QFileSystemModel::filename() uses wrong role value for call to data() method

Currently (even for Qt-5), the code look like that:
inline QString QFileSystemModel::fileName(const QModelIndex &aindex) const

{ return aindex.data(Qt::DisplayRole).toString(); }

However, the implementation of the data() method uses a different role:
case FileNameRole:
return d->name(index);

So the filename() method fails whenever the column in aindex is not zero.
The corrected method should look like:
inline QString QFileSystemModel::fileName(const QModelIndex &aindex) const

{ return aindex.data(FileNameRole).toString(); }