Merge pull request #287 from lorentey/fix-BitSet-isEqualSet

[BitSet] Fix a thinko in BitSet.isEqualSet

Author: lorentey

Sources/BitCollections/BitSet/BitSet._UnsafeHandle.swift

@@ -223,8 +223,8 @@ extension _UnsafeBitSet {
     let r = range.clamped(to: 0 ..< UInt(capacity))
     guard r == range else { return false }
 
-    let lower = Index(range.lowerBound)
-    let upper = Index(range.upperBound)
+    let lower = Index(range.lowerBound).split
+    let upper = Index(range.upperBound).endSplit
 
     guard upper.word == wordCount &- 1 else { return false }
 

Tests/BitCollectionsTests/BitSetTests.swift

@@ -1109,6 +1109,14 @@ final class BitSetTest: CollectionTestCase {
 
     let c = BitSet(130 ..< 160)
     expectTrue(c.isEqualSet(to: 130 ..< 160))
+
+    withEvery("i", in: stride(from: 0, to: 200, by: 4)) { i in
+      withEvery("j", in: stride(from: i, to: 200, by: 4)) { j in
+        let c = BitSet(i ..< j)
+        expectTrue(c.isEqualSet(to: i ..< j))
+        expectFalse(c.isEqualSet(to: i ..< (j + 1)))
+      }
+    }
   }
 
   func test_isEqual_to_counted_BitSet() {