Closed
Description
Summary
In my arch-ops library, I have an enum called X86EncodingPrefix representing different prefixes. To simply some encoding code, I use a hidden variant cast to usize to count the number of supported prefixes. The enum is declared #[non_exhaustive] explicitly to indicate that it can be extended with future prefixes as intel comes out with new extensions (and decides that EVEX is insufficient).
Lint Name
manual_non_exhaustive
Reproducer
I tried this code:
#![deny(clippy::manual_non_exhaustive)]
#[derive(Copy, Clone, Debug, Hash, PartialEq, Eq)]
#[non_exhaustive]
pub enum X86EncodingPrefix {
NoPrefix,
Rex,
Rex2,
Vex,
Evex,
#[doc(hidden)]
__PrefixCount,
}
impl X86EncodingPrefix{
pub const PREFIX_COUNT: usize = Self::__PrefixCount as usize;
}I saw this happen:
error: this seems like a manual implementation of the non-exhaustive pattern
--> src/lib.rs:5:1
|
5 | / pub enum X86EncodingPrefix {
6 | | NoPrefix,
7 | | Rex,
8 | | Rex2,
... |
13 | | __PrefixCount,
14 | | }
| |_^
|
help: remove this variant
--> src/lib.rs:13:5
|
13 | __PrefixCount,
| ^^^^^^^^^^^^^
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#manual_non_exhaustive
note: the lint level is defined here
--> src/lib.rs:1:9
|
1 | #![deny(clippy::manual_non_exhaustive)]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error: could not compile `playground` (lib) due to previous error
I expected to see this happen:
No Diagnostic, compiles without issue.
Version
rustc 1.74.0-nightly (7b4d9e155 2023-09-28)
binary: rustc
commit-hash: 7b4d9e155fec06583c763f176fc432dc779f1fc6
commit-date: 2023-09-28
host: x86_64-unknown-linux-gnu
release: 1.74.0-nightly
LLVM version: 17.0.2
Additional Labels
@rustbot label +I-suggestion-causes-error