values and each are OA_DANGEROUS

values and each are OA_DANGEROUS

OA_DANGEROUS indicates that temporary copies may need to be made in
list assignment, to handle things like:

($a, $b) = ($b, $a);

In other words, an op type is flagged with OA_DANGEROUS if its return
values could occur elsewhere on the stack.

values and each can both return scalars that are referenced elsewhere,
causing list assignment to behave erratically if temporary copies
are not made.