rust-lang / rust-lang/rust-clippy

New Lint: No recursion without tail calls

Open
#1,678 7 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

A-lint good first issue L-perf T-middle
Dominant language
Rust
Stars
13.5k
Forks
2.2k
Avg merge
2d 10h
Merged PRs (30d)
32

Description

Based on this HIC++ guideline.

The stack explodes much faster using recursion than a huge BFS work queue would explode the heap. Therefore, if clippy detects some direct or indirect recursion that does not benefit from tail call optimisation, clippy should issue a warning along with a short description about why this is potentially bad and a short hint on how to transform recursive algorithms to iterative ones (e.g. using a work queue and BFS). And maybe a tl;dr about what tail calls are and how to make the algorithm tail recursive.

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reviewing the linked HIC++ guideline and the proposal in issue #1678. Determine how direct and indirect recursion, tail-call optimization, and potential stack growth should be identified and explained. Done means a decided, implementable lint scope with warnings and guidance for transforming recursive algorithms into iterative ones.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
tooling
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.