Improve error message when attempting to evaluate against a VM-internal object (e.g., a Megamorphic…

runtime/vm/service.cc

 // Copyright (c) 2013, 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/service.h"
 
 #include "include/dart_api.h"
 #include "include/dart_native_api.h"
 #include "platform/globals.h"
 
@@ skipping 2141 matching lines @@
     instance ^= obj.raw();
     const Object& result =
         Object::Handle(zone, instance.Evaluate(expr_str,
                                                Array::empty_array(),
                                                Array::empty_array()));
     result.PrintJSON(js, true);
     return true;
   }
   js->PrintError(kInvalidParams,
                  "%s: invalid 'targetId' parameter: "
-                 "id '%s' does not correspond to a "
-                 "library, class, or instance", js->method(), target_id);
+                 "Cannot evaluate against a VM-internal object", js->method());
   return true;
 }
 
 
 static const MethodParameter* evaluate_in_frame_params[] = {
   RUNNABLE_ISOLATE_PARAMETER,
   new UIntParameter("frameIndex", true),
   new MethodParameter("expression", true),
   NULL,
 };
@@ skipping 1934 matching lines @@
     if (strcmp(method_name, method.name) == 0) {
       return &method;
     }
   }
   return NULL;
 }
 
 #endif  // !PRODUCT
 
 }  // namespace dart