Statically check for assignments to const in harmony mode.

src/compiler.cc

 // Copyright 2011 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 374 matching lines @@
   // parsing statistics.
   HistogramTimer* rate = info->is_eval()
       ? info->isolate()->counters()->compile_eval()
       : info->isolate()->counters()->compile();
   HistogramTimerScope timer(rate);
 
   // Compile the code.
   FunctionLiteral* lit = info->function();
   LiveEditFunctionTracker live_edit_tracker(isolate, lit);
   if (!MakeCode(info)) {
-    isolate->StackOverflow();
+    if (!isolate->has_pending_exception()) isolate->StackOverflow();
     return Handle<SharedFunctionInfo>::null();
   }
 
   // Allocate function.
   ASSERT(!info->code().is_null());
   Handle<SharedFunctionInfo> result =
       isolate->factory()->NewSharedFunctionInfo(
           lit->name(),
           lit->materialized_literal_count(),
           info->code(),
@@ skipping 391 matching lines @@
     }
   }
 
   GDBJIT(AddCode(Handle<String>(shared->DebugName()),
                  Handle<Script>(info->script()),
                  Handle<Code>(info->code()),
                  info));
 }
 
 } }  // namespace v8::internal