salsa VS merlin

There are some excellent crates already in the Rust ecosystem (notably Salsa) for performing incremental computation, although they generally have different goals to Depends.

The content of that "Core Concepts" page sounds a lot like https://github.com/salsa-rs/salsa

I know of salsa, but I don't know if it can persist changes to disk (and my guess from looking at this issue is that it can't).

- the practical approach to this is to split workload into work units (aka tasks/queries/etc.) and then force information flow through centralized "request"/"query" APIs that automatically track dependencies - see https://github.com/salsa-rs/salsa for more information

This, and as pointed Salsa.

These guys might be of interest for you, they think a lot about incremental parsers. https://github.com/salsa-rs/salsa

salsa-rs authored by niko matsakis and other top rust devs

Some optimizations are not easy with Go. For example caching like in Rust Analyser Salsa Framework

How would this differ from salsa (https://github.com/salsa-rs/salsa) and the query-driven approach used by rustc?

Merlin: Context sensitive completion for OCaml in Vim and Emacs\ (0 comments)

Instead of searching functions based on their type structure (like Hoogle), you could search for functions that "consume"/"produce" values of given types (like OCaml's Merlin). I think Rust already computes variance of type constructors, so such a tool just would have to obtain this information.

However, after posting this question I stumbled upon this Github issue where they say it isn't supposed to work out of the box and you're supposed to bind a key to it by editing your .emacs file. Turns out the default .emacs file binds auto-complete to "backtab" which means Shift+Tab but that didn't work. I did eventually discover that I can get some kind of completion by binding backtab to completion-at-point like this:

Self-advertising: I partcipated to the writing of Merlin: A Language Server for OCaml (Experience Report), which explains the overall design of Merlin, a language server for OCaml. A key idea of Merlin are that classic lexing-parsing-typing pipelines can easily be adapted to be incremental for a Language Server, especially when they are using immutable data structures.