# File lib/rspec/mocks/argument_expectation.rb, line 22
      def matcher_for(arg)
        return ArgumentMatchers::MatcherMatcher.new(arg) if is_matcher?(arg)
        return ArgumentMatchers::RegexpMatcher.new(arg)  if arg.is_a?(Regexp)
        return ArgumentMatchers::EqualityProxy.new(arg)
      end