Visual Studio Code

Types are elided in Rust code, which makes a good IDE even more useful than for C++. Visual Studio code works well for Rust in Chromium. To use it,

  • Ensure your VSCode has the rust-analyzer extension, not earlier forms of Rust support
  • gn gen out/Debug --export-rust-project (or equivalent for your output directory)
  • ln -s out/Debug/rust-project.json rust-project.json
Example screenshot from VSCode

A demo of some of the code annotation and exploration features of rust-analyzer might be beneficial if the audience are naturally skeptical of IDEs.

The following steps may help with the demo (but feel free to instead use a piece of Chromium-related Rust that you are most familiar with):

  • Open components/qr_code_generator/qr_code_generator_ffi_glue.rs
  • Place the cursor over the QrCode::new call (around line 26) in `qr_code_generator_ffi_glue.rs
  • Demo show documentation (typical bindings: vscode = ctrl k i; vim/CoC = K).
  • Demo go to definition (typical bindings: vscode = F12; vim/CoC = g d). (This will take you to //third_party/rust/.../qr_code-.../src/lib.rs.)
  • Demo outline and navigate to the QrCode::with_bits method (around line 164; the outline is in the file explorer pane in vscode; typical vim/CoC bindings = space o)
  • Demo type annotations (there are quite a few nice examples in the QrCode::with_bits method)

It may be worth pointing out that gn gen ... --export-rust-project will need to be rerun after editing BUILD.gn files (which we will do a few times throughout the exercises in this session).