diff -u b/core/includes/theme.inc b/core/includes/theme.inc
--- b/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -1128,7 +1128,7 @@
             // \Drupal\Core\Render\Element::children(), which cannot be used
             // here, since it triggers an error on string values.
             foreach ($child as $child_key => $child_value) {
-              if (is_integer($child_key) || $child_key[0] !== '#') {
+              if (is_int($child_key) || $child_key[0] !== '#') {
                 $child['#items'][$child_key] = $child_value;
                 unset($child[$child_key]);
               }
diff -u b/core/lib/Drupal/Component/Annotation/Doctrine/DocParser.php b/core/lib/Drupal/Component/Annotation/Doctrine/DocParser.php
--- b/core/lib/Drupal/Component/Annotation/Doctrine/DocParser.php
+++ b/core/lib/Drupal/Component/Annotation/Doctrine/DocParser.php
@@ -990,7 +990,7 @@
     {
         $peek = $this->lexer->glimpse();
 
-        if (!empty($peek) && DocLexer::T_EQUALS === $peek['type']) {
+        if ($peek !== NULL && DocLexer::T_EQUALS === $peek['type']) {
             return $this->FieldAssignment();
         }
 
diff -u b/core/lib/Drupal/Core/Render/Element.php b/core/lib/Drupal/Core/Render/Element.php
--- b/core/lib/Drupal/Core/Render/Element.php
+++ b/core/lib/Drupal/Core/Render/Element.php
@@ -78,7 +78,7 @@
     $i = 0;
     $sortable = FALSE;
     foreach ($elements as $key => $value) {
-      if (is_integer($key) || $key === '' || $key[0] !== '#') {
+      if (is_int($key) || $key === '' || $key[0] !== '#') {
         if (is_array($value)) {
           if (isset($value['#weight'])) {
             $weight = $value['#weight'];
diff -u b/core/modules/link/src/Plugin/Field/FieldType/LinkItem.php b/core/modules/link/src/Plugin/Field/FieldType/LinkItem.php
--- b/core/modules/link/src/Plugin/Field/FieldType/LinkItem.php
+++ b/core/modules/link/src/Plugin/Field/FieldType/LinkItem.php
@@ -185,12 +185,12 @@
       $values += [
         'options' => [],
       ];
-    }
-    // Unserialize the values, this is deprecated as the storage takes care of
-    // this, options must not be passed as a string anymore.
-    if (isset($values['options']) && is_string($values['options'])) {
-      @trigger_error('Support for passing options as a serialized string is deprecated in 8.7.0 and will be removed before Drupal 9.0.0. Pass them as an array instead. See https://www.drupal.org/node/2961643.', E_USER_DEPRECATED);
-      $values['options'] = unserialize($values['options'], ['allowed_classes' => FALSE]);
+      // Unserialize the values, this is deprecated as the storage takes care of
+      // this, options must not be passed as a string anymore.
+      if (is_string($values['options'])) {
+        @trigger_error('Support for passing options as a serialized string is deprecated in 8.7.0 and will be removed before Drupal 9.0.0. Pass them as an array instead. See https://www.drupal.org/node/2961643.', E_USER_DEPRECATED);
+        $values['options'] = unserialize($values['options'], ['allowed_classes' => FALSE]);
+      }
     }
     parent::setValue($values, $notify);
   }
diff -u b/core/modules/locale/tests/src/Functional/LocaleJavascriptTranslationTest.php b/core/modules/locale/tests/src/Functional/LocaleJavascriptTranslationTest.php
--- b/core/modules/locale/tests/src/Functional/LocaleJavascriptTranslationTest.php
+++ b/core/modules/locale/tests/src/Functional/LocaleJavascriptTranslationTest.php
@@ -152,7 +152,7 @@
 
     // Calculate the filename of the JS including the translations.
     $js_translation_files = \Drupal::state()->get('locale.translation.javascript');
-    $js_filename = $prefix . '_' . ($js_translation_files[$prefix] ?? NULL) . '.js';
+    $js_filename = $prefix . '_' . ($js_translation_files[$prefix] ?? '') . '.js';
 
