[Bug c++/115809] New: Gcc can't parse code where the decltype is written, which depends on the runtime arguments passed to the function.

[linuxnyasha at tutanota dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115809

            Bug ID: 115809
           Summary: Gcc can't parse code where the decltype is written,
                    which depends on the runtime arguments passed to the
                    function.
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: linuxnyasha at tutanota dot com
  Target Milestone: ---

template <int...>
auto Foo() {};

auto Foo2(auto... is) {
  return Foo<is...>(); // works fine
};

auto Foo3(auto... is) -> decltype(Foo<is...>()) {}; // error


auto main() -> int {
  auto f = [](auto... is) -> decltype(Foo<is...>()){}; // error
};

On clang everything works
https://godbolt.org/z/vKqa9368d