[bug] Changes type to reference to the wrong variable

[nicolo-ribaudo]

Bug report

Input code

// index.ts
import { fn } from "./other-file";
export function a() {}
a.fn = fn;

// other-file.ts
export function fn() {}

Actual output

// Generated by dts-bundle-generator v9.5.1

declare function fn(): void;
export declare function a(): void;
export declare namespace a {
    var fn: typeof fn;
}

export {};

Notice that the type of var fn refers to var fn and not to function fn

Expected output

Maybe this?

// Generated by dts-bundle-generator v9.5.1

declare function fn(): void;
type fn_type = typeof fn;
export declare function a(): void;
export declare namespace a {
    var fn: fn_type;
}

export {};

or this

// Generated by dts-bundle-generator v9.5.1

declare function fn$1(): void;
export declare function a(): void;
export declare namespace a {
    var fn: typeof fn$1;
}

export {};

Additional context

This also happens in rollup-plugin-dts

[timocov]

https://www.typescriptlang.org/dev/bug-workbench/?#code/PTAEAEGcAsHsHcCiBbAlgFwFAgjBKN0BTAEwDFUAbIgLlFQDsSiAPAOhLfUmzHGYDGlAIYAnYelSwGddKICuRTLwgAzKkQbDktek1ZceqZAAdYo9KADeoVQ1ABfW6NjJQAIjbBY6aEVEAtOrU7gDcmKxmFrbyDAKS0qDCABQAlNYOmMJsdqAAvLYM4bx8wZrauj5+gWWGESxRlqqx8VL2dml0AG6wqCQZQA

[timocov]

So the issue is that the compiler generates dts like so:

export declare function a(): void;
export declare namespace a {
    var fn: typeof import("./other-file").fn;
}

And then the tool traverse this and removes all dynamic imports of local files (it happens here) and resolves the name on the right with its registered "local" name. The issue is that the tool doesn't consider any names declared in namespaces thus fn stays fn, not being renamed to something fn$1 or so.