Preliminary code for block scopes and block contexts.

src/variables.h

Index: src/variables.h
diff --git a/src/variables.h b/src/variables.h
index a9c06d1eeaa486411e95b66ec7eab69a729b29f9..509396f9b6536c67f83c754c683e2e7d1afefe37 100644
--- a/src/variables.h
+++ b/src/variables.h
@@ -99,6 +99,7 @@ class Variable: public ZoneObject {
     return is_accessed_from_inner_scope_;
   }
   void MarkAsAccessedFromInnerScope() {
+    ASSERT(mode_ != TEMPORARY);
     is_accessed_from_inner_scope_ = true;
   }
   bool is_used() { return is_used_; }