I need to investigate this. However, I had this issue and didn't find a solution.

• https://code.visualstudio.com/api/language-extensions/semantic-highlight-guide
• https://github.com/dotnet/interactive/blob/main/src/polyglot-notebooks-vscode-common/src/dynamicGrammarSemanticTokenProvider.ts

Maybe one solution would be for the highlighter to highlight all it can even if there is a syntax error? But this probably requires significant changes in the Juvix highlighter.

But this is a bug. It's very annoying to use the VSCode extension because of this. It should be fixed one way or another.

But somehow it didn't happen with an earlier version, so something changed.

Can you please track the version where it's supposed to be working?

Well, it doesn't seem to be working with any of the extension versions. Maybe the VSCode version changed or something changed in the juvix binary. Or I just misremembered this.

In any case, I would say this is the most serious issue with the VSCode extension as of now.

A solution might be not to update the highlighting if there is an error, but use the old highlighting if there is one?

My take on this is that if we can't easily have non-disappearing semantic highlighting, then it's better to have dumb highlighting like we currently have with JuvixCore and JuvixAsm.

This is partly solved in 0.1.39. Semantic highlighting still disappears while I'm typing after the position where I'm typing. If I make an error, depending on the kind of error, all semantic highlighting in the entire file may disappear, plus basic highlighting after the error point.

Ultimately, highlighting shouldn't disappear. It should behave more-or-less the way the Haskell extension behaves, where I guess the extension remembers things that were highlighted - at least that's how it looks from the user perspective.

Original state before editing: