[5.8] Fix self-referencing MorphOneOrMany existence queries

src/Illuminate/Database/Eloquent/Relations/MorphOneOrMany.php

@@ -91,7 +91,7 @@ protected function setForeignAttributesForCreate(Model $model)
     public function getRelationExistenceQuery(Builder $query, Builder $parentQuery, $columns = ['*'])
     {
         return parent::getRelationExistenceQuery($query, $parentQuery, $columns)->where(
-            $this->morphType, $this->morphClass
+            $query->qualifyColumn($this->getMorphType()), $this->morphClass
         );
     }
 

tests/Integration/Database/EloquentMorphManyTest.php

@@ -43,6 +43,19 @@ public function test_update_model_with_default_withCount()
 
         $this->assertEquals('new name', $post->title);
     }
+
+    public function test_self_referencing_existence_query()
+    {
+        $post = Post::create(['title' => 'foo']);
+
+        $comment = tap((new Comment(['name' => 'foo']))->commentable()->associate($post))->save();
+
+        (new Comment(['name' => 'bar']))->commentable()->associate($comment)->save();
+
+        $comments = Comment::has('replies')->get();
+
+        $this->assertEquals([1], $comments->pluck('id')->all());
+    }
 }
 
 class Post extends Model
@@ -68,4 +81,9 @@ public function commentable()
     {
         return $this->morphTo();
     }
+
+    public function replies()
+    {
+        return $this->morphMany(self::class, 'commentable');
+    }
 }