module RSpec::Rails::Matchers::BaseMatcher::DefaultFailureMessages

def self.has_default_failure_messages?(matcher)
  matcher.method(:failure_message).owner == self &&
    matcher.method(:failure_message_when_negated).owner == self
rescue NameError
  false
end

def failure_message
  "expected #{description_of @actual} to #{description}".dup
end

def failure_message_when_negated
  "expected #{description_of @actual} not to #{description}".dup
end