rust-lang / rust-lang/rust-clippy

lint functions returning only either positive dynamic values or negative constants

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A-lint E-hard E-medium L-style T-middle
Dominant language
Rust
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Description

These functions should probably return a Result and not represent their error cases by returning negative values.

Example:

fn foo(v: &[&'static str]) -> isize {
    if v.iter().any(|s| s.is_empty()) {
        return -1;
    }
    if v.iter().any(|s| s[0] == "_") {
        return -2;
    }
    v.len() as isize
}

There are probably harder cases that can be automatically detected but require some form of dataflow analysis.

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First steps

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Research direction

No file, test, or entry point is named; start by studying the example and defining which functions returning dynamic positive values and negative constants the lint should detect. Done should include a clear scope for harder dataflow cases and tests demonstrating the supported patterns.

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
25/100

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