diff --git a/debugger/breakpoint/breakpointmodel.cpp b/debugger/breakpoint/breakpointmodel.cpp
--- a/debugger/breakpoint/breakpointmodel.cpp
+++ b/debugger/breakpoint/breakpointmodel.cpp
@@ -202,7 +202,7 @@
 {
     /* FIXME: all this logic must be in item */
     if (!index.isValid())
-        return nullptr;
+        return Qt::NoItemFlags;
 
     if (index.column() == 0)
         return static_cast<Qt::ItemFlags>(
diff --git a/debugger/util/treemodel.cpp b/debugger/util/treemodel.cpp
--- a/debugger/util/treemodel.cpp
+++ b/debugger/util/treemodel.cpp
@@ -65,7 +65,7 @@
 Qt::ItemFlags TreeModel::flags(const QModelIndex &index) const
 {
     if (!index.isValid())
-        return nullptr;
+        return Qt::NoItemFlags;
 
     return Qt::ItemIsEnabled | Qt::ItemIsSelectable;
 }
diff --git a/interfaces/idocumentcontroller.h b/interfaces/idocumentcontroller.h
--- a/interfaces/idocumentcontroller.h
+++ b/interfaces/idocumentcontroller.h
@@ -113,7 +113,7 @@
      */
     KDevelop::IDocument* openDocument( const QUrl &url,
             const KTextEditor::Cursor& cursor,
-            DocumentActivationParams activationParams = nullptr,
+            DocumentActivationParams activationParams = {},
             const QString& encoding = {});
 
     /**
@@ -131,7 +131,7 @@
      */
     virtual KDevelop::IDocument* openDocument( const QUrl &url,
             const KTextEditor::Range& range = KTextEditor::Range::invalid(),
-            DocumentActivationParams activationParams = nullptr,
+            DocumentActivationParams activationParams = {},
             const QString& encoding = {},
             IDocument* buddy = nullptr) = 0;
 
@@ -148,7 +148,7 @@
      */
     virtual bool openDocument(IDocument* doc,
             const KTextEditor::Range& range = KTextEditor::Range::invalid(),
-            DocumentActivationParams activationParams = nullptr,
+            DocumentActivationParams activationParams = {},
             IDocument* buddy = nullptr) = 0;
 
     /**
diff --git a/project/projectmodel.cpp b/project/projectmodel.cpp
--- a/project/projectmodel.cpp
+++ b/project/projectmodel.cpp
@@ -1064,8 +1064,8 @@
     ProjectBaseItem* item = itemFromIndex( index );
     if(item)
         return item->flags();
-    else
-        return nullptr;
+
+    return Qt::NoItemFlags;
 }
 
 bool ProjectModel::insertColumns(int, int, const QModelIndex&)
diff --git a/shell/documentcontroller.h b/shell/documentcontroller.h
--- a/shell/documentcontroller.h
+++ b/shell/documentcontroller.h
@@ -109,7 +109,7 @@
     
     bool openDocument(IDocument* doc,
                               const KTextEditor::Range& range = KTextEditor::Range::invalid(),
-                              DocumentActivationParams activationParams = nullptr,
+                              DocumentActivationParams activationParams = {},
                               IDocument* buddy = nullptr) override;
 
     KTextEditor::Document* globalTextEditorInstance() override;
@@ -124,7 +124,7 @@
     */
     IDocument* openDocument( const QUrl &url,
             const KTextEditor::Range& range = KTextEditor::Range::invalid(),
-            DocumentActivationParams activationParams = nullptr,
+            DocumentActivationParams activationParams = {},
             const QString& encoding = {},
             IDocument* buddy = nullptr ) override;
 
diff --git a/sublime/aggregatemodel.cpp b/sublime/aggregatemodel.cpp
--- a/sublime/aggregatemodel.cpp
+++ b/sublime/aggregatemodel.cpp
@@ -81,7 +81,7 @@
 Qt::ItemFlags AggregateModel::flags(const QModelIndex &index) const