[Issue 23175] -preview=in silently adds possible stack memory escape

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=23175

--- Comment #13 from Mathias LANG <pro.mathias.lang at gmail.com> ---
> Thanks, I didn't know about this switch. However, it just lists all the places where `in` is a parameter, even ones where it is effectively const, i.e.:

The `-transition` switch was put in place because `in` also means `ref`, which
one may find "breaks code" (hint: it doesn't). The compiler *will* tell you
when you're doing something wrong, though: With DIP1000 and @safe. As the spec
says it will.

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