- Avoid returning "<optimized out>" strings as contexts.

runtime/vm/debugger.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/debugger.h"
 
 #include "include/dart_api.h"
 
 #include "vm/code_generator.h"
 #include "vm/code_patcher.h"
@@ skipping 583 matching lines @@
 
 
 RawInstance* ActivationFrame::GetLocalInstanceVar(intptr_t slot_index) {
   Instance& instance = Instance::Handle();
   instance ^= GetLocalVar(slot_index);
   return instance.raw();
 }
 
 
 RawContext* ActivationFrame::GetLocalContextVar(intptr_t slot_index) {
-  Context& context = Context::Handle();
-  context ^= GetLocalVar(slot_index);
-  return context.raw();
+  Object& context = Object::Handle(GetLocalVar(slot_index));
+  if (context.IsContext()) {
+    return Context::Cast(context).raw();
+  }
+  return Context::null();
 }
 
 
 void ActivationFrame::VariableAt(intptr_t i,
                                  String* name,
                                  intptr_t* token_pos,
                                  intptr_t* end_pos,
                                  Instance* value) {
   GetDescIndices();
   ASSERT(i < desc_indices_.length());
@@ skipping 1662 matching lines @@
 }
 
 
 void Debugger::RegisterCodeBreakpoint(CodeBreakpoint* bpt) {
   ASSERT(bpt->next() == NULL);
   bpt->set_next(code_breakpoints_);
   code_breakpoints_ = bpt;
 }
 
 }  // namespace dart