[php-src] Issue #20327: Strange and confusing behaviour of foreach with iteration by reference

Issue: https://github.com/php/php-src/issues/20327 Author: phront ### Description The following code: ```php <?php $aaa = [[1,2,3,4]]; $i = 5; foreach ($aaa as &$aa) { foreach ($aa as &$a) { $a = $i; $i--; } } var_dump ($aaa); foreach ($aaa as &$aa) { foreach ($aa as $a) { } } var_dump ($aaa); ``` Resulted in this output: ``` array(1) { [0]=> &array(4) { [0]=> int(5) [1]=> int(4) [2]=> int(3) [3]=> &int(2) } } array(1) { [0]=> &array(4) { [0]=> int(5) [1]=> int(4) [2]=> int(3) [3]=> &int(3) } } ``` But I expected at least this output instead: ``` array(1) { [0]=> &array(4) { [0]=> int(5) [1]=> int(4) [2]=> int(3) [3]=> int(2) } } array(1) { [0]=> &array(4) { [0]=> int(5) [1]=> int(4) [2]=> int(3) [3]=> int(2) } } ``` Played the script with different versions on https://onlinephp.io?s=s7EvyCjg5eLlUklMTFSwVYiONtQx0jHWMYmNtQYKZgKFTIGMtPyi1MTkDAUNsLLEYgU1IENToZqXixNZCioDkeBUARmokmkNZmfq6oIYtbxctSDryhKL4lNKcwsgJmqSZgXMBohhmEaBoIKCAogCAA%2C%2C&v=8.4.10 ### PHP Version ```plain PHP Version => 8.4.10 Zend Engine v4.4.10, Copyright (c) Zend Technologies Build Date => Jul 13 2025 00:21:23 Build System => Linux 4.14.290-217.505.amzn2.x86_64 #1 SMP Wed Aug 10 09:52:16 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux ``` ### Operating System Linux 5.10.214-202.855.amzn2.x86_64 #1 SMP Tue Apr 9 06:57:12 UTC 2024 x86_64