[Bug c++/66336] New: [C++14][Variable templates] Spurious "error: expansion pattern contains no argument packs"

["lucdanton at free dot fr" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66336

            Bug ID: 66336
           Summary: [C++14][Variable templates] Spurious "error: expansion
                    pattern contains no argument packs"
           Product: gcc
           Version: 5.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: lucdanton at free dot fr
  Target Milestone: ---

Created attachment 35651
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35651&action=edit
Minimal testcase

$ g++-trunk --version
g++-trunk (GCC) 5.1.0
Copyright (C) 2015 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$ cat main.cpp            
template<typename>
int i {};

template<typename... Xs>
void f()
{
    // error: expansion pattern 'i<Xs>' contains no argument packs
    int is[] = { i<Xs>... };
}

int main()
{
    f<void, void, void>();
}
$ g++-trunk -std=c++14 main.cpp
main.cpp: In function 'void f()':
main.cpp:8:23: error: expansion pattern 'i<Xs>' contains no argument packs
     int is[] = { i<Xs>... };