Inconsistent behavior overriding functions from abstract classes that implement interfaces.

[dlangBugzillaToGithub]

IM reported this on 2017-12-07T07:16:34Z

Transferred from https://issues.dlang.org/show_bug.cgi?id=18041

Description

This issue was discussed here in the forum: https://forum.dlang.org/thread/wvysznguwwapxdcjtkge@forum.dlang.org

I will repeat my description from there:

Assume the following:


interface IFace {
  void foo();
  void bar();
}

abstract class A : IFace {
  override void foo() {}
}

class B : A {
  override void bar() {}
}


This fails to compile with the following message:

--->>>
function bar does not override any function, did you mean to override 'IFace.bar()'?
<<<---

So `override` works for A::foo(), but doesn't work for B::bar(). This is inconsistent and confusing. I would expect that `override` works for both cases. Please fix. Thank you.