class A
{
  void foo(int i) {}
  void foo(float f) {}
}

class B: A
{
  alias A.foo foo; // (9)
  override void foo(int i) { foo(); } // (10)
  void foo() {};
}

void main()
{
  B b;
  b.foo(1.0f);
}

DMD 0.108 outputs:
ta.d(10): need 'this' to access member foo

If (10) rewrite as 'override void foo(int i) { this.foo(); } program compiles successfully.