[Basic] Conform OrderedSet to RangeReplaceableCollection

Author: aciidgh

Sources/Basic/OrderedSet.swift

@@ -112,6 +112,12 @@ public struct OrderedSet<E: Hashable>: Equatable, MutableCollection, RandomAcces
     }
 }
 
+extension OrderedSet: RangeReplaceableCollection {
+    mutating public func replaceSubrange<C>(_ subrange: Range<Int>, with newElements: C) where C : Collection, C.Iterator.Element == Element {
+        self[subrange] = ArraySlice(newElements)
+    }
+}
+
 extension OrderedSet: ExpressibleByArrayLiteral {
     /// Create an instance initialized with `elements`.
     ///

Tests/BasicTests/OrderedSetTests.swift

@@ -75,6 +75,13 @@ class OrderedSetTests: XCTestCase {
         XCTAssert(set.contains(6))
         XCTAssertFalse(set.contains(2))
         XCTAssert(set.contains(7))
+
+        set.replaceSubrange(0..<2, with: [1, 2])
+        XCTAssertEqual(set.contents, [1, 2, 9])
+        XCTAssertFalse(set.contains(6))
+        XCTAssert(set.contains(1))
+        XCTAssertFalse(set.contains(7))
+        XCTAssert(set.contains(2))
     }
 
     static var allTests = [