anchor.diff:      // TODO(brianwilkerson) Return the last consumed token.
       listener.beginMixinApplication(token);
       Token withKeyword = token;
  -    token = expect('with', token);
  +    expect('with', token);
       token = parseTypeList(token);
       listener.endMixinApplication(withKeyword);
       return token;
  
positive.code:   /// identifier in the given [context], create a synthetic identifier, report
    /// an error, and return the synthetic identifier.
    Token ensureIdentifier(Token token, IdentifierContext context) {
      if (!token.isIdentifier) {
        if (optional("void", token)) {
          reportRecoverableError(token, fasta.messageInvalidVoid);
  
negative.code:   /// ```
    Token parseQualified(Token token, IdentifierContext context,
        IdentifierContext continuationContext) {
      token = ensureIdentifier(token.next, context);
      while (optional('.', token.next)) {
        token = parseQualifiedRest(token, continuationContext);
      }
  