Clippy lint · Nursery · checked with Clippy 0.1.99

clippy::redundant_clone: Checks for a redundant clone() (and its relatives) which clones an owned value that is going to be dropped without further use

What it meansChecks for a redundant clone() (and its relatives) which clones an owned value that is going to be dropped without further use. It is in the nursery group and off by default.

Does it matter?

It is not always possible for the compiler to eliminate useless allocations and deallocations generated by redundant clone()s.

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 x = Foo::new();
    call(x.clone());
    call(x.clone()); // this can just pass `x`
}

["lorem", "ipsum"].join(" ").to_string();

Path::new("/a/b").join("c").to_path_buf();

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]
redundant_clone = "warn"

In code

#![warn(clippy::redundant_clone)]

One run

cargo clippy -- -W clippy::redundant-clone

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

1.32.0added in Rust

Clippy's own documentation

What it does

Checks for a redundant clone() (and its relatives) which clones an owned value that is going to be dropped without further use.

Why is this bad?

It is not always possible for the compiler to eliminate useless allocations and deallocations generated by redundant clone()s.

Known problems

False-negatives: analysis performed by this lint is conservative and limited.

Example

{
    let x = Foo::new();
    call(x.clone());
    call(x.clone()); // this can just pass `x`
}

["lorem", "ipsum"].join(" ").to_string();

Path::new("/a/b").join("c").to_path_buf();

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

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