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 8b059b1bea0e320c149c6c5426a837ebe9f55a3a..fc9cb2b279c06b0ad954dd805cbc95cfa30b79b2 100644
--- a/src/parsing/preparser.cc
+++ b/src/parsing/preparser.cc
@@ -278,7 +278,7 @@ PreParser::Statement PreParser::ParseScopedStatement(bool legacy, bool* ok) {
       (legacy && allow_harmony_restrictive_declarations())) {
     return ParseSubStatement(kDisallowLabelledFunctionStatement, ok);
   } else {
-    return ParseFunctionDeclaration(CHECK_OK);
+    return ParseOnlyFunctionDeclaration(ok);
   }
 }
 
@@ -546,6 +546,30 @@ PreParser::Statement PreParser::ParseVariableDeclarations(
   return Statement::Default();
 }
 
+PreParser::Statement PreParser::ParseOnlyFunctionDeclaration(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();
+  }
+  bool is_strict_reserved = false;
+  Identifier name =
+      ParseIdentifierOrStrictReservedWord(&is_strict_reserved, CHECK_OK);
+  ParseFunctionLiteral(name, scanner()->location(),
+                       is_strict_reserved ? kFunctionNameIsStrictReserved
+                                          : kFunctionNameValidityUnknown,
+                       is_generator ? FunctionKind::kGeneratorFunction
+                                    : FunctionKind::kNormalFunction,
+                       pos, FunctionLiteral::kDeclaration,

[adamk, 2016/04/20 19:09:28]

This is a lot of boilerplate to copy; what if you split the existing
ParseFunctionDeclaration into two, as it is for the Parser? Also consider the
same renaming.

[Dan Ehrenberg, 2016/04/26 22:24:19]

Done

+                       language_mode(), CHECK_OK);
+  return Statement::FunctionDeclaration();
+}
+
 PreParser::Statement PreParser::ParseExpressionOrLabelledStatement(
     AllowLabelledFunctionStatement allow_function, bool* ok) {
   // ExpressionStatement | LabelledStatement ::
@@ -583,7 +607,7 @@ PreParser::Statement PreParser::ParseExpressionOrLabelledStatement(
     // ES#sec-labelled-function-declarations Labelled Function Declarations
     if (peek() == Token::FUNCTION && is_sloppy(language_mode())) {
       if (allow_function == kAllowLabelledFunctionStatement) {
-        return ParseFunctionDeclaration(ok);
+        return ParseOnlyFunctionDeclaration(ok);
       } else {
         return ParseScopedStatement(true, ok);
       }