The following (incorrect) code causes DMD to segfault on compilation:

  template Foo(T) if (is(T == int))
  {
      enum bool Foo = true;
  }

  template Foo(T) if (!is(T == int))
  {
      enum bool Foo = Foo(typeof(int.min));
  }

  static assert (Foo!double);

In the second template, note the following two things which are BOTH required to reproduce the bug:

 1) The ! is missing from the template instantiation.
 2) The template parameter is typeof(int.min) instead of just int.