Language
C++
Compiler
gcc HEAD 9.0.0 20180901 (experimental)
Options
Warnings
Don't Use Boost
C++2a
-pedantic-errors
$ g++ prog.cc -Wall -Wextra -std=c++2a -pedantic-errors In file included from /opt/wandbox/gcc-head/include/c++/9.0.0/unordered_set:46,
from prog.cc:3:
/opt/wandbox/gcc-head/include/c++/9.0.0/bits/hashtable.h: In instantiation of 'std::pair<typename std::__detail::_Hashtable_base<_Key, _Value, _ExtractKey, _Equal, _H1, _H2, _Hash, _Traits>::iterator, bool> std::_Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash, _RehashPolicy, _Traits>::_M_insert(_Arg&&, const _NodeGenerator&, std::true_type, std::_Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash, _RehashPolicy, _Traits>::size_type) [with _Arg = S; _NodeGenerator = std::__detail::_AllocNode<std::allocator<std::__detail::_Hash_node<std::__cxx11::basic_string<char>, true> > >; _Key = std::__cxx11::basic_string<char>; _Value = std::__cxx11::basic_string<char>; _Alloc = std::allocator<std::__cxx11::basic_string<char> >; _ExtractKey = std::__detail::_Identity; _Equal = std::equal_to<std::__cxx11::basic_string<char> >; _H1 = std::hash<std::__cxx11::basic_string<char> >; _H2 = std::__detail::_Mod_range_hashing; _Hash = std::__detail::_Default_ranged_hash; _RehashPolicy = std::__detail::_Prime_rehash_policy; _Traits = std::__detail::_Hashtable_traits<true, true, true>; typename std::__detail::_Hashtable_base<_Key, _Value, _ExtractKey, _Equal, _H1, _H2, _Hash, _Traits>::iterator = std::__detail::_Node_iterator<std::__cxx11::basic_string<char>, true, true>; std::true_type = std::integral_constant<bool, true>; std::_Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash, _RehashPolicy, _Traits>::size_type = long unsigned int]':
/opt/wandbox/gcc-head/include/c++/9.0.0/bits/hashtable_policy.h:869:19: required from 'void std::__detail::_Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash, _RehashPolicy, _Traits>::_M_insert_range(_InputIterator, _InputIterator, const _NodeGetter&, std::true_type) [with _InputIterator = std::move_iterator<S*>; _NodeGetter = std::__detail::_AllocNode<std::allocator<std::__detail::_Hash_node<std::__cxx11::basic_string<char>, true> > >; _Key = std::__cxx11::basic_string<char>; _Value = std::__cxx11::basic_string<char>; _Alloc = std::allocator<std::__cxx11::basic_string<char> >; _ExtractKey = std::__detail::_Identity; _Equal = std::equal_to<std::__cxx11::basic_string<char> >; _H1 = std::hash<std::__cxx11::basic_string<char> >; _H2 = std::__detail::_Mod_range_hashing; _Hash = std::__detail::_Default_ranged_hash; _RehashPolicy = std::__detail::_Prime_rehash_policy; _Traits = std::__detail::_Hashtable_traits<true, true, true>; std::true_type = std::integral_constant<bool, true>]'
/opt/wandbox/gcc-head/include/c++/9.0.0/bits/hashtable_policy.h:846:71: required from 'void std::__detail::_Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash, _RehashPolicy, _Traits>::insert(_InputIterator, _InputIterator) [with _InputIterator = std::move_iterator<S*>; _Key = std::__cxx11::basic_string<char>; _Value = std::__cxx11::basic_string<char>; _Alloc = std::allocator<std::__cxx11::basic_string<char> >; _ExtractKey = std::__detail::_Identity; _Equal = std::equal_to<std::__cxx11::basic_string<char> >; _H1 = std::hash<std::__cxx11::basic_string<char> >; _H2 = std::__detail::_Mod_range_hashing; _Hash = std::__detail::_Default_ranged_hash; _RehashPolicy = std::__detail::_Prime_rehash_policy; _Traits = std::__detail::_Hashtable_traits<true, true, true>]'
/opt/wandbox/gcc-head/include/c++/9.0.0/bits/unordered_set.h:469:4: required from 'void std::unordered_set<_Value, _Hash, _Pred, _Alloc>::insert(_InputIterator, _InputIterator) [with _InputIterator = std::move_iterator<S*>; _Value = std::__cxx11::basic_string<char>; _Hash = std::hash<std::__cxx11::basic_string<char> >; _Pred = std::equal_to<std::__cxx11::basic_string<char> >; _Alloc = std::allocator<std::__cxx11::basic_string<char> >]'
prog.cc:17:80: required from here
/opt/wandbox/gcc-head/include/c++/9.0.0/bits/hashtable.h:1828:18: error: invalid initialization of reference of type 'const key_type&' {aka 'const std::__cxx11::basic_string<char>&'} from expression of type 'S'
1828 | const key_type& __k = this->_M_extract()(__v);
| ^~~
Exit Code:
1