module RuboCop::Cop::MethodPreference

def default_cop_config
  ConfigLoader.default_configuration[cop_name]
end

def preferred_method(method)
  preferred_methods[method.to_sym]
end

def preferred_methods
  @preferred_methods ||=
    begin
      # Make sure default configuration 'foo' => 'bar' is removed from
      # the total configuration if there is a 'bar' => 'foo' override.
      default = default_cop_config['PreferredMethods']
      merged = cop_config['PreferredMethods']
      overrides = merged.values - default.values
      merged.reject { |key, _| overrides.include?(key) }.transform_keys(&:to_sym)
    end
end