rust-lang / rust-lang/rust-clippy
Add `for_loopable_loop` which converts loops into for range loops
Nobody has claimed this yet.
- Dominant language
- Rust
- Stars
- 13.5k
- Forks
- 2.2k
- Avg merge
- 2d 10h
- Merged PRs (30d)
- 32
Description
What it does
This lint converts loops that increment a state counter into for range loops. It should be able to handle infinite loops (using an unbounded range) as well as loops that stop iteration once they reach a certain iteration count.
Advantage
- Reduces the amount of mutable state to track when reading the code
- Makes it clearer how many iterations the loop would run for
- More idiomatic
Drawbacks
- Using a loop may make more sense semantically if the loop was written to update a shared state and just so happens to increment a counter on every iteration.
Example
let mut i = 0;
loop {
println!("Loop iteration: {i}");
i += 1;
}
Could be written as:
for i in 0.. {
println!("Loop iteration: {i}");
}
The lint could also handle breaking out of the loop
let mut i = 0;
loop {
println!("Loop iteration: {i}");
i += 1;
if i >= 5 {
break
}
}
Could be written as:
for i in 0..5 {
println!("Loop iteration: {i}");
}
Comparison with existing lints
Unlike clippy::explicit_counter_loop this lint works even when the loop is not iterating over a slice.
Additional Context
No response
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by comparing the proposed behavior with the existing clippy::explicit_counter_loop lint and the two loop examples in the issue. The work is done when the lint covers both unbounded loops and loops that break at a specified iteration count while preserving the stated semantic caveat.
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
- Mostly clear
- Newbie friendliness
- 35/100