Using static in conditional return

[tdtm]

Should @return (T is static ? bool : false) work? Here anything I try seems to evaluate T is static as false.

https://psalm.dev/r/59c4ae8585

As comparison, in PhpStan, it does work: https://phpstan.org/r/1048dce8-8d8c-47ac-86e6-383ef17984d7

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/59c4ae8585

<?php declare(strict_types=1);
  
interface Comparable {
    /**
    * @template T of mixed
    *
    * @param T $compareTo
    * 
    * If the param is the same class as $this, then it's possible it will be true (but it could still be false)
    * If the param is a different class from $this, even if it implements Comparable, then it's impossible for it to be true.
    *
    * @return (T is static ? bool : false)
    */
    public function compare(mixed $compareTo) : bool;
}

class Foo implements Comparable {
   /**
    * @template T of mixed
    * @param T $compareTo
    * @return (T is static ? bool : false)
    */
    public function compare(mixed $compareTo) : bool
    {
        return $this == $compareTo;
    }
}

class Bar implements Comparable {
   /**
    * @template T of mixed
    * @param T $compareTo
    * @return (T is static ? bool : false)
    */
    public function compare(mixed $compareTo) : bool
    {
        return $this == $compareTo;
    }
}

$a = new Foo();
$b = new Bar();

/** @psalm-trace $ab */ // these are different classes, so we should be able to infer it's false
$ab = $a->compare($b);

/** @psalm-trace $ba */ // these are different classes, so we should be able to infer it's false
$ba = $b->compare($a);

/** @psalm-trace $aa */ // these the same class, so we should infer bool as it could be either
$aa = $a->compare($a);

Psalm output (using commit f8d1dd8):

INFO: Trace - 45:1 - $ab: false

INFO: Trace - 48:1 - $ba: false

INFO: Trace - 51:1 - $aa: false

INFO: UnusedVariable - 45:1 - $ab is never referenced or the value is not used

INFO: UnusedVariable - 48:1 - $ba is never referenced or the value is not used

INFO: UnusedVariable - 51:1 - $aa is never referenced or the value is not used