[Issue 23086] spurious case of `expression has no effect` message

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=23086

--- Comment #3 from Basile-z <b2.temp at gmx.com> ---
`a` was supposed to return a global, closed an opened
https://issues.dlang.org/show_bug.cgi?id=23088 for less confusion.

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