PHP8 usort with version_compare as callback

[pschombara]

Bug report

Using \usort with an PHP core function(version_compare) reports an error in PHP8.
Parameter #2 $callback of function usort expects callable(string, string): int, 'version_compare' given.

Code snippet that reproduces the problem

https://phpstan.org/r/e27b69c8-d3df-4347-b251-de8aa66a89a2

Expected output

No error

[ondrejmirtes]

version_compare returns int|bool: https://www.php.net/manual/en/function.version-compare.php

[pschombara]

Okay it returns bool if the third parameter operator is defined, which is not the case using the function the way mentioned.

usort($versions, static fn (string $a, string $b): int => version_compare($a, $b));
does not complain any error.

https://phpstan.org/r/501d12f7-a2b8-4418-bfac-68a595f22f06

[ondrejmirtes]

Until this is supported you can use the arrow function version, thanks.

[staabm]

@herndlm this is another issue which would benefit from a AST rewrite into a arrow function like phpstan/phpstan-src#938

wdyt? :)

[ondrejmirtes]

That’s not needed, it’s just that dynamic return type extension needs to be invoked for cases like this.

[Sweetchuck]

Not ideal, but works with PHP 7.4 and 8.1 at the same time:

/** @var callable(string $a, string $b): int $comparer */
$comparer = 'version_compare';
usort($versions, $comparer);