class Shoulda::Matchers::ActiveModel::ValidateComparisonOfMatcher

def matches?(subject)
  @subject = subject
  @number_of_submatchers = @submatchers.size
  unless @comparison_matcher
    raise(ArgumentError, "matcher isn't qualified with any comparison matcher")
  end
  qualify_submatchers
  first_submatcher_that_fails_to_match.nil?
end