rust-lang / rust-lang/rustfmt

Ugly formatting

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#7,119 3 comments 0 reactions 0 assignees View on GitHub

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A-call-chains C-bug I-poor-formatting
Dominant language
Rust
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Avg merge
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Merged PRs (30d)
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Description

/// Returns n_1, b_1, n_2, b_2
fn distribute(sum: u64) -> (u64, u64, u64, u64) {
    let mut a = sum;
    // ...
    if a == 1 {
        // ...
    } else {
        let kmax: u64 = a.ilog2().into();
        let pow_2_kmax: u64 = (2_i32
            .pow(kmax.try_into().expect("k_max could not convert into u32")))
        .try_into()
        .expect("2^(k_max) could not convert to u64");
        return (kmax + 1 + m, 1, a - pow_2_kmax + 1 + m, a - pow_2_kmax);
    }
}

What I would expect:

/// Returns n_1, b_1, n_2, b_2
fn distribute(sum: u64) -> (u64, u64, u64, u64) {
    let mut a = sum;
    // ...
    if a == 1 {
        // ...
    } else {
        let kmax: u64 = a.ilog2().into();
        let pow_2_kmax: u64 = (2_i32
                .pow(kmax.try_into().expect("k_max could not convert into u32")))
            .try_into()
            .expect("2^(k_max) could not convert to u64");
        return (kmax + 1 + m, 1, a - pow_2_kmax + 1 + m, a - pow_2_kmax);
    }
}

Contributor guide

Open the contributing guide

First steps

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  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 reproducing the formatting of the distribute function shown in the issue and trace the formatter behavior that produces the nested .pow(...) indentation. Done means the formatted output matches the expected example, with the continuation and chained .try_into() aligned as shown.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
tooling
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Active
Clarity
Mostly clear
Newbie friendliness
68/100

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