Implement updated method overriding rules in the vm.

runtime/vm/object.h

 // 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.
 
 #ifndef VM_OBJECT_H_
 #define VM_OBJECT_H_
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "platform/utils.h"
@@ skipping 921 matching lines @@
   void set_allocation_stub(const Code& value) const;
 
   RawArray* constants() const;
 
   RawFunction* GetInvocationDispatcher(const String& target_name,
                                        const Array& args_desc,
                                        RawFunction::Kind kind) const;
 
   void Finalize() const;
 
-  const char* ApplyPatch(const Class& patch) const;
+  // Apply given patch class to this class.
+  // Return true on success, or false and error otherwise.
+  bool ApplyPatch(const Class& patch, Error* error) const;
 
   RawError* EnsureIsFinalized(Isolate* isolate) const;
 
   // Allocate a class used for VM internal objects.
   template <class FakeObject> static RawClass* New();
 
   // Allocate instance classes.
   static RawClass* New(const String& name,
                        const Script& script,
                        intptr_t token_pos);
@@ skipping 702 matching lines @@
                          String* error_message) const;
   bool AreValidArguments(const ArgumentsDescriptor& args_desc,
                          String* error_message) const;
 
   // Fully qualified name uniquely identifying the function under gdb and during
   // ast printing. The special ':' character, if present, is replaced by '_'.
   const char* ToFullyQualifiedCString() const;
 
   // Returns true if this function has parameters that are compatible with the
   // parameters of the other function in order for this function to override the
-  // other function. Parameter types are ignored.
-  bool HasCompatibleParametersWith(const Function& other) const;
+  // other function.
+  bool HasCompatibleParametersWith(const Function& other,
+                                   Error* malformed_error) const;
 
   // Returns true if the type of this function is a subtype of the type of
   // the other function.
   bool IsSubtypeOf(const AbstractTypeArguments& type_arguments,
                    const Function& other,
                    const AbstractTypeArguments& other_type_arguments,
                    Error* malformed_error) const {
     return TypeTest(kIsSubtypeOf,
                     type_arguments,
                     other,
@@ skipping 4372 matching lines @@
 
 
 RawObject* MegamorphicCache::GetTargetFunction(const Array& array,
                                                intptr_t index) {
   return array.At((index * kEntryLength) + kTargetFunctionIndex);
 }
 
 }  // namespace dart
 
 #endif  // VM_OBJECT_H_