namespace exports circularly references themselves

[kraenhansen]

Checklist

• I can reproduce this issue when running this plugin on its own.
  Other plugins, such as node-resolve are known to cause issues.
• I am running this plugin on .d.ts files generated by TypeScript.
  The plugin can consume .ts and even .js files (with allowJs: true), but this is known to cause issues.
• This issue is not related to rolling up @types.
  The plugin ignores these by default, unless respectExternal is set. @types can contain hand-crafted code which is known to cause issues.

Code Snipped

I've pushed a reproduction of this https://github.com/kraenhansen/rollup-plugin-dts-issue-223

// thing.ts
export class Thing {};

// index.ts
import * as thing from "./thing";
export namespace MyNamespace {
  export type Thing = thing.Thing;
}

Results in the following output:

// types.d.ts
declare class Thing {
}

declare namespace MyNamespace {
    type Thing = Thing;
}

export { MyNamespace };

Error Message

The type Thing = Thing; in the output file above yields:

Type alias 'Thing' circularly references itself.

Which effectively results in the type being any for a consumer (see consumer.ts in the reproduction).

Workaround

Note that if I add a local type alias in the index.ts, the output turns out as expected:

// index.ts
import * as thing from "./thing";
type MyThing = thing.Thing;
export namespace MyNamespace {
  export type Thing = MyThing;
}

yields

// types.d.ts
declare class Thing {
}

declare type MyThing = Thing;
declare namespace MyNamespace {
    type Thing = MyThing;
}

export { MyNamespace };

[Swatinem]

Thanks for the report!
This is unfortunately a restriction that TS does variable hoisting for namespaces. Working around this is annoying and fragile :-(

[kraenhansen]

@Swatinem how / when was this fixed?

[Swatinem]

I mass-closed all the issues, as I transition the project into maintenance mode and won’t be working on any of it, see #277
However I wasn’t able to mass-close-and-comment mentioning that.