Add test

Author: VincentLanglet

tests/PHPStan/Rules/Variables/data/bug-12364.php

@@ -17,3 +17,20 @@ function foo(): array {
 assertType('string|null', $y); // <-- should be: null|string
 var_dump($x);
 var_dump($y); // <-- does exist
+
+/** @return array{xx: string, yy?: string} */
+function foo2(): array {
+	return [ 'xx' => 'foo' ];
+}
+
+if (rand(0, 1)) {
+	$xx = $yy = null;
+	assertType('null', $xx);
+	assertType('null', $yy);
+}
+
+extract(foo2());
+assertType('string', $xx);
+assertType('string|null', $yy); // <-- should be: null|string
+var_dump($xx);
+var_dump($yy); // <-- does exist