$ dmd -c foo.d

Fails with 2.071.1-b1 with error:
bar.d(3): Error: T.Zoo is not a template, it is a overloadset
bar.d(8): Error: template instance bar.Boo!(Foo) error instantiating
foo.d(3): Error: mixin foo.Foo.Bar!() error instantiating


// file foo.d
class Foo {
  import bar;
  mixin Bar;
}

// file bar.d
class Zoo(V) {}
template Boo(T) {
  alias Boo = T.Zoo!T;
}
mixin template Bar() {
  class Zoo(V) {}
  alias U = typeof(this);
  alias BooThis = Boo!U;
}