Bug 7451 – [Git regression] AAs broken for interfaces keys and values with opEquals

Very similar to issue 7365, using DMD and druntime from Git, this program --- struct TickDuration { bool opEquals(ref const TickDuration rhs) const { return true; } } interface Test {} AssociativeArray!(TickDuration, Test) aa; --- fails with --- object.di(379): Error: function object.opEquals (const(Object) lhs, const(Object) rhs) is not callable using argument types (const(Test),const(Test)) object.di(379): Error: cannot implicitly convert expression (this.value) of type const(Test) to object.Object object.di(379): Error: cannot implicitly convert expression (p.value) of type const(Test) to object.Object --- The error is encountered while generating the default opEquals for the Slot type added in https://github.com/D-Programming-Language/druntime/commit/cd7b477b83cc8a75a90258bd2ab63fa8c92ba10b.

(if TickDuration[Test] is used directly, DMD ICE's instead because the template cannot be instantiated)

Is this really a regression? Note that this also similarly fails: ---- interface Test {} bool foo(Test x, Test y) { return x == y; } ---- foo2.d(6): Error: function object.opEquals (const(Object) lhs, const(Object) rhs) is not callable using argument types (Test,Test) Because an interface cannot be implicitly converted to an Object: ---- interface Test {} Object foo(Test x) { return x; } ---- foo2.d(6): Error: cannot implicitly convert expression (x) of type foo2.Test to object.Object

The question is whether interfaces can be used as AA keys. They could in 2.057 and before, and can't quite now, hence I marked it as regression.

*** This issue has been marked as a duplicate of issue 4088 ***