anchor.diff:  import '../fasta_codes.dart' as fasta;
   
   import '../scanner.dart' show ErrorToken, Token;
  -
  -import '../scanner/recover.dart' show skipToEof;
   
   import '../../scanner/token.dart'
       show
  
positive.code:       bool errorReported = false;
        while (next is ErrorToken) {
          errorReported = true;
          reportErrorToken(next, true);
          token = next;
          next = token.next;
        }
  
negative.code:     }
    }
  
    void reportErrorToken(ErrorToken token) {
      listener.handleRecoverableError(token.assertionMessage, token, token);
    }
  
    Token parseInvalidTopLevelDeclaration(Token token) {
  