ConfigurableLanguageManager language_switch_links alter use undefined path variable

Problem/Motivation

'path' variable in $this->moduleHandler->alter('language_switch_links', $result, $type, $path); line 427 is undefined.

Line 412

  /**
   * {@inheritdoc}
   */
  public function getLanguageSwitchLinks($type, Url $url) {
    $links = FALSE;

    if ($this->negotiator) {
      foreach ($this->negotiator->getNegotiationMethods($type) as $method_id => $method) {
        $reflector = new \ReflectionClass($method['class']);

        if ($reflector->implementsInterface('\Drupal\language\LanguageSwitcherInterface')) {
          $result = $this->negotiator->getNegotiationMethodInstance($method_id)->getLanguageSwitchLinks($this->requestStack->getCurrentRequest(), $type, $url);

          if (!empty($result)) {
            // Allow modules to provide translations for specific links.
            $this->moduleHandler->alter('language_switch_links', $result, $type, $path);
            $links = (object) array('links' => $result, 'method_id' => $method_id);
            break;
          }
        }
      }
    }

    return $links;
  }

Proposed resolution

Pass $url instead of $path to hook_language_switch_links_alter.

Remaining tasks

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User interface changes

None.

API changes

hook_language_switch_links_alter third param is now a \Drupal\Core\Url object.

Data model changes

None.