __x, const complex<_Tp>& __y)
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/complex:483:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   ‘std::string’ {aka ‘std::__cxx11::basic_string<char>’} is not derived from ‘const std::complex<_Tp>’
    8 |         return hw==a;
      |                    ^
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/deque:66,
                 from stdc++.h:139:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_deque.h:2294:5: note: candidate: ‘template<class _Tp, class _Alloc> bool std::operator==(const deque<_Tp, _Alloc>&, const deque<_Tp, _Alloc>&)’
 2294 |     operator==(const deque<_Tp, _Alloc>& __x, const deque<_Tp, _Alloc>& __y)
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_deque.h:2294:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::deque<_Tp, _Alloc>’ and ‘int’
    8 |         return hw==a;
      |                    ^
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/list:65,
                 from stdc++.h:150:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_list.h:2131:5: note: candidate: ‘template<class _Tp, class _Alloc> bool std::operator==(const __cxx11::list<_Tp, _Alloc>&, const __cxx11::list<_Tp, _Alloc>&)’
 2131 |     operator==(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_list.h:2131:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::__cxx11::list<_Tp, _Alloc>’ and ‘int’
    8 |         return hw==a;
      |                    ^
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/map:63,
                 from stdc++.h:152:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_map.h:1512:5: note: candidate: ‘template<class _Key, class _Tp, class _Compare, class _Alloc> bool std::operator==(const map<_Key, _Tp, _Compare, _Alloc>&, const map<_Key, _Tp, _Compare, _Alloc>&)’
 1512 |     operator==(const map<_Key, _Tp, _Compare, _Alloc>& __x,
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_map.h:1512:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::map<_Key, _Tp, _Compare, _Alloc>’ and ‘int’
    8 |         return hw==a;
      |                    ^
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/map:64:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_multimap.h:1134:5: note: candidate: ‘template<class _Key, class _Tp, class _Compare, class _Alloc> bool std::operator==(const multimap<_Key, _Tp, _Compare, _Alloc>&, const multimap<_Key, _Tp, _Compare, _Alloc>&)’
 1134 |     operator==(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_multimap.h:1134:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::multimap<_Key, _Tp, _Compare, _Alloc>’ and ‘int’
    8 |         return hw==a;
      |                    ^
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/vector:66,
                 from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/queue:63,
                 from stdc++.h:157:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_vector.h:2050:5: note: candidate: ‘template<class _Tp, class _Alloc> bool std::operator==(const vector<_Tp, _Alloc>&, const vector<_Tp, _Alloc>&)’
 2050 |     operator==(const vector<_Tp, _Alloc>& __x, const vector<_Tp, _Alloc>& __y)
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_vector.h:2050:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::vector<_Tp, _Alloc>’ and ‘int’
    8 |         return hw==a;
      |                    ^
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/queue:66:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_queue.h:378:5: note: candidate: ‘template<class _Tp, class _Seq> bool std::operator==(const queue<_Tp, _Seq>&, const queue<_Tp, _Seq>&)’
  378 |     operator==(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_queue.h:378:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::queue<_Tp, _Seq>’ and ‘int’
    8 |         return hw==a;
      |                    ^
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/set:63,
                 from stdc++.h:158:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_set.h:987:5: note: candidate: ‘template<class _Key, class _Compare, class _Alloc> bool std::operator==(const set<_Key, _Compare, _Alloc>&, const set<_Key, _Compare, _Alloc>&)’
  987 |     operator==(const set<_Key, _Compare, _Alloc>& __x,
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_set.h:987:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::set<_Key, _Compare, _Alloc>’ and ‘int’
    8 |         return hw==a;
      |                    ^
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/set:64:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_multiset.h:973:5: note: candidate: ‘template<class _Key, class _Compare, class _Alloc> bool std::operator==(const multiset<_Key, _Compare, _Alloc>&, const multiset<_Key, _Compare, _Alloc>&)’
