Created attachment 35651 [details]
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>... };