Update MorphTo.php

Author: hans-thomas

src/Relations/MorphTo.php

@@ -17,9 +17,9 @@ public function addConstraints()
             // or has many relationships, we need to actually query on the primary key
             // of the related models matching on the foreign key that's on a parent.
             $this->query->where(
-                $this->ownerKey ?: $this->query->getModel()->getKeyName(),
+                $this->ownerKey,
                 '=',
-                $this->parent->{$this->foreignKey},
+                $this->getForeignKeyFrom($this->parent),
             );
         }
     }