This is now built into rustlings
You can now do rustlings lsp to fix rust analyzer so it works with rustlings.
# Install rustlings-fix from cargo
cargo install rustlings-fix
# Change directory into wherever rustlings is cloned
cd ~/src/rustlings
# Run the binary
rustlings-fixbecause rustlings is a special type of project where we don't have a cargo.toml linking to each exercise, we need a way to tell rust-analyzer how to parse the exercises. rust-analyzer can use a rust-project.json at the root of the folder you're working from, to work without having a Cargo.toml specifying the binary or library. rustlings-fix generates that file by looping through each exercise to build the configuration in a way that allows rust-analyzer to work with the exercises.