class SyntaxTree::Parser

def on_args_add_star(arguments, argument)

on_args_add_star: (Args arguments, untyped star) -> Args
:call-seq: 
def on_args_add_star(arguments, argument)
  beginning = consume_operator(:*)
  ending = argument || beginning
  location =
    if arguments.parts.empty?
      ending.location
    else
      arguments.location.to(ending.location)
    end
  arg_star =
    ArgStar.new(
      value: argument,
      location: beginning.location.to(ending.location)
    )
  Args.new(parts: arguments.parts << arg_star, location: location)
end