Fix runtimeType for strings, integers and double: return their interface type.

runtime/lib/mirrors.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 "lib/invocation_mirror.h"
 #include "vm/bootstrap_natives.h"
 #include "vm/class_finalizer.h"
 #include "vm/dart_entry.h"
 #include "vm/exceptions.h"
 #include "vm/object_store.h"
@@ skipping 1130 matching lines @@
       Array::Handle(ArgumentsDescriptor::New(args.Length()));
 
   return InvokeDynamicFunction(reflectee,
                                setter,
                                internal_setter_name,
                                args,
                                args_descriptor);
 }
 
 
+DEFINE_NATIVE_ENTRY(InstanceMirror_computeType, 1) {
+  GET_NON_NULL_NATIVE_ARGUMENT(Instance, instance, arguments->NativeArgAt(0));
+  const Type& type = Type::Handle(instance.GetType());
+  // The static type of null is specified to be the bottom type, however, the
+  // runtime type of null is the Null type, which we correctly return here.
+  return type.Canonicalize();
+}
+
+
 DEFINE_NATIVE_ENTRY(ClosureMirror_apply, 3) {
   GET_NON_NULL_NATIVE_ARGUMENT(Instance, closure, arguments->NativeArgAt(0));
   ASSERT(!closure.IsNull() && closure.IsCallable(NULL, NULL));
   GET_NON_NULL_NATIVE_ARGUMENT(Array, args, arguments->NativeArgAt(1));
   GET_NON_NULL_NATIVE_ARGUMENT(Array, arg_names, arguments->NativeArgAt(2));
 
   const Array& args_descriptor =
       Array::Handle(ArgumentsDescriptor::New(args.Length(), arg_names));
 
   const Object& result =
@@ skipping 522 matching lines @@
 }
 
 
 DEFINE_NATIVE_ENTRY(VariableMirror_type, 1) {
   GET_NON_NULL_NATIVE_ARGUMENT(MirrorReference, ref, arguments->NativeArgAt(0));
   const Field& field = Field::Handle(ref.GetFieldReferent());
   return field.type();
 }
 
 }  // namespace dart