Disable const in strict mode.

Using const in strict mode yields SyntaxError.

Review URL: http://codereview.chromium.org/6592031/

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6974 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/messages.js

@@ -226,6 +226,7 @@ function FormatMessage(message) {
       strict_reserved_word:         ["Use of future reserved word in strict mode"],
       strict_delete:                ["Delete of an unqualified identifier in strict mode."],
       strict_delete_property:       ["Cannot delete property '", "%0", "' of ", "%1"],
+      strict_const:                 ["Use of const in strict mode."],
     };
   }
   var message_type = %MessageGetType(message);

src/parser.cc

@@ -1515,6 +1515,11 @@ Block* Parser::ParseVariableDeclarations(bool accept_IN,
     Consume(Token::VAR);
   } else if (peek() == Token::CONST) {
     Consume(Token::CONST);
+    if (temp_scope_->StrictMode()) {
+      ReportMessage("strict_const", Vector<const char*>::empty());
+      *ok = false;
+      return NULL;
+    }
     mode = Variable::CONST;
     is_const = true;
   } else {

test/mjsunit/strict-mode.js

@@ -280,6 +280,11 @@ CheckStrictMode("function strict() { print(--arguments); }", SyntaxError);
 CheckStrictMode("function strict() { var x = --eval; }", SyntaxError);
 CheckStrictMode("function strict() { var x = --arguments; }", SyntaxError);
 
+// Use of const in strict mode is disallowed in anticipation of ES Harmony.
+CheckStrictMode("const x = 0;", SyntaxError);
+CheckStrictMode("for (const x = 0; false;) {}", SyntaxError);
+CheckStrictMode("function strict() { const x = 0; }", SyntaxError);
+
 // Delete of an unqualified identifier
 CheckStrictMode("delete unqualified;", SyntaxError);
 CheckStrictMode("function strict() { delete unqualified; }", SyntaxError);