Definition of m_artistEntriesMap:

   QMap<int, MagnatuneDatabaseEntry *> m_artistEntriesMap;

Definition of MagnatuneDatabaseEntry:

   class MagnatuneDatabaseEntry
{

private:

    int m_type;
    int m_id;


public:

    MagnatuneDatabaseEntry( const int type, const int id );
    ~MagnatuneDatabaseEntry( );

    const int getType( );
    const int getId( );
};

insertion code that fails:

  m_artistEntriesMap.insert(artist.getId(), new MagnatuneDatabaseEntry( MAGNATUNE_ARTIST, artist.getId() ));

Error message: 
/home/amarok-dev/multimedia/amarok/src/servicebrowser/magnatunestore/magnatunecontentmodel.cpp: In member function 'virtual QModelIndex MagnatuneContentModel::index(int, int, const QModelIndex&) const':
/home/amarok-dev/multimedia/amarok/src/servicebrowser/magnatunestore/magnatunecontentmodel.cpp:105: error: passing 'const QMap<int, MagnatuneDatabaseEntry*>' as 'this' argument of 'typename QMap<Key, T>::iterator QMap<Key, T>::insert(const Key&, const T&) [with Key = int, T = MagnatuneDatabaseEntry*]' discards qualifiers