https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106980
Bug ID: 106980
Summary: Concept on a variadig template
Product: gcc
Version: 12.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: spiegelneuron at gmail dot com
Target Milestone: ---
The following code compiles fine with the current version of VC++ 2022:
#include <iostream>
#include <utility>
using namespace std;
template<size_t N, typename ... Fns>
#if defined(_MSC_VER)
requires (N >= 1) && (requires( Fns fn ) { { fn.template operator
()<(size_t)N - 1>() } -> std::same_as<void>; } && ...)
#elif defined(__GNUC__)
requires (N >= 1) && (requires( Fns ... fn ) { { fn.template operator
()<(size_t)N - 1>() } -> std::same_as<void>; } && ...)
#endif
void unroll( Fns ... fns )
{
auto unroll_n = [&]<typename Fn, size_t ... Indices>( Fn fn,
std::index_sequence<Indices ...> )
{
(fn.template operator ()<Indices>(), ...);
};
(unroll_n( fns, std::make_index_sequence<N>() ), ...);
}
int main()
{
unroll<3>(
[]<size_t I>() { cout << "hello " << I << endl; },
[]<size_t I>() { cout << "this " << I << endl; },
[]<size_t I>() { cout << "world " << I << endl; } );
}
g++ 11.2.0 crashes.
