diff --git a/Command/ConfigDebugCommand.php b/Command/ConfigDebugCommand.php
index 758c605ec..6aa3fbf9b 100644
--- a/Command/ConfigDebugCommand.php
+++ b/Command/ConfigDebugCommand.php
@@ -139,7 +139,7 @@ private function getConfigForPath(array $config, $path, $alias)
         $steps = explode('.', $path);
 
         foreach ($steps as $step) {
-            if (!array_key_exists($step, $config)) {
+            if (!\array_key_exists($step, $config)) {
                 throw new LogicException(sprintf('Unable to find configuration for "%s.%s"', $alias, $path));
             }
 
diff --git a/Console/Descriptor/JsonDescriptor.php b/Console/Descriptor/JsonDescriptor.php
index 83f607cc3..6b05612ff 100644
--- a/Console/Descriptor/JsonDescriptor.php
+++ b/Console/Descriptor/JsonDescriptor.php
@@ -156,7 +156,7 @@ protected function describeContainerAlias(Alias $alias, array $options = [], Con
      */
     protected function describeEventDispatcherListeners(EventDispatcherInterface $eventDispatcher, array $options = [])
     {
-        $this->writeData($this->getEventDispatcherListenersData($eventDispatcher, array_key_exists('event', $options) ? $options['event'] : null), $options);
+        $this->writeData($this->getEventDispatcherListenersData($eventDispatcher, \array_key_exists('event', $options) ? $options['event'] : null), $options);
     }
 
     /**
diff --git a/Console/Descriptor/MarkdownDescriptor.php b/Console/Descriptor/MarkdownDescriptor.php
index a0a0dc851..6575b05ec 100644
--- a/Console/Descriptor/MarkdownDescriptor.php
+++ b/Console/Descriptor/MarkdownDescriptor.php
@@ -275,7 +275,7 @@ protected function describeContainerParameter($parameter, array $options = [])
      */
     protected function describeEventDispatcherListeners(EventDispatcherInterface $eventDispatcher, array $options = [])
     {
-        $event = array_key_exists('event', $options) ? $options['event'] : null;
+        $event = \array_key_exists('event', $options) ? $options['event'] : null;
 
         $title = 'Registered listeners';
         if (null !== $event) {
diff --git a/Console/Descriptor/TextDescriptor.php b/Console/Descriptor/TextDescriptor.php
index 7aed45bd4..90c760260 100644
--- a/Console/Descriptor/TextDescriptor.php
+++ b/Console/Descriptor/TextDescriptor.php
@@ -385,7 +385,7 @@ protected function describeContainerParameter($parameter, array $options = [])
      */
     protected function describeEventDispatcherListeners(EventDispatcherInterface $eventDispatcher, array $options = [])
     {
-        $event = array_key_exists('event', $options) ? $options['event'] : null;
+        $event = \array_key_exists('event', $options) ? $options['event'] : null;
 
         if (null !== $event) {
             $title = sprintf('Registered Listeners for "%s" Event', $event);
diff --git a/Console/Descriptor/XmlDescriptor.php b/Console/Descriptor/XmlDescriptor.php
index 38efe8575..53e2ee1fa 100644
--- a/Console/Descriptor/XmlDescriptor.php
+++ b/Console/Descriptor/XmlDescriptor.php
@@ -111,7 +111,7 @@ protected function describeContainerAlias(Alias $alias, array $options = [], Con
      */
     protected function describeEventDispatcherListeners(EventDispatcherInterface $eventDispatcher, array $options = [])
     {
-        $this->writeDocument($this->getEventDispatcherListenersDocument($eventDispatcher, array_key_exists('event', $options) ? $options['event'] : null));
+        $this->writeDocument($this->getEventDispatcherListenersDocument($eventDispatcher, \array_key_exists('event', $options) ? $options['event'] : null));
     }
 
     /**
diff --git a/DependencyInjection/Configuration.php b/DependencyInjection/Configuration.php
index f49c5f11e..52c770645 100644
--- a/DependencyInjection/Configuration.php
+++ b/DependencyInjection/Configuration.php
@@ -371,7 +371,7 @@ private function addWorkflowSection(ArrayNodeDefinition $rootNode)
                                                 }
 
                                                 foreach ($transitions as $name => $transition) {
-                                                    if (array_key_exists('name', $transition)) {
+                                                    if (\array_key_exists('name', $transition)) {
                                                         continue;
                                                     }
                                                     $transition['name'] = $name;
diff --git a/DependencyInjection/FrameworkExtension.php b/DependencyInjection/FrameworkExtension.php
index a46e552a2..ee5dc86df 100644
--- a/DependencyInjection/FrameworkExtension.php
+++ b/DependencyInjection/FrameworkExtension.php
@@ -602,7 +602,7 @@ private function registerWorkflowConfiguration(array $config, ContainerBuilder $
         $registryDefinition = $container->getDefinition('workflow.registry');
 
         foreach ($config['workflows'] as $name => $workflow) {
-            if (!array_key_exists('type', $workflow)) {
+            if (!\array_key_exists('type', $workflow)) {
                 $workflow['type'] = 'workflow';
                 @trigger_error(sprintf('The "type" option of the "framework.workflows.%s" configuration entry must be defined since Symfony 3.3. The default value will be "state_machine" in Symfony 4.0.', $name), E_USER_DEPRECATED);
             }
@@ -1052,7 +1052,7 @@ private function registerAssetsConfiguration(array $config, ContainerBuilder $co
         foreach ($config['packages'] as $name => $package) {
             if (null !== $package['version_strategy']) {
                 $version = new Reference($package['version_strategy']);
-            } elseif (!array_key_exists('version', $package) && null === $package['json_manifest_path']) {
+            } elseif (!\array_key_exists('version', $package) && null === $package['json_manifest_path']) {
                 // if neither version nor json_manifest_path are specified, use the default
                 $version = $defaultVersion;
             } else {
@@ -1273,7 +1273,7 @@ private function registerValidationConfiguration(array $config, ContainerBuilder
         $definition = $container->findDefinition('validator.email');
         $definition->replaceArgument(0, $config['strict_email']);
 
-        if (array_key_exists('enable_annotations', $config) && $config['enable_annotations']) {
+        if (\array_key_exists('enable_annotations', $config) && $config['enable_annotations']) {
             if (!$this->annotationsConfigEnabled) {
                 throw new \LogicException('"enable_annotations" on the validator cannot be set as Annotations support is disabled.');
             }
@@ -1281,7 +1281,7 @@ private function registerValidationConfiguration(array $config, ContainerBuilder
             $validatorBuilder->addMethodCall('enableAnnotationMapping', [new Reference('annotation_reader')]);
         }
 
-        if (array_key_exists('static_method', $config) && $config['static_method']) {
+        if (\array_key_exists('static_method', $config) && $config['static_method']) {
             foreach ($config['static_method'] as $methodName) {
                 $validatorBuilder->addMethodCall('addMethodMapping', [$methodName]);
             }