GCC9 issue: static_assert(std::is_same<uint64_or_128_t<UInt>, UInt>::value, "");

[Vertexwahn]

Commit fd87a23 gives me the following error using GCC9:

Use --sandbox_debug to see verbose messages from the sandbox and retain the sandbox build root for debugging
In file included from bazel-out/k8-fastbuild/bin/external/fmt~override/_virtual_includes/fmt/fmt/format-inl.h:25,
                 from external/fmt~override/src/format.cc:8:
bazel-out/k8-fastbuild/bin/external/fmt~override/_virtual_includes/fmt/fmt/format.h: In instantiation of 'OutputIt fmt::v10::detail::write_int(OutputIt, UInt, unsigned int, const fmt::v10::format_specs<Char>&, const fmt::v10::detail::digit_grouping<Char>&) [with OutputIt = fmt::v10::basic_appender<char>; UInt = __int128 unsigned; Char = char]':
bazel-out/k8-fastbuild/bin/external/fmt~override/_virtual_includes/fmt/fmt/format.h:2234:14:   required from 'bool fmt::v10::detail::loc_writer<Char>::operator()(T) [with T = __int128; typename std::enable_if<std::integral_constant<bool, (((fmt::v10::detail::is_integral<T>::value && (! std::is_same<T, bool>::value)) && (! std::is_same<T, char>::value)) && (! std::is_same<T, wchar_t>::value))>::value, int>::type <anonymous> = 0; Char = char]'
bazel-out/k8-fastbuild/bin/external/fmt~override/_virtual_includes/fmt/fmt/base.h:1677:17:   required from 'constexpr decltype (vis(0)) fmt::v10::basic_format_arg<Context>::visit(Visitor&&) [with Visitor = fmt::v10::detail::loc_writer<>&; Context = fmt::v10::context; decltype (vis(0)) = bool]'
bazel-out/k8-fastbuild/bin/external/fmt~override/_virtual_includes/fmt/fmt/format.h:1118:28:   required from 'decltype (vis(0)) fmt::v10::loc_value::visit(Visitor&&) [with Visitor = fmt::v10::detail::loc_writer<>; decltype (vis(0)) = bool]'
bazel-out/k8-fastbuild/bin/external/fmt~override/_virtual_includes/fmt/fmt/format-inl.h:143:78:   required from here
bazel-out/k8-fastbuild/bin/external/fmt~override/_virtual_includes/fmt/fmt/format.h:2141:60: error: static assertion failed
 2141 |   static_assert(std::is_same<uint64_or_128_t<UInt>, UInt>::value, "");

How to reproduce?

Use Ubuntu 20.04 + GCC9

Add hello.cpp file to fmt repo:

#include <iostream>
#include "fmt/core.h"

using namespace std;

int main(int argc, char *argv[]) {
  std::string name = "Julian";
  cout << fmt::format("Hello! {}", name) << std::endl;
  return 0;
}

Try to compile

g++ -std=c++2a -o hello hello.cpp format.cc os.cc

In file included from fmt/format-inl.h:25,
                 from format.cc:8:
fmt/format.h: In instantiation of ‘OutputIt fmt::v10::detail::write_int(OutputIt, UInt, unsigned int, const fmt::v10::format_specs<Char>&, const fmt::v10::detail::digit_grouping<Char>&) [with OutputIt = fmt::v10::basic_appender<char>; UInt = __int128 unsigned; Char = char]’:
fmt/format.h:2234:14:   required from ‘bool fmt::v10::detail::loc_writer<Char>::operator()(T) [with T = __int128; typename std::enable_if<std::integral_constant<bool, (((fmt::v10::detail::is_integral<T>::value && (! std::is_same<T, bool>::value)) && (! std::is_same<T, char>::value)) && (! std::is_same<T, wchar_t>::value))>::value, int>::type <anonymous> = 0; Char = char]’
fmt/base.h:1677:17:   required from ‘constexpr decltype (vis(0)) fmt::v10::basic_format_arg<Context>::visit(Visitor&&) [with Visitor = fmt::v10::detail::loc_writer<>&; Context = fmt::v10::context; decltype (vis(0)) = bool]’
fmt/format.h:1118:28:   required from ‘decltype (vis(0)) fmt::v10::loc_value::visit(Visitor&&) [with Visitor = fmt::v10::detail::loc_writer<>; decltype (vis(0)) = bool]’
fmt/format-inl.h:143:78:   required from here
fmt/format.h:2141:60: error: static assertion failed
 2141 |   static_assert(std::is_same<uint64_or_128_t<UInt>, UInt>::value, "");
      |                                                            ^~~~~
fmt/format.h: In instantiation of ‘constexpr OutputIt fmt::v10::detail::write_int(OutputIt, fmt::v10::detail::write_int_arg<T>, const fmt::v10::format_specs<Char>&, fmt::v10::detail::locale_ref) [with Char = char; OutputIt = fmt::v10::basic_appender<char>; T = __int128 unsigned]’:
fmt/format.h:2305:19:   required from ‘constexpr OutputIt fmt::v10::detail::write_int_noinline(OutputIt, fmt::v10::detail::write_int_arg<T>, const fmt::v10::format_specs<Char>&, fmt::v10::detail::locale_ref) [with Char = char; OutputIt = fmt::v10::basic_appender<char>; T = __int128 unsigned]’
fmt/format.h:2315:28:   required from ‘constexpr OutputIt fmt::v10::detail::write(OutputIt, T, const fmt::v10::format_specs<Char>&, fmt::v10::detail::locale_ref) [with Char = char; OutputIt = fmt::v10::basic_appender<char>; T = __int128; typename std::enable_if<((fmt::v10::detail::is_integral<T>::value && (! std::is_same<T, bool>::value)) && std::is_same<OutputIt, fmt::v10::basic_appender<T> >::value), int>::type <anonymous> = 0]’
fmt/format.h:3855:25:   required from ‘constexpr fmt::v10::detail::arg_formatter<Char>::iterator fmt::v10::detail::arg_formatter<Char>::operator()(T) [with T = __int128; Char = char; fmt::v10::detail::arg_formatter<Char>::iterator = fmt::v10::basic_appender<char>]’
fmt/base.h:1677:17:   required from ‘constexpr decltype (vis(0)) fmt::v10::basic_format_arg<Context>::visit(Visitor&&) [with Visitor = fmt::v10::detail::arg_formatter<char>; Context = fmt::v10::context; decltype (vis(0)) = fmt::v10::basic_appender<char>]’
fmt/format.h:4384:7:   required from ‘const Char* fmt::v10::detail::vformat_to(fmt::v10::detail::buffer<T>&, fmt::v10::basic_string_view<Char>, typename fmt::v10::detail::vformat_args<Char>::type, fmt::v10::detail::locale_ref)::format_handler::on_format_specs(int, const Char*, const Char*) [with Char = char]’
fmt/format.h:4390:3:   required from ‘void fmt::v10::detail::vformat_to(fmt::v10::detail::buffer<T>&, fmt::v10::basic_string_view<Char>, typename fmt::v10::detail::vformat_args<Char>::type, fmt::v10::detail::locale_ref) [with Char = char; typename fmt::v10::detail::vformat_args<Char>::type = fmt::v10::basic_format_args<fmt::v10::context>]’
format.cc:32:75:   required from here
fmt/format.h:2249:60: error: static assertion failed
 2249 |   static_assert(std::is_same<T, uint32_or_64_or_128_t<T>>::value, "");
      |                                                            ^~~~~

If it try on my Ubuntu 20.04 system:

gh repo clone fmtlib/fmt
cd fmt
mkdir build
cd build
cmake -DCMAKE_BUILD_TYPE=Debug -DBUILD_SHARED_LIBS=ON \
              -DCMAKE_CXX_STANDARD=17 -DFMT_DOC=OFF \
              -DCMAKE_CXX_VISIBILITY_PRESET=hidden -DCMAKE_VISIBILITY_INLINES_HIDDEN=ON \
              -DFMT_PEDANTIC=ON -DFMT_WERROR=ON ..
cmake --build .

it works without any problems - still unclear what the difference is here

I do not have this issue with the latest release 10.2.1

[vitaut]

Godbolt repro: https://www.godbolt.org/z/WGdTWKqaf

[vitaut]

Commit that introduced the issue: 401f087.

[phprus]

GCC bug, fixed in GCC 10.3: gcc-mirror/gcc@8eb9a45

We need define num_bits<uint128_t>() and if uint128_t is not equal to uint128_fallback then define num_bits<uint128_fallback>().

[phprus]

Fix demo on Godbolt: https://www.godbolt.org/z/cGaMxvKxc

[rexainn]

So we should installed gcc 10+ to solve this problem?

[phprus]

gcc 10.3+ or use -std=gnu++2a (with gcc extensions) instead of -std=c++2a

[vitaut]

Fixed in 0cdee90. Thanks for reporting.