Deriving namespace of types

[falsandtru]

A extends keyword derives only namespace of variables.

TypeScript Version:

master

Code

class B {
}
namespace B {
    export type M = number;
    export var m = 0;
}
class D extends B {}
var m: D.M = D.m;

Expected behavior:

$ node built/local/tsc.js index.ts

Actual behavior:

$ node built/local/tsc.js index.ts
index.ts(8,8): error TS2503: Cannot find namespace 'D'.

[falsandtru]

If TypeScript derives namespace of types, I can use partial classes using mixins. #563 (comment)

cc @RyanCavanaugh

[mhegazy]

This is working as intend. initially in 0.8.* extends would get you all the declarations but that seemed a lot like statics.

So the recommendation is to use statics if you want your declarations to be inherited, and use namespaces for augmentation to the current symbol.

[falsandtru]

Is your comment a deciding of design for this proposal?

[mhegazy]

I do not think there is new information to warrant a design reconsideration.

[falsandtru]

My description has a diff of behaviors. Or, what formats for proposals do you need?

[mhegazy]

My description has a diff of behaviors. Or, what formats for proposals do you need?

A use-case description that is not possible today because of this issue.

[falsandtru]

So I'll create this proposal.