Do not lint when range is completely included into another one

rust-lang · Jan 17, 2021 · 70704db · 70704db
1 parent 583715f
commit 70704db
Show file tree

Hide file tree

Showing 3 changed files with 24 additions and 26 deletions.
diff --git a/clippy_lints/src/matches.rs b/clippy_lints/src/matches.rs
@@ -1544,7 +1544,17 @@ 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 +57,18 @@ 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"),
+ _ => (),
+ }
+
  /*
  // 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
@@ -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 +35,5 @@ note: overlaps with this
 LL | 0..=11 => println!("0 ... 11"),
  | ^^^^^^
 
-error: aborting due to 5 previous errors
+error: aborting due to 3 previous errors