Merge pull request swiftlang#22870 from compnerd/old-school-cool

Author: swift-ci

include/swift/ABI/Metadata.h

@@ -1645,7 +1645,11 @@ class TargetProtocolDescriptorRef {
     assert(!isObjC());
 #endif
 
-    return reinterpret_cast<ProtocolDescriptorPointer>(storage & ~IsObjCBit);
+    // NOTE: we explicitly use a C-style cast here because cl objects to the
+    // reinterpret_cast from a uintptr_t type to an unsigned type which the
+    // Pointer type may be depending on the instantiation.  Using the C-style
+    // cast gives us a single path irrespective of the template type parameters.
+    return (ProtocolDescriptorPointer)(storage & ~IsObjCBit);
   }
 
   /// Retrieve the raw stored pointer and discriminator bit.