class RuboCop::Cop::Style::For

allowed, however.
parameter. An each call with a block on a single line is always
preferred alternative is set in the EnforcedStyle configuration
This cop looks for uses of the for keyword, or each method. The

def incorrect_style_detected(method) 

def incorrect_style_detected(method)
  end_pos = method.source_range.end_pos
  range = range_between(end_pos - EACH_LENGTH, end_pos)
  add_offense(range, range, 'Prefer `for` over `each`.') do
    opposite_style_detected
  end
end

def on_block(node) 

def on_block(node)
  return if node.single_line?
  return unless node.send_node.method?(:each) &&
                !node.send_node.arguments?
  if style == :for
    incorrect_style_detected(node.send_node)
  else
    correct_style_detected
  end
end

def on_for(node) 

def on_for(node)
  if style == :each
    add_offense(node, :keyword, 'Prefer `each` over `for`.') do
      opposite_style_detected
    end
  else
    correct_style_detected
  end
end