minor #49763 Replace "use-by-ref" by static vars when possible in closures (nicolas-grekas)

This PR was merged into the 6.3 branch.

Discussion
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Replace "use-by-ref" by static vars when possible in closures

| Q             | A
| ------------- | ---
| Branch?       | 6.3
| Bug fix?      | no
| New feature?  | no
| Deprecations? | no
| Tickets       | -
| License       | MIT
| Doc PR        | -

Might be easier to grasp.

Commits
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65422ecf4b Replace "use-by-ref" by static vars when possible in closures

Author: nicolas-grekas

Question/Question.php

@@ -148,8 +148,9 @@ public function setAutocompleterValues(?iterable $values): static
 
             $callback = static fn () => $values;
         } elseif ($values instanceof \Traversable) {
-            $valueCache = null;
-            $callback = static function () use ($values, &$valueCache) {
+            $callback = static function () use ($values) {
+                static $valueCache;
+
                 return $valueCache ??= iterator_to_array($values, false);
             };
         } else {