harmony-scoping: Disallow cross-script assignment to const

src/hydrogen.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/hydrogen.h"
 
 #include <sstream>
 
 #include "src/v8.h"
 
@@ skipping 6538 matching lines @@
     Variable* var,
     HValue* value,
     BailoutId ast_id) {
   Handle<GlobalObject> global(current_info()->global_object());
 
   if (FLAG_harmony_scoping) {
     Handle<ScriptContextTable> script_contexts(
         global->native_context()->script_context_table());
     ScriptContextTable::LookupResult lookup;
     if (ScriptContextTable::Lookup(script_contexts, var->name(), &lookup)) {
+      if (lookup.mode == CONST) {
+        return Bailout(kNonInitializerAssignmentToConst);
+      }
       Handle<Context> script_context =
           ScriptContextTable::GetContext(script_contexts, lookup.context_index);
       HStoreNamedField* instr = Add<HStoreNamedField>(
           Add<HConstant>(script_context),
           HObjectAccess::ForContextSlot(lookup.slot_index), value);
       USE(instr);
       DCHECK(instr->HasObservableSideEffects());
       Add<HSimulate>(ast_id, REMOVABLE_SIMULATE);
       return;
     }
@@ skipping 6196 matching lines @@
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 } }  // namespace v8::internal