class RSpec::Matchers::BuiltIn::RaiseError

def initialize(expected_error_or_message, expected_message, &block)
  @block = block
  @actual_error = nil
  @warn_about_bare_error = UndefinedValue === expected_error_or_message
  @warn_about_nil_error = expected_error_or_message.nil?
  case expected_error_or_message
  when nil, UndefinedValue
    @expected_error = Exception
    @expected_message = expected_message
  when String
    @expected_error = Exception
    @expected_message = expected_error_or_message
  else
    @expected_error = expected_error_or_message
    @expected_message = expected_message
  end
end