Rust IDE Features Wishlist

Some ideas for editor/IDE features to make working on Rust code more pleasant.

Reading code

• Go to definition
• Show where a function is used
• Show documentation
• Show type on hover

Writing code

• Show errors/warnings inline (including those from external lints like clippy)
• Autocomplete (stand-alone tool: racer)
• Automatic code formatting (using rustfmt)
• Insert the usual boilerplate code for impls (the method signatures from the trait definition)
• Add missing imports/use statements (when they can be guessed)
• Apply suggestions for "Did you mean …?" errors (e.g. for typos in identifier names)

Refactoring code

• Apply suggestions from (clippy) lints (experimental tool: rustfix), e.g.:
  • Remove unneeded return statements and redundant closures
  • Replace .or_insert(Vec::new()) with .or_insert_with(Vec::new)
  • Use list.iter().enumerate instead of for i in 0..list.len()
• Replace glob imports with a concrete list of used imported items
• Extract impl Type into a new trait
• Replace a function argument with a type parameter (e.g., with shortcuts for fn foo(x: i32) → fn foo<T: Into>(x: T))
• Move type definition and impls into new module (i.e., move parts of a large module into new file)
• Move #[test] functions into a #[cfg(test)] mod test

Some of these things already work with RustyCode, the extension for VSCode I'm currently using.

The official and most promising effort for implementing the features mentioned above in a way that editor/IDE plugins can easily use them is the plan for a Rust Language Server:

• RFC #1317
• rustls (experimental implementation, not to be confused with the Rust TLS stack)
• rustls_vscode (VSCode extension using language server)