bug #19088 [Routing] treat fragment after resolving query string params (xabbuh)

This PR was merged into the 3.2-dev branch.

Discussion
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[Routing] treat fragment after resolving query string params

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        |

The implementation from #12979 led to a conflict with #18280 which was merged in the meantime.

Commits
-------

7475aa8 treat fragment after resolving query string params

src/Symfony/Component/Routing/Generator/UrlGenerator.php

@@ -257,18 +257,15 @@ class UrlGenerator implements UrlGeneratorInterface, ConfigurableRequirementsInt
             $url = $schemeAuthority.$this->context->getBaseUrl().$url;
         }
 
-        // extract unused parameters
-        $extra = array_diff_key($parameters, $variables, $defaults);
-
-        // extract fragment
-        $fragment = isset($extra['_fragment']) ? $extra['_fragment'] : '';
-        unset($extra['_fragment']);
-
         // add a query string if needed
         $extra = array_udiff_assoc(array_diff_key($parameters, $variables), $defaults, function ($a, $b) {
             return $a == $b ? 0 : 1;
         });
 
+        // extract fragment
+        $fragment = isset($extra['_fragment']) ? $extra['_fragment'] : '';
+        unset($extra['_fragment']);
+
         if ($extra && $query = http_build_query($extra, '', '&')) {
             // "/" and "?" can be left decoded for better user experience, see
             // http://tools.ietf.org/html/rfc3986#section-3.4