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Auto merge of #6603 - ThibsG:MatchOverlappingArm5986, r=flip1995

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Do not lint when range is completely included into another one

This fix has been developed following this [comment](https://github.com/rust-lang/rust-clippy/issues/5986#issuecomment-703313548).
So this will be linted:
```
|----------|
        |-----------|
```
Now this won't be linted:
```
              |---|
|--------------------|
```
and this will still lint:
```
|--------|
|--------------|
```

Fixes: #5986

changelog: Fix FPs in match_overlapping_arm, when first arm is completely included in second arm
This commit is contained in:
bors 2021-01-31 15:09:55 +00:00
commit c5f3f9df3b
3 changed files with 65 additions and 25 deletions
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12
clippy_lints/src/matches.rs
View File

@ -1592,7 +1592,17 @@ fn cmp(&self, other: &Self) -> Ordering {
}
},
(&Kind::End(a, _), &Kind::Start(b, _)) if a != Bound::Included(b) => (),
_ => return Some((a.range(), b.range())),
_ => {
// skip if the range `a` is completely included into the range `b`
if let Ordering::Equal | Ordering::Less = a.cmp(&b) {
let kind_a = Kind::End(a.range().node.1, a.range());
let kind_b = Kind::End(b.range().node.1, b.range());
if let Ordering::Equal | Ordering::Greater = kind_a.cmp(&kind_b) {
return None;
}
}
return Some((a.range(), b.range()));
},
}
}

30
tests/ui/match_overlapping_arm.rs
View File

@ -57,6 +57,36 @@ fn overlapping() {
_ => (),
}
match 42 {
5..7 => println!("5 .. 7"),
0..10 => println!("0 .. 10"),
_ => (),
}
match 42 {
5..10 => println!("5 .. 10"),
0..=10 => println!("0 ... 10"),
_ => (),
}
match 42 {
0..14 => println!("0 .. 14"),
5..10 => println!("5 .. 10"),
_ => (),
}
match 42 {
5..14 => println!("5 .. 14"),
0..=10 => println!("0 ... 10"),
_ => (),
}
match 42 {
0..7 => println!("0 .. 7"),
0..=10 => println!("0 ... 10"),
_ => (),
}
/*
// FIXME(JohnTitor): uncomment this once rustfmt knows half-open patterns
match 42 {

48
tests/ui/match_overlapping_arm.stderr
View File

@ -23,30 +23,6 @@ note: overlaps with this
LL | FOO..=11 => println!("0 ... 11"),
| ^^^^^^^^
error: some ranges overlap
--> $DIR/match_overlapping_arm.rs:26:9
|
LL | 0..=5 => println!("0 ... 5"),
| ^^^^^
|
note: overlaps with this
--> $DIR/match_overlapping_arm.rs:25:9
|
LL | 2 => println!("2"),
| ^
error: some ranges overlap
--> $DIR/match_overlapping_arm.rs:32:9
|
LL | 0..=2 => println!("0 ... 2"),
| ^^^^^
|
note: overlaps with this
--> $DIR/match_overlapping_arm.rs:31:9
|
LL | 2 => println!("2"),
| ^
error: some ranges overlap
--> $DIR/match_overlapping_arm.rs:55:9
|
@ -59,5 +35,29 @@ note: overlaps with this
LL | 0..=11 => println!("0 ... 11"),
| ^^^^^^
error: some ranges overlap
--> $DIR/match_overlapping_arm.rs:80:9
|
LL | 0..=10 => println!("0 ... 10"),
| ^^^^^^
|
note: overlaps with this
--> $DIR/match_overlapping_arm.rs:79:9
|
LL | 5..14 => println!("5 .. 14"),
| ^^^^^
error: some ranges overlap
--> $DIR/match_overlapping_arm.rs:85:9
|
LL | 0..7 => println!("0 .. 7"),
| ^^^^
|
note: overlaps with this
--> $DIR/match_overlapping_arm.rs:86:9
|
LL | 0..=10 => println!("0 ... 10"),
| ^^^^^^
error: aborting due to 5 previous errors