[Issue 21321] Class with unimplemented interface method compiles, links, then segfaults, if inherited through abstract base class

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=21321

--- Comment #4 from moonlightsentinel at disroot.org ---
(In reply to Adam D. Ruppe from comment #3)
> As such I'm upping the severity of this to regression.

Regression introduced by https://github.com/dlang/dmd/pull/11191
(wow)

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