Editing ".js" file does not update errors in ".ts" file

TypeScript Version: nightly (2.4.0-dev.20170513)

Code

(with --allowJs)

a.js

export const x = 0;

b.ts

import * as a from "./a";
a.x;
a.y;

See the error in b.ts on a.y. Then add export const y = 1; to a.js.

Expected behavior:

No more error in b.ts.

Actual behavior:

Still see the error.

Note: I tried writing a fourslash test but couldn't produce the error that way. May be a problem in vscode.

/// <reference path="fourslash.ts" />

// @allowJs: true

// @Filename: /a.js
////export const x = 0;
/////*insert*/

// @Filename: /b.ts
/// <reference path="fourslash.ts" />
////import * as a from "./a";
////a.x;
////a.y;

goTo.file("/b.ts");
verify.numberOfErrorsInCurrentFile(1);

goTo.marker("insert");
edit.insertLine("export const y = 1;");

goTo.file("/b.ts");
verify.numberOfErrorsInCurrentFile(0);

[mhegazy]

Does making an edit to b.ts cause the error to disappear?

[DanielRosenwasser]

Is it possible that because only the trivia is being changed, that some check on whether the tree changes isn't getting triggered?

[mhegazy]

Ah u are right. We are not clearing the jsdoc when do an incremental parsing if the edit is in the jsdoc only. You need to change the node. Looks like you found a good one :)

There's no jsdoc here, the problem is that even actual node changes in '.js' files aren't picked up.
Editing 'b.ts' gets you correct errors again.

[mhegazy]

In this case that should be expected. You should see the same behavior in two TS files.

If I use '.ts' files the error in 'b.ts' will be fixed the moment I add the missing export to 'a.ts'.

[DanielRosenwasser]

There's no jsdoc here

Derp - sorry, though that is certainly something we should look at.

[mhegazy]

Could not reproduce this locally. please reopen if it is still an issue.

I can still reproduce this with typescript@next.