`export let x: Type` and type declaration without ending semicolon last in script block breaks syntax highlighting

[poppa]

Describe the bug

When running Typescript mode and you have either an export let varName: Type, or type Type = type without a line-ending semicolon last in a script block, the syntax highlighting breaks.

The problem with type declarations I've seen for ages, but the problem with component properties arrived yesterday after updating VS Code.

I think the screenshots are quite explanatory.

Syntax highlight breaks after ZeRow

Syntax highlighting breaks after the ending curly brace for type declaration Test

Syntax highlight works when ending type declaration with a semicolon

Syntax highlighting works when ending property declaration with semicolon

Syntax highlighting works when ending script block with some other statement or expression

Reproduction

This simple snippet is sufficient to to reproduce the bug.

<script lang="ts">
export let test: any
</script>

Expected behaviour

I expect the ending </script> tag to be correctly highlighted

System Info

• IDE: VS Code

Which package is the issue about?

Svelte for VS Code extension

Additional Information, eg. Screenshots

No response

[jasonlyu123]

This is an "issue" with the upstream TypeScript syntax highlight. But I can't find a situation where it will break inside a ts file. It was changed to be more precise in multiple lines type alias. But it breaks in vue, svelte and astro files. I am afraid there is not much we can do.

[poppa]

Ok, so does upstream mean VS Code itself? Does this issue get propagated there or should I create a new bug report there (where ever that might be)?

I have never seen this bug inside a pure .ts file, so I guess it has something to do with the <script> block.

It got worse with the latest VS Code update:

Version: 1.77.0
Commit: 7f329fe6c66b0f86ae1574c2911b681ad5a45d63
Date: 2023-03-29T09:57:11.797Z
Electron: 19.1.11
Chromium: 102.0.5005.196
Node.js: 16.14.2
V8: 10.2.154.26-electron.0
OS: Darwin x64 22.1.0
Sandboxed: Yes

Before that only the type case was causing problem, but after this update the export let varName: Type problem arose.

[babak-bxp]

[jasonlyu123]

Type alias without a semi also breaks highlight in a ts file. It's tracked here in #1110.

About let without a semi, Yes, it is related to the script tag because it doesn't exist in a ts file. So </script> won't be a condition for ending the match. Therefore, I don't think they will consider that a bug on their side.

We have a config file to define regex rules for VSCode to highlight the script tag section with TypeScirpt. But sometimes it seems like if one of the embed language matching rules hasn't ended, It won't consider top-level "</script>". So we either have to change TypeScript's highlight somehow to stop matching type annotation if there is a "</script>" or we'll have to find a way to force any TypeScript matching if there is a "</script>".

We know this problem when it's still in beta. But I haven't found a way to work around it on our side yet. I don't think this will be fixed anytime soon. You can work around it with a comment or an empty line afterwards.

[JUNGHUNKIM-7]

same issue here, without semi, syntax crashing happens anywhere. AstroJs has same problems too. i think those problems might be related vscode's side.

[einarpersson]

Seems to have been fixed now, but I don't know how to update 😆
(maybe I have to switch to Visual Studio Code Insiders...)

microsoft/TypeScript-TmLanguage#971
microsoft/vscode#179068

[jasonlyu123]

Once it's merged into VSCode main, You can test it with VSCode insider. Or you can try it with the TypeScript nightly extension for the nightly release of TSServer and TypeScript-TmLanguage. I tested it, and it seems to be fixed yesterday by another commit. A by-product of other TypeScript statements 😆.

[einarpersson]

Is this still an issue for people? I think this is fixed in vscode 1.77.1.

If confirmed this could be closed, I suppose?

[poppa]

This still seems to be a problem in VSC 1.77.1

[jasonlyu123]

It's fixed by another issue other than the linked one, and it's only in the TypeScript nightly extension now.

[poppa]

This seems to be fixed in the latest VS Code, so I'm all good 👍

(And thanks for all the good work you guys do 🤩)