https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106980
Martin Liška <marxin at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |marxin at gcc dot gnu.org --- Comment #1 from Martin Liška <marxin at gcc dot gnu.org> --- Apparently clang also rejects the code: $ clang++ pr106980.C -c -std=c++20 pr106980.C:10:27: error: requirement contains unexpanded parameter pack 'fn' requires (N >= 1) && (requires( Fns ... fn ) { { fn.template operator ()<(size_t)N - 1>() } -> std::same_as<void>; } && ...) ^ ~~ 1 error generated.