diff --git a/src/plugins/diffeditor/diffeditorcontroller.h b/src/plugins/diffeditor/diffeditorcontroller.h
index 2a9a49fe399..3a88b914bd7 100644
--- a/src/plugins/diffeditor/diffeditorcontroller.h
+++ b/src/plugins/diffeditor/diffeditorcontroller.h
@@ -59,7 +59,6 @@ public:
                                                  const QString &displayName);
     static DiffEditorController *controller(Core::IDocument *document);
 
-public slots:
     void informationForCommitReceived(const QString &output);
 
 signals:
diff --git a/src/plugins/diffeditor/diffeditordocument.h b/src/plugins/diffeditor/diffeditordocument.h
index 5e0f6770622..c61d17ad909 100644
--- a/src/plugins/diffeditor/diffeditordocument.h
+++ b/src/plugins/diffeditor/diffeditordocument.h
@@ -77,6 +77,8 @@ public:
     OpenResult open(QString *errorString, const QString &fileName,
                     const QString &realFileName) override;
     bool isReloading() const { return m_isReloading; }
+    void beginReload();
+    void endReload(bool success);
 
     QString plainText() const;
 
@@ -87,10 +89,6 @@ signals:
     void chunkActionsRequested(QMenu *menu, int diffFileIndex, int chunkIndex);
     void requestMoreInformation();
 
-public slots:
-    void beginReload();
-    void endReload(bool success);
-
 private:
     void setController(DiffEditorController *controller);
 
diff --git a/src/plugins/diffeditor/diffeditorplugin.h b/src/plugins/diffeditor/diffeditorplugin.h
index 5b19046bdd1..688ba1ccfc3 100644
--- a/src/plugins/diffeditor/diffeditorplugin.h
+++ b/src/plugins/diffeditor/diffeditorplugin.h
@@ -56,22 +56,23 @@ public:
     bool initialize(const QStringList &arguments, QString *errorMessage = 0);
     void extensionsInitialized();
 
-private slots:
+private:
     void updateDiffCurrentFileAction();
     void updateDiffOpenFilesAction();
     void diffCurrentFile();
     void diffOpenFiles();
     void diffExternalFiles();
 
+    QAction *m_diffCurrentFileAction = nullptr;
+    QAction *m_diffOpenFilesAction = nullptr;
+
 #ifdef WITH_TESTS
+private slots:
     void testMakePatch_data();
     void testMakePatch();
     void testReadPatch_data();
     void testReadPatch();
 #endif // WITH_TESTS
-private:
-    QAction *m_diffCurrentFileAction = nullptr;
-    QAction *m_diffOpenFilesAction = nullptr;
 };
 
 } // namespace Internal
diff --git a/src/plugins/diffeditor/sidebysidediffeditorwidget.cpp b/src/plugins/diffeditor/sidebysidediffeditorwidget.cpp
index 40aba5fff86..92f0fdf4aa7 100644
--- a/src/plugins/diffeditor/sidebysidediffeditorwidget.cpp
+++ b/src/plugins/diffeditor/sidebysidediffeditorwidget.cpp
@@ -87,7 +87,6 @@ public:
     void saveState();
     void restoreState();
 
-public slots:
     void setDisplaySettings(const DisplaySettings &ds) override;
 
 signals:
@@ -534,8 +533,8 @@ SideBySideDiffEditorWidget::SideBySideDiffEditorWidget(QWidget *parent)
 
     connect(m_leftEditor, &QPlainTextEdit::cursorPositionChanged,
             this, &SideBySideDiffEditorWidget::leftCursorPositionChanged);
-//    connect(m_leftEditor->document()->documentLayout(), SIGNAL(documentSizeChanged(QSizeF)),
-//            this, SLOT(leftDocumentSizeChanged()));
+//    connect(m_leftEditor->document()->documentLayout(), &QAbstractTextDocumentLayout::documentSizeChanged,
+//            this, &SideBySideDiffEditorWidget::leftDocumentSizeChanged);
 
     connect(m_rightEditor->verticalScrollBar(), &QAbstractSlider::valueChanged,
             this, &SideBySideDiffEditorWidget::rightVSliderChanged);
diff --git a/src/plugins/diffeditor/sidebysidediffeditorwidget.h b/src/plugins/diffeditor/sidebysidediffeditorwidget.h
index 4fdb97c1544..a80c11aa7cc 100644
--- a/src/plugins/diffeditor/sidebysidediffeditorwidget.h
+++ b/src/plugins/diffeditor/sidebysidediffeditorwidget.h
@@ -70,7 +70,7 @@ public:
 signals:
     void currentDiffFileIndexChanged(int index);
 
-private slots:
+private:
     void setFontSettings(const TextEditor::FontSettings &fontSettings);
     void slotLeftJumpToOriginalFileRequested(int diffFileIndex,
                                              int lineNumber, int columnNumber);
@@ -87,7 +87,6 @@ private slots:
     void leftCursorPositionChanged();
     void rightCursorPositionChanged();
 
-private:
     void showDiff();
 
     SideDiffEditorWidget *m_leftEditor;
diff --git a/src/plugins/diffeditor/unifieddiffeditorwidget.h b/src/plugins/diffeditor/unifieddiffeditorwidget.h
index 5ba853e42e4..5812c5b234e 100644
--- a/src/plugins/diffeditor/unifieddiffeditorwidget.h
+++ b/src/plugins/diffeditor/unifieddiffeditorwidget.h
@@ -64,25 +64,22 @@ public:
     void restoreState();
 
     void clear(const QString &message = QString());
+    void setDisplaySettings(const TextEditor::DisplaySettings &ds) override;
 
 signals:
     void currentDiffFileIndexChanged(int index);
 
-public slots:
-    void setDisplaySettings(const TextEditor::DisplaySettings &ds) override;
-
 protected:
     void mouseDoubleClickEvent(QMouseEvent *e) override;
     void contextMenuEvent(QContextMenuEvent *e) override;
     QString lineNumber(int blockNumber) const override;
     int lineNumberDigits() const override;
 
-private slots:
+private:
     void setFontSettings(const TextEditor::FontSettings &fontSettings);
 
     void slotCursorPositionChangedInEditor();
 
-private:
     void setLeftLineNumber(int blockNumber, int lineNumber);
     void setRightLineNumber(int blockNumber, int lineNumber);
     void setFileInfo(int blockNumber,