anchor.diff:  
   const int numOfMatchesToShow = 10;
   
  +final _fileNamesCache = <String, String>{};
  +
   class FileSearchField extends StatefulWidget {
     const FileSearchField({
       @required this.debuggerController,
  
positive.code:     // If the current query is a continuation of the previous query, then
      // filter down the previous matches. Otherwise search through all scripts:
      final scripts = currentQuery.startsWith(previousQuery)
          ? _matches
          : widget.debuggerController.sortedScripts.value;
  
      final matches = _findMatches(currentQuery, scripts);
      if (matches.isEmpty) {
        autoCompleteController.searchAutoComplete.value = [];
      } else {
        final topMatches = _takeTopMatches(matches);
        topMatches.forEach(_addScriptRefToCache);
        autoCompleteController.searchAutoComplete.value = topMatches
            .map((scriptRef) =>
                _createAutoCompleteMatch(scriptRef.uri, currentQuery))
            .toList();
      }
  
      _query = currentQuery;
      _matches = matches;
    }
  
    void _handleAutoCompleteOverlay() {
  
negative.code:   AutoCompleteController autoCompleteController;
  
    final _scriptsCache = <String, ScriptRef>{};
  
    final fileSearchFieldKey = GlobalKey(debugLabel: 'fileSearchFieldKey');
  
    String _query;
    FileSearchResults _searchResults;
  
    @override
    void initState() {
  