[Issue 23104] case where use of mixin() is rejected but use of the mixin content as code is not

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=23104

--- Comment #1 from Basile-z <b2.temp at gmx.com> ---
actually compilation fails/succeeds only depending on

  is(mixin(getMember)==module

VS

  is(__traits(getMember, sym, m)==module

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