     $content = $this->getSession()->getPage()->getContent();
     // Assert translations JS is included before drupal.js.
diff -u b/core/modules/views/src/Plugin/views/display/PathPluginBase.php b/core/modules/views/src/Plugin/views/display/PathPluginBase.php
--- b/core/modules/views/src/Plugin/views/display/PathPluginBase.php
+++ b/core/modules/views/src/Plugin/views/display/PathPluginBase.php
@@ -101,7 +101,7 @@
   protected function isDefaultTabPath() {
     $menu = $this->getOption('menu');
     $tab_options = $this->getOption('tab_options');
-    return !empty($menu) && $menu['type'] == 'default tab' && !empty($tab_options['type']) && $tab_options['type'] != 'none';
+    return $menu && $menu['type'] == 'default tab' && !empty($tab_options['type']) && $tab_options['type'] != 'none';
   }
 
   /**
reverted:
--- b/core/tests/Drupal/KernelTests/Core/Entity/EntityTranslationTest.php
+++ a/core/tests/Drupal/KernelTests/Core/Entity/EntityTranslationTest.php
@@ -664,7 +664,7 @@
     $controller = $this->entityTypeManager->getViewBuilder($entity_type);
     $build = $controller->view($entity);
     $renderer->renderRoot($build);
+    $this->assertEqual($build['label']['#markup'], $values[$current_langcode]['name'], 'By default the entity is rendered in the current language.');
-    $this->assertEqual($build['label']['#markup'] ?? NULL, $values[$current_langcode]['name'], 'By default the entity is rendered in the current language.');
 
     $langcodes = array_combine($this->langcodes, $this->langcodes);
     // We have no translation for the $langcode2 language, hence the expected
reverted:
--- b/core/tests/Drupal/KernelTests/Core/Entity/EntityViewBuilderTest.php
+++ a/core/tests/Drupal/KernelTests/Core/Entity/EntityViewBuilderTest.php
@@ -194,7 +194,7 @@
     $renderer->renderRoot($view);
 
     // Check that the weight is respected.
+    $this->assertEqual($view['label']['#weight'], 20, 'The weight of a display component is respected.');
-    $this->assertEqual($view['label']['#weight'] ?? NULL, 20, 'The weight of a display component is respected.');
   }
 
   /**
only in patch2:
unchanged:
--- a/core/lib/Drupal/Core/Config/StorageComparer.php
+++ b/core/lib/Drupal/Core/Config/StorageComparer.php
@@ -388,7 +388,7 @@ public function hasChanges() {
   public function validateSiteUuid() {
     $source = $this->sourceStorage->read('system.site');
     $target = $this->targetStorage->read('system.site');
-    return $source['uuid'] === $target['uuid'];
+    return $source && $target && $source['uuid'] === $target['uuid'];
   }
 
   /**
only in patch2:
unchanged:
--- a/core/lib/Drupal/Core/FileTransfer/FileTransfer.php
+++ b/core/lib/Drupal/Core/FileTransfer/FileTransfer.php
@@ -363,7 +363,7 @@ public function findChroot() {
     $parts = explode('/', $path);
     $chroot = '';
     while (count($parts)) {
-      $check = implode($parts, '/');
+      $check = implode('/', $parts);
       if ($this->isFile($check . '/' . \Drupal::service('file_system')->basename(__FILE__))) {
         // Remove the trailing slash.
         return substr($chroot, 0, -1);
only in patch2:
unchanged:
--- a/core/modules/views/tests/src/Unit/Plugin/field/FieldPluginBaseTest.php
+++ b/core/modules/views/tests/src/Unit/Plugin/field/FieldPluginBaseTest.php
@@ -136,6 +136,9 @@ protected function setUp() {
     $this->executable = $this->getMockBuilder('Drupal\views\ViewExecutable')
       ->disableOriginalConstructor()
       ->getMock();
+    $this->executable->style_plugin = $this->getMockBuilder('Drupal\views\Plugin\views\style\StylePluginBase')
+      ->disableOriginalConstructor()
+      ->getMock();
     $this->display = $this->getMockBuilder('Drupal\views\Plugin\views\display\DisplayPluginBase')
       ->disableOriginalConstructor()
       ->getMock();