implode() Arguments Order
It was possible to call implode() with a random order of argument : string first, or array first. PHP would figure out which one to use.
In PHP 8.0, it is now compulsory to put the string in the first place, as the types are checked. Or used named parameters.
PHP code
<?php
print_r(implode([1,2], '3'));
?>
Before
PHP Deprecated: implode(): Passing glue string after array is deprecated. Swap the parameters
Deprecated: implode(): Passing glue string after array is deprecated. Swap the parameters
132
After
PHP Fatal error: Uncaught TypeError: implode(): Argument #2 ($array) must be of type ?array, string given
Fatal error: Uncaught TypeError: implode(): Argument #2 ($array) must be of type ?array, string given
PHP version change
This behavior changed in 8.0.