When tracing type checks in runtime, also print the method where the type check occured.

runtime/lib/error.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 "lib/error.h"
 
 #include "vm/bootstrap_natives.h"
 #include "vm/exceptions.h"
 #include "vm/object_store.h"
 #include "vm/runtime_entry.h"
@@ skipping 254 matching lines @@
       const AbstractType& instantiated_dst_type = AbstractType::Handle(
           dst_type.InstantiateFrom(dst_type_instantiator));
       OS::Print("TypeCheck: '%s' %s assignable to '%s' of '%s' "
                 "instantiated from '%s'.\n",
                 String::Handle(src_type.Name()).ToCString(),
                 is_assignable ? "is" : "is not",
                 String::Handle(instantiated_dst_type.Name()).ToCString(),
                 dst_name.ToCString(),
                 String::Handle(dst_type.Name()).ToCString());
     }
+    DartFrameIterator iterator;
+    DartFrame* caller_frame = iterator.NextFrame();
+    ASSERT(caller_frame != NULL);
+    const Function& function = Function::Handle(
+        caller_frame->LookupDartFunction());
+    OS::Print(" -> Function %s\n", function.ToFullyQualifiedCString());
   }
   if (!is_assignable) {
     const Type& src_type = Type::Handle(src_instance.GetType());
     const String& src_type_name = String::Handle(src_type.Name());
     String& dst_type_name = String::Handle();
     if (!dst_type.IsInstantiated()) {
       // Instantiate dst_type before reporting the error.
       const AbstractType& instantiated_dst_type = AbstractType::Handle(
           dst_type.InstantiateFrom(dst_type_instantiator));
       dst_type_name = instantiated_dst_type.Name();
@@ skipping 70 matching lines @@
         dst_type_name = element_type.Name();
       }
       const String& dst_name = String::Handle(String::New(buf));
       ThrowTypeError(location, src_type_name, dst_type_name, dst_name);
       UNREACHABLE();
     }
   }
 }
 
 }  // namespace dart