Assumed filter_var return type can be incorrect

[pontus-mp]

Psalm gets a bit confused about the return value from filter_var when called with FILTER_VALIDATE_INT, a numeric value and some options.

https://psalm.dev/r/c1579d2079

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/c1579d2079

<?php
// validate(50) returns 50
// validate(9000) returns NULL
function validate(mixed $c): ?int {
    // This is_numeric check makes psalm confused about $ret
    if (is_numeric($c))
    {
        $ret = filter_var($c, FILTER_VALIDATE_INT, [
            'options' => [
                'default'   => null,
                'min_range' => 1,
                'max_range' => 100,
            ],
        ]);
        if ($ret !== null) {
            return $ret;
        }
    }
    return null;
}

Psalm output (using commit 64868c5):

ERROR: TypeDoesNotContainType - 15:13 - Type null for $ret is always !null

ERROR: NoValue - 16:13 - All possible types for this return were invalidated - This may be dead code

[NicolasCARPi]

This bug is introduced in #10498 and the PR author indicates:

I only handled the most commonly used basic ones. This is just a starting point and can be easily improved with additional types once errors/issues are reported.

So here we are, reporting issues and gently pinging @kkmuffme to ask if they would have the time to look into it :)

Downgrading to 5.18.0 is the current workaround if one doesn't want to add ignore comments.