export import in declare module

Suggestion

🔍 Search Terms

declare module enum export import

✅ Viability Checklist

My suggestion meets these guidelines:

• [v] This wouldn't be a breaking change in existing TypeScript/JavaScript code
• [v] This wouldn't change the runtime behavior of existing JavaScript code
• [v] This could be implemented without emitting different JS based on the types of the expressions
• [v] This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, new syntax sugar for JS, etc.)
• [v] This feature would agree with the rest of TypeScript's Design Goals.

⭐ Suggestion

Allow export import for types and values in declare module

📃 Motivating Example

declare module './back_module' {
    /** @deprecated for backward compatible */
    export import EnumType = import('./front_module').EnumType; // Suggestion feature
}
(back_module as any).RawTypeId = front_module.RawTypeId;

// ...

import { EnumType } from './back_module';
type foobar = EnumType.Value; // it's impossible with just `type =` and `let =`
type foobar2 = OnlyForEnumType<EnumType>; // it's impossible if enum is new

💻 Use Cases

I moved EnumType to a different module but I wish to keep it backward compatible.
and back_module cannot import front_module for my situation.
So I want to declare it on the other module which combines them.

Start with the motivating example and the existing handling of declare module, import types, and export assignments. Determine how TypeScript would represent export import for both types and values without changing emitted JavaScript; done means the back_module declaration supports the shown EnumType usage while preserving backward compatibility.