https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114400
--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Alternatively:
--- a/libstdc++-v3/include/std/string_view
+++ b/libstdc++-v3/include/std/string_view
@@ -602,15 +602,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// deduction and the other argument gets implicitly converted to the deduced
// type (see N3766).
+#if __cpp_lib_three_way_comparison
template<typename _CharT, typename _Traits>
[[nodiscard]]
constexpr bool
operator==(basic_string_view<_CharT, _Traits> __x,
- __type_identity_t<basic_string_view<_CharT, _Traits>> __y)
+ type_identity_t<basic_string_view<_CharT, _Traits>> __y)
noexcept
{ return __x.size() == __y.size() && __x.compare(__y) == 0; }
-#if __cpp_lib_three_way_comparison
template<typename _CharT, typename _Traits>
[[nodiscard]]
constexpr auto
@@ -620,7 +620,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
-> decltype(__detail::__char_traits_cmp_cat<_Traits>(0))
{ return __detail::__char_traits_cmp_cat<_Traits>(__x.compare(__y)); }
#else
- template<typename _CharT, typename _Traits>
+ template<typena template<typename _CharT, typename _Traits>
+ [[nodiscard]]
+ constexpr bool
+ operator==(basic_string_view<_CharT, _Traits> __x,
+ __type_identity_t<basic_string_view<_CharT, _Traits>> __y)
+ noexcept
+ { return __x.size() == __y.size() && __x.compare(__y) == 0; }
+
+me _CharT, typename _Traits>
[[nodiscard]]
constexpr bool
operator==(basic_string_view<_CharT, _Traits> __x,
Our other uses of __type_identity_t (e.g. in container constructors) are
probably OK. Users can't overload those, and the exact signatures of member
functions are unspecified anyway (we can add/remove default arguments).
