Closed
Description
When using a match statement at the end of a function that has a return statement in a match arm and is followed by a semicolon, cargo clippy will suggest replacing the return with a unit value. However, it does this regardless of what type the match statement actually returns, so if it is something other than unit, it breaks.
Minimal reproducible example:
fn main() {
match 0 {
0 => 0,
_ => return,
};
}cargo clippy --fix:
Checking test v0.1.0 (/root/test)
warning: failed to automatically apply fixes suggested by rustc to crate `test`
after fixes were automatically applied the compiler reported errors within these files:
* src/main.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/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]: `match` arms have incompatible types
--> src/main.rs:4:14
|
2 | / match 0 {
3 | | 0 => 0,
| | - this is found to be of type `{integer}`
4 | | _ => (),
| | ^^ expected integer, found `()`
5 | | }
| |_____- `match` arms have incompatible types
error: aborting due to previous error
For more information about this error, try `rustc --explain E0308`.
Original diagnostics will follow.
warning: unneeded `return` statement
--> src/main.rs:4:14
|
4 | _ => return,
| ^^^^^^
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_return
= note: `#[warn(clippy::needless_return)]` on by default
= help: replace `return` with a unit value
warning: `test` (bin "test") generated 1 warning (run `cargo clippy --fix --bin "test"` to apply 1 suggestion)
warning: `test` (bin "test" test) generated 1 warning (1 duplicate)
Finished dev [unoptimized + debuginfo] target(s) in 0.18s
rustc --version --verbose:
rustc 1.70.0-nightly (8be3c2bda 2023-03-24)
binary: rustc
commit-hash: 8be3c2bda6b683f87b24714ba595e8b04faef54c
commit-date: 2023-03-24
host: x86_64-unknown-linux-gnu
release: 1.70.0-nightly
LLVM version: 15.0.7