  973 |     operator==(const multiset<_Key, _Compare, _Alloc>& __x,
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_multiset.h:973:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::multiset<_Key, _Compare, _Alloc>’ and ‘int’
    8 |         return hw==a;
      |                    ^
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/stack:63,
                 from stdc++.h:160:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_stack.h:354:5: note: candidate: ‘template<class _Tp, class _Seq> bool std::operator==(const stack<_Tp, _Seq>&, const stack<_Tp, _Seq>&)’
  354 |     operator==(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_stack.h:354:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::stack<_Tp, _Seq>’ and ‘int’
    8 |         return hw==a;
      |                    ^
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/valarray:605,
                 from stdc++.h:166:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/valarray_after.h:417:5: note: candidate: ‘template<class _Dom1, class _Dom2> std::_Expr<std::__detail::_BinClos<std::__equal_to, std::_Expr, std::_Expr, _Dom1, _Dom2>, typename std::__fun<std::__equal_to, typename _Dom1::value_type>::result_type> std::operator==(const _Expr<_Dom1, typename _Dom1::value_type>&, const _Expr<_Dom2, typename _Dom2::value_type>&)’
  417 |     _DEFINE_EXPR_BINARY_OPERATOR(==, struct std::__equal_to)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/valarray_after.h:417:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::_Expr<_Dom1, typename _Dom1::value_type>’ and ‘int’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/valarray_after.h:417:5: note: candidate: ‘template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__equal_to, std::_Expr, std::_Constant, _Dom, typename _Dom::value_type>, typename std::__fun<std::__equal_to, typename _Dom1::value_type>::result_type> std::operator==(const _Expr<_Dom1, typename _Dom1::value_type>&, const typename _Dom::value_type&)’
  417 |     _DEFINE_EXPR_BINARY_OPERATOR(==, struct std::__equal_to)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/valarray_after.h:417:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::_Expr<_Dom1, typename _Dom1::value_type>’ and ‘int’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/valarray_after.h:417:5: note: candidate: ‘template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__equal_to, std::_Constant, std::_Expr, typename _Dom::value_type, _Dom>, typename std::__fun<std::__equal_to, typename _Dom1::value_type>::result_type> std::operator==(const typename _Dom::value_type&, const _Expr<_Dom1, typename _Dom1::value_type>&)’
  417 |     _DEFINE_EXPR_BINARY_OPERATOR(==, struct std::__equal_to)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/valarray_after.h:417:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   ‘std::string’ {aka ‘std::__cxx11::basic_string<char>’} is not derived from ‘const std::_Expr<_Dom1, typename _Dom1::value_type>’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/valarray_after.h:417:5: note: candidate: ‘template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__equal_to, std::_Expr, std::_ValArray, _Dom, typename _Dom::value_type>, typename std::__fun<std::__equal_to, typename _Dom1::value_type>::result_type> std::operator==(const _Expr<_Dom1, typename _Dom1::value_type>&, const valarray<typename _Dom::value_type>&)’
  417 |     _DEFINE_EXPR_BINARY_OPERATOR(==, struct std::__equal_to)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/valarray_after.h:417:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::_Expr<_Dom1, typename _Dom1::value_type>’ and ‘int’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/valarray_after.h:417:5: note: candidate: ‘template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__equal_to, std::_ValArray, std::_Expr, typename _Dom::value_type, _Dom>, typename std::__fun<std::__equal_to, typename _Dom1::value_type>::result_type> std::operator==(const valarray<typename _Dom::value_type>&, const _Expr<_Dom1, typename _Dom1::value_type>&)’
  417 |     _DEFINE_EXPR_BINARY_OPERATOR(==, struct std::__equal_to)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/valarray_after.h:417:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   ‘std::string’ {aka ‘std::__cxx11::basic_string<char>’} is not derived from ‘const std::_Expr<_Dom1, typename _Dom1::value_type>’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/valarray:1208:1: note: candidate: ‘template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__equal_to, std::_ValArray, std::_ValArray, _Tp, _Tp>, typename std::__fun<std::__equal_to, _Tp>::result_type> std::operator==(const valarray<_Tp>&, const valarray<_Tp>&)’
