diff --git a/src/variables.cc b/src/variables.cc
index c1440b7..7f580fc 100644
--- a/src/variables.cc
+++ b/src/variables.cc
@@ -98,6 +98,12 @@
 }
 
 
+bool Variable::IsContextSlot() const {
+  Slot* s = AsSlot();
+  return s != NULL && s->type() == Slot::CONTEXT;
+}
+
+
 Variable::Variable(Scope* scope,
                    Handle<String> name,
                    Mode mode,