Getting an error if null condition is not explicit.

[davidkmenta]

Bug report

Getting an error if null condition is not explicit.

Code snippet that reproduces the problem

<?php declare(strict_types = 1);

class Bar {
	public function foo(): ?string
	{
		return null;
	}
}

class HelloWorld
{
	public function sayHello(Bar $object): string
	{
		if ($object->foo()) {
			return $object->foo();
		}
		
		return '';
	}
}

Code above generates an error: https://phpstan.org/r/bc5bd55d-64db-4f6f-a30a-e4fc367e81c7

This works: https://phpstan.org/r/296a2b2d-d3ce-42b7-b479-3293ba43c36a
The difference is in condition $object->foo() !== null.

Expected output

No errors expected. Or is it a feature? 😄

[ondrejmirtes]

Yes, currently a feature. I'll do something about it. Duplicate of #2288 and others.