Enable references and assignments to lookup slots in the toplevel code...

src/full-codegen.h

 // Copyright 2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 227 matching lines @@
     kAccumulator,
     kStack
   };
 
   int SlotOffset(Slot* slot);
 
   // Emit code to convert a pure value (in a register, slot, as a literal,
   // or on top of the stack) into the result expected according to an
   // expression context.
   void Apply(Expression::Context context, Register reg);
+
+  // Slot cannot have type Slot::LOOKUP.
   void Apply(Expression::Context context, Slot* slot);
+
   void Apply(Expression::Context context, Literal* lit);
   void ApplyTOS(Expression::Context context);
 
   // Emit code to discard count elements from the top of stack, then convert
   // a pure value into the result expected according to an expression
   // context.
   void DropAndApply(int count, Expression::Context context, Register reg);
 
   // Emit code to convert pure control flow to a pair of labels into the
   // result expected according to an expression context.
@@ skipping 174 matching lines @@
 
   friend class NestedStatement;
 
   DISALLOW_COPY_AND_ASSIGN(FullCodeGenerator);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_FAST_CODEGEN_H_