Prohibit let in lexical bindings

src/parser.cc

 // Copyright 2012 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/parser.h"
 
 #include "src/api.h"
 #include "src/ast.h"
 #include "src/ast-literal-reindexer.h"
 #include "src/bailout-reason.h"
@@ skipping 2517 matching lines @@
     if (!first_declaration) Consume(Token::COMMA);
 
     Expression* pattern;
     {
       ExpressionClassifier pattern_classifier;
       Token::Value next = peek();
       pattern = ParsePrimaryExpression(&pattern_classifier, ok);
       if (!*ok) return;
       ValidateBindingPattern(&pattern_classifier, ok);
       if (!*ok) return;
+      if (IsLexicalVariableMode(parsing_result->descriptor.mode)) {
+        ValidateLetPattern(&pattern_classifier, ok);
+        if (!*ok) return;
+      }
       if (!allow_harmony_destructuring() && !pattern->IsVariableProxy()) {
         ReportUnexpectedToken(next);
         *ok = false;
         return;
       }
     }
 
     Scanner::Location variable_loc = scanner()->location();
     const AstRawString* single_name =
         pattern->IsVariableProxy() ? pattern->AsVariableProxy()->raw_name()
@@ skipping 3771 matching lines @@
 
 Expression* Parser::SpreadCallNew(Expression* function,
                                   ZoneList<v8::internal::Expression*>* args,
                                   int pos) {
   args->InsertAt(0, function, zone());
 
   return factory()->NewCallRuntime(Context::REFLECT_CONSTRUCT_INDEX, args, pos);
 }
 }  // namespace internal
 }  // namespace v8