Incorrect UninitializedProperty / PossiblyNullReference error due to buggy parent constructor detection

[colinodell]

In the following example, I have three classes which extend from each other (C extends B extends A): https://psalm.dev/r/6f670c1ffe The middle class does not have a constructor but the other two do.

Psalm doesn't seem to realize that when C's constructor calls parent::__construct() it results in A's constructor being called. As a result, Psalm thinks the property is never set, although it definitely is: https://3v4l.org/Q8lq3

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/6f670c1ffe

<?php

class A
{
    protected DateTimeImmutable $date;
    
    public function __construct()
    {
        $this->date = new DateTimeImmutable();
    }
}

class B extends A
{
}

class C extends B
{
    public function __construct()
    {
        parent::__construct();

        echo "I was instantiated at " . $this->date->format('c');
    }
}

new C();

Psalm output (using commit 929efcc):

ERROR: UninitializedProperty - 23:41 - Cannot use uninitialized property $this->date

ERROR: PossiblyNullReference - 23:54 - Cannot call method format on possibly null value

ERROR: PropertyNotSetInConstructor - 17:7 - Property C::$date is not defined in constructor of C and in any methods called in the constructor

[muglug]

One workaround is to specify the constructor explicitly: https://psalm.dev/r/0851f087dc

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/0851f087dc

<?php

class A
{
    protected DateTimeImmutable $date;
    
    public function __construct()
    {
        $this->date = new DateTimeImmutable();
    }
}

class B extends A
{
}

class C extends B
{
    public function __construct()
    {
        A::__construct();

        echo "I was instantiated at " . $this->date->format('c');
    }
}

new C();

Psalm output (using commit 3dd185e):

No issues!

[weirdan]

One workaround is to specify the constructor explicitly

It's would be very unusual to see the code like that. parent::__construct() is idiomatic in PHP, it's not something that's going to change.