Not sure how unresolved imports are expected to impact hover and other LSP features, but from what I can see this path now returns early when driver::Program::from_parse reports an UnknownLibrary error for a use declaration. Since that returns doc = None, the document is no longer indexed, so semantic tokens, hover, references, and completion stop working for otherwise parseable files that contain imports. Should we still create the LSP Document from the parsed program here, and report unresolved imports separately?

Yep, there is no support for modules in LSP right now. I'm working on this right now so probably I will build on top of this PR, so converting it to a draft for now.

closing because the LSP project has migrated to https://github.com/BlockstreamResearch/simplicityhl-lsp.