[Issue 23676] Static foreach hangs compilation for some time

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=23676

Basile-z <b2.temp at gmx.com> changed:

           What    |Removed                     |Added
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                 CC|                            |b2.temp at gmx.com

--- Comment #5 from Basile-z <b2.temp at gmx.com> ---
The `static foreach` is not great (btw  you can drop `static`) but the real
culprit is the access to the struct member `_index` from the nested functions.
That would be a problem of counter performance caused by the creation of
closures.

kcachegrind shows that the costy thing would be a cycle between
`FuncDeclaration.needsClosure` and checkEscapingSiblings.

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