Update handling of ambiguous name references

runtime/vm/exceptions.cc

 // Copyright (c) 2011, 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/exceptions.h"
 
 #include "vm/dart_api_impl.h"
 #include "vm/dart_entry.h"
 #include "vm/debugger.h"
 #include "vm/flags.h"
@@ skipping 305 matching lines @@
 static RawField* LookupStacktraceField(const Instance& instance) {
   if (instance.GetClassId() < kNumPredefinedCids) {
     // 'class Error' is not a predefined class.
     return Field::null();
   }
   Isolate* isolate = Isolate::Current();
   Class& error_class = Class::Handle(isolate,
                                      isolate->object_store()->error_class());
   if (error_class.IsNull()) {
     const Library& core_lib = Library::Handle(isolate, Library::CoreLibrary());
-    error_class = core_lib.LookupClass(Symbols::Error(), NULL);
+    error_class = core_lib.LookupClass(Symbols::Error());
     ASSERT(!error_class.IsNull());
     isolate->object_store()->set_error_class(error_class);
   }
   // If instance class extends 'class Error' return '_stackTrace' field.
   Class& test_class = Class::Handle(isolate, instance.clazz());
   AbstractType& type = AbstractType::Handle(isolate, AbstractType::null());
   while (true) {
     if (test_class.raw() == error_class.raw()) {
       return error_class.LookupInstanceField(Symbols::_stackTrace());
     }
@@ skipping 139 matching lines @@
 }
 
 
 // Allocate a new instance of the given class name.
 // TODO(hausner): Rename this NewCoreInstance to call out the fact that
 // the class name is resolved in the core library implicitly?
 RawInstance* Exceptions::NewInstance(const char* class_name) {
   const String& cls_name = String::Handle(Symbols::New(class_name));
   const Library& core_lib = Library::Handle(Library::CoreLibrary());
   // No ambiguity error expected: passing NULL.
-  Class& cls = Class::Handle(core_lib.LookupClass(cls_name, NULL));
+  Class& cls = Class::Handle(core_lib.LookupClass(cls_name));
   ASSERT(!cls.IsNull());
   // There are no parameterized error types, so no need to set type arguments.
   return Instance::New(cls);
 }
 
 
 // Allocate, initialize, and throw a TypeError or CastError.
 void Exceptions::CreateAndThrowTypeError(intptr_t location,
                                          const String& src_type_name,
                                          const String& dst_type_name,
@@ skipping 198 matching lines @@
       break;
   }
 
   return DartLibraryCalls::InstanceCreate(library,
                                           *class_name,
                                           *constructor_name,
                                           arguments);
 }
 
 }  // namespace dart