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

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/v8.h"
 
 #include "src/api.h"
 #include "src/ast.h"
 #include "src/bailout-reason.h"
 #include "src/base/platform/platform.h"
@@ skipping 2461 matching lines @@
       !scanner()->HasAnyLineTerminatorBeforeNext() && expr != NULL &&
       expr->AsVariableProxy() != NULL &&
       expr->AsVariableProxy()->raw_name() ==
           ast_value_factory()->native_string() &&
       !scanner()->literal_contains_escapes()) {
     return ParseNativeDeclaration(ok);
   }
 
   // Parsed expression statement, or the context-sensitive 'module' keyword.
   // Only expect semicolon in the former case.
+  // Also detect attempts at 'let' declarations in sloppy mode.
   if (!FLAG_harmony_modules || peek() != Token::IDENTIFIER ||
       scanner()->HasAnyLineTerminatorBeforeNext() ||
       expr->AsVariableProxy() == NULL ||
       expr->AsVariableProxy()->raw_name() !=
           ast_value_factory()->module_string() ||
       scanner()->literal_contains_escapes()) {
+    if (peek() == Token::IDENTIFIER && expr->AsVariableProxy() != NULL &&
+        expr->AsVariableProxy()->raw_name() ==
+            ast_value_factory()->let_string()) {
+      ReportMessage("lexical_strict_mode", NULL);
+      *ok = false;
+      return NULL;
+    }
     ExpectSemicolon(CHECK_OK);
   }
   return factory()->NewExpressionStatement(expr, pos);
 }
 
 
 IfStatement* Parser::ParseIfStatement(ZoneList<const AstRawString*>* labels,
                                       bool* ok) {
   // IfStatement ::
   //   'if' '(' Expression ')' Statement ('else' Statement)?
@@ skipping 709 matching lines @@
   ZoneList<const AstRawString*> let_bindings(1, zone());
 
   // Create an in-between scope for let-bound iteration variables.
   Scope* saved_scope = scope_;
   Scope* for_scope = NewScope(scope_, BLOCK_SCOPE);
   scope_ = for_scope;
 
   Expect(Token::FOR, CHECK_OK);
   Expect(Token::LPAREN, CHECK_OK);
   for_scope->set_start_position(scanner()->location().beg_pos);
+  bool is_let_identifier_expression = false;
   if (peek() != Token::SEMICOLON) {
     if (peek() == Token::VAR ||
         (peek() == Token::CONST && strict_mode() == SLOPPY)) {
       bool is_const = peek() == Token::CONST;
       const AstRawString* name = NULL;
       VariableDeclarationProperties decl_props = kHasNoInitializers;
       Block* variable_statement =
           ParseVariableDeclarations(kForStatement, &decl_props, NULL, &name,
                                     CHECK_OK);
       bool accept_OF = decl_props == kHasNoInitializers;
@@ skipping 91 matching lines @@
         return loop;
 
       } else {
         init = variable_statement;
       }
     } else {
       Scanner::Location lhs_location = scanner()->peek_location();
       Expression* expression = ParseExpression(false, CHECK_OK);
       ForEachStatement::VisitMode mode;
       bool accept_OF = expression->IsVariableProxy();
+      is_let_identifier_expression =
+        expression->IsVariableProxy() &&
+        expression->AsVariableProxy()->raw_name() ==
+            ast_value_factory()->let_string();
 
       if (CheckInOrOf(accept_OF, &mode)) {
         expression = this->CheckAndRewriteReferenceExpression(
             expression, lhs_location, "invalid_lhs_in_for", CHECK_OK);
 
         ForEachStatement* loop =
             factory()->NewForEachStatement(mode, labels, stmt_pos);
         Target target(&this->target_stack_, loop);
 
         Expression* enumerable = ParseExpression(true, CHECK_OK);
@@ skipping 12 matching lines @@
         init = factory()->NewExpressionStatement(expression, position());
       }
     }
   }
 
   // Standard 'for' loop
   ForStatement* loop = factory()->NewForStatement(labels, stmt_pos);
   Target target(&this->target_stack_, loop);
 
   // 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 NULL;
+  }
   Expect(Token::SEMICOLON, CHECK_OK);
 
   // If there are let bindings, then condition and the next statement of the
   // for loop must be parsed in a new scope.
   Scope* inner_scope = NULL;
   if (let_bindings.length() > 0) {
     inner_scope = NewScope(for_scope, BLOCK_SCOPE);
     inner_scope->set_start_position(scanner()->location().beg_pos);
     scope_ = inner_scope;
   }
@@ skipping 1916 matching lines @@
 
     const AstRawString* raw_str = ast_value_factory()->GetOneByteString(
         OneByteVector(raw_chars.get(), to_index));
     Literal* raw_lit = factory()->NewStringLiteral(raw_str, span_start - 1);
     raw_strings->Add(raw_lit, zone());
   }
 
   return raw_strings;
 }
 } }  // namespace v8::internal