EventedConstructor incorrectly typed about typings HOT 4 OPEN

Yeah, the pattern used with DeclareConstructor makes this a sticky issue to resolve.

It's usage should be OK with declare, but I was trying to extend Evented like a class

export default class<T> extends Evented implements StateMachineEvents<T> {

Which results in the error

error TS2510: Base constructors must all have the same return type.

The error may be due to Evented having two different constructors:

interface EventedConstructor extends _base.DeclareConstructor<Evented> {
	new (params?: Object): Evented;
}

interface DeclareConstructor<T> {
	new (...args: any[]): T & DeclareCreatedObject;

I was able to resolve by "fixing" the typings

export interface FixedEventedConstructor {
	new (params?: Object): dojo.Evented;
}
export const FixedEvented: FixedEventedConstructor = <any> Evented;

I haven't had a chance to play with TypeScript 2.2. Hopefully we'll be able to define mixin classes as purely ambient declarations that return functional constructors. If we have to apply it as a pattern in code and actually have to return a class that extends from a declare statement, I would be concerned about losing the metadata added by declare to allow for functional chaining via inherited. Hopefully it'll be the former and we'll have a good way of declaring define.

Anyway, all of this created a rabbit hole I knew I didn't want to go down on my own.

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@mmckenziedev have you run into an issue with this yet?

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@dylans I haven't had problems using Declare to mix this in to other classes.

I agree that technically this class is an ES5 class and shouldn't use DeclareConstructor. However, in practice, if you're using Declare to create a new class and you try to mix this in, if it is not a DeclareConstructor then it won't work properly due to the way Declare is defined.
_base.d.ts#L620

If it's not breaking anything I would prefer to leave this as it is for now. When Typescript 2.2 comes out, and we can finally have a better expression syntax for mixins, then we could refactor the way Declare works.

https://github.com/Microsoft/TypeScript/wiki/Roadmap#22-february-2017
microsoft/TypeScript#13743

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This issue bit me as well. Is #113 (comment) the prescribed way around it for now?

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