diff --git a/core/lib/Drupal/Core/Routing/UrlGenerator.php b/core/lib/Drupal/Core/Routing/UrlGenerator.php
index f1f8a57..e1e984e 100644
--- a/core/lib/Drupal/Core/Routing/UrlGenerator.php
+++ b/core/lib/Drupal/Core/Routing/UrlGenerator.php
@@ -155,7 +155,8 @@ public function getPathFromRoute($name, $parameters = array()) {
    *   The route name or other identifying string from ::getRouteDebugMessage().
    *
    * @return string
-   *   The url path, without any base path, including possible query string.
+   *   The url path, without any base path, without the query string, not URL
+   *   encoded.
    *
    * @throws MissingMandatoryParametersException
    *   When some parameters are missing that are mandatory for the route.
@@ -230,7 +231,8 @@ protected function doGenerate(array $variables, array $defaults, array $tokens,
    *   $parameters merged in.
    *
    * @return string
-   *   The url path corresponding to the route, without the base path.
+   *   The URL path corresponding to the route, without the base path, not URL
+   *   encoded.
    */
   protected function getInternalPathFromRoute($name, SymfonyRoute $route, $parameters = array(), &$query_params = array()) {
     // The Route has a cache of its own and is not recompiled as long as it does
@@ -253,9 +255,11 @@ public function generate($name, $parameters = array(), $referenceType = self::AB
    */
   public function generateFromRoute($name, $parameters = array(), $options = array(), $collect_bubbleable_metadata = FALSE) {
     $options += array('prefix' => '');
-    if (!isset($options['query']) || !is_array($options['query'])) {
-      $options['query'] = array();
+    // Provide a BC layer for code that passed a string in there.
+    if (is_string($options['query'])) {
+      parse_str($options['query'], $options['query']);
     }
+
     $route = $this->getRoute($name);
     $generated_url = $collect_bubbleable_metadata ? new GeneratedUrl() : NULL;
 
@@ -285,7 +289,8 @@ public function generateFromRoute($name, $parameters = array(), $options = array
     if ($options['path_processing']) {
       $path = $this->processPath($path, $options, $generated_url);
     }
-    // The contexts base URL is already encoded (see Symfony\Component\HttpFoundation\Request)
+    // The contexts base URL is already encoded
+    // (see Symfony\Component\HttpFoundation\Request).
     $path = str_replace($this->decodedChars[0], $this->decodedChars[1], rawurlencode($path));
 
     // Drupal paths rarely include dots, so skip this processing if possible.
@@ -304,14 +309,14 @@ public function generateFromRoute($name, $parameters = array(), $options = array
       }
     }
 
-    $query = $options['query'] ? '?' . UrlHelper::buildQuery($options['query']) : '';
-
     if (!empty($options['prefix'])) {
       $path = ltrim($path, '/');
       $prefix = empty($path) ? rtrim($options['prefix'], '/') : $options['prefix'];
       $path = '/' . str_replace('%2F', '/', rawurlencode($prefix)) . $path;
     }
 
+    $query = $options['query'] ? '?' . UrlHelper::buildQuery($options['query']) : '';
+
     // The base_url might be rewritten from the language rewrite in domain mode.
     if (isset($options['base_url'])) {
       $base_url = $options['base_url'];
diff --git a/core/tests/Drupal/Tests/Core/Routing/UrlGeneratorTest.php b/core/tests/Drupal/Tests/Core/Routing/UrlGeneratorTest.php
index b0c1ca3..6f7d2f8 100644
--- a/core/tests/Drupal/Tests/Core/Routing/UrlGeneratorTest.php
+++ b/core/tests/Drupal/Tests/Core/Routing/UrlGeneratorTest.php
@@ -505,7 +505,7 @@ public function providerTestNoPath() {
   }
 
   /**
-   * @covers \Drupal\Core\Routing\UrlGenerator::generateFromRoute
+   * @covers ::generateFromRoute
    *
    * Note: We use absolute covers to let
    * \Drupal\Tests\Core\Render\MetadataBubblingUrlGeneratorTest work.
@@ -514,7 +514,7 @@ public function testGenerateWithPathProcessorChangingQueryParameter() {
     $path_processor = $this->getMock(OutboundPathProcessorInterface::CLASS);
     $path_processor->expects($this->atLeastOnce())
       ->method('processOutbound')
-      ->willReturnCallback(function ($path, &$options = array(), Request $request = NULL, BubbleableMetadata $bubbleable_metadata = NULL) {
+      ->willReturnCallback(function ($path, &$options = [], Request $request = NULL, BubbleableMetadata $bubbleable_metadata = NULL) {
         $options['query'] = ['zoo' => 5];
         return $path;
       });