https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82249
--- Comment #2 from Benjamin Buch <benni.buch at gmail dot com> ---
The ICE is fixed in trunk, but the wrong argument pack lengths mismatch does
still exist:
constexpr auto calc = [](auto, auto dim)noexcept{ return dim; };
template < typename ... Ds >
constexpr auto f(Ds ...)noexcept{
return [](auto ... n){ return (calc(n, Ds{}), ...); }(Ds{} ...);
}
int main(){
f(); // Wrong error
f(0); // OK
f(0, 0); // Wrong error
}
$ g++ -std=c++1z main.cpp
main.cpp: In instantiation of 'constexpr auto f(Ds ...) [with Ds = {}]':
main.cpp:9:7: required from here
main.cpp:5:57: error: mismatched argument pack lengths while expanding 'calc(n,
Ds{})'
return [](auto ... n){ return (calc(n, Ds{}), ...); }(Ds{} ...);
^
main.cpp: In instantiation of 'constexpr auto f(Ds ...) [with Ds = {int,
int}]':
main.cpp:11:11: required from here
main.cpp:5:57: error: mismatched argument pack lengths while expanding 'calc(n,
Ds{})'
$ g++ --version
g++ (GCC) 8.0.0 20171201 (experimental)
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