Match expression on get_class or ::class should infer like instanceof checks #5371
Description
Feature request
Currently, PHPStan support using isinstance checks to find out whether or not a class might be a superclass, and infers that correctly. For example, the following code produces no errors:
class A {
public function methodA(): int {
return 1;
}
}
class B extends A {
public function methodB(): int {
return 2;
}
}
function getSomeClass(): A {
return new B();
}
$somePossibleSuperclass = getSomeClass();
$number = null;
if ($somePossibleSuperclass instanceof B) {
$number = $somePossibleSuperclass->methodB();
}
else if ($somePossibleSuperclass instanceof A) {
$number = $somePossibleSuperclass->methodA();
}
//PHPStan sees `number` as an int here.However, when using the match expression with get_class or ::class, it does not work correctly:
class A {
public function methodA(): int {
return 1;
}
}
class B extends A {
public function methodB(): int {
return 2;
}
}
function getSomeClass(): A {
return new B();
}
$somePossibleSuperclass = getSomeClass();
$number = match($somePossibleSuperclass::class) {
B::class => $somePossibleSuperclass->methodB(),
A::class => $somePossibleSuperclass->methodA()
};------ -------------------------------------------------------------------
Line test.php
------ -------------------------------------------------------------------
20 Match expression does not handle remaining value: class-string<A>
21 Call to an undefined method A::methodB().
------ -------------------------------------------------------------------
It would be great if this kind of inference would work correctly, as it is a very nice pattern to use.
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PHPStan saved me a couple of times, and the generics support is amazing :)