Where to start using rust-analyzer programmatically?

[sanmai-NL]

I'd like to e.g., list all structs that implement a certain trait within a crate programmatically for new tooling I'm developing, separate from an IDE. Ideally I'd use the LSP, but I can use the Rust API. Where to start?

[lnicola]

Before trying that, you should also make sure that the JSON output of rustdoc and our LSIF index don't provide enough information.

[sanmai-NL]

Are there samples of this information somewhere online for a quick look?

[lnicola]

Don't think so, but try cargo +nightly rustdoc --package=$package -- -Z unstable-options --output-format=json and rust-analyzer lsif . in a project.

[sanmai-NL]

@lnicola Did you mean cargo doc --message-format=json? That doesn't produce this information (e.g., about traits) on stdout. The --json option is unavaible here with Cargo 1.66.0.

[sanmai-NL]

Navigating the LSIF file, I don't understand how this encodes which structs there are and which traits they implement.

[lnicola]

I was thinking of https://rust-lang.github.io/rfcs/2963-rustdoc-json.html, but I'm not sure how to use it.

[sanmai-NL]

The right command for a workspace is:

cargo +nightly rustdoc --package=$package -- -Z unstable-options --output-format=json

The JSON file is saved under target/doc/. Indeed, this JSON data seems informative enough (at least for further study).