rust-lang / rust-lang/rust-clippy
`non_canonical_clone_impl` sugg fails due to lifetime
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@saberoueslati is already working on this.
Since Sep 19, 2026.
E-hard
I-suggestion-causes-error
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Description
Using the following flags
--force-warn clippy::non_canonical_clone_impl
this code:
struct Weird<'a>(&'a i32);
impl Clone for Weird<'_> {
fn clone(&self) -> Self {
println!("clone() called");
Weird(self.0)
}
}
impl Copy for Weird<'static> {}
fn main() {
let local = 1;
let _ = [Weird(&local)].clone();
}
caused the following diagnostics:
Checking _snippet_0 v0.1.0 (/tmp/icemaker_global_tempdir.W9mV5T7suTWy/icemaker_clippyfix_tempdir.EE0EO9b2vI7W/_snippet_0)
warning: non-canonical implementation of `clone` on a `Copy` type
--> src/main.rs:4:29
|
4 | fn clone(&self) -> Self {
| _____________________________^
5 | | println!("clone() called");
6 | | Weird(self.0)
7 | | }
| |_____^ help: change this to: `{ *self }`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#non_canonical_clone_impl
= note: requested on the command line with `--force-warn clippy::non-canonical-clone-impl`
warning: `_snippet_0` (bin "_snippet_0") generated 1 warning
Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.22s
However after applying these diagnostics, the resulting code:
struct Weird<'a>(&'a i32);
impl Clone for Weird<'_> {
fn clone(&self) -> Self { *self }
}
impl Copy for Weird<'static> {}
fn main() {
let local = 1;
let _ = [Weird(&local)].clone();
}
no longer compiled:
Checking _snippet_0 v0.1.0 (/tmp/icemaker_global_tempdir.W9mV5T7suTWy/icemaker_clippyfix_tempdir.EE0EO9b2vI7W/_snippet_0)
error: lifetime may not live long enough
--> src/main.rs:4:31
|
4 | fn clone(&self) -> Self { *self }
| ----- ^^^^^ copying this value requires that `'1` must outlive `'static`
| |
| has type `&Weird<'1>`
error: could not compile `_snippet_0` (bin "_snippet_0" test) due to 1 previous error
warning: build failed, waiting for other jobs to finish...
error: could not compile `_snippet_0` (bin "_snippet_0") due to 1 previous error
Version:
rustc 1.91.0-nightly (91ee6a405 2025-08-26)
binary: rustc
commit-hash: 91ee6a4057ce4bf1ab6d2f932cae497488d67c81
commit-date: 2025-08-26
host: x86_64-unknown-linux-gnu
release: 1.91.0-nightly
LLVM version: 21.1.0
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