is_subclass_of is true only for parent classes, not the same one

[mvorisek]

Bug report

is_subclass_of(new A(), A::class) is false, phpstan assumes true

Code snippet that reproduces the problem

https://3v4l.org/Z4Yb2

https://phpstan.org/r/b41d286a-72cb-45a7-b48f-5dbedc4dee73

Expected output

Call to function is_subclass_of() with B and 'A' will always evaluate to true. only

[staabm]

Looking at https://github.com/phpstan/phpstan-src/blob/7667265bba564eb61711ad52376a6e7823708bda/src/Type/Php/TypeSpecifyingFunctionsDynamicReturnTypeExtension.php I guess the problem is in ImpossibleTypeChecker

[ondrejmirtes]

The problem is that PHPStan isn't able to represent "subclass of A but not A".

[ondrejmirtes]

But I guess it could be if-elsed out in IsSubclassOfFunctionTypeSpecifyingExtension.

[herndlm]

because @staabm found that further up - https://github.com/phpstan/phpstan-src/blob/7667265bba564eb61711ad52376a6e7823708bda/src/Type/Php/TypeSpecifyingFunctionsDynamicReturnTypeExtension.php#L40
should is_a be added there as well? I'm not entirely sure what affects this will have

[mvorisek]

https://phpstan.org/r/d16311bf-3c5a-4e70-84d0-6da5cf01efa2 seems quite broken to me

[herndlm]

is_subclass_of is fine I think, but it seems weird to me that $b is considered to be A only in https://phpstan.org/r/045b5d07-ca5c-45c9-8cd1-3665296236b3

[staabm]

is_subclass_of is fine I think, but it seems weird to me that $b is considered to be A only

I think so too

[mvorisek]

https://phpstan.org/r/d37934ec-1b06-428a-ad62-bd4b9f54e905

l11 and l17 errors seems wrong to me

[staabm]

l11 and l17 errors seems wrong to me

checking a condition which already was checked one layer above is redundant. if you don't find a more complete example, IMO phpstan is correct.

[mvorisek]

I agree, but if it is part of a more complex condition, it can be needed. And MUST always result the same output.

[staabm]

I agree, but if it is part of a more complex condition, it can be needed. And MUST always result the same output.

please find a example illustrating your case and open a new issue with it

[herndlm]

Fyi I'm trying to fix this properly, I have something that is working, but need to clean it up and add more tests still

[github-actions]

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