Statically check for assignments to const in harmony mode.

src/scopes.h

 // 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
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   void VisitIllegalRedeclaration(AstVisitor* visitor);
 
   // Check if the scope has (at least) one illegal redeclaration.
   bool HasIllegalRedeclaration() const { return illegal_redecl_ != NULL; }
 
   // For harmony block scoping mode: Check if the scope has conflicting var
   // declarations, i.e. a var declaration that has been hoisted from a nested
   // scope over a let binding of the same name.
   Declaration* CheckConflictingVarDeclarations();
 
+  // For harmony block scoping mode: Check if the scope has variable proxies
+  // that are used as lvalues and point to const variables. Assumes that scopes
+  // have been analyzed and variables been resolved.
+  VariableProxy* CheckAssignmentToConst();
+
   // ---------------------------------------------------------------------------
   // Scope-specific info.
 
   // Inform the scope that the corresponding code contains a with statement.
   void RecordWithStatement() { scope_contains_with_ = true; }
 
   // Inform the scope that the corresponding code contains an eval call.
   void RecordEvalCall() { if (!is_global_scope()) scope_calls_eval_ = true; }
 
   // Set the strict mode flag (unless disabled by a global flag).
@@ skipping 351 matching lines @@
   }
 
   void SetDefaults(ScopeType type,
                    Scope* outer_scope,
                    Handle<ScopeInfo> scope_info);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_SCOPES_H_