Deprecate omitting the alias in QueryBuilder::update() and delete()

UPGRADE.md

@@ -1,5 +1,29 @@
 # Upgrade to 2.13
 
+## Deprecated omitting alias argument for `QueryBuilder::update` and `QueryBuilder::delete`
+
+When making an Update or Delete Query and when passing a class/type to the function, the alias argument should not be omitted.
+
+### Before
+
+```php
+$qb = $em->createQueryBuilder()
+    ->delete('User u')
+    ->where('u.id = :user_id')
+    ->setParameter('user_id', 1);
+```
+
+### After
+
+For backward-compatibility reasons, the parameter has to be optional and to make it possible to call `update()` and `delete()` without class/type argument.
+
+```php
+$qb = $em->createQueryBuilder()
+    ->delete('User', 'u')
+    ->where('u.id = :user_id')
+    ->setParameter('user_id', 1);
+```
+
 ## Deprecated omitting second argument to `NamingStrategy::joinColumnName`
 
 When implementing `NamingStrategy`, it is deprecated to implement

lib/Doctrine/ORM/QueryBuilder.php

@@ -6,6 +6,7 @@
 
 use Doctrine\Common\Collections\ArrayCollection;
 use Doctrine\Common\Collections\Criteria;
+use Doctrine\Deprecations\Deprecation;
 use Doctrine\ORM\Query\Expr;
 use Doctrine\ORM\Query\Parameter;
 use Doctrine\ORM\Query\QueryExpressionVisitor;
@@ -844,6 +845,14 @@ public function delete($delete = null, $alias = null)
             return $this;
         }
 
+        if (! $alias) {
+            Deprecation::trigger(
+                'doctrine/orm',
+                'https://github.com/doctrine/orm/issues/9733',
+                'Omitting the alias is deprecated and will throw an exception in Doctrine 3.0.'
+            );
+        }
+
         return $this->add('from', new Expr\From($delete, $alias));
     }
 
@@ -871,6 +880,14 @@ public function update($update = null, $alias = null)
             return $this;
         }
 
+        if (! $alias) {
+            Deprecation::trigger(
+                'doctrine/orm',
+                'https://github.com/doctrine/orm/issues/9733',
+                'Omitting the alias is deprecated and will throw an exception in Doctrine 3.0.'
+            );
+        }
+
         return $this->add('from', new Expr\From($update, $alias));
     }