Getting a PossiblyInvalidMethodCall error complaining about a method call on a possibly other variable

[ollieread]

I have a value storing the following property

/**
 * @var \Smpl\Utils\Contracts\Supplier<\Smpl\Collections\Contracts\Collection<array-key, E>>|iterable<E>
 * @noinspection PhpDocFieldTypeMismatchInspection
 */
private Supplier|iterable $elementSupplier;

Then later on I have the following method.

/**
 * @return iterable<E>
 *
 * @throws \Smpl\Collections\Exceptions\InvalidArgumentException
 */
protected function getElements(): iterable
{
    $elements = $this->elementSupplier;

    if ($elements instanceof Supplier) {
        $elements = $elements->get();
    }

    if (! is_iterable($elements)) {
        throw InvalidArgumentException::invalidElementSupplier(static::class);
    }

    return $elements;
}

The $elements = $elements->get() line is causing the following error, even though it's wrapped in an instanceof check.

ERROR: PossiblyInvalidMethodCall - src/Concerns/SuppliesElementsForOperation.php:40:36 - Cannot call method on possible iterable<mixed, E:Smpl\Collections\Operations\DifferenceOperation as mixed> variable $elements (see https://psalm.dev/113)
            $elements = $elements->get();

[orklah]

That's weird indeed, did you try reproducing on psalm.dev?

Is it a new issue since Psalm 5 or did you already had this on Psalm 4?

[ollieread]

That's weird indeed, did you try reproducing on psalm.dev?

Will try and recreate now @orklah.

Is it a new issue since Psalm 5 or did you already had this on Psalm 4?

No, I actually had 0 errors on 4, and now I'm down to 95 XD

[ollieread]

That's weird indeed, did you try reproducing on psalm.dev?

Here you go, recreated https://psalm.dev/r/937ba0306a

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/937ba0306a

<?php
interface Supplier {
	public function get(): iterable;
}

class SomeClass {
    protected Supplier|iterable $prop;
    
    public function __construct(Supplier|iterable $value) {
        $this->prop = $value;
    }
    
    public function do(): void {
        $var = $this->prop;
        
        if ($var instanceof Supplier) {
            $var->get();
        }
    }
}

Psalm output (using commit 2ae819e):

ERROR: PossiblyInvalidMethodCall - 17:19 - Cannot call method on possible iterable<mixed, mixed> variable $var

[ollieread]

Thanks all, will give you a break for a bit 🤣

[orklah]

😄 Thanks for those reports , really! Everything that can be fixed before release is a lot of pain we won't have to go through the day after !

If you have more, please post them!