harmony-scoping: better error messages for let declarations in sloppy mode.

src/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 491 matching lines @@
     DCHECK(!expr.AsIdentifier().IsFutureReserved());
     DCHECK(strict_mode() == SLOPPY ||
            !IsFutureStrictReserved(expr.AsIdentifier()));
     Consume(Token::COLON);
     return ParseStatement(ok);
     // Preparsing is disabled for extensions (because the extension details
     // aren't passed to lazily compiled functions), so we don't
     // accept "native function" in the preparser.
   }
   // Parsed expression statement.
+  // Detect attempts at 'let' declarations in sloppy mode.
+  if (peek() == Token::IDENTIFIER && strict_mode() == SLOPPY &&
+      expr.IsIdentifier() && expr.AsIdentifier().IsLet()) {
+    ReportMessage("lexical_strict_mode", NULL);
+    *ok = false;
+    return Statement::Default();
+  }
   ExpectSemicolon(CHECK_OK);
   return Statement::ExpressionStatement(expr);
 }
 
 
 PreParser::Statement PreParser::ParseIfStatement(bool* ok) {
   // IfStatement ::
   //   'if' '(' Expression ')' Statement ('else' Statement)?
 
   Expect(Token::IF, CHECK_OK);
@@ skipping 159 matching lines @@
   return false;
 }
 
 
 PreParser::Statement PreParser::ParseForStatement(bool* ok) {
   // ForStatement ::
   //   'for' '(' Expression? ';' Expression? ';' Expression? ')' Statement
 
   Expect(Token::FOR, CHECK_OK);
   Expect(Token::LPAREN, CHECK_OK);
+  bool is_let_identifier_expression = false;
   if (peek() != Token::SEMICOLON) {
     if (peek() == Token::VAR || peek() == Token::CONST ||
         (peek() == Token::LET && strict_mode() == STRICT)) {
       bool is_lexical = peek() == Token::LET ||
                         (peek() == Token::CONST && strict_mode() == STRICT);
       int decl_count;
       VariableDeclarationProperties decl_props = kHasNoInitializers;
       ParseVariableDeclarations(
           kForStatement, &decl_props, &decl_count, CHECK_OK);
       bool has_initializers = decl_props == kHasInitializers;
       bool accept_IN = decl_count == 1 && !(is_lexical && has_initializers);
       bool accept_OF = !has_initializers;
       if (accept_IN && CheckInOrOf(accept_OF)) {
         ParseExpression(true, CHECK_OK);
         Expect(Token::RPAREN, CHECK_OK);
 
         ParseStatement(CHECK_OK);
         return Statement::Default();
       }
     } else {
       Expression lhs = ParseExpression(false, CHECK_OK);
+      is_let_identifier_expression =
+          lhs.IsIdentifier() && lhs.AsIdentifier().IsLet();
       if (CheckInOrOf(lhs.IsIdentifier())) {
         ParseExpression(true, CHECK_OK);
         Expect(Token::RPAREN, CHECK_OK);
 
         ParseStatement(CHECK_OK);
         return Statement::Default();
       }
     }
   }
 
   // Parsed initializer at this point.
+  // Detect attempts at 'let' declarations in sloppy mode.
+  if (peek() == Token::IDENTIFIER && strict_mode() == SLOPPY &&
+      is_let_identifier_expression) {
+    ReportMessage("lexical_strict_mode", NULL);
+    *ok = false;
+    return Statement::Default();
+  }
   Expect(Token::SEMICOLON, CHECK_OK);
 
   if (peek() != Token::SEMICOLON) {
     ParseExpression(true, CHECK_OK);
   }
   Expect(Token::SEMICOLON, CHECK_OK);
 
   if (peek() != Token::RPAREN) {
     ParseExpression(true, CHECK_OK);
   }
@@ skipping 256 matching lines @@
   ParseIdentifier(kAllowEvalOrArguments, CHECK_OK);
   ParseArguments(ok);
 
   return Expression::Default();
 }
 
 #undef CHECK_OK
 
 
 } }  // v8::internal