Proposed resolution:
This wording is relative to N4910.
Modify [string.syn], header <string> synopsis, as indicated:
[…] // [basic.string.hash], hash support template<class T> struct hash;template<> struct hash<string>; template<> struct hash<u8string>; template<> struct hash<u16string>; template<> struct hash<u32string>; template<> struct hash<wstring>; template<> struct hash<pmr::string>; template<> struct hash<pmr::u8string>; template<> struct hash<pmr::u16string>; template<> struct hash<pmr::u32string>; template<> struct hash<pmr::wstring>;template<class A> struct hash<basic_string<char, char_traits<char>, A>>; template<class A> struct hash<basic_string<char8_t, char_traits<char8_t>, A>>; template<class A> struct hash<basic_string<char16_t, char_traits<char16_t>, A>>; template<class A> struct hash<basic_string<char32_t, char_traits<char32_t>, A>>; template<class A> struct hash<basic_string<wchar_t, char_traits<wchar_t>, A>>; […]
Modify [basic.string.hash] as indicated:
template<> struct hash<string>; template<> struct hash<u8string>; template<> struct hash<u16string>; template<> struct hash<u32string>; template<> struct hash<wstring>; template<> struct hash<pmr::string>; template<> struct hash<pmr::u8string>; template<> struct hash<pmr::u16string>; template<> struct hash<pmr::u32string>; template<> struct hash<pmr::wstring>;template<class A> struct hash<basic_string<char, char_traits<char>, A>>; template<class A> struct hash<basic_string<char8_t, char_traits<char8_t>, A>>; template<class A> struct hash<basic_string<char16_t, char_traits<char16_t>, A>>; template<class A> struct hash<basic_string<char32_t, char_traits<char32_t>, A>>; template<class A> struct hash<basic_string<wchar_t, char_traits<wchar_t>, A>>;-1- If S is one of these string types, SV is the corresponding string view type, and s is an object of type S, then hash<S>()(s) == hash<SV>()(SV(s))