Clippy lints / Pedantic
Clippy lint · Pedantic · checked with Clippy 0.1.99
clippy::cloned_instead_of_copied: used `cloned` where `copied` could be used instead
What it meansChecks for usage of cloned() on an Iterator or Option where copied() could be used instead. It is in the pedantic group and off by default.
What you see
warning: used `cloned` where `copied` could be used instead --> main.rs:3:18 | 3 | [1, 2, 3].iter().cloned(); | ^^^^^^ help: try: `copied` | = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#cloned_instead_of_copied = note: `-W clippy::cloned-instead-of-copied` implied by `-W clippy::pedantic`
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?
copied() is better because it guarantees that the type being cloned implements Copy.
Stricter lints with some false positives. Off by default; opt in with clippy::pedantic.
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
[1, 2, 3].iter().cloned();
Write this instead
[1, 2, 3].iter().copied();
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]
cloned_instead_of_copied = "warn"In code
#![warn(clippy::cloned_instead_of_copied)]One run
cargo clippy -- -W clippy::cloned-instead-of-copiedThe [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.
Settings in clippy.toml
msrv: The minimum rust version that the project supports. Defaults to the rust-version field in Cargo.toml
Clippy's own documentation
What it does
Checks for usage of cloned() on an Iterator or Option where
copied() could be used instead.
Why is this bad?
copied() is better because it guarantees that the type being cloned
implements Copy.
Example
[1, 2, 3].iter().cloned();
Use instead:
[1, 2, 3].iter().copied();
Configuration
-
msrv: The minimum rust version that the project supports. Defaults to therust-versionfield inCargo.toml(default:
current version)
From the Clippy lint list (0.1.99), part of the Rust project, MIT or Apache-2.0. Official entry.
Related lints
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- cast_sign_losscasting `i8` to `u64` may lose the sign of the value
- checked_conversionsChecks for explicit bounds checking when casting
- collapsible_else_ifChecks for collapsible else { if
- comparison_chainChecks comparison chains written with if that can be rewritten with match and cmp
- copy_iteratorChecks for types that implement Copy as well as Iterator
All 847 Clippy lints · Rust compiler errors · Cargo.toml checker
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