% perl -I. -Mfeature::each_on_array -E'say $^V; @a = (qw/a b c/); while (($i, $e) = each @a) { say $i, $e } package Foo; @b = (qw/a b c/); while (($i, $e) = each @b) { say $i, $e }'
Type of arg 1 to each must be hash (not array dereference) at -e line 1, near "@b) "