# File lib/parser/builders/default.rb, line 685
    def restarg_expr(star_t, expr=nil)
      if expr.nil?
        n0(:restarg, token_map(star_t))
      elsif expr.type == :lvasgn
        expr.updated(:restarg)
      else
        n(:restarg_expr, [ expr ],
          expr.loc.dup)
      end
    end