I found bug in our product that aborts iterator unexpectedly, with return statement.

def iterate
    array.each do |item|
        return if item.skip? # oh, no! it returns from "iterate" method!
        ...
    end
end

NonLocalExitFromIterator detects misused return statements in iterator block.
It uses heuristic way to distinguish intended use of return or not:

• No return value.
  Because where next should be used tend to have no return value (but of map).
• Method chain.
  E.g. array.each do |item| ... end and not before_fork do |server| ... end.
• Block with arguments.
  E.g. not foobar.with_lock do ... end.

Cops affect with this bug also found: LiteralInInterpolation and AssignmentInCondition.
UnneededCapitalW is false-positive, but is still easy to use any? instead.

Thanks for great product!