Fix handling of 'c: if (0) break c; else ()' where a parser optimization

src/parser.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2110 matching lines @@
   Expect(Token::BREAK, CHECK_OK);
   Handle<String> label;
   Token::Value tok = peek();
   if (!scanner().HasAnyLineTerminatorBeforeNext() &&
       tok != Token::SEMICOLON && tok != Token::RBRACE && tok != Token::EOS) {
     label = ParseIdentifier(CHECK_OK);
   }
   // Parse labeled break statements that target themselves into
   // empty statements, e.g. 'l1: l2: l3: break l2;'
   if (!label.is_null() && ContainsLabel(labels, label)) {
+    // Consume the 'break' SEMICOLON if present
+    if (peek() == Token::SEMICOLON) {
+      scanner().Next();
+    }

[Lasse Reichstein Nielsen, 2012/02/02 10:05:19]

The semicolon *must* be there (or be inserted by automatic semicolon insertion),
so use 
  ExpectSemicolon(CHECK_OK);
like below.
Otherwise it'll still match something like
  foo: break foo var x = 10;

     return EmptyStatement();
   }
   BreakableStatement* target = NULL;
   target = LookupBreakTarget(label, CHECK_OK);
   if (target == NULL) {
     // Illegal break statement.
     const char* message = "illegal_break";
     Vector<Handle<String> > args;
     if (!label.is_null()) {
       message = "unknown_label";
@@ skipping 3548 matching lines @@
       ASSERT(info->isolate()->has_pending_exception());
     } else {
       result = parser.ParseProgram(info);
     }
   }
   info->SetFunction(result);
   return (result != NULL);
 }
 
 } }  // namespace v8::internal