Overridden EntityReferenceFieldItemListInterface::referencedEntities generics error (#879)

* Overridden EntityReferenceFieldItemListInterface::referencedEntities generics error

* Define referencedEntities on EntityReferenceFieldItemList stub

Author: mglaman

stubs/Drupal/Core/Field/EntityReferenceFieldItemList.stub

@@ -12,4 +12,9 @@ use Drupal\Core\Field\Plugin\Field\FieldType\EntityReferenceItem;
  */
 class EntityReferenceFieldItemList extends FieldItemList implements EntityReferenceFieldItemListInterface {
 
-}
+  /**
+   * @return array<int, T>
+   */
+  public function referencedEntities();
+
+}

tests/src/Generics/EntityReferenceFieldItemListGenericTest.php

@@ -14,6 +14,7 @@ final class EntityReferenceFieldItemListGenericTest extends TypeInferenceTestCas
     public static function dataFileAsserts(): iterable
     {
         yield from self::gatherAssertTypes(__DIR__ . '/data/entity-reference-field-item-list.php');
+        yield from self::gatherAssertTypes(__DIR__ . '/data/bug-878.php');
     }
 
     /**

tests/src/Generics/data/bug-878.php

@@ -0,0 +1,44 @@
+<?php
+
+namespace Bug878;
+
+use Drupal\Core\Field\EntityReferenceFieldItemList;
+use Drupal\Core\Field\EntityReferenceFieldItemListInterface;
+use Drupal\node\Entity\Node;
+use function PHPStan\Testing\assertType;
+
+class EntityReferenceRevisionsFieldItemList extends EntityReferenceFieldItemList implements EntityReferenceFieldItemListInterface {
+
+    /**
+     * {@inheritdoc}
+     */
+    public function referencedEntities() {
+        $target_entities = [];
+        foreach ($this->list as $delta => $item) {
+            if ($item->entity) {
+                $target_entities[$delta] = $item->entity;
+            }
+        }
+        return $target_entities;
+    }
+
+
+}
+
+$paragraphFields = [];
+
+$node = Node::load(1);
+assert($node instanceof Node);
+
+foreach ($node as $field) {
+    if ($field instanceof EntityReferenceRevisionsFieldItemList) {
+        $paragraphFields[] = $field;
+    }
+}
+
+foreach ($paragraphFields as $field) {
+    foreach ($field->referencedEntities() as $entity) {
+        assertType('Drupal\Core\Entity\EntityInterface', $entity);
+        assertType('int|string|null', $entity->id());
+    }
+}