Cannot construct constexpr array from braced-init-list

Question

I\'ve implemented a constexpr array like this:

template 
class const_array {
  const T* p;
  unsigned n;
public:
  template 

        

Answer 1

The problem was that you cannot imbue the constant nature of the pointer to T in the inner template through the outer template's T parameter.

template  class const_array {
    const T * p;
    unsigned n;
public:
    template 
        constexpr const_array(const T(& a)[N]): p(a), n(N) { }
};

int main(int argc, char* argv[]) {
    constexpr const_array ca{(const double []) { 1., 2. }};
    return 0;
}

I tried a few dozen permutations to get rid of the cast without success.