Create bug-6799c.php

Author: staabm

tests/PHPStan/Analyser/nsrt/bug-6799c.php

@@ -0,0 +1,18 @@
+<?php declare(strict_types = 1);
+
+namespace Bug6799C;
+
+use function PHPStan\Testing\assertType;
+
+// https://3v4l.org/g5UjS
+
+$a = [&$x];
+function doFoo(array &$arr) {
+	$arr[0] = 'string';
+}
+
+var_dump($x);
+assertType('mixed', $x);
+doFoo($a);
+var_dump($x);
+assertType('mixed', $x); // could be string