[Bug c++/79442] New: GCC 5.4 does not fully support N3652 (Relaxing constraints on constexpr functions)

["zuverliantellabrach at hotmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79442

            Bug ID: 79442
           Summary: GCC 5.4 does not fully support N3652 (Relaxing
                    constraints on constexpr functions)
           Product: gcc
           Version: 5.4.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zuverliantellabrach at hotmail dot com
  Target Milestone: ---

GCC 5 is supposed to provide full support for N3652, but the code below does
not compile under GCC 5.4 (it does, however, compile under GCC 6.1).



#include <iostream>

template<class... Ts>
constexpr bool allTrue(Ts... ts) {
  const bool bs[]={ts...};
  for(size_t i=0; i<sizeof...(Ts); ++i) {if(!bs[i]) {return false;}}
  return true;
}

template<bool B>
struct S {S() {std::cout<<std::boolalpha<<B<<std::endl;}};

int main() {
  S<allTrue(true,true,true,false)>{};
  return 0;
}