`is` do not accept classes with private/protected constructors

[GerkinDev]

Given the following code:

class Foo {
  #type = "foo";
}
class Bar {
  #type = "bar";
  protected constructor() {}
}
abstract class Baz {
  #type = "baz";
  protected constructor() {}
}

const list: Array<Foo | Bar | Baz> = [];
// OK
const foos: Foo[] = list.filter(is(Foo));
// Argument of type 'typeof Bar' is not assignable to parameter of type 'abstract new (...args: any[]) => any'.
//  Cannot assign a 'protected' constructor type to a 'public' constructor type.
const bars: Bar[] = list.filter(is(Bar));
const bazs: Baz[] = list.filter(is(Baz));

However, I managed to get it work in the 3 samples above using the following declaration:

type PrivateConstructor<TClass = any> = { new (): never } & TClass;
declare function is<C extends PrivateConstructor<any>>(ctor: C): (val: any) => val is InstanceType<PrivateConstructor<C>>;

Based on https://stackoverflow.com/a/78887842

I did not checked for more situations with the suggested declaration