Prefer Array over ContiguousArray for public API

Author: ejmarchant

Sources/SparseSetModule/SparseSet+Elements+SubSequence.swift

@@ -36,7 +36,7 @@ extension SparseSet.Elements.SubSequence {
   /// - Complexity: O(1)
   @inlinable
   @inline(__always)
-  public var keys: ContiguousArray<Key>.SubSequence {
+  public var keys: Array<Key>.SubSequence {
     _base.keys[_bounds]
   }
 

Sources/SparseSetModule/SparseSet+Elements.swift

@@ -49,8 +49,8 @@ extension SparseSet.Elements {
   /// - Complexity: O(1)
   @inlinable
   @inline(__always)
-  public var keys: ContiguousArray<Key> {
-    _base._dense._keys
+  public var keys: Array<Key> {
+    Array(_base._dense._keys)
   }
 
   /// A mutable collection view containing the values in this collection.

Sources/SparseSetModule/SparseSet.swift

@@ -32,13 +32,13 @@ public struct SparseSet<Key, Value> where Key: FixedWidthInteger, Key.Stride ==
 
 extension SparseSet {
   /// A read-only collection view for the keys contained in this sparse set, as
-  /// a `ContiguousArray`.
+  /// an `Array`.
   ///
   /// - Complexity: O(1)
   @inlinable
   @inline(__always)
-  public var keys: ContiguousArray<Key> {
-    _dense._keys
+  public var keys: Array<Key> {
+    Array(_dense._keys)
   }
 
   /// A mutable collection view containing the values in this sparse set.