[Bug c++/70521] New: [C++14] nonempty constexpr noexcept constructor rejected

["meiomorphism at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70521

            Bug ID: 70521
           Summary: [C++14] nonempty constexpr noexcept constructor
                    rejected
           Product: gcc
           Version: 5.2.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: meiomorphism at gmail dot com
  Target Milestone: ---

Created attachment 38170
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=38170&action=edit
test case

The following code is rejected by gcc 5.2.1.

====
#include <cassert>

struct A
{
    int v;
    constexpr A() noexcept : v(3) { assert(v != 0); }
};

int main() { }
====


====
$ g++ -std=c++14 err.cpp 
err.cpp: In constructor âconstexpr A::A()â:
err.cpp:6:53: error: member âA::vâ must be initialized by mem-initializer in
âconstexprâ constructor
     constexpr A() noexcept : v(3) { assert(v != 0); }
                                                     ^
err.cpp:5:9: note: declared here
     int v;
         ^
====

The mem-initializer in question is clearly present. clang 3.6.2 and 3.7.0
accept this code without diagnostics.

Removing any of "constexpr", "noexcept", or the "assert()" call results in the
code being accepted.