Runtime type checking should be skipped for Object as destination type.

runtime/vm/code_generator_ia32.cc

 // Copyright (c) 2011, 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/globals.h"  // Needed here to get TARGET_ARCH_IA32.
 #if defined(TARGET_ARCH_IA32)
 
 #include "vm/code_generator.h"
 
 #include "lib/error.h"
 #include "vm/ast_printer.h"
 #include "vm/class_finalizer.h"
 #include "vm/dart_entry.h"
 #include "vm/ic_data.h"
 #include "vm/longjump.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
 #include "vm/parser.h"
 #include "vm/resolver.h"
 #include "vm/stub_code.h"
 
 namespace dart {
 
 DEFINE_FLAG(bool, print_ast, false, "Print abstract syntax tree.");
 DEFINE_FLAG(bool, print_scopes, false, "Print scopes of local variables.");
 DEFINE_FLAG(bool, trace_functions, false, "Trace entry of each function.");
 DEFINE_FLAG(int, optimization_invocation_threshold, 1000,
-    "number of invocations before a fucntion is optimized, -1 means never.");
+    "number of invocations before a function is optimized, -1 means never.");
 DECLARE_FLAG(bool, enable_type_checks);
 DECLARE_FLAG(bool, report_invocation_count);
 DECLARE_FLAG(bool, trace_compiler);
 
 #define __ assembler_->
 
 
 class CodeGeneratorState : public StackResource {
  public:
   explicit CodeGeneratorState(CodeGenerator* codegen)
@@ skipping 1462 matching lines @@
 // - object in EAX for successful assignable check (or throws TypeError).
 void CodeGenerator::GenerateAssertAssignable(intptr_t node_id,
                                              intptr_t token_index,
                                              const Type& dst_type,
                                              const String& dst_name) {
   ASSERT(FLAG_enable_type_checks);
   ASSERT(token_index >= 0);
   ASSERT(!dst_type.IsNull());
   ASSERT(dst_type.IsFinalized());
 
-  // Any expression is assignable to the DynamicType. Skip the test.
-  if (dst_type.IsDynamicType()) {
+  // Any expression is assignable to the DynamicType or Object. Skip the test.

[regis, 2011/11/08 21:18:10]

Any expression is always assignable to the Dynamic type and to the Object type.

[srdjan, 2011/11/08 21:28:47]

Done.

+  if (dst_type.IsDynamicType() || dst_type.IsObjectType()) {
     return;
   }
 
   // It is a compile-time error to explicitly return a value (including null)
   // from a void function. However, functions that do not explicitly return a
   // value, implicitly return null. This includes void functions. Therefore, we
   // skip the type test here and trust the parser to only return null in void
   // function.
   if (dst_type.IsVoidType()) {
     return;
@@ skipping 1156 matching lines @@
   const Class& cls = Class::Handle(parsed_function_.function().owner());
   const Script& script = Script::Handle(cls.script());
   Parser::ReportMsg(script, token_index, "Error", error_msg, format, args);
   Isolate::Current()->long_jump_base()->Jump(1, error_msg);
   UNREACHABLE();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_IA32