Replace QRegExp with QRegularExpression

src/playlist/playlistcontainer.cpp

@@ -30,7 +30,7 @@
 #include <QVariant>
 #include <QPoint>
 #include <QString>
-#include <QRegExp>
+#include <QRegularExpression>
 #include <QSize>
 #include <QFont>
 #include <QIcon>
@@ -46,6 +46,9 @@
 #include <QUndoStack>
 #include <QtEvents>
 #include <QSettings>
+#if QT_VERSION < QT_VERSION_CHECK(5, 12, 0)
+#  include <QRegExp>
+#endif
 
 #include "core/iconloader.h"
 #include "playlist.h"
@@ -197,7 +200,11 @@ void PlaylistContainer::SetViewModel(Playlist *playlist) {
   emit ViewSelectionModelChanged();
 
   // Update filter
+#if QT_VERSION >= QT_VERSION_CHECK(5, 12, 0)
+  ui_->filter->setText(playlist->proxy()->filterRegularExpression().pattern());
+#else
   ui_->filter->setText(playlist->proxy()->filterRegExp().pattern());
+#endif
 
   // Update the no matches label
   connect(playlist_->proxy(), SIGNAL(modelReset()), SLOT(UpdateNoMatchesLabel()));