Remove overlap between `manual_split_once` and `needless_splitn`
changelog: Remove overlap between [`manual_split_once`] and [`needless_splitn`]. Fixes some incorrect `rsplitn` suggestions for [`manual_split_once`]
Things that can trigger `needless_splitn` no longer trigger `manual_split_once`, e.g.
```rust
s.[r]splitn(2, '=').next();
s.[r]splitn(2, '=').nth(0);
s.[r]splitn(3, '=').next_tuple();
```
Fixes some suggestions:
```rust
let s = "should not match";
s.rsplitn(2, '.').nth(1);
// old -> Some("should not match")
Some(s.rsplit_once('.').map_or(s, |x| x.0));
// new -> None
s.rsplit_once('.').map(|x| x.0);
s.rsplitn(2, '.').nth(1)?;
// old -> "should not match"
s.rsplit_once('.').map_or(s, |x| x.0);
// new -> early returns
s.rsplit_once('.')?.0;
```
53 lines
1.5 KiB
Rust
53 lines
1.5 KiB
Rust
// run-rustfix
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#![feature(custom_inner_attributes)]
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#![warn(clippy::manual_split_once)]
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#![allow(clippy::iter_skip_next, clippy::iter_nth_zero)]
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extern crate itertools;
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#[allow(unused_imports)]
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use itertools::Itertools;
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fn main() {
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let _ = "key=value".splitn(2, '=').nth(2);
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let _ = "key=value".split_once('=').unwrap().1;
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let _ = "key=value".split_once('=').unwrap().1;
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let (_, _) = "key=value".split_once('=').unwrap();
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let s = String::from("key=value");
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let _ = s.split_once('=').unwrap().1;
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let s = Box::<str>::from("key=value");
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let _ = s.split_once('=').unwrap().1;
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let s = &"key=value";
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let _ = s.split_once('=').unwrap().1;
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fn _f(s: &str) -> Option<&str> {
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let _ = s.split_once('=')?.1;
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let _ = s.split_once('=')?.1;
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let _ = s.rsplit_once('=')?.0;
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let _ = s.rsplit_once('=')?.0;
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None
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}
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// Don't lint, slices don't have `split_once`
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let _ = [0, 1, 2].splitn(2, |&x| x == 1).nth(1).unwrap();
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// `rsplitn` gives the results in the reverse order of `rsplit_once`
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let _ = "key=value".rsplit_once('=').unwrap().0;
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let (_, _) = "key=value".rsplit_once('=').map(|(x, y)| (y, x)).unwrap();
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let _ = s.rsplit_once('=').map(|x| x.0);
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}
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fn _msrv_1_51() {
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#![clippy::msrv = "1.51"]
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// `str::split_once` was stabilized in 1.52. Do not lint this
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let _ = "key=value".splitn(2, '=').nth(1).unwrap();
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}
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fn _msrv_1_52() {
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#![clippy::msrv = "1.52"]
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let _ = "key=value".split_once('=').unwrap().1;
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}
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