     // unconditionally, resulting in O(n) copies even for immutable dictionaries.
     //
     // <rdar://problem/20690755> CFDictionaryCreateCopy() does not call copyWithZone:
+    //
+    // The bug is fixed in: OS X 10.11.0, iOS 9.0, all versions of tvOS
+    // and watchOS.
     self = Dictionary(
       _immutableCocoaDictionary:
         unsafeBitCast(_cocoaDictionary.copyWithZone(nil), _NSDictionaryType.self))

    //
    // <rdar://problem/19773555> CFArrayCreateCopy() is >10x slower than
    // -[NSArray copyWithZone:]
    self = Array(
      _immutableCocoaArray:
        unsafeBitCast(_cocoaArray.copyWithZone(nil), _NSArrayCoreType.self))

    // unconditionally, resulting in O(n) copies even for immutable dictionaries.
    //
    // <rdar://problem/20697680> CFSetCreateCopy() does not call copyWithZone:
    //
    // The bug is fixed in: OS X 10.11.0, iOS 9.0, all versions of tvOS
    // and watchOS.
    self = Set(
      _immutableCocoaSet:
        unsafeBitCast(_cocoaSet.copyWithZone(nil), _NSSetType.self))
