Type narrowing not working with int|string

darkdog

I have only tested this with int|string, so I don't know if other types are affected as well.

If an argument is of two types, checking against one type does not narrow it afterwards.
In the example below, int|string should have been narrowed to string, because int would have returned already.

public static function findByIdOrPath(int|string $idOrPath): void
{
    if (is_int($idOrPath)) {
        return self::find($idOrPath);
    }

    $idOrPath; // Hover shows int|string, wrong, should be string

    if (!is_int($idOrPath)) {
        return self::find($idOrPath);
    }

    $idOrPath; // Hover shows int, correct
}

JakubMisek

darkdog great test case, thank you!

JakubMisek

darkdog, it seems to work as expected (tested version 1.62.18042):

Can you verify you've the version 1.62?

darkdog

JakubMisek Can confirm it works for me as well now.

However, I found an edge case where it still doesn't work 100 %.
I think is_numeric() should also narrow it down from int|string to string, as PHPStan correctly does this:

public static function findByIdOrPath(int|string $reference): ?self
{
    if (is_numeric($reference)) {
        return self::query()->find($reference);
    }

    /** @trace $reference: int|string */
    \PHPStan\dumpType($reference); // string

Yes, a bit of an edge case, but I think if PHPStan does this narrowing you would be safe to do so as well.

JakubMisek

darkdog, thank you, good point!

Right, is_numeric() is a bit tricky with strings, but some narrowing with int|float will be possible.

JakubMisek

updated in the pre-release (todays)