    //=============================================================================
    //  MuseScore
    //  Music Composition & Notation
    //
    //  Copyright (C) 2011 Werner Schweer and others
    //
    //  This program is free software; you can redistribute it and/or modify
    //  it under the terms of the GNU General Public License version 2
    //  as published by the Free Software Foundation and appearing in
    //  the file LICENSE.GPL
    //=============================================================================

    #ifndef __MSCOREVIEW_H__
    #define __MSCOREVIEW_H__

    namespace Ms {

    class Element;
    class Score;
    class Note;
    class Page;
    class ChordRest;

    enum class Grip : int;
    enum class HairpinType : char;

    //---------------------------------------------------------
    //   MuseScoreView
    //---------------------------------------------------------

    class MuseScoreView {

       protected:
          Score* _score;

       public:
          MuseScoreView() {}
          Page* point2page(const QPointF&);
          Element* elementAt(const QPointF& p);
          const QList<Element*> elementsAt(const QPointF&);
          virtual Element* elementNear(QPointF) { return 0; }

          virtual void layoutChanged() {}
          virtual void dataChanged(const QRectF&) = 0;
          virtual void updateAll() = 0;

          virtual void moveCursor()          {}
          virtual void showLoopCursors(bool) {}

          virtual void adjustCanvasPosition(const Element*, bool /*playBack*/, int /*staffIdx*/ = 0) {};
          virtual void setScore(Score* s) { _score = s; }
          Score* score() const            { return _score; }
          virtual void removeScore() {};

          virtual void changeEditElement(Element*) {};
          virtual QCursor cursor() const { return QCursor(); }
          virtual void setCursor(const QCursor&) {};
          virtual int gripCount() const { return 0; }
          virtual void setDropRectangle(const QRectF&) {};
          virtual void cmdAddSlur(ChordRest*, ChordRest*) {};
          virtual void cmdAddHairpin(HairpinType) {};
          virtual void startEdit() {};
          virtual void startEditMode(Element*) {};
          virtual void startEdit(Element*, Grip /*startGrip*/) {};
          virtual void startNoteEntryMode() {};
          virtual void drawBackground(QPainter*, const QRectF&) const = 0;
          virtual void setDropTarget(const Element*) {}

          virtual void lyricsTab(bool /*back*/, bool /*end*/, bool /*moveOnly*/) {}
          virtual void lyricsReturn() {}
          virtual void lyricsEndEdit() {}
          virtual void lyricsUpDown(bool /*up*/, bool /*end*/)  {}
          virtual void lyricsMinus()  {}
          virtual void lyricsUnderscore()  {}

          virtual const QRect geometry() const = 0;
          };

    }     // namespace Ms

    #endif

↑ V730 Not all members of a class are initialized inside the constructor. Consider inspecting: _score.