anchor.diff:      listener.beginImport(importKeyword);
       token = ensureLiteralString(importKeyword);
       Token uri = token;
  -    token = parseConditionalUris(token);
  +    token = parseConditionalUriStar(token);
       token = parseImportPrefixOpt(token);
       token = parseCombinatorStar(token).next;
       if (optional(';', token)) {
  
positive.code:   ///   conditionalUri*
    /// ;
    /// ```
    Token parseConditionalUris(Token token) {
      // TODO(brianwilkerson): Rename to `parseConditionalUriStar`?
      listener.beginConditionalUris(token.next);
      int count = 0;
      while (optional('if', token.next)) {
  
negative.code:       // During recovery, clauses are parsed in the same order
        // and generate the same events as in the parseImport method above.
        recoveryListener.clear();
        token = parseConditionalUriStar(token);
        if (recoveryListener.ifKeyword != null) {
          if (firstDeferredKeyword != null) {
            // TODO(danrubel): report error indicating conditional should
  