Misuse check: re-iterating arguments has different argument count

[BenWoodworth]

This is an easy way to check that the argument iterator is pure.

An even simpler sub-case of this is when re-iterating the arguments, if the iterator is empty when it wasn't before. Though this occuring doesn't seem like it'd be a common occurrence

[BenWoodworth]

Depends on #3, since arguments instances won't re-iterated without it.