[stdlib] Remove workaround for an old clang bug (rdar://18950072).

stdlib/public/stubs/SwiftNativeNSXXXBase.mm.gyb

@@ -48,10 +48,7 @@ using namespace swift;
 SWIFT_RUNTIME_STDLIB_INTERFACE
 @interface _SwiftNativeNS${Class}Base : NS${Class}
 {
-  // TODO: Workaround for rdar://problem/18950072
-  // SWIFT_HEAPOBJECT_NON_OBJC_MEMBERS;
-  uint32_t __magic_refCount;
-  uint32_t __magic_weakRefCount;
+  SWIFT_HEAPOBJECT_NON_OBJC_MEMBERS;
 }
 @end
 

test/1_stdlib/Inputs/SwiftNativeNSBase/SwiftNativeNSBase.m

@@ -0,0 +1,87 @@
+//===--- SwiftNativeNSBase.m - Test _SwiftNativeNS*Base classes -----------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See http://swift.org/LICENSE.txt for license information
+// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+// This file is compiled and run by SwiftNativeNSBase.swift.
+
+#include <Foundation/Foundation.h>
+#include <objc/runtime.h>
+
+static int Errors;
+
+#define expectTrue(expr)                                            \
+  do {                                                              \
+    if (!(expr)) {                                                  \
+      printf("%s:%d: not true:  %s\n", __FILE__, __LINE__, #expr);  \
+      Errors++;                                                     \
+    }                                                               \
+  } while (0)
+
+#define expectFalse(expr)                                           \
+  do {                                                              \
+    if (expr) {                                                     \
+      printf("%s:%d: not false: %s\n", __FILE__, __LINE__, #expr);  \
+      Errors++;                                                     \
+    }                                                               \
+  } while (0)
+
+#define fail(format, ...)                                           \
+  do {                                                              \
+    printf("%s:%d: " format, __FILE__, __LINE__, ##__VA_ARGS__);    \
+    Errors++;                                                       \
+  } while (0)
+
+
+void TestSwiftNativeNSBase(void) 
+{
+  printf("TestSwiftNativeNSBase\n");
+
+  unsigned int classCount;
+  Class *classes = objc_copyClassList(&classCount);
+
+  NSMutableSet *expectedClasses =
+    [NSMutableSet setWithObjects:
+      @"_SwiftNativeNSArrayBase",
+      @"_SwiftNativeNSDictionaryBase",
+      @"_SwiftNativeNSSetBase",
+      @"_SwiftNativeNSStringBase",
+      @"_SwiftNativeNSEnumeratorBase",
+      @"_SwiftNativeNSDataBase",
+      @"_SwiftNativeNSCharacterSetBase",
+      @"_SwiftNativeNSIndexSetBase",
+      nil];
+
+  for (unsigned int i = 0; i < classCount; i++) {
+    Class cls = classes[i];
+    NSString *name = @(class_getName(cls));
+    if (! ([name hasPrefix:@"_SwiftNativeNS"] && [name hasSuffix:@"Base"])) {
+      continue;
+    }
+    if (! [expectedClasses containsObject:name]) {
+      fail("did not expect class %s\n", name.UTF8String);
+      continue;
+    }
+
+    // cls is some _SwiftNativeNS*Base class
+    [expectedClasses removeObject:name];
+    printf("checking class %s\n", name.UTF8String);
+
+    // Check for unwanted C++ cdtors (rdar://18950072)
+    expectFalse([cls instancesRespondToSelector:sel_registerName(".cxx_construct")]);
+    expectFalse([cls instancesRespondToSelector:sel_registerName(".cxx_destruct")]);
+  }
+
+  expectTrue(expectedClasses.count == 0);
+
+  printf("TestSwiftNativeNSBase: %d error%s\n",
+         Errors, Errors == 1 ? "" : "s");
+  exit(Errors ? 1 : 0);
+}

validation-test/stdlib/SwiftNativeNSBase.swift

@@ -0,0 +1,28 @@
+//===--- SwiftNativeNSBase.swift - Test _SwiftNativeNS*Base classes -------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See http://swift.org/LICENSE.txt for license information
+// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+// RUN: rm -rf %t  &&  mkdir -p %t
+// 
+// RUN: %target-clang %S/Inputs/SwiftNativeNSBase/SwiftNativeNSBase.m -c -o %t/SwiftNativeNSBase.o -g
+// RUN: %target-build-swift %s -I %S/Inputs/SwiftNativeNSBase/ -Xlinker %t/SwiftNativeNSBase.o -o %t/SwiftNativeNSBase
+// RUN: %target-run %t/SwiftNativeNSBase
+// REQUIRES: executable_test
+
+// REQUIRES: objc_interop
+
+import Foundation
+
+@_silgen_name("TestSwiftNativeNSBase") 
+func TestSwiftNativeNSBase()
+
+TestSwiftNativeNSBase()
+// does not return