Disallow generator declarations in certain locations

src/parsing/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/parsing/parser.h"
 
 #include "src/api.h"
 #include "src/ast/ast.h"
 #include "src/ast/ast-expression-rewriter.h"
 #include "src/ast/ast-expression-visitor.h"
@@ skipping 2369 matching lines @@
   if (labels != NULL) {
     for (int i = labels->length(); i-- > 0; ) {
       if (labels->at(i) == label) {
         return true;
       }
     }
   }
   return false;
 }
 
+Statement* Parser::ParseOnlyFunctionDeclaration(bool* ok) {
+  Consume(Token::FUNCTION);
+  int pos = position();
+  bool is_generator = Check(Token::MUL);
+  if (allow_harmony_restrictive_declarations() && is_generator) {
+    ParserTraits::ReportMessageAt(
+        scanner()->location(),
+        MessageTemplate::kGeneratorInLegacyContext);
+    *ok = false;
+    return nullptr;
+  }
+  return ParseFunctionDeclaration(pos, is_generator, NULL, CHECK_OK);

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

Nit: nullptr

[Dan Ehrenberg, 2016/04/26 22:24:18]

Fixed

+}
+
 Statement* Parser::ParseExpressionOrLabelledStatement(
     ZoneList<const AstRawString*>* labels,
     AllowLabelledFunctionStatement allow_function, bool* ok) {
   // ExpressionStatement | LabelledStatement ::
   //   Expression ';'
   //   Identifier ':' Statement
   //
   // ExpressionStatement[Yield] :
   //   [lookahead ∉ {{, function, class, let [}] Expression[In, ?Yield] ;
 
@@ skipping 36 matching lines @@
     }
     labels->Add(label, zone());
     // Remove the "ghost" variable that turned out to be a label
     // from the top scope. This way, we don't try to resolve it
     // during the scope processing.
     scope_->RemoveUnresolved(var);
     Expect(Token::COLON, CHECK_OK);
     // ES#sec-labelled-function-declarations Labelled Function Declarations
     if (peek() == Token::FUNCTION && is_sloppy(language_mode())) {
       if (allow_function == kAllowLabelledFunctionStatement) {
-        return ParseFunctionDeclaration(labels, ok);

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

Was this passing of labels just wrong?

[Dan Ehrenberg, 2016/04/26 22:24:18]

Actually, yes. We were confusing labels for exported names. Maybe this would've
been visible if you made a label as the same name as a function in a weird
place, or something.

+        return ParseOnlyFunctionDeclaration(ok);
       } else {
         return ParseScopedStatement(labels, true, ok);
       }
     }
     return ParseStatement(labels, kDisallowLabelledFunctionStatement, ok);
   }
 
   // If we have an extension, we allow a native function declaration.
   // A native function declaration starts with "native function" with
   // no line-terminator between the two words.
@@ skipping 973 matching lines @@
     return ParseSubStatement(labels, kDisallowLabelledFunctionStatement, ok);
   } else {
     if (legacy) {
       ++use_counts_[v8::Isolate::kLegacyFunctionDeclaration];
     }
     // Make a block around the statement for a lexical binding
     // is introduced by a FunctionDeclaration.
     Scope* body_scope = NewScope(scope_, BLOCK_SCOPE);
     BlockState block_state(&scope_, body_scope);
     Block* block = factory()->NewBlock(NULL, 1, false, RelocInfo::kNoPosition);
-    Statement* body = ParseFunctionDeclaration(NULL, CHECK_OK);
+    Statement* body = ParseOnlyFunctionDeclaration(CHECK_OK);
     block->statements()->Add(body, zone());
     body_scope->set_end_position(scanner()->location().end_pos);
     body_scope = body_scope->FinalizeBlockScope();
     block->set_scope(body_scope);
     return block;
   }
 }
 
 Statement* Parser::ParseForStatement(ZoneList<const AstRawString*>* labels,
                                      bool* ok) {
@@ skipping 3334 matching lines @@
                         try_block, target);
     final_loop = target;
   }
 
   return final_loop;
 }
 
 
 }  // namespace internal
 }  // namespace v8