strict type does not work array functions (array_map, array_walk, array_filter) using closures

[proggeler]

Description

The following code:

<?php

declare(strict_types=1); // unfortunately strict types can not be declared on 3v4l.org

$array = [1, 1.2, '1.2.3'];

// var_dump(array_filter($array, function (string $value) { return is_string($value); })); // will not filter
// var_dump(array_map(fn (string $value) => $value, $array)); // all returned values are strings 

array_walk($array, fn (string &$value) => $value); 
var_dump($array);

Resulted in this output:

array(3) {
  [0]=>
  string(1) "1"
  [1]=>
  string(3) "1.2"
  [2]=>
  string(5) "1.2.3"
}

But I expected this output instead:

PHP Fatal error:  Uncaught TypeError: {closure}(): Argument #1 ($a) must be of type string, int given, .....

(as is thrown when call_user_func is used with a closure with a wrong argument type) 

PHP Version

PHP 8.3.6

Operating System

No response

[Girgias]

This is expected behaviour. Any function that is "run" by the engine is always in weak mode, which is the case here.

[proggeler]

@Girgias thank you for clarifying.