rust-analyzer wanted features & bugfixes

[ojeda]

Features that we would like to see

Required (we almost certainly want them)

• discoverConfig.

  • Details/discussion: Support .rust-project.json (i.e. hidden) rust-lang/rust-analyzer#17816 (comment).
  • PR: feature: teach rust-analyzer to discover linked_projects rust-lang/rust-analyzer#17246.
  • Issue: Lazy Workspace/Project Discovery rust-lang/rust-analyzer#17537.
  • Issue: Announcements: Client Changes rust-lang/rust-analyzer#4604.

• Edition 2024 support.

  • Our plan is to migrate to Edition 2024 as soon as possible (unless a blocker is found, of course).
  • Issue: 2024 Edition  rust-lang/rust-analyzer#16146.

Nice to have (not critical, we could workaround if needed, etc.)

Low priority (we will likely not use them in the end)

Done (stabilized, fixed, not needed anymore, etc.)

• A way to avoid exploding the size of rust-project.json with thousands of cfgs defined repeatedly per crate.

  • Issue: Specifying a set of cfgs for given crates (cfg groups) rust-lang/rust-analyzer#17815.
  • If we end up using the discoverConfig support (and we replace completely rust-project.json -- see also a few notes at Support .rust-project.json (i.e. hidden) rust-lang/rust-analyzer#17816 (comment)), then we would not need this anymore, and rust-analyzer will likely remove it: feat: Allow declaring cfg groups in rust-project.json, to help sharing common cfgs rust-lang/rust-analyzer#17857 (comment).
  • PR: feat: Allow declaring cfg groups in rust-project.json, to help sharing common cfgs rust-lang/rust-analyzer#17857.

• Support .rust-project.json (i.e. hidden).

  • Issue: Support .rust-project.json (i.e. hidden) rust-lang/rust-analyzer#17816.
  • PR: Allow rust-project.json to be hidden rust-lang/rust-analyzer#17818 (1.82.0).

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Bugs that we would like to see fixed

Required (we almost certainly want them)

• Support goto-definition for include!(concat!(env!("OBJTREE"), "/..._generated.rs"));
  • Potentially the cause of rust-analyzer: go to definition for bindings::* for out of tree builds #1050.
  • Issue: goto-definition for include*!(expr), where expr is not a string literal rust-lang/rust-analyzer#15836.

Nice to have (probably not critical, we could workaround if needed, etc.)

• Limitations around #[path = "..."].
  • A possible workaround is to use a symlink.
  • Issue: unresolved import for some `#[path = ".."] rust-lang/rust-analyzer#3898.
  • Lore: https://lore.kernel.org/rust-for-linux/20250319-pin-init-internal-quote-v1-1-19de6a33a257@gmail.com/.

Low priority (we will likely not use them in the end)

Done (stabilized, fixed, or not needed anymore, etc.)