Remove support for legacy const, part 1

src/parsing/preparser.cc

 // Copyright 2011 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 <cmath>
 
 #include "src/allocation.h"
 #include "src/base/logging.h"
 #include "src/conversions-inl.h"
 #include "src/conversions.h"
@@ skipping 353 matching lines @@
                           : MessageTemplate::kSloppyFunction);
       *ok = false;
       return Statement::Default();
 
     case Token::DEBUGGER:
       return ParseDebuggerStatement(ok);
 
     case Token::VAR:
       return ParseVariableStatement(kStatement, ok);
 
-    case Token::CONST:
-      // In ES6 CONST is not allowed as a Statement, only as a
-      // LexicalDeclaration, however we continue to allow it in sloppy mode for
-      // backwards compatibility.
-      if (is_sloppy(language_mode()) && allow_legacy_const()) {
-        return ParseVariableStatement(kStatement, ok);
-      }
-
-    // Fall through.
     default:
       return ParseExpressionOrLabelledStatement(ok);
   }
 }
 
 
 PreParser::Statement PreParser::ParseFunctionDeclaration(bool* ok) {
   // FunctionDeclaration ::
   //   'function' Identifier '(' FormalParameterListopt ')' '{' FunctionBody '}'
   // GeneratorDeclaration ::
@@ skipping 93 matching lines @@
     //
     // ConstDeclaration : const ConstBinding (',' ConstBinding)* ';'
     //
     // * It is a Syntax Error if the code that matches this production is not
     //   contained in extended code.
     //
     // However disallowing const in sloppy mode will break compatibility with
     // existing pages. Therefore we keep allowing const with the old
     // non-harmony semantics in sloppy mode.
     Consume(Token::CONST);
-    if (is_strict(language_mode()) ||
-        (allow_harmony_sloppy() && !allow_legacy_const())) {
+    if (is_strict(language_mode()) || allow_harmony_sloppy()) {
       DCHECK(var_context != kStatement);
       require_initializer = true;
       lexical = true;
     }
   } else if (peek() == Token::LET && allow_let()) {
     Consume(Token::LET);
     DCHECK(var_context != kStatement);
     lexical = true;
   } else {
     *ok = false;
@@ skipping 648 matching lines @@
     Expect(Token::RBRACE, CHECK_OK);
     return PreParserExpression::Default();
   }
 }
 
 #undef CHECK_OK
 
 
 }  // namespace internal
 }  // namespace v8