Nightly clippy: manual_unwrap_or false positive #13018
Description
Summary
This is the same as (now fixed) #12564, but now the lint is manual_unwrap_or instead of manual_unwrap_or_default.
There is a false positive; cargo clippy --fix fails
Lint Name
manual_unwrap_or
Reproducer
I tried this code:
#[allow(unknown_lints)] // XXX FIXME (aseipp): nightly bogons; re-test this occasionally
#[allow(clippy::manual_unwrap_or_default)]
pub fn get(&self, id: &CommitId) -> &[Rc<RefName>] {
if let Some(names) = self.index.get(id) {
names
} else {
&[]
}
}from
Running cargo clippy --fix fails with:
warning: this pattern reimplements `Option::unwrap_or`
--> cli/src/commit_templater.rs:1033:9
|
1033 | / if let Some(names) = self.index.get(id) {
1034 | | names
1035 | | } else {
1036 | | &[]
1037 | | }
| |_________^ help: replace with: `self.index.get(id).unwrap_or(&[])`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#manual_unwrap_or
= note: `#[warn(clippy::manual_unwrap_or)]` on by default
warning: `jj-cli` (lib) generated 1 warning (run `cargo clippy --fix --lib -p jj-cli` to apply 1 suggestion)
warning: failed to automatically apply fixes suggested by rustc to crate `jj_cli`
after fixes were automatically applied the compiler reported errors within these files:
* cli/src/commit_templater.rs
This likely indicates a bug in either rustc or cargo itself,
and we would appreciate a bug report! You're likely to see
a number of compiler warnings after this message which cargo
attempted to fix but failed. If you could open an issue at
https://github.com/rust-lang/rust-clippy/issues
quoting the full output of this command we'd be very appreciative!
Note that you may be able to make some more progress in the near-term
fixing code with the `--broken-code` flag
The following errors were reported:
error[E0308]: mismatched types
--> cli/src/commit_templater.rs:1033:38
|
1033 | self.index.get(id).unwrap_or(&[])
| --------- ^^^ expected `&Vec<Rc<...>>`, found `&[_; 0]`
| |
| arguments to this method are incorrect
|
= note: expected reference `&std::vec::Vec<std::rc::Rc<commit_templater::RefName>>`
found reference `&[_; 0]`
help: the return type of this call is `&[_; 0]` due to the type of the argument passed
--> cli/src/commit_templater.rs:1033:9
|
1033 | self.index.get(id).unwrap_or(&[])
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^---^
| |
| this argument influences the return type of `unwrap_or`
note: method defined here
--> /Users/ilyagr/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/option.rs:983:12
|
983 | pub fn unwrap_or(self, default: T) -> T {
| ^^^^^^^^^
error: aborting due to 1 previous error
For more information about this error, try `rustc --explain E0308`.
Original diagnostics will follow.
Version
rustc 1.81.0-nightly (e9e6e2e44 2024-06-28)
binary: rustc
commit-hash: e9e6e2e444c30c23a9c878a88fbc3978c2acad95
commit-date: 2024-06-28
host: aarch64-apple-darwin
release: 1.81.0-nightly
LLVM version: 18.1.7
This issue was not present in the nightly from a week ago (2024-06-21).
Additional Labels
No response