On the insiders channel, VS Code now provides apis for semantic token highlighting. This would allow Dart Code to enhance the static grammar-based highlighter with highlighting information from the analyzer.

In particular, the extension could use it to:

• be more accurate at semantic highlighting (members starting with an uppercase, named get/set, complex string literals, ...)
• highlight non-Dart files via analysis server plugins

To my knowledge, LSP doesn't support syntax highlighting (yet). So I think this would have to be implemented using the DAS protocol and a contributor for now. I've started some work on this and I hope I can open a PR next week.

Current issues

• Not available in a stable VS Code release
• The analysis server doesn't highlight null and throw tokens, https://dart-review.googlesource.com/c/sdk/+/131071