During my day job as a flutter developer, we use the Firebase stack as our cloud solution. The current landscape for extension support is lacking in the LSP department for this language. There are numerous extensions but all are modeled as VSCode extensions. So I set a goal to learn rust (and consequently building grammars with tree-sitter) by building a LSP that uses its own parser for the firestore language to enable type inference, diagnostics, linting, etc.

Its still in its infancy stage but at least there is an LSP in this space right now. As expected there is a vscode companion extension that simply wraps this lsp https://github.com/JulindM/firestore-rules-lsp-vscode