Psalm 4.5 and later ignores assertions of instanceof Interface

[ArtemGoutsoul]

Here's an example:
https://psalm.dev/r/863377401f

This worked in 4.4.1

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/863377401f

<?php

function get_header(bool $param = false): ArrayIterator|HeaderInterface
{
    if ($param) return new ArrayIterator();
    else return new Header();
}

class Header implements HeaderInterface
{
    public function doStuff(): void {}
}

interface HeaderInterface
{
    public function doStuff(): void;
}

$header = get_header();
assert($header instanceof HeaderInterface);
$header->doStuff();

Psalm output (using commit 7b24552):

ERROR: UndefinedMethod - 21:10 - Method ArrayIterator::doStuff does not exist

[weirdan]

It appears assert removes HeaderInterface in this case 😮 : https://psalm.dev/r/50cf76d7eb

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/50cf76d7eb

<?php

function get_header(bool $param = false): ArrayIterator|HeaderInterface
{
    if ($param) return new ArrayIterator();
    else return new Header();
}

class Header implements HeaderInterface
{
    public function doStuff(): void {}
}

interface HeaderInterface
{
    public function doStuff(): void;
}

$header = get_header();
/** @psalm-trace $header */;
assert($header instanceof HeaderInterface);
/** @psalm-trace $header */;
$header->doStuff();

Psalm output (using commit 7b24552):

INFO: Trace - 20:28 - $header: ArrayIterator<array-key, mixed>|HeaderInterface

INFO: Trace - 22:28 - $header: ArrayIterator<array-key, mixed>

ERROR: UndefinedMethod - 23:10 - Method ArrayIterator::doStuff does not exist

[ArtemGoutsoul]

@weirdan Should have tried the trace too, thanks for the example! :)

Kinda funny regression, assert should have caused ArrayIterator|HeaderInterface to become (not sure how to write it): HeaderInterface for sure AND possibly ArrayIterator, and instead it somehow just dropped HeaderInterface

[muglug]

Simplified: https://psalm.dev/r/84f2bd0e92

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/84f2bd0e92

<?php

class SomeClass {}
interface SomeInterface {
	public function doStuff(): void;
}

function takesAorB(SomeClass|SomeInterface $some): void {
    if ($some instanceof SomeInterface) {
        $some->doStuff();
    }
}

Psalm output (using commit cafbdb6):

ERROR: UndefinedMethod - 10:16 - Method SomeClass::doStuff does not exist

[muglug]

Sorry, this is a pretty bad bug and should have been caught in a test