Psalm no longer recognizes boolean returns on enum functions

[bitwise-operators]

Take this example:

https://psalm.dev/r/8c3364a135

Failing the first if statement incorrectly assigns $value as null, ignoring the possibility that $value->isOne() evaluated to false.

This is a regression, as it popped up when I upgraded from tag 4e177bf (last commit on the 5.x branch) to 9cf4f60 (current 5.8 state)

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/8c3364a135

<?php
enum Val
{
    case One;
    case Two;
    case Three;
    
    public function isOne():bool {
        return $this == static::One;
    }
    
    public function isTwo(): bool {
        return $this == static::Two;
    }
    
	public static function random(): ?static {
    	return match (rand(1,5)) {
            1 => static::One,
            2 => static::Two,
            3 => static::Three,
            default => null,
        };
    }
}
$value = Val::random();

if ($value?->isOne()) {
    echo 'Solo';
} elseif ($value?->isTwo()) {
    echo 'In pairs';
} else {
    echo 'Grouped';
}

Psalm output (using commit 0af503a):

ERROR: RedundantCondition - 29:11 - $value is null has already been asserted

ERROR: NullReference - 29:20 - Cannot call method isTwo on null value

ERROR: TypeDoesNotContainType - 29:11 - Type null for $value is always !null

[weirdan]

Likely due to #9538

Well, no, that hasn't been tagged yet.

[weirdan]

@bitwise-operators can you check on master?

[orklah]

#9457 could be related