 1208 | _DEFINE_BINARY_OPERATOR(==, __equal_to)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/valarray:1208:1: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::valarray<_Tp>’ and ‘int’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/valarray:1208:1: note: candidate: ‘template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__equal_to, std::_ValArray, std::_Constant, _Tp, _Tp>, typename std::__fun<std::__equal_to, _Tp>::result_type> std::operator==(const valarray<_Tp>&, const typename valarray<_Tp>::value_type&)’
 1208 | _DEFINE_BINARY_OPERATOR(==, __equal_to)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/valarray:1208:1: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::valarray<_Tp>’ and ‘int’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/valarray:1208:1: note: candidate: ‘template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__equal_to, std::_Constant, std::_ValArray, _Tp, _Tp>, typename std::__fun<std::__equal_to, _Tp>::result_type> std::operator==(const typename valarray<_Tp>::value_type&, const valarray<_Tp>&)’
 1208 | _DEFINE_BINARY_OPERATOR(==, __equal_to)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/valarray:1208:1: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   ‘std::string’ {aka ‘std::__cxx11::basic_string<char>’} is not derived from ‘const std::valarray<_Tp>’
    8 |         return hw==a;
      |                    ^
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/forward_list:42,
                 from stdc++.h:175:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/forward_list.tcc:393:5: note: candidate: ‘template<class _Tp, class _Alloc> bool std::operator==(const forward_list<_Tp, _Alloc>&, const forward_list<_Tp, _Alloc>&)’
  393 |     operator==(const forward_list<_Tp, _Alloc>& __lx,
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/forward_list.tcc:393:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::forward_list<_Tp, _Alloc>’ and ‘int’
    8 |         return hw==a;
      |                    ^
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/random:50,
                 from stdc++.h:179:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/random.tcc:1908:5: note: candidate: ‘template<class _RealType1> bool std::operator==(const normal_distribution<_RealType>&, const normal_distribution<_RealType>&)’
 1908 |     operator==(const std::normal_distribution<_RealType>& __d1,
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/random.tcc:1908:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::normal_distribution<_RealType>’ and ‘int’
    8 |         return hw==a;
      |                    ^
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/unordered_map:41,
                 from stdc++.h:188:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/unordered_map.h:2144:5: note: candidate: ‘template<class _Key, class _Tp, class _Hash, class _Pred, class _Alloc> bool std::operator==(const unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>&, const unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>&)’
 2144 |     operator==(const unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/unordered_map.h:2144:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>’ and ‘int’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/unordered_map.h:2158:5: note: candidate: ‘template<class _Key, class _Tp, class _Hash, class _Pred, class _Alloc> bool std::operator==(const unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>&, const unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>&)’
 2158 |     operator==(const unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/unordered_map.h:2158:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>’ and ‘int’
    8 |         return hw==a;
      |                    ^
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/unordered_set:41,
                 from stdc++.h:189:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/unordered_set.h:1813:5: note: candidate: ‘template<class _Value, class _Hash, class _Pred, class _Alloc> bool std::operator==(const unordered_set<_Value, _Hash, _Pred, _Alloc>&, const unordered_set<_Value, _Hash, _Pred, _Alloc>&)’
 1813 |     operator==(const unordered_set<_Value, _Hash, _Pred, _Alloc>& __x,
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/unordered_set.h:1813:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::unordered_set<_Value, _Hash, _Pred, _Alloc>’ and ‘int’
    8 |         return hw==a;
      |                    ^
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/unordered_set.h:1827:5: note: candidate: ‘template<class _Value, class _Hash, class _Pred, class _Alloc> bool std::operator==(const unordered_multiset<_Value, _Hash, _Pred, _Alloc>&, const unordered_multiset<_Value, _Hash, _Pred, _Alloc>&)’
