class Gem::Dependency

def merge(other)
  unless name == other.name
    raise ArgumentError,
          "#{self} and #{other} have different names"
  end
  default = Gem::Requirement.default
  self_req = requirement
  other_req = other.requirement
  return self.class.new name, self_req  if other_req == default
  return self.class.new name, other_req if self_req  == default
  self.class.new name, self_req.as_list.concat(other_req.as_list)
end