Return MaybeHandle from NewConsString.

src/isolate.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 161 matching lines @@
   } while (false)
 
 #define ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, dst, call)  \
   ASSIGN_RETURN_ON_EXCEPTION_VALUE(isolate, dst, call, Failure::Exception())
 
 #define ASSIGN_RETURN_ON_EXCEPTION(isolate, dst, call, T)  \
   ASSIGN_RETURN_ON_EXCEPTION_VALUE(isolate, dst, call, MaybeHandle<T>())
 
 #define RETURN_ON_EXCEPTION_VALUE(isolate, dst, call, value)  \
   do {                                                             \
-    if (call.is_null()) {                                          \
+    if ((call).is_null()) {                                        \
       ASSERT((isolate)->has_pending_exception());                  \
       return value;                                                \
     }                                                              \
   } while (false)
 
 #define RETURN_FAILURE_ON_EXCEPTION(isolate, call)  \
   RETURN_ON_EXCEPTION_VALUE(isolate, dst, call, Failure::Exception())
 
 #define RETURN_ON_EXCEPTION(isolate, call, T)  \
   RETURN_ON_EXCEPTION_VALUE(                   \
@@ skipping 1389 matching lines @@
   }
 
   EmbeddedVector<char, 128> filename_;
   FILE* file_;
   int scope_depth_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_ISOLATE_H_