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

runtime/vm/code_generator.cc

 // Copyright (c) 2013, 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 "vm/code_generator.h"
 
 #include "vm/assembler.h"
 #include "vm/ast.h"
 #include "vm/code_patcher.h"
 #include "vm/compiler.h"
@@ skipping 187 matching lines @@
 // Arg0: uninstantiated type.
 // Arg1: instantiator type arguments.
 // Return value: instantiated type.
 DEFINE_RUNTIME_ENTRY(InstantiateType, 2) {
   AbstractType& type = AbstractType::CheckedHandle(arguments.ArgAt(0));
   const TypeArguments& instantiator =
       TypeArguments::CheckedHandle(arguments.ArgAt(1));
   ASSERT(!type.IsNull() && !type.IsInstantiated());
   ASSERT(instantiator.IsNull() || instantiator.IsInstantiated());
   Error& bound_error = Error::Handle();
-  type = type.InstantiateFrom(instantiator, &bound_error, NULL, Heap::kOld);
+  type =
+      type.InstantiateFrom(instantiator, &bound_error, NULL, NULL, Heap::kOld);
   if (!bound_error.IsNull()) {
     // Throw a dynamic type error.
     const TokenPosition location = GetCallerLocation();
     String& bound_error_message =  String::Handle(
         String::New(bound_error.ToErrorCString()));
     Exceptions::CreateAndThrowTypeError(
         location, Symbols::Empty(), Symbols::Empty(),
         Symbols::Empty(), bound_error_message);
     UNREACHABLE();
   }
@@ skipping 1679 matching lines @@
   const intptr_t elm_size = old_data.ElementSizeInBytes();
   const TypedData& new_data =
       TypedData::Handle(TypedData::New(cid, new_size, Heap::kOld));
   TypedData::Copy(new_data, 0, old_data, 0, old_size * elm_size);
   typed_data_cell.SetAt(0, new_data);
   arguments.SetReturn(new_data);
 }
 
 
 }  // namespace dart