`enforce-check-test.cc`: fails with GCC 12.2.0 (no problem with 12.1.0)

[vobloeb]

In file included from /build/fetchgit/include/fmt/format.h:48,
                 from /build/fetchgit/include/fmt/chrono.h:21,
                 from /build/fetchgit/test/enforce-checks-test.cc:11:
/build/fetchgit/include/fmt/core.h: In instantiation of 'constexpr decltype (ctx.begin()) fmt::v9::detail::parse_format_specs(ParseContext&) [with T = std::vector<char>; ParseContext = compile_parse_context<char, error_handler>; decltype (ctx.begin()) = const char*]':
/build/fetchgit/include/fmt/core.h:2923:22:   required from 'constexpr fmt::v9::detail::format_string_checker<Char, ErrorHandler, Args>::format_string_checker(fmt::v9::basic_string_view<Char>, ErrorHandler) [with Char = char; ErrorHandler = fmt::v9::detail::error_handler; Args = {std::vector<char, std::allocator<char>
>}]'
/build/fetchgit/test/enforce-checks-test.cc:55:20:   required from here
/build/fetchgit/include/fmt/core.h:2713:12: error: use of deleted function 'fmt::v9::detail::fallback_formatter<T, Char, Enable>::fallback_formatter() [with T = std::vector<char>; Char = char; Enable = void]'
 2713 |   auto f = conditional_t<has_formatter<mapped_type, context>::value,
      |            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 2714 |                          formatter<mapped_type, char_type>,
      |                          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 2715 |                          fallback_formatter<stripped_type, char_type>>();
      |                          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/build/fetchgit/include/fmt/core.h:1105:3: note: declared here
 1105 |   fallback_formatter() = delete;
      |   ^~~~~~~~~~~~~~~~~~

[vobloeb]

reproducible with 9.0.0 and git master (fbb568b)

8.1.1 has no problem

[vitaut]

Could you provide a godbolt repro? I tried to reproduce on gcc trunk but to no avail: https://godbolt.org/z/5444Eazv5. Perhaps some specific compiler options are required.

[vobloeb]

Could you provide a godbolt repro? I tried to reproduce on gcc trunk but to no avail: https://godbolt.org/z/5444Eazv5. Perhaps some specific compiler options are required.

golbolt does not have GCC 12.2.0, the latest GCC there is 12.1.0 which has no problem

[chronoxor]

gcc 12.x is buggy, for example it generates another error for return "(" + std::to_string(123) + ")";
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105329

C:/msys64/mingw64/include/c++/12.2.0/bits/char_traits.h:431:56: error: 'void* __builtin_memcpy(void*, const void*, long long unsigned int)' accessing 9223372036854775810 or more bytes at offsets [2, 9223372036854775807] and 1 may overlap up to 9223372036854775813 bytes at offset -3 [-Werror=restrict]
  431 |         return static_cast<char_type*>(__builtin_memcpy(__s1, __s2, __n));
      |         

So it's better to wait until gcc 12.x becomes more stable.

[strega-nil-ms]

This is not GCC's bug - it is correctly (I assume) implementing P2499 (see #3030)

[vitaut]

@kvtb, does e4f4fc7 fix the issue?

[vitaut]

Should be fixed in 4a8e294.