Support @typedef importing a CommonJS default exported class as type into another file

[TheLarkInn]

TypeScript Version: 2.9.0-dev.20180412

Search Terms: import("./") jsdoc JavaScript TypeScript CommonJs

Code
https://github.com/webpack/webpack/blob/10282ea20648b465caec6448849f24fc34e1ba3e/lib/Chunk.js#L477 Chunk.js

module.exports = Chunk; // Chunk is a class as seen linked above

/**
 * @typedef { import("./Chunk.js") } Chunk
 */

// A *self-contained* demonstration of the problem follows...
// Test this by running `tsc` on the command-line, rather than through another build tool such as Gulp, Webpack, etc.

Expected behavior:
No error, and that the Class is a Type that can be referenced.
Actual behavior:

lib/ChunkGroup.js:8:15 - error TS1340: Module './Chunk.js' does not refer to a type, but is used as a type here.

* @typedef { import("./Chunk.js") } Chunk

Playground Link:
Not possible because this is across two separate CommonJS modules.

[sandersn]

module.exports = Chunk is currently not an alias like export = Chunk is, so only the value meaning of the class gets exported. Basically, Javascript should use the same infrastructure as Typescript, instead of a hacked-on imitation.

I have a fix that does this, but it breaks the change in #23228, which relies on the incorrect structure. (#23228 allows both module.exports = Chunk and module.exports.staticFunction = () => 12 in the same file)

I'll put up a PR after I get everything working. In the meantime, the branch I'm working in is js/module-exports-is-alias