Protected nested classes

TypeScript Version: 1.8.9

Code

class Outer {
    protected static Inner = class {}
    private myInner: Outer.Inner;
}

Expected behavior: No errors.

Actual behavior: Compiler error: Cannot find namespace 'Outer'. Line 3, Column 24

Code

class Outer {
    protected static Inner = class {}
    private myInner: Outer.Inner;
}
namespace Outer {}

Expected behavior: No errors.

Actual behavior: Compiler error: Module 'Outer' has no exported member 'Inner'. Line 3, Column 32

Code

export class Outer {
    protected static Inner = class {};
}

export class Child extends Outer {
    static temp = class extends Outer.Inner {}
}

Expected behavior: No errors.

Actual behavior: Compiler error: Property 'Inner' is protected and only accessible within class 'Outer' and its subclasses. Line 6, Column 35

---

The problem here is that there is no way to define a protected nested class in a way that makes it possible to use in a type declaration. The third example shows why I want to use this: I want a nested class that can only be extended by classes that extend the parent class.

[michalburger1]

The compilation error for the first example now (in Typescript 3) reads:

'Outer' only refers to a type, but is being used as a namespace here.

I’m not sure if there’s a better way to do this but I managed to get it to compile using this workaround:

class Outer {
    protected static Inner = class {}
    private myInner: InstanceType<typeof Outer.Inner>;
}

[whzx5byb]

It seems there is a different error in Example 3 in 3.3.3 and later.

export class Outer {
    protected static Inner = class {};
}

export class Child extends Outer {
    static temp = class extends Outer.Inner {}
    //            ~~~~~ '(Anonymous class)' is referenced directly or indirectly in its own base expression.ts(2506)
}

And it is possible to inherite from a public reference to the protected nested class.

export class Outer {
  protected static A1 = class {}

  static A2 = Outer.A1;

  static B1 = class extends Outer.A1 {
    // Error
  }

  static B2 = class extends Outer.A2 {
    // OK, as expected.
  }
}