[strong] Implement static restrictions on binding/assignment to 'undefined' identifier.

src/parser.cc

Index: src/parser.cc
diff --git a/src/parser.cc b/src/parser.cc
index 4412b8a98cdca5618ec0b7caf1a77caf246718b3..75a4f2517562aba9e566fb316641a06faffe6e38 100644
--- a/src/parser.cc
+++ b/src/parser.cc
@@ -465,6 +465,9 @@ bool ParserTraits::IsEvalOrArguments(const AstRawString* identifier) const {
   return IsEval(identifier) || IsArguments(identifier);
 }
 
+bool ParserTraits::IsUndefined(const AstRawString* identifier) const {
+  return identifier == parser_->ast_value_factory()->undefined_string();
+}
 
 bool ParserTraits::IsPrototype(const AstRawString* identifier) const {
   return identifier == parser_->ast_value_factory()->prototype_string();
@@ -1475,6 +1478,10 @@ ZoneList<ImportDeclaration*>* Parser::ParseNamedImports(int pos, bool* ok) {
       *ok = false;
       ReportMessage("strict_eval_arguments");
       return NULL;
+    } else if (is_strong(language_mode()) && IsUndefined(local_name)) {
+      *ok = false;
+      ReportMessage("strong_undefined");
+      return NULL;
     }
     VariableProxy* proxy = NewUnresolved(local_name, IMPORT);
     ImportDeclaration* declaration =
@@ -1524,7 +1531,7 @@ Statement* Parser::ParseImportDeclaration(bool* ok) {
   ImportDeclaration* import_default_declaration = NULL;
   if (tok != Token::MUL && tok != Token::LBRACE) {
     const AstRawString* local_name =
-        ParseIdentifier(kDontAllowEvalOrArguments, CHECK_OK);
+        ParseIdentifier(kDontAllowRestrictedIdentifiers, CHECK_OK);
     VariableProxy* proxy = NewUnresolved(local_name, IMPORT);
     import_default_declaration = factory()->NewImportDeclaration(
         proxy, ast_value_factory()->default_string(), NULL, scope_, pos);
@@ -1539,7 +1546,7 @@ Statement* Parser::ParseImportDeclaration(bool* ok) {
         Consume(Token::MUL);
         ExpectContextualKeyword(CStrVector("as"), CHECK_OK);
         module_instance_binding =
-            ParseIdentifier(kDontAllowEvalOrArguments, CHECK_OK);
+            ParseIdentifier(kDontAllowRestrictedIdentifiers, CHECK_OK);
         // TODO(ES6): Add an appropriate declaration.
         break;
       }
@@ -2028,11 +2035,12 @@ Statement* Parser::ParseNativeDeclaration(bool* ok) {
   int pos = peek_position();
   Expect(Token::FUNCTION, CHECK_OK);
   // Allow "eval" or "arguments" for backward compatibility.
-  const AstRawString* name = ParseIdentifier(kAllowEvalOrArguments, CHECK_OK);
+  const AstRawString* name =
+      ParseIdentifier(kAllowRestrictedIdentifiers, CHECK_OK);
   Expect(Token::LPAREN, CHECK_OK);
   bool done = (peek() == Token::RPAREN);
   while (!done) {
-    ParseIdentifier(kAllowEvalOrArguments, CHECK_OK);
+    ParseIdentifier(kAllowRestrictedIdentifiers, CHECK_OK);
     done = (peek() == Token::RPAREN);
     if (!done) {
       Expect(Token::COMMA, CHECK_OK);
@@ -2314,7 +2322,7 @@ Block* Parser::ParseVariableDeclarations(
 
