tl;dr: Rust Glancer is an alternative Rust LSP that targets <100MB RAM usage (vs rust-analyzer's multi-GB footprint) by abandoning incremental analysis in favor of a frozen, filesystem-persisted index that reloads instantly after editor restart. It's built on rust-analyzer's syntax library and Chalk for trait solving, and while incomplete, it supports type inference, macro expansion, and common LSP actions like goto-definition and completions. The author acknowledges heavy LLM use during development but reviewed all code, and positions it as a tradeoff—slower and less complete than rust-analyzer, but viable for low-memory machines.