icc bug with nested parameter packs

[rnickb]

The below code compiles fine with gcc and clang but gives this error with icc 2016:

main.cpp(11): error: parameter pack "IX2" was referenced but not expanded

    KA(const A<IX2>&... ax) {

               ^

compilation aborted for main.cpp (code 2)

template<int I>                                                                  
struct A {};                                                                     
                                                                                 
template<int... IX>                                                              
struct KA {                                                                      
  template<int... IX2>                                                           
  KA(const A<IX2>&... ax) {                                                      
  }                                                                              
};                                                                               
                                                                                 
int main() {                                                                     
  return 0;                                                                      
}