https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94628
Bug ID: 94628
Summary: segfault decltype
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: roland at rschulz dot eu
Target Milestone: ---
GCC 9.3 and trunk. Internal compiler error: Segmentation fault
#include <type_traits>
#include <utility>
template<int i>
using int_constant = std::integral_constant<int, i>;
template<int I, int...Is, class F, class...Args>
auto select(int i, F&&f, Args&&...args) ->
std::common_type_t<decltype(std::forward<F>(f)(int_constant<I>(),
std::forward<decltype(args)>(args)...)),
decltype(std::forward<F>(f)(int_constant<Is>(),
std::forward<decltype(args)>(args)...))...>
{
if (i == I) return std::forward<F>(f)(int_constant<I>(),
std::forward<Args>(args)...);
else {
if constexpr(sizeof...(Is)>0)
return select<Is...>(i, std::forward<F>(f),
std::forward<Args>(args)...);
}
}
int t(int i) {
return select<0, 1>(i, [](auto x){ return int(x);});
}
No problem if `decltype(args)` is replaced with `Args`.
https://godbolt.org/z/kPpEK8
