Merge branch '3.4.x' into 3.5.x

* 3.4.x:
  Generate explicit nullable types for proxies
  Add doctrine-project.json to .gitattributes (#1004)
  Remove no longer needed ignore rules
  Add phpstan.neon.dist and psalm.xml to .gitattributes
  Add missing strict parameter to in_array

.gitattributes

@@ -1,6 +1,9 @@
 tests export-ignore
+.doctrine-project.json export-ignore
 .gitattributes export-ignore
 .gitignore export-ignore
 .github export-ignore
 phpunit.xml.dist export-ignore
 /phpcs.xml.dist export-ignore
+/phpstan.neon.dist export-ignore
+/psalm.xml export-ignore

src/Proxy/ProxyGenerator.php

@@ -203,7 +203,7 @@ public function __setInitialized($initialized): void
      * {@inheritDoc}
      * @internal generated method: use only when explicitly handling proxy specific loading logic
      */
-    public function __setInitializer(\Closure $initializer = null): void
+    public function __setInitializer(?\Closure $initializer = null): void
     {
         $this->__initializer__ = $initializer;
     }
@@ -221,7 +221,7 @@ public function __getInitializer(): ?\Closure
      * {@inheritDoc}
      * @internal generated method: use only when explicitly handling proxy specific loading logic
      */
-    public function __setCloner(\Closure $cloner = null): void
+    public function __setCloner(?\Closure $cloner = null): void
     {
         $this->__cloner__ = $cloner;
     }
@@ -942,7 +942,7 @@ private function generateMethods(ClassMetadata $class)
             if ($this->isShortIdentifierGetter($method, $class)) {
                 $identifier = lcfirst(substr($name, 3));
                 $fieldType  = $class->getTypeOfField($identifier);
-                $cast       = in_array($fieldType, ['integer', 'smallint']) ? '(int) ' : '';
+                $cast       = in_array($fieldType, ['integer', 'smallint'], true) ? '(int) ' : '';
 
                 $methods .= '        if ($this->__isInitialized__ === false) {' . "\n";
                 $methods .= '            ';