Clippy: Wrongly suggests Option::if_let_else in const function #7902
Description
Lint name: option_if_let_else
I tried this code:
#[must_use]
pub const fn new_from_parts(db_version: [u8; 10], tx_version: Option<[u8; 2]>) -> Self {
let database_version: [u8; 8] = [
db_version[0],
db_version[1],
db_version[2],
db_version[3],
db_version[4],
db_version[5],
db_version[6],
db_version[7],
];
let batch_version: [u8; 2] = [db_version[8], db_version[9]];
Self {
database_version,
batch_version,
tx_version: if let Some(txv) = tx_version {
([MaybeUninit::new(txv[0]), MaybeUninit::new(txv[1])], true)
} else {
([MaybeUninit::uninit(); 2], false)
},
}
}Then clippy generated a warning:
error: use Option::map_or_else instead of an if let/else
--> <project>/src/db.rs:77:16
|
77 | tx_version: if let Some(txv) = tx_version {
| _________________________^
78 | | ([MaybeUninit::new(txv[0]), MaybeUninit::new(txv[1])], true)
79 | | } else {
80 | | ([MaybeUninit::uninit(); 2], false)
81 | | },
| |_____________^ help: try: `tx_version.map_or_else(|| ([MaybeUninit::uninit(); 2], false), |txv| ([MaybeUninit::new(txv[0]), MaybeUninit::new(txv[1])], true))`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#option_if_let_elseI'm generally not a fan of this lint anyone, but I do it to hopefully be consistent with the rest of the ecosystem and juggling lints is really hard to do. However, replacing this particular code results in a failure to compile on stable as you cannot call if_let_else in a constant function. Meaning the resulting checked code fails to compile.
Meta
Rust version (rustc -Vv):
rustc 1.56.0 (09c42c458 2021-10-18)
binary: rustc
commit-hash: 09c42c45858d5f3aedfa670698275303a3d19afa
commit-date: 2021-10-18
host: x86_64-unknown-linux-gnu
release: 1.56.0
LLVM version: 13.0.0