$object = new class() {
    public string $uninitialized;
};

$this->propertyAccessor->getValue($object, 'uninitialized');

Expected

Throws UninitializedPropertyException with message "The property "class@anonymous::$uninitialized" is not readable because it is typed "string". You should initialize it or declare a default value instead.".

Actual

Throws Error with message "Typed property class@anonymous::$publication must not be accessed before initialization".

Side efect

Form with data of an anonymous class instance cannot be created. This code throws "Typed property class@anonymous::$name must not be accessed before initialization":

// in controller

$data = new class() {
    public string $name;
};

$form = $this->createForm(SomeFormType::class, $data);

This works as expected:

// in controller

class SomeClass {
    public string $name;
};

$data = new SomeClass;

$form = $this->createForm(SomeFormType::class, $data);

No exception is thrown because PropertyPathAccessor catches UninitializedPropertyException and returns null instead.