Disallow generator declarations in certain locations

src/parsing/preparser.cc

Index: src/parsing/preparser.cc
diff --git a/src/parsing/preparser.cc b/src/parsing/preparser.cc
index 3f7adedd931c74fa475666f8ef2296ea76c4d99d..c0db7ef9dd72c0dd02e41491229bce6fdbf74e4c 100644
--- a/src/parsing/preparser.cc
+++ b/src/parsing/preparser.cc
@@ -179,7 +179,7 @@ PreParser::Statement PreParser::ParseStatementListItem(bool* ok) {
 
   switch (peek()) {
     case Token::FUNCTION:
-      return ParseFunctionDeclaration(ok);
+      return ParseHoistableDeclaration(ok);
     case Token::CLASS:
       return ParseClassDeclaration(ok);
     case Token::CONST:
@@ -378,15 +378,8 @@ PreParser::Statement PreParser::ParseSubStatement(
 }
 
 
-PreParser::Statement PreParser::ParseFunctionDeclaration(bool* ok) {
-  // FunctionDeclaration ::
-  //   'function' Identifier '(' FormalParameterListopt ')' '{' FunctionBody '}'
-  // GeneratorDeclaration ::
-  //   'function' '*' Identifier '(' FormalParameterListopt ')'
-  //      '{' FunctionBody '}'
-  Expect(Token::FUNCTION, CHECK_OK);
-  int pos = position();
-  bool is_generator = Check(Token::MUL);
+PreParser::Statement PreParser::ParseHoistableDeclaration(
+    int pos, bool is_generator, bool* ok) {
   bool is_strict_reserved = false;
   Identifier name = ParseIdentifierOrStrictReservedWord(
       &is_strict_reserved, CHECK_OK);
@@ -401,6 +394,19 @@ PreParser::Statement PreParser::ParseFunctionDeclaration(bool* ok) {
 }
 
 
+PreParser::Statement PreParser::ParseHoistableDeclaration(bool* ok) {
+  // FunctionDeclaration ::
+  //   'function' Identifier '(' FormalParameterListopt ')' '{' FunctionBody '}'
+  // GeneratorDeclaration ::
+  //   'function' '*' Identifier '(' FormalParameterListopt ')'
+  //      '{' FunctionBody '}'
+  Expect(Token::FUNCTION, CHECK_OK);
+  int pos = position();
+  bool is_generator = Check(Token::MUL);
+  return ParseHoistableDeclaration(pos, is_generator, CHECK_OK);
+}
+
+
 PreParser::Statement PreParser::ParseClassDeclaration(bool* ok) {
   Expect(Token::CLASS, CHECK_OK);
 
@@ -553,6 +559,20 @@ PreParser::Statement PreParser::ParseVariableDeclarations(
   return Statement::Default();
 }
 
+PreParser::Statement PreParser::ParseFunctionDeclaration(bool* ok) {
+  Consume(Token::FUNCTION);
+  int pos = position();
+  bool is_generator = Check(Token::MUL);
+  if (allow_harmony_restrictive_declarations() && is_generator) {
+    PreParserTraits::ReportMessageAt(
+        scanner()->location(),
+        MessageTemplate::kGeneratorInLegacyContext);
+    *ok = false;
+    return Statement::Default();
+  }
+  return ParseHoistableDeclaration(pos, is_generator, ok);
+}
+
 PreParser::Statement PreParser::ParseExpressionOrLabelledStatement(
     AllowLabelledFunctionStatement allow_function, bool* ok) {
   // ExpressionStatement | LabelledStatement ::