Refactor resolution code in the vm to properly handle ambiguity errors.

runtime/vm/debugger.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 "vm/debugger.h"
 
 #include "include/dart_api.h"
 
 #include "vm/code_generator.h"
 #include "vm/code_patcher.h"
@@ skipping 792 matching lines @@
   }
   // Signal isolate shutdown event.
   SignalIsolateEvent(Debugger::kIsolateShutdown);
 }
 
 
 static RawFunction* ResolveLibraryFunction(
                         const Library& library,
                         const String& fname) {
   ASSERT(!library.IsNull());
-  const Object& object = Object::Handle(library.LookupObject(fname));
+  String& ambiguity_error_msg = String::Handle();
+  const Object& object = Object::Handle(
+      library.LookupObject(fname, &ambiguity_error_msg));
   if (!object.IsNull() && object.IsFunction()) {
     return Function::Cast(object).raw();
   }
   return Function::null();
 }
 
 void Debugger::SetSingleStep() {
   isolate_->set_single_step(true);
   resume_action_ = kSingleStep;
 }
@@ skipping 10 matching lines @@
 
 RawFunction* Debugger::ResolveFunction(const Library& library,
                                        const String& class_name,
                                        const String& function_name) {
   ASSERT(!library.IsNull());
   ASSERT(!class_name.IsNull());
   ASSERT(!function_name.IsNull());
   if (class_name.Length() == 0) {
     return ResolveLibraryFunction(library, function_name);
   }
-  const Class& cls = Class::Handle(library.LookupClass(class_name));
+  String& ambiguity_error_msg = String::Handle();
+  const Class& cls = Class::Handle(
+      library.LookupClass(class_name, &ambiguity_error_msg));
   Function& function = Function::Handle();
   if (!cls.IsNull()) {
     function = cls.LookupStaticFunction(function_name);
     if (function.IsNull()) {
       function = cls.LookupDynamicFunction(function_name);
     }
   }
   return function.raw();
 }
 
@@ skipping 1005 matching lines @@
 }
 
 
 void Debugger::RegisterCodeBreakpoint(CodeBreakpoint* bpt) {
   ASSERT(bpt->next() == NULL);
   bpt->set_next(code_breakpoints_);
   code_breakpoints_ = bpt;
 }
 
 }  // namespace dart