[Issue 13179] AA key type TagIndex now requires equality rather than comparison

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=13179

Jonathan M Davis <jmdavisProg at gmx.com> changed:

           What    |Removed                     |Added
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                 CC|                            |jmdavisProg at gmx.com

--- Comment #9 from Jonathan M Davis <jmdavisProg at gmx.com> ---
I would not expect `a == b` to _ever_ be converted to `a.opCmp(b) == 0`. That's
what opEquals is for. However, I also wouldn't expect declaring opCmp to make
it so that the compiler no longer generates an opEquals for the struct. The
compiler should either continue to declare the opEquals or make it an error if
you define opCmp but not opEquals. It makes no sense whatsoever to have a type
which is comparable with <, <=, >=, and > but not ==. And it should _always_ be
considered a bug if `a.opCmp(b) == 0` is not equivalent to `a == b` or if `a <=
b && a >= b` is not equivalent to `a == b`.

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