I don't consider assignment to have a "side effect". Assignment is the effect.
So, 
map {$sum += $_} @array;

[download]
is side-effect free?
This seems disingenuous. While I agree that arguing that assignment is “side-effect free” seems a little strange, your example isn't just assigning, it's mutating. Even in the purest of functional languages, x = 5 is OK (I think!); but x += 1 isn't.

In reply to Re^5: map in void context by JadeNB
in thread map in void context by dharanivasan

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