Clippy lint · Correctness · checked with Clippy 0.1.99

clippy::suspicious_splitn: Checks for calls to [splitn] (https://doc.rust-lang.org/std/primitive.str.html#method.splitn) and related functions with either zero or one splits

What it meansChecks for calls to [splitn] (https://doc.rust-lang.org/std/primitive.str.html#method.splitn) and related functions with either zero or one splits. It is in the correctness group and denied by default (the build fails).

Does it matter?

These calls don’t actually split the value and are likely to be intended as a different number.

Code that is almost certainly wrong. Denied by default: the build fails until you fix it or allow it.

How to fix it

Clippy does not fix this one automatically. Change the code by hand:

Flagged

for x in s.splitn(1, ":") {
    // ..
}

Write this instead

for x in s.splitn(2, ":") {
    // ..
}

Turn it off, or on

Allow it where it does not fit your code, as narrowly as you can:

On one item

#[allow(clippy::suspicious_splitn)]
fn my_function() { /* ... */ }

Whole crate (Cargo.toml)

[lints.clippy]
suspicious_splitn = "allow"

One run

cargo clippy -- -A clippy::suspicious-splitn

The [lints] table needs Rust 1.74 or newer. In a workspace, put it under [workspace.lints.clippy] and add [lints] workspace = true to each member.

Correctnessgroup

denydefault level

nofixed by cargo clippy --fix

1.54.0added in Rust

Clippy's own documentation

What it does

Checks for calls to [splitn] (https://doc.rust-lang.org/std/primitive.str.html#method.splitn) and related functions with either zero or one splits.

Why is this bad?

These calls don’t actually split the value and are likely to be intended as a different number.

Example

for x in s.splitn(1, ":") {
    // ..
}

Use instead:

for x in s.splitn(2, ":") {
    // ..
}

From the Clippy lint list (0.1.99), part of the Rust project, MIT or Apache-2.0. Official entry.

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