     // Parse variable name.
     if (nvars > 0) Consume(Token::COMMA);
-    name = ParseIdentifier(kDontAllowEvalOrArguments, CHECK_OK);
+    name = ParseIdentifier(kDontAllowRestrictedIdentifiers, CHECK_OK);
     if (!first_name) first_name = name;
     Scanner::Location variable_loc = scanner()->location();
     if (fni_ != NULL) fni_->PushVariableName(name);
@@ -2666,7 +2674,7 @@ Statement* Parser::ParseContinueStatement(bool* ok) {
   if (!scanner()->HasAnyLineTerminatorBeforeNext() &&
       tok != Token::SEMICOLON && tok != Token::RBRACE && tok != Token::EOS) {
     // ECMA allows "eval" or "arguments" as labels even in strict mode.
-    label = ParseIdentifier(kAllowEvalOrArguments, CHECK_OK);
+    label = ParseIdentifier(kAllowRestrictedIdentifiers, CHECK_OK);
   }
   IterationStatement* target = LookupContinueTarget(label, CHECK_OK);
   if (target == NULL) {
@@ -2696,7 +2704,7 @@ Statement* Parser::ParseBreakStatement(ZoneList<const AstRawString*>* labels,
   if (!scanner()->HasAnyLineTerminatorBeforeNext() &&
       tok != Token::SEMICOLON && tok != Token::RBRACE && tok != Token::EOS) {
     // ECMA allows "eval" or "arguments" as labels even in strict mode.
-    label = ParseIdentifier(kAllowEvalOrArguments, CHECK_OK);
+    label = ParseIdentifier(kAllowRestrictedIdentifiers, CHECK_OK);
   }
   // Parse labeled break statements that target themselves into
   // empty statements, e.g. 'l1: l2: l3: break l2;'
@@ -2921,7 +2929,7 @@ TryStatement* Parser::ParseTryStatement(bool* ok) {
     Expect(Token::LPAREN, CHECK_OK);
     catch_scope = NewScope(scope_, CATCH_SCOPE);
     catch_scope->set_start_position(scanner()->location().beg_pos);
-    name = ParseIdentifier(kDontAllowEvalOrArguments, CHECK_OK);
+    name = ParseIdentifier(kDontAllowRestrictedIdentifiers, CHECK_OK);
 
     Expect(Token::RPAREN, CHECK_OK);
 
@@ -3868,6 +3876,9 @@ FunctionLiteral* Parser::ParseFunctionLiteral(
     Scanner::Location dupe_error_loc = Scanner::Location::invalid();
     Scanner::Location reserved_error_loc = Scanner::Location::invalid();
 
+    // Similarly for strong mode.
+    Scanner::Location undefined_error_loc = Scanner::Location::invalid();
+
     bool is_rest = false;
     bool done = arity_restriction == FunctionLiteral::GETTER_ARITY ||
         (peek() == Token::RPAREN &&
@@ -3886,6 +3897,9 @@ FunctionLiteral* Parser::ParseFunctionLiteral(
       if (!eval_args_error_loc.IsValid() && IsEvalOrArguments(param_name)) {
         eval_args_error_loc = scanner()->location();
       }
+      if (!undefined_error_loc.IsValid() && IsUndefined(param_name)) {
+        undefined_error_loc = scanner()->location();
+      }
       if (!reserved_error_loc.IsValid() && is_strict_reserved) {
         reserved_error_loc = scanner()->location();
       }
@@ -4004,8 +4018,8 @@ FunctionLiteral* Parser::ParseFunctionLiteral(
                       CHECK_OK);
     const bool use_strict_params = is_rest || IsConciseMethod(kind);
     CheckFunctionParameterNames(language_mode(), use_strict_params,
-                                eval_args_error_loc, dupe_error_loc,
-                                reserved_error_loc, CHECK_OK);
+                                eval_args_error_loc, undefined_error_loc,
+                                dupe_error_loc, reserved_error_loc, CHECK_OK);
 
     if (is_strict(language_mode())) {
       CheckStrictOctalLiteral(scope->start_position(), scope->end_position(),
@@ -4257,6 +4271,11 @@ ClassLiteral* Parser::ParseClassLiteral(const AstRawString* name,
     *ok = false;
     return NULL;
   }
+  if (is_strong(language_mode()) && IsUndefined(name)) {
+    ReportMessageAt(class_name_location, "strong_undefined");
+    *ok = false;
+    return NULL;
+  }
 
   // Create a block scope which is additionally tagged as class scope; this is
   // important for resolving variable references to the class name in the strong
@@ -4348,7 +4367,8 @@ Expression* Parser::ParseV8Intrinsic(bool* ok) {
   int pos = peek_position();
   Expect(Token::MOD, CHECK_OK);
   // Allow "eval" or "arguments" for backward compatibility.
-  const AstRawString* name = ParseIdentifier(kAllowEvalOrArguments, CHECK_OK);
+  const AstRawString* name =
+      ParseIdentifier(kAllowRestrictedIdentifiers, CHECK_OK);
   ZoneList<Expression*>* args = ParseArguments(CHECK_OK);
 
   if (extension_ != NULL) {