class Rubocop::Cop::Style::WhileUntilModifier

if written as a modifier while/until.
Checks for while and until statements that would fit on one line

def investigate(processed_source) 

def investigate(processed_source)
  return unless processed_source.ast
  on_node([:while, :until], processed_source.ast) do |node|
    # discard modifier while/until
    next unless node.loc.end
    if check(node, processed_source.comments)
      convention(node, :keyword)
    end
  end
end