6910 – __traits(hasMember, "<name>") does not work, if template has alias param

Given this code fragment:
--------------
struct Bag(S...)
{
  alias S Types;
}
template Test(alias i, B)
{
  void fn() {
    foreach(t; B.Types)
    {
      switch(i) {
        case IndexOf!(t, B.Types):
        {
          pragma(msg, __traits(allMembers, t));
          pragma(msg, __traits(hasMember, t, "m"));
          break;
        }
        default: {}
      }
    }
  }
}
struct A
{
  int m;
}
void main()
{
  int i;
  alias Test!(i, Bag!(A)).fn func;
}
----------------------
DMD will output:
----------------------
tuple("m")
false
---------------------
It seems that __traits(hasMember, ..) evaluates to false, despite the fact that the type 
does have a member "m". However if the template Test does not have an alias parameter, everything will work just fine.

I think this is an issue that both of D1 and D2 have.
D2 patch:
https://github.com/D-Programming-Language/dmd/pull/509 

https://github.com/D-Programming-Language/dmd/commit/6fb5861528c7568d2546774a1c884f99594024c0
https://github.com/D-Programming-Language/dmd/commit/129c1ae7fe50cb3cb9a218e232f42f9a5a987e29