Stale errors in watch mode

[andrewgreenh]

Hello everyone!
I'm not quite sure that this is really a bug or if I am missing a simple configuration option but I googled for 1.5 hours and came up with nothing:

TypeScript Version: 3.0.0-dev.20180619

Search Terms: Stale error, watch mode, saved file, closed file

Code

File a.ts:

import test from './b';

test(4, 5);

File b.ts:

function test(x: number, y: number) {
  return x + y / 5;
}

export default test;

tsconfig.json:

{
  "compilerOptions": {
    "module": "commonjs",
    "noEmit": true,
    "strict": true,
    "watch": true
  }
}

Expected behavior:
When running tsc on console, everything is fine. When one of the parameter types in b.ts is changed to string, the running compiler (in watch mode) should now show an error, becuase test is called with 2 numbers.

Actual behavior:
Errors only show up when compiler is restarted or when a.ts is saved.

Playground Link: https://github.com/andreasgruenh/typescript-watch

Related Issues: #21325 sounds similar but was fixed according to comments.

[mhegazy]

I am not seeing this on typescript@next. do you get the stale errors consistently? what version are you using?

[andrewgreenh]

I'm using the version that was installed with @next this morning (as stated in the initial post). Don't know if this matters, but I'm on Windows 10 and it doesn't matter what program I use to save files (vscode/np++/notepad)

When I omit the noEmit flag, the files are getting updated, but the error is not.

[mhegazy]

I think there is something else going on.. here is what i am seeing...

do you have other @types in your node_modules?

[andrewgreenh]

This is really weird... This is what I'm seeing:

Note that the timestamps in the watch output get updated.
You can also see, that the project is empty.

One addition: I addded ./node_modules/.bin to my path, so the tsc call from console starts the cli from inside node_modules

[andrewgreenh]

Oh wow, update: When updating the second parameter, it is working. When updating the first, it's not.

Ah nvm. It is not working on your site either. You only get the error from b.ts, but a.ts has an error, too, that is not beeing reported.
When updating the second parameter, there are errors in b.ts and a.ts (compiler only shows errors in b.ts). When updating the first one, there are only errors in a.ts (which are not shown)