Implement proposed new identity spec.

runtime/vm/flow_graph_builder.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/flow_graph_builder.h"
 
 #include "vm/ast_printer.h"
 #include "vm/code_descriptors.h"
 #include "vm/dart_entry.h"
 #include "vm/flags.h"
@@ skipping 1581 matching lines @@
       node->function_name(), Token::kILLEGAL, arguments,
       node->arguments()->names(), 1);
   ReturnDefinition(call);
 }
 
 
 // <Expression> ::= StaticCall { function: Function
 //                               arguments: <ArgumentList> }
 void EffectGraphVisitor::VisitStaticCallNode(StaticCallNode* node) {
   if (node->function().name() == Symbols::Identical()) {
-    // Attempt to replace identical with strcit equal early on.
+    // Attempt to replace top level defined 'identical' from the core
+    // library with strict equal early on.
     // TODO(hausner): Evaluate if this can happen at AST building time.
     const Class& cls = Class::Handle(node->function().Owner());
     if (cls.IsTopLevel()) {
       const Library& core_lib = Library::Handle(Library::CoreLibrary());
       if (cls.library() == core_lib.raw()) {
         ASSERT(node->arguments()->length() == 2);
         ValueGraphVisitor for_left_value(owner(), temp_index(), loop_depth());
         node->arguments()->NodeAt(0)->Visit(&for_left_value);
         Append(for_left_value);
         ValueGraphVisitor for_right_value(owner(), temp_index(), loop_depth());
@@ skipping 1346 matching lines @@
   intptr_t len = OS::SNPrint(NULL, 0, kFormat, function_name, reason) + 1;
   char* chars = Isolate::Current()->current_zone()->Alloc<char>(len);
   OS::SNPrint(chars, len, kFormat, function_name, reason);
   const Error& error = Error::Handle(
       LanguageError::New(String::Handle(String::New(chars))));
   Isolate::Current()->long_jump_base()->Jump(1, error);
 }
 
 
 }  // namespace dart