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

Do not lint when range is completely included into another one This fix has been developed following this [comment](#5986 (comment)). So this will be linted: ``` |----------| |-----------| ``` Now this won't be linted: ``` |---| |--------------------| ``` and this will still lint: ``` |--------| |--------------| ``` Fixes: #5986 changelog: none
rust-lang · Jan 31, 2021 · cdc75dc · cdc75dc
2 parents ed11274 + 0518911
commit cdc75dc
Show file tree

Hide file tree

Showing 3 changed files with 57 additions and 17 deletions.
diff --git a/clippy_lints/src/matches.rs b/clippy_lints/src/matches.rs
@@ -1592,7 +1592,17 @@ where
  }
  },
  (&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()));
+ },
  }
  }
 

diff --git a/tests/ui/match_overlapping_arm.rs b/tests/ui/match_overlapping_arm.rs
@@ -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 {

diff --git a/tests/ui/match_overlapping_arm.stderr b/tests/ui/match_overlapping_arm.stderr
@@ -24,39 +24,39 @@ LL | FOO..=11 => println!("0 ... 11"),
  | ^^^^^^^^
 
 error: some ranges overlap
- --> $DIR/match_overlapping_arm.rs:26:9
+ --> $DIR/match_overlapping_arm.rs:55:9
  |
-LL | 0..=5 => println!("0 ... 5"),
+LL | 0..11 => println!("0 .. 11"),
  | ^^^^^
  |
 note: overlaps with this
- --> $DIR/match_overlapping_arm.rs:25:9
+ --> $DIR/match_overlapping_arm.rs:56:9
  |
-LL | 2 => println!("2"),
- | ^
+LL | 0..=11 => println!("0 ... 11"),
+ | ^^^^^^
 
 error: some ranges overlap
- --> $DIR/match_overlapping_arm.rs:32:9
+ --> $DIR/match_overlapping_arm.rs:80:9
  |
-LL | 0..=2 => println!("0 ... 2"),
- | ^^^^^
+LL | 0..=10 => println!("0 ... 10"),
+ | ^^^^^^
  |
 note: overlaps with this
- --> $DIR/match_overlapping_arm.rs:31:9
+ --> $DIR/match_overlapping_arm.rs:79:9
  |
-LL | 2 => println!("2"),
- | ^
+LL | 5..14 => println!("5 .. 14"),
+ | ^^^^^
 
 error: some ranges overlap
- --> $DIR/match_overlapping_arm.rs:55:9
+ --> $DIR/match_overlapping_arm.rs:85:9
  |
-LL | 0..11 => println!("0 .. 11"),
- | ^^^^^
+LL | 0..7 => println!("0 .. 7"),
+ | ^^^^
  |
 note: overlaps with this
- --> $DIR/match_overlapping_arm.rs:56:9
+ --> $DIR/match_overlapping_arm.rs:86:9
  |
-LL | 0..=11 => println!("0 ... 11"),
+LL | 0..=10 => println!("0 ... 10"),
  | ^^^^^^
 
 error: aborting due to 5 previous errors