[Bug c++/66656] New: static constexpr array member: cannot get size via constexpr function

[g5834847 at trbvm dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66656

            Bug ID: 66656
           Summary: static constexpr array member: cannot get size via
                    constexpr function
           Product: gcc
           Version: 4.9.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: g5834847 at trbvm dot com
  Target Milestone: ---

////////////////////////////////////////

#include <iostream>

template <typename T, size_t N>
constexpr size_t array_size(const T (&)[N])
{
  return N;
}

class X {
public:
  struct item {
    char const* const name;
    int               price;
  };

  static const     item arr0[2];
  static constexpr item arr1[3] = {{"asdf", 0}, {"qwer", 1}, {"zxcv", 2}};

  static size_t constexpr size0() {
    return array_size(arr0);    // perfect
  }

  static size_t constexpr size1() {
    return array_size(arr1);    // problem!!
  }

};

const X::item X::arr0[] = {{"asdf", 0}, {"qwer", 1}};

int main()
{
  X x;
  std::cout << x.size0() << std::endl; // perfect
  std::cout << x.size1() << std::endl; // ERROR IN THIS LINE (cannot link!??)
  return 0;
}
////////////////////////////////////////////



$ c++ -std=c++14 -o go go.cpp

/tmp/ccPGS4ZN.o: In function `X::size1()':
go.cpp:(.text._ZN1X5size1Ev[_ZN1X5size1Ev]+0x5): undefined reference to
`X::arr1'
collect2: error: ld returned 1 exit status