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

runtime/vm/code_generator_test.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 "platform/assert.h"
 #include "vm/globals.h"
 #include "vm/ast.h"
 #include "vm/assembler.h"
 #include "vm/class_finalizer.h"
 #include "vm/code_generator.h"
@@ skipping 254 matching lines @@
   ASSERT(!core_lib.IsNull());
   const Namespace& core_ns = Namespace::Handle(
       Namespace::New(core_lib, Array::Handle(), Array::Handle()));
   lib.AddImport(core_ns);
   return lib;
 }
 
 
 static RawClass* LookupClass(const Library& lib, const char* name) {
   const String& cls_name = String::ZoneHandle(Symbols::New(name));
-  return lib.LookupClass(cls_name);
+  String& ambiguity_error_msg = String::Handle();
+  return lib.LookupClass(cls_name, &ambiguity_error_msg);
 }
 
 
 CODEGEN_TEST_GENERATE(StaticCallCodegen, test) {
   const char* kScriptChars =
       "class A {\n"
       "  static bar() { return 42; }\n"
       "  static fly() { return 5; }\n"
       "}\n";
 
   String& url = String::Handle(String::New("dart-test:CompileScript"));
   String& source = String::Handle(String::New(kScriptChars));
   Script& script = Script::Handle(Script::New(url,
                                               source,
                                               RawScript::kScriptTag));
   Library& lib = MakeTestLibrary("TestLib");
   EXPECT(CompilerTest::TestCompileScript(lib, script));
   EXPECT(ClassFinalizer::FinalizePendingClasses());
   Class& cls = Class::Handle(LookupClass(lib, "A"));
-  EXPECT(!cls.IsNull());
+  EXPECT(!cls.IsNull());  // No ambiguity error expected.
 
   // 'bar' will not be compiled.
   String& function_bar_name = String::Handle(String::New("bar"));
   Function& function_bar =
       Function::ZoneHandle(cls.LookupStaticFunction(function_bar_name));
   EXPECT(!function_bar.IsNull());
   EXPECT(!function_bar.HasCode());
 
   // 'fly' will be compiled.
   String& function_fly_name = String::Handle(String::New("fly"));
@@ skipping 26 matching lines @@
 
   String& url = String::Handle(String::New("dart-test:CompileScript"));
   String& source = String::Handle(String::New(kScriptChars));
   Script& script = Script::Handle(Script::New(url,
                                               source,
                                               RawScript::kScriptTag));
   Library& lib = MakeTestLibrary("TestLib");
   EXPECT(CompilerTest::TestCompileScript(lib, script));
   EXPECT(ClassFinalizer::FinalizePendingClasses());
   Class& cls = Class::ZoneHandle(LookupClass(lib, "A"));
-  EXPECT(!cls.IsNull());
+  EXPECT(!cls.IsNull());  // No ambiguity error expected.
 
   String& constructor_name = String::Handle(String::New("A."));
   Function& constructor =
       Function::ZoneHandle(cls.LookupConstructor(constructor_name));
   EXPECT(!constructor.IsNull());
 
   // The unit test creates an instance of class A and calls function 'bar'.
   String& function_bar_name = String::ZoneHandle(Symbols::New("bar"));
   ArgumentListNode* no_arguments = new ArgumentListNode(kPos);
   const TypeArguments& no_type_arguments = TypeArguments::ZoneHandle();
@@ skipping 165 matching lines @@
 
   String& url = String::Handle(String::New("dart-test:CompileScript"));
   String& source = String::Handle(String::New(kScriptChars));
   Script& script = Script::Handle(Script::New(url,
                                               source,
                                               RawScript::kScriptTag));
   Library& lib = MakeTestLibrary("TestLib");
   EXPECT(CompilerTest::TestCompileScript(lib, script));
   EXPECT(ClassFinalizer::FinalizePendingClasses());
   Class& cls = Class::ZoneHandle(LookupClass(lib, "A"));
-  EXPECT(!cls.IsNull());
+  EXPECT(!cls.IsNull());  // No ambiguity error expected.
 
   String& constructor_name = String::Handle(String::New("A."));
   Function& constructor =
       Function::ZoneHandle(cls.LookupConstructor(constructor_name));
   EXPECT(!constructor.IsNull());
 
   const TypeArguments& no_type_arguments = TypeArguments::ZoneHandle();
   ArgumentListNode* no_arguments = new ArgumentListNode(kPos);
   test->node_sequence()->Add(new ReturnNode(kPos, new ConstructorCallNode(
       kPos, no_type_arguments, constructor, no_arguments)));
 }
 
 
 CODEGEN_TEST_RAW_RUN(AllocateNewObjectCodegen, function) {
   const Object& result = Object::Handle(
       DartEntry::InvokeFunction(function, Object::empty_array()));
   EXPECT(!result.IsError());
   const GrowableObjectArray& libs =  GrowableObjectArray::Handle(
       Isolate::Current()->object_store()->libraries());
   ASSERT(!libs.IsNull());
   // App lib is the last one that was loaded.
   intptr_t num_libs = libs.Length();
   Library& app_lib = Library::Handle();
   app_lib ^= libs.At(num_libs - 1);
   ASSERT(!app_lib.IsNull());
+  String& ambiguity_error_msg = String::Handle();
   const Class& cls = Class::Handle(
-      app_lib.LookupClass(String::Handle(Symbols::New("A"))));
-  EXPECT_EQ(cls.raw(), result.clazz());
+      app_lib.LookupClass(String::Handle(Symbols::New("A")),
+                          &ambiguity_error_msg));
+  EXPECT_EQ(cls.raw(), result.clazz());  // No ambiguity error expected.
 }
 
 }  // namespace dart