[Issue 24096] a pure function is in fact impure for local automatic external variables

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=24096

--- Comment #4 from andreiD at yopmail.com ---
Shouldn't in the delegate, we capture the variable of the function itself where
the delegate is called, and not an external variable outside the function!

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