Generic return type via static method damage template type (with bound)

[hrach]

Bug report

https://phpstan.org/r/f04e6af3-c413-4d94-93b4-0b9b21572598

class E {}

/**
 * @template T of E
 */
class R {
	/** @var T */
	public $e;
	
	/** @return T */
	function ret() { return $this->e; } // nonsense, to silence missing return
	
	function test(): void {
		$this->e = static::ret(); // not ok
		$this->e = self::ret(); // not ok
		$this->e = $this->ret(); // ok
	}
}

self::ret() is evaluated to E type

Property R<T of E>::$e (T of E) does not accept E.

Expected output

No error

[ondrejmirtes]

You're losing the instance-level @template T if you're calling a method statically, that's kind of expected...

[muglug]

It's not really called statically, though:

<?php declare(strict_types = 1);

class E {}
class EChild extends E {};

/**
 * @template T of E
 */
class R {
    /** @var T */
    private $t;
    
    /** @param T $t */
    public function __construct($t) {
        $this->t = $t;
    }
	
    /** @return T */
    public function ret() {
        var_dump(get_class($this->t));
        return $this->t;
    }
	
    public function test(): void {
        $this->t = static::ret();
        $this->t = self::ret();
        $this->t = $this->ret();
    }
}

(new R(new EChild()))->test();

results in

string(6) "EChild"
string(6) "EChild"
string(6) "EChild"

[ondrejmirtes]

Yeah, I get it, we should figure out which self:: and static:: are really $this->. But I consider this "nice to have" as the user can always use $this->.

[hrach]

Well, actually, I wanted to have this behavior on real static. I think the bug is it doesn't report unknown T definition over the static method.

https://phpstan.org/r/66eb9b43-0130-4c2e-97e2-b2d65579e39b

[ondrejmirtes]

#2738

[LukasVitek]

Next reproduction of the same bug: https://phpstan.org/r/8ca83eff-7db3-4e98-a322-1d963e20aabb

[phpstan-bot]

@hrach After the latest commit in dev-master, PHPStan now reports different result with your code snippet:

@@ @@
-16: Property R<T of E>::$e (T of E) does not accept E.
-17: Property R<T of E>::$e (T of E) does not accept E.
+16: Property R<T of E>::$e (T of E) does not accept E.

Full report

Line	Error
16	Property R<T of E>::$e (T of E) does not accept E.

[phpstan-bot]

@hrach After the latest commit in dev-master, PHPStan now reports different result with your code snippet:

@@ @@
 13: Method R::ret() should return class-string<T of E> but returns string.
-16: Property R<T of E>::$e (class-string<T of E>) does not accept class-string<E>.
-17: Property R<T of E>::$e (class-string<T of E>) does not accept class-string<E>.
+16: Property R<T of E>::$e (class-string<T of E>) does not accept class-string<E>.

Full report

Line	Error
13	Method R::ret() should return class-string<T of E> but returns string.
16	Property R<T of E>::$e (class-string<T of E>) does not accept class-string<E>.

[phpstan-bot]

@LukasVitek After the latest commit in dev-master, PHPStan now reports different result with your code snippet:

@@ @@
-44: Method Parameters::add() should return Parameters<TCriterion of IOrderCriterion> but returns Parameters<IOrderCriterion>.
+No errors

[phpstan-bot]

@hrach After the latest commit in dev-master, PHPStan now reports different result with your code snippet:

@@ @@
-16: Property R<T of E>::$e (T of E) does not accept E.
-17: Property R<T of E>::$e (T of E) does not accept E.
+No errors

[phpstan-bot]

@hrach After the latest commit in dev-master, PHPStan now reports different result with your code snippet:

@@ @@
-13: Method R::ret() should return class-string<T of E> but returns string.
-16: Property R<T of E>::$e (class-string<T of E>) does not accept class-string<E>.
-17: Property R<T of E>::$e (class-string<T of E>) does not accept class-string<E>.
+13: Method R::ret() should return class-string<T of E> but returns string.

Full report

Line	Error
13	Method R::ret() should return class-string<T of E> but returns string.

[ondrejmirtes]

Fixed: phpstan/phpstan-src@4acbc6c + phpstan/phpstan-src@d4e0177

[github-actions]

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