Rule `use_arrow_functions`

Anonymous functions with one-liner return statement must use arrow functions.

Warning

Risky when using isset() on outside variables that are not imported with use ().

--- Original
+++ New
 <?php
-foo(function ($a) use ($b) {
-    return $a + $b;
-});
+foo(fn ($a) => $a + $b);

The rule is part of the following rule sets: