Incorrect behavior of ReturnTypeFromStrictNativeCallRector

[Dan-Suite]

Bug Report

Subject	Details
Rector version	last dev-main
Installed as	composer dependency

Minimal PHP Code Causing Issue

See https://getrector.com/demo/8c5d72b6-135f-43c4-8688-d4976d7ce331

<?php
class DemoFile
{
    public function run(bool $param)
    {
        return array_filter($this->value ?? []);
    }
}

Responsible rules

• ReturnTypeFromStrictNativeCallRector

Expected Behavior

return array_filter ought to always be typed as array. This only seems to be an issue if $this->value is dynamic or typed as mixed. When typed as 'array', the expected behaviour is there.

[samsonasik]

That's expected as mixed can be anything that not null, if you want to return array, make value as property, with define nullable array, so fallback of nullable array make sense to always pass array, see https://getrector.com/demo/93548248-7598-4fc8-9703-ca4b94ce0a46

[adnweedon]

@samsonasik I'm not sure I follow you - under what scenario can array_filter ever return anything other than an array, regardless of whether the input is mixed or not?

[samsonasik]

we use phpstan to detect type, the result of mixed ?? null passed to array_filter is nullable array, see https://phpstan.org/r/3f0d0348-dd07-42cb-b598-1b2297e3dd4e

If you think it is bug, you can report bug to phpstan side :)

https://github.com/phpstan/phpstan/issues