diff --git a/core/modules/views/src/Plugin/views/argument/ArgumentPluginBase.php b/core/modules/views/src/Plugin/views/argument/ArgumentPluginBase.php
index cdb24ae..2aeaaaa 100644
--- a/core/modules/views/src/Plugin/views/argument/ArgumentPluginBase.php
+++ b/core/modules/views/src/Plugin/views/argument/ArgumentPluginBase.php
@@ -1197,15 +1197,15 @@ public function getCacheContexts() {
     $contexts[] = 'cache.context.url';
 
     if (($plugin = $this->getPlugin('argument_default')) && $plugin instanceof CacheablePluginInterface) {
-      $contexts = array_merge($plugin->getCacheContexts(). $contexts);
+      $contexts = array_merge($plugin->getCacheContexts(), $contexts);
     }
 
     if (($plugin = $this->getPlugin('argument_validator')) && $plugin instanceof CacheablePluginInterface) {
-      $contexts = array_merge($plugin->getCacheContexts(). $contexts);
+      $contexts = array_merge($plugin->getCacheContexts(), $contexts);
     }
 
     if (($plugin = $this->getPlugin('style')) && $plugin instanceof CacheablePluginInterface) {
-      $contexts = array_merge($plugin->getCacheContexts(). $contexts);
+      $contexts = array_merge($plugin->getCacheContexts(), $contexts);
     }
 
     return $contexts;