Fix #9844: Calling a static method over non-generic class-string results in ErrorType

[phpstan-bot]

Summary

Calling a static method on a non-generic class-string (e.g., $class::foo() where $class is typed as class-string) resulted in ErrorType instead of MixedType. This also affected static method calls on mixed values.

Changes

• Modified src/Analyser/MutatingScope.php (getStaticCallType method): Added a check so that when methodCallReturnType() returns null for a static call on an expression, and the resolved type has no known class names (i.e., it's something like ObjectWithoutClassType) and hasMethod() is not definitively no, the result is MixedType instead of ErrorType.
• Added regression test tests/PHPStan/Analyser/nsrt/bug-9844.php

Root cause

When a static method is called on a class-string variable, the type goes through getObjectTypeOrClassStringObjectType() which converts it to ObjectWithoutClassType. This type returns TrinaryLogic::createMaybe() for hasMethod(), meaning the method might exist but we don't know. However, filterTypeWithMethod() only accepts types where hasMethod() returns yes, so it rejects ObjectWithoutClassType and returns null. The calling code then fell back to ErrorType.

The fix distinguishes between:

1. Unknown class types (from class-string or mixed): ObjectWithoutClassType with no class names → return MixedType since any method could exist
2. Known class types accessed via variable (e.g., $foo::method() where $foo: SomeClass): These have known class names even though hasMethod() may return maybe for non-final classes → correctly return ErrorType when the method doesn't exist

Test

Added tests/PHPStan/Analyser/nsrt/bug-9844.php which tests that $class::foo() where $class is class-string returns mixed instead of *ERROR*.

Fixes phpstan/phpstan#9844