 1827 |     operator==(const unordered_multiset<_Value, _Hash, _Pred, _Alloc>& __x,
      |     ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/unordered_set.h:1827:5: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   mismatched types ‘const std::unordered_multiset<_Value, _Hash, _Pred, _Alloc>’ and ‘int’
    8 |         return hw==a;
      |                    ^
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/x86_64-unknown-linux-gnu/bits/c++allocator.h:33,
                 from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/allocator.h:46:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/new_allocator.h:215:9: note: candidate: ‘template<class _Up> bool std::operator==(const __new_allocator<char>&, const __new_allocator<_Tp>&)’
  215 |         operator==(const __new_allocator&, const __new_allocator<_Up>&)
      |         ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/new_allocator.h:215:9: note:   template argument deduction/substitution failed:
foo.cc:8:20: note:   ‘std::string’ {aka ‘std::__cxx11::basic_string<char>’} is not derived from ‘const std::__new_allocator<_Tp>’
    8 |         return hw==a;
      |                    ^
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/ios_base.h:46,
                 from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/streambuf:43,
                 from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/streambuf_iterator.h:35:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/system_error:449:3: note: candidate: ‘bool std::operator==(const error_code&, const error_code&)’
  449 |   operator==(const error_code& __lhs, const error_code& __rhs) noexcept
      |   ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/system_error:449:32: note:   no known conversion for argument 1 from ‘int’ to ‘const std::error_code&’
  449 |   operator==(const error_code& __lhs, const error_code& __rhs) noexcept
      |              ~~~~~~~~~~~~~~~~~~^~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/system_error:465:3: note: candidate: ‘bool std::operator==(const error_code&, const error_condition&)’
  465 |   operator==(const error_code& __lhs, const error_condition& __rhs) noexcept
      |   ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/system_error:465:32: note:   no known conversion for argument 1 from ‘int’ to ‘const std::error_code&’
  465 |   operator==(const error_code& __lhs, const error_condition& __rhs) noexcept
      |              ~~~~~~~~~~~~~~~~~~^~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/system_error:480:3: note: candidate: ‘bool std::operator==(const error_condition&, const error_condition&)’
  480 |   operator==(const error_condition& __lhs,
      |   ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/system_error:480:37: note:   no known conversion for argument 1 from ‘int’ to ‘const std::error_condition&’
  480 |   operator==(const error_condition& __lhs,
      |              ~~~~~~~~~~~~~~~~~~~~~~~^~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/system_error:517:3: note: candidate: ‘bool std::operator==(const error_condition&, const error_code&)’
  517 |   operator==(const error_condition& __lhs, const error_code& __rhs) noexcept
      |   ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/system_error:517:37: note:   no known conversion for argument 1 from ‘int’ to ‘const std::error_condition&’
  517 |   operator==(const error_condition& __lhs, const error_code& __rhs) noexcept
      |              ~~~~~~~~~~~~~~~~~~~~~~~^~~~~
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/future:51,
                 from stdc++.h:176:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/std_thread.h:333:3: note: candidate: ‘bool std::operator==(thread::id, thread::id)’
  333 |   operator==(thread::id __x, thread::id __y) noexcept
      |   ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/std_thread.h:333:25: note:   no known conversion for argument 1 from ‘int’ to ‘std::thread::id’
  333 |   operator==(thread::id __x, thread::id __y) noexcept
      |              ~~~~~~~~~~~^~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/allocator.h:214:7: note: candidate: ‘bool std::operator==(const allocator<char>&, const allocator<char>&)’
  214 |       operator==(const allocator&, const allocator&) _GLIBCXX_NOTHROW
      |       ^~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/allocator.h:214:18: note:   no known conversion for argument 1 from ‘int’ to ‘const std::allocator<char>&’
  214 |       operator==(const allocator&, const allocator&) _GLIBCXX_NOTHROW
      |                  ^~~~~~~~~~~~~~~~