Rust: False positive for unused variable names

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#22,342 创建于 2026年8月13日 1 条评论 0 个 reaction 已指派 0 人在 GitHub 查看

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难度: 4/5
预计耗时: 3-5 天
新手友好度: 38/100

Issue 类型: 缺陷
描述清晰度: 需要澄清
活跃度: 冷清
技术栈: rust
领域: security

调研方向

先从链接的代码扫描警报和 Rust 代码片段开始，然后跟踪 CodeQL Rust 未使用变量查询对 format! 插值的处理方式。完成的标准是：查询不再将 name 报告为未使用，同时仍能检测出确实未使用的变量。

由索引模型根据 Issue 内容生成。

描述

false-positive

Description of the false positive

CodeQL seems to produce false positives for Rust variables in format strings.

Code samples or links to source code

On 2026-08-13, the folllowing Rust snippet got flagged by CodeQL on https://github.com/alltheplaces/osm-diffs/pull/660. CodeQL posted a notice, claiming Variable 'name' is not used. However, the variable does get used in this snippet, via a format! macro. We also check for unused variables with clippy, which does not flag an unused variable for this code. So, this looks like a false positive from CodeQL.

        let producers: Vec<_> = sources
            .into_iter()
            .map(|(name, reader)| {
                let tx = tx.clone();
                s.spawn(move || -> Result<()> {
                    for record in reader.iter()? {
                        let bytes = record?;
                        let fti = FeatureToIndex::decode(bytes.as_slice()).with_context(|| {
                            format!("failed to decode a FeatureToIndex record from {name}")
                        })?;
                        tx.send(fti)?;
                        progress_bar.inc(1);
                    }
                    Ok(())
                })
            })
            .collect();

URL to the alert on GitHub code scanning (optional)

https://github.com/alltheplaces/osm-diffs/security/code-scanning/30