anchor.diff:      if (name != null) {
         parts.add(name!);
       }
  -    parts.add(file);
  +    if (file != null) {
  +      parts.add(file!);
  +    }
       parts..add('$line')..add('$column');
       return parts.join(':');
     }
  
positive.code:   });
  
    /// File path of the location.
    final String file;
  
    /// 1-based line number.
    final int line;
  
negative.code:     if (location == null || location.file == null) {
        return false;
      }
      final String file = Uri.parse(location.file!).path;
  
      // By default check whether the creation location was within package:flutter.
      if (_pubRootDirectories == null) {
  