class RuboCop::Cop::Lint::ToJSON

def on_def(node)
  return unless node.method?(:to_json) && node.arguments.empty?
  add_offense(node) do |corrector|
    # The following used `*_args` because `to_json(*args)` has
    # an offense of `Lint/UnusedMethodArgument` cop if `*args`
    # is not used.
    corrector.insert_after(node.loc.name, '(*_args)')
  end
end