[Issue 21298] Missing error when overriding interface method without in contract with class method with contract

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=21298

--- Comment #4 from Walter Bright <bugzilla at digitalmars.com> ---
I'm not convinced this should be an error. An interface doesn't implement a
function. The class providing the function isn't overriding the interface, it
is implementing it.

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