wrong d.ts generated when importing same name classes with alias

[hdmr14]

• Version: 1.3.8
• Rollup Version: 2.38.0
• TypeScript Version: 4.1.3

Reproduction

1. create a class module with the same name in different named files (b.ts and b2.ts)
2. import them to same place(index.ts) using alias
3. export something using them(it just re-exported them in Repl)
4. wrong d.ts generated(js is fine)

Here's Repl:
https://repl.it/@hdmr14/wrong-type-declaration
Config file:
https://repl.it/@hdmr14/wrong-type-declaration#rollup.config.js
Generated files:
https://repl.it/@hdmr14/wrong-type-declaration#out/index.d.ts
https://repl.it/@hdmr14/wrong-type-declaration#out/index.js

Expected Behavior

it should be based on the generated js code.

declare class B {
}
declare class B$1 {
}
type B2 = B$1;
export { B, B2 };

or some BWrappers generated?

Actual Behavior

unexpected BWrapper generated

declare class B {
    b(): void;
}
declare module BWrapper {
    export { B };
}
import B2 = BWrapper.B$0; // <= B$0 not declared
export { B, B2 };

[wessberg]

That's definitely a bug. Thanks for the repro, I'll look into it.

As for why there's a ModuleDeclaration in there and we don't do a TypeAliasDeclaration such as you suggest (type B2 = B$1), there's actually a very good reason for it, and you can read more about it here. Classes are treated a little bit different than other types in TypeScript and type aliases cannot be instantiated.

The correct output should have been:

declare class B {
}
declare class B$0 {
}
declare module BWrapper {
    export { B$0 as B };
}
import B2 = BWrapper.B;
export { B, B2 };

[wessberg]

This has been fixed and was caused by the deconflicting logic of the declaration bundler not handling QualifiedName nodes. A new version will be released on NPM shortly containing this fix.