I just tested that #1 in fact does use $foo++, and warnings::unused handles it properly

You forgot about tied variables. $foo++ can be tied to code that prints out "Hello World" as a side effect.

I guess the short version of this is, I don't see any situation where using a declare-once-and-forget variable is ever clearer or substantially more efficient than an alternative, so I don't see any of these situations as warranting exceptions from warnings, even if they are in common use.

You haven't programmed much with resource acquisition/release systems then. C has lots of problems with that, Windows COM has lots of problems with that and Perls reference counting also has these problems (although many of them have been fixed in all instances). With Reference Counting as the instance of resource acquisition and release, you have exactly the problem that the points of acquisition (increase of refcount) and release (decrement of refcount) are not in the same place of the code and hence, quite unpleasantly, not every acquisition is matched with a release, because it's hard to see that they match up because they do not happen in the same place. Which is why a "execute this code at scope exit" functionality is wanted.

In reply to Re^5: Warnings on unused variables? by Corion
in thread Warnings on unused variables? by AZed

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