In scala is it possible for a trait to extend a class which needs parameters?

Question

I know a trait can extend a class which has an empty parameter constructor:

class Foo
trait Bar extends Foo

but is it possible to extend a class which constructor has some parameters?

class Foo(b: Boolean)
trait Bar extends Foo(true)

Is it possible to achieve this? It seems it's not possible. but why?

Thanks

Answer 1

Yes, it's possible, you just can't give constructor arguments:

trait Bar extends Foo { ... }

But to instantiate it you need to call the constructor as well:

new Foo(false) with Bar