You are missing a parent::__construct() call. Possibly 

class B extends A {
    public function __construct(
        public string $b = 'hello'
    ) {
        parent::__construct(); // Use default for A::$a
    }
}

or

class B extends A {
    public function __construct(
        $a,
        public string $b = 'hello'
    ) {
        parent::__construct($a); // Set A::$a = $a
    }
}

You still have to call the parent constructor.

Sorry I meant the deshugaring code is like 

```php
<?php

class A {
    public $a;
    public function __construct(
        $a = 1
    ) {
       $this->a = $a;
    }
}

class B extends A {
    public function __construct(
        public string $b = 'hello'
    ) {}
}

$b = new B();
var_dump($b->a, $b->b);
```

And this code does not show warning.

> You are missing a parent::__construct() call.

That has never been mandatory, has it?

> That has never been mandatory, has it?

No, and it's still not mandatory -- for example, you could also do a manual $this->a = 42 assignment if you like. The state of the parent class just needs to be initialized *somehow* and parent::__construct() is the most typical and most robust way to do so.

I can see the argument for giving $a a null default value though, because that's what normally happens with untyped properties. Right now constructor promotion gives you a property declaration that (for untyped properties) you cannot achieve in any other way, which is certainly odd, and not really intentional.

Alright, but w/o constructor promotion, when I define property it's auth initilized. I.e.

```
class A {
   public $a;
}
```

does not require an additional initialization.

Yep, Nikita. I missed you last comment, it's exactly what I mean.