Clippy lint · Nursery · checked with Clippy 0.1.99

clippy::search_is_some: called `is_some()` after searching an `Iterator` with `find`

What it meansChecks for an iterator or string search (such as find(), position(), or rposition()) followed by a call to is_some() or is_none(). It is in the nursery group and off by default.

What you see

warning: called `is_some()` after searching an `Iterator` with `find`
 --> main.rs:4:12
  |
4 | vec.iter().find(|x| **x == 0).is_some();
  |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `any(|x| *x == 0)`
  |
  = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#search_is_some
  = note: `-W clippy::search-is-some` implied by `-W clippy::nursery`

Real output of Clippy 0.1.99 (Rust 1.99) on the example below. Names and line numbers in yours will differ.

Does it matter?

Readability, this can be written more concisely as: _.any(_), or _.contains(_) for is_some(), !_.any(_), or !_.contains(_) for is_none().

New lints still being finished. Off by default and may have false positives.

How to fix it

Clippy can fix this one for you: run cargo clippy --fix (add --allow-dirty if you have uncommitted changes). Review the diff before you commit.

Flagged

let vec = vec![1];
vec.iter().find(|x| **x == 0).is_some();

"hello world".find("world").is_none();

Write this instead

let vec = vec![1];
vec.iter().any(|x| *x == 0);

!"hello world".contains("world");

Turn it off, or on

It is off by default. To use it, set it to warn or deny:

Whole crate (Cargo.toml)

[lints.clippy]
search_is_some = "warn"

In code

#![warn(clippy::search_is_some)]

One run

cargo clippy -- -W clippy::search-is-some

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.

Nurserygroup

allowdefault level

yesfixed by cargo clippy --fix

pre 1.29.0added in Rust

Clippy's own documentation

What it does

Checks for an iterator or string search (such as find(), position(), or rposition()) followed by a call to is_some() or is_none().

Why is this bad?

Readability, this can be written more concisely as:

_.any(_), or _.contains(_) for is_some(),
!_.any(_), or !_.contains(_) for is_none().

Example

let vec = vec![1];
vec.iter().find(|x| **x == 0).is_some();

"hello world".find("world").is_none();

Use instead:

let vec = vec![1];
vec.iter().any(|x| *x == 0);

!"hello world".contains("world");

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

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