Empty if clause changes type of variable from T|null to T|array|null

[AJenbo]

Bug report

    /** @var array<int, T> */
    protected $items = [];

    /**
     * @return ?T
     */
	public function broken(int $key)
    {
        $item = $this->items[$key] ?? null;
        if ($item) {
        }

        return $item;
    }

Method GenericList::broken() should return T|null but returns array|T|null.

Code snippet that reproduces the problem

https://phpstan.org/r/54561da3-8e55-438b-91b1-cf4c73eed57f

Expected output

No errors

[ondrejmirtes]

I'm not surprised this happens, the relationship between NonEmptyArrayType and TemplateMixedType will have to be fixed I guess.

[phpstan-bot]

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

@@ @@
-30: Method GenericList::broken() should return T|null but returns array|T|null.
+30: Method GenericList::broken() should return T|null but returns array|(float&T)|(int&T)|(string&T)|(string&T)|T|(T&bool)|null.

Full report

Line	Error
30	`Method GenericList::broken() should return T

[AJenbo]

Different, but not correct 🙂

[phpstan-bot]

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

@@ @@
-30: Method GenericList::broken() should return T|null but returns array|T|null.
+PHP 7.4 – 8.0 (1 error)
+==========
+
+30: Method GenericList::broken() should return T|null but returns array|(float&T)|(int&T)|(string&T)|(string&T)|T|(T&bool)|null.
+
+PHP 7.1 – 7.3 (2 errors)
+==========
+
+16: Return type ArrayIterator of method GenericList::getIterator() is not compatible with return type Traversable of method IteratorAggregate::getIterator().
+30: Method GenericList::broken() should return T|null but returns array|(float&T)|(int&T)|(string&T)|(string&T)|T|(T&bool)|null.

Full report

PHP 7.4 – 8.0 (1 error)

Line	Error
30	`Method GenericList::broken() should return T

PHP 7.1 – 7.3 (2 errors)

Line	Error
16	Return type ArrayIterator of method GenericList::getIterator() is not compatible with return type Traversable of method IteratorAggregate::getIterator().
30	`Method GenericList::broken() should return T

[phpstan-bot]

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

@@ @@
-30: Method GenericList::broken() should return T|null but returns array|T|null.
+30: Method GenericList::broken() should return T|null but returns array|(float&T)|(int&T)|(''&T)|('0'&T)|T|(T&bool)|null.

Full report

Line	Error
30	`Method GenericList::broken() should return T

[phpstan-bot]

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

@@ @@
-30: Method GenericList::broken() should return T|null but returns array|T|null.
+30: Method GenericList::broken() should return T|null but returns array|(float&T)|(int&T)|(string&T)|(string&T)|T of mixed|(T&bool)|null.

Full report

Line	Error
30	`Method GenericList::broken() should return T

[phpstan-bot]

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

@@ @@
-30: Method GenericList::broken() should return T|null but returns array|T|null.
+30: Method GenericList::broken() should return T but returns array|(float&T)|(int&T)|(string&T)|(string&T)|T of mixed|(T&bool)|null.
+40: Method GenericList::works() should return T but returns T|null.

Full report

Line	Error
30	`Method GenericList::broken() should return T but returns array
40	`Method GenericList::works() should return T but returns T

[phpstan-bot]

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

@@ @@
-30: Method GenericList::broken() should return T|null but returns array|T|null.
+30: Method GenericList::broken() should return T but returns array|T of mixed|null.
+40: Method GenericList::works() should return T but returns T|null.

Full report

Line	Error
30	`Method GenericList::broken() should return T but returns array
40	`Method GenericList::works() should return T but returns T

[phpstan-bot]

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

@@ @@
-30: Method GenericList::broken() should return T|null but returns array|T|null.
+30: Method GenericList::broken() should return T|null but returns array|T of mixed|null.

Full report

Line	Error
30	`Method GenericList::broken() should return T

[phpstan-bot]

@AJenbo After the latest commit in 1.7.x, PHPStan now reports different result with your code snippet:

@@ @@
-30: Method GenericList::broken() should return T|null but returns array|T|null.
+30: Method GenericList::broken() should return (T)|null but returns array|(T of mixed)|null.

Full report

Line	Error
30	`Method GenericList::broken() should return (T)

[phpstan-bot]

@AJenbo After the latest commit in 1.7.x, PHPStan now reports different result with your code snippet:

@@ @@
-30: Method GenericList::broken() should return T|null but returns array|T|null.
+30: Method GenericList::broken() should return T|null but returns array|(T of mixed)|null.

Full report

Line	Error
30	`Method GenericList::broken() should return T

[github-actions]

This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.