class RSpec::Expectations::LegacyMatcherAdapter::RSpec2

def self.interface_matches?(matcher)
  (
    !matcher.respond_to?(:failure_message) &&
    matcher.respond_to?(:failure_message_for_should)
  ) || (
    !matcher.respond_to?(:failure_message_when_negated) &&
    matcher.respond_to?(:failure_message_for_should_not)
  )
end