In an Angular app Webstorm doesn't recognize annotations (like @Input and @Output) of the parent class

I have a parent class like this: 

@Component({
    selector: 'app-parent',
})
export class ParentComponent {
    @Input() test;
}

... and a child class like this:

@Component({
    selector: 'app-child'
})
export class ChildComponent extends ParentComponent {}

Now when I want to assign the inputs in a template like this...

<app-child [test]="data"></app-child>

... the [test] is marked as an error with the message "Property test is not provided by any applicable directives nor by app-child element".

That should work or am I wrong?