Error when applying class mixins in 2.3-dev

[justinfagnani]

TypeScript Version: 2.3.0-dev.20170221

Code

export interface Foo { foo(): string; }

export type Constructor<T extends object> = new (...args: any[]) => T;

export const Foo =
    <T extends Constructor<{}>>(superclass: T): Constructor<Foo>& T =>
        class extends superclass implements Foo {
  foo() {
    return 'baz';
  }
}

export class Bar extends Foo(Object) {
}

Expected behavior:
no errors

Actual behavior:

[ts] 'extends' clause of exported class 'Bar' refers to a type whose name cannot be referenced.

[DanielRosenwasser]

To note, this shows up because you have --declaration set. Unfortunately you'll need to write out the exact type to get rid of the error.

I think there are two issues:

1. This error doesn't signal that --declaration is part of the cause.
2. This makes using mixin classes cumbersome.

(2) is something I've definitely noticed, but I don't know how much of a problem it will tend to be.

[mhegazy]

Here is the issue tracking @DanielRosenwasser's point (2): #14075