diff --cc core/modules/user/src/Plugin/views/filter/Roles.php
index 47adafb8b6,83b68c4c20..0000000000
--- a/core/modules/user/src/Plugin/views/filter/Roles.php
+++ b/core/modules/user/src/Plugin/views/filter/Roles.php
@@@ -74,10 -74,15 +74,19 @@@ class Roles extends ManyToOne 
     */
    public function calculateDependencies() {
      $dependencies = [];
+ 
 +    if (in_array($this->operator, ['empty', 'not empty'])) {
 +      return $dependencies;
 +    }
-     foreach ($this->value as $role_id) {
++
+     // Due to a bug $this->value might be a string, see
+     // https://www.drupal.org/node/2846614. In the empty case stop early.
+     // Otherwise we cast it to an array later.
+     if (is_string($this->value) && $this->value === '') {
+       return [];
+     }
+ 
+     foreach ((array) $this->value as $role_id) {
        $role = $this->roleStorage->load($role_id);
        $dependencies[$role->getConfigDependencyKey()][] = $role->getConfigDependencyName();
      }