44   using StrStream = std::basic_istringstream<CharT, TraitsT, AllocT>;  in test_sfinae()  typedef
46   static_assert(is_valid_argument_for_str_member<StrStream, CharT*>);  in test_sfinae()
47   static_assert(is_valid_argument_for_str_member<StrStream, const CharT*>);  in test_sfinae()
48 …static_assert(is_valid_argument_for_str_member<StrStream, std::basic_string_view<CharT, TraitsT>>);  in test_sfinae()
49 …static_assert(is_valid_argument_for_str_member<StrStream, std::basic_string<CharT, TraitsT, AllocT…  in test_sfinae()
50 …static_assert(is_valid_argument_for_str_member<StrStream, ConstConvertibleStringView<CharT, Traits…  in test_sfinae()
52   static_assert(!is_valid_argument_for_str_member<StrStream, CharT>);  in test_sfinae()
53   static_assert(!is_valid_argument_for_str_member<StrStream, int>);  in test_sfinae()
54   static_assert(!is_valid_argument_for_str_member<StrStream, SomeObject>);  in test_sfinae()
55   static_assert(!is_valid_argument_for_str_member<StrStream, std::nullptr_t>);  in test_sfinae()
56 …static_assert(!is_valid_argument_for_str_member<StrStream, NonConstConvertibleStringView<CharT, Tr…  in test_sfinae()