Wrong type detection when variable is changed by reference

[ossinkine]

Example

class Test extends \PHPUnit\Framework\TestCase
{
    public function testAssertVariable()
    {
        $foo = null;
        $value = new \stdClass();
        $mock = $this->getMockBuilder('Foo')->setMethods(['update'])->getMock();
        $mock->method('update')->willReturnCallback(function () use (&$foo, $value) {
            $foo = $value;
        });
        $this->assertSame($value, $foo);
    }
}

$foo variable equals $value after $mock->update() call but PHPStan throws error Call to assertSame() with different types stdClass and null will always result in test failure.

[ondrejmirtes]

Yes, understanding of the could could be improved on PHPStan's part. Meanwhile, you can annotate the variable:

/** @var \stdClass|null $foo */
$foo = null;

[ossinkine]

Yes, I already use @var annotation as workaround, thanks

[staabm]

running the above example with dumpType:

<?php declare(strict_types = 1);

use function PHPStan\dumpType;
use function PHPStan\Testing\assertType;

class Test extends \PHPUnit\Framework\TestCase
{
	public function testAssertVariable()
	{
		$foo = null;
		$value = new \stdClass();
		$mock = $this->getMockBuilder('Foo')->setMethods(['update'])->getMock();
		$mock->method('update')->willReturnCallback(function () use (&$foo, $value) {
			$foo = $value;
		});
		dumpType($foo);
		$this->assertSame($value, $foo);
	}
}

in the latest phpstan outputs

 16     Dumped type: stdClass|null

which makes me think this issue has been resolved somewhen in the past and can be closed