Open
Description
Summary
.
Lint Name
redundant_clone
Reproducer
I tried this code:
pub fn main() {
let i: Box<_> = Box::new(1);
let j = i.clone();
assert_eq!(*i, 2);
}I saw this happen:
warning: redundant clone
--> unique-decl-init-copy.rs:3:14
|
3 | let j = i.clone();
| ^^^^^^^^ help: remove this
|
note: cloned value is neither consumed nor mutated
--> unique-decl-init-copy.rs:3:13
|
3 | let j = i.clone();
| ^^^^^^^^^
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#redundant_clone
= note: `#[warn(clippy::redundant_clone)]` on by defaul
But
pub fn main() {
let i: Box<_> = Box::new(1);
let j = i;
assert_eq!(*i, 2);
}does not compile
warning: unused variable: `j`
--> unique-decl-init-copy.rs:3:9
|
3 | let j = i;
| ^ help: if this is intentional, prefix it with an underscore: `_j`
|
= note: `#[warn(unused_variables)]` on by default
error[E0382]: borrow of moved value: `i`
--> unique-decl-init-copy.rs:4:5
|
2 | let i: Box<_> = Box::new(1);
| - move occurs because `i` has type `std::boxed::Box<i32>`, which does not implement the `Copy` trait
3 | let j = i;
| - value moved here
4 | assert_eq!(*i, 2);
| ^^^^^^^^^^^^^^^^^ value borrowed here after move
|
= note: this error originates in the macro `assert_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
help: consider cloning the value if the performance cost is acceptable
|
3 | let j = i.clone();
| ++++++++
error: aborting due to previous error; 1 warning emitted
Version
rustc 1.70.0-nightly (511364e78 2023-03-16)
binary: rustc
commit-hash: 511364e7874dba9649a264100407e4bffe7b5425
commit-date: 2023-03-16
host: x86_64-unknown-linux-gnu
release: 1.70.0-nightly
LLVM version: 15.0.7
Additional Labels
No response