Statically check for assignments to const in harmony mode.

src/scopes.h

Index: src/scopes.h
diff --git a/src/scopes.h b/src/scopes.h
index 523a251fae2ffd18f5bb1148a2c17b575b6faf8b..af0449e93c7dea6895f06d42cf7a95ca7624071c 100644
--- a/src/scopes.h
+++ b/src/scopes.h
@@ -187,6 +187,11 @@ class Scope: public ZoneObject {
   // 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.