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

runtime/vm/code_generator_ia32.cc

Index: runtime/vm/code_generator_ia32.cc
===================================================================
--- runtime/vm/code_generator_ia32.cc	(revision 1325)
+++ runtime/vm/code_generator_ia32.cc	(working copy)
@@ -25,7 +25,7 @@
 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);
@@ -1508,8 +1508,8 @@
   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;
   }