Keep a trail while checking upper bounds in the VM in order to properly handle

runtime/lib/mirrors.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "lib/mirrors.h"
 
 #include "lib/invocation_mirror.h"
 #include "vm/bootstrap_natives.h"
 #include "vm/class_finalizer.h"
 #include "vm/compiler.h"
@@ skipping 765 matching lines @@
   }
 
   ASSERT(!instantiator.IsNull());
   ASSERT(instantiator.IsFinalized());
   PROPAGATE_IF_MALFORMED(instantiator);
 
   const TypeArguments& type_args =
       TypeArguments::Handle(instantiator.arguments());
   Error& bound_error = Error::Handle();
   AbstractType& result = AbstractType::Handle(
-      type.InstantiateFrom(type_args, &bound_error, NULL, Heap::kOld));
+      type.InstantiateFrom(type_args, &bound_error, NULL, NULL, Heap::kOld));
   if (!bound_error.IsNull()) {
     Exceptions::PropagateError(bound_error);
     UNREACHABLE();
   }
   ASSERT(result.IsFinalized());
   return result.Canonicalize();
 }
 
 
 DEFINE_NATIVE_ENTRY(MirrorSystem_libraries, 0) {
@@ skipping 871 matching lines @@
   Function& redirected_constructor = Function::Handle(lookup_constructor.raw());
   if (lookup_constructor.IsRedirectingFactory()) {
     ClassFinalizer::ResolveRedirectingFactory(klass, lookup_constructor);
     Type& redirect_type = Type::Handle(lookup_constructor.RedirectionType());
 
     if (!redirect_type.IsInstantiated()) {
       // The type arguments of the redirection type are instantiated from the
       // type arguments of the type reflected by the class mirror.
       Error& bound_error = Error::Handle();
       redirect_type ^= redirect_type.InstantiateFrom(
-          type_arguments, &bound_error, NULL, Heap::kOld);
+          type_arguments, &bound_error, NULL, NULL, Heap::kOld);
       if (!bound_error.IsNull()) {
         Exceptions::PropagateError(bound_error);
         UNREACHABLE();
       }
       redirect_type ^= redirect_type.Canonicalize();
     }
 
     type = redirect_type.raw();
     type_arguments = redirect_type.arguments();
 
@@ skipping 395 matching lines @@
 }
 
 DEFINE_NATIVE_ENTRY(TypeMirror_subtypeTest, 2) {
   GET_NON_NULL_NATIVE_ARGUMENT(AbstractType, a, arguments->NativeArgAt(0));
   GET_NON_NULL_NATIVE_ARGUMENT(AbstractType, b, arguments->NativeArgAt(1));
   return Bool::Get(a.IsSubtypeOf(b, NULL)).raw();
 }
 
 
 }  // namespace dart