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// { dg-options "-std=gnu++20" }
// { dg-do run { target c++20 } }
#include <format>
#include <testsuite_hooks.h>
enum color { red, green, blue };
const char* color_names[] = { "red", "green", "blue" };
template<> struct std::formatter<color> : std::formatter<const char*> {
auto format(color c, format_context& ctx) const {
return formatter<const char*>::format(color_names[c], ctx);
}
};
struct err {};
void
test_specializations() // [format.formatter.spec]
{
std::string s0 = std::format("{}", 42); // OK, library-provided formatter
VERIFY( s0 == "42" );
using Fi = std::format_context::formatter_type<int>;
static_assert( std::is_default_constructible_v<Fi> );
static_assert( std::is_copy_constructible_v<Fi> );
static_assert( std::is_move_constructible_v<Fi> );
static_assert( std::is_copy_assignable_v<Fi> );
static_assert( std::is_move_assignable_v<Fi> );
// std::string s1 = std::format("{}", L"foo"); // error: disabled formatter
using Fw = std::format_context::formatter_type<wchar_t>;
static_assert( ! std::is_default_constructible_v<Fw> );
static_assert( ! std::is_copy_constructible_v<Fw> );
static_assert( ! std::is_move_constructible_v<Fw> );
static_assert( ! std::is_copy_assignable_v<Fw> );
static_assert( ! std::is_move_assignable_v<Fw> );
std::string s2 = std::format("{}", red); // OK, user-provided formatter
VERIFY( s2 == "red" );
using Fc = std::format_context::formatter_type<color>;
static_assert( std::is_default_constructible_v<Fc> );
static_assert( std::is_copy_constructible_v<Fc> );
static_assert( std::is_move_constructible_v<Fc> );
static_assert( std::is_copy_assignable_v<Fc> );
static_assert( std::is_move_assignable_v<Fc> );
// std::string s3 = std::format("{}", err{}); // error: disabled formatter
using Ferr = std::format_context::formatter_type<err>;
static_assert( ! std::is_default_constructible_v<Ferr> );
static_assert( ! std::is_copy_constructible_v<Ferr> );
static_assert( ! std::is_move_constructible_v<Ferr> );
static_assert( ! std::is_copy_assignable_v<Ferr> );
static_assert( ! std::is_move_assignable_v<Ferr> );
// LWG 3833. Remove specialization
// template<size_t N> struct formatter<const charT[N], charT>
using Farr = std::format_context::formatter_type<const char[1]>;
static_assert( ! std::is_default_constructible_v<Farr> );
static_assert( ! std::is_copy_constructible_v<Farr> );
static_assert( ! std::is_move_constructible_v<Farr> );
static_assert( ! std::is_copy_assignable_v<Farr> );
static_assert( ! std::is_move_assignable_v<Farr> );
}
int main()
{
test_specializations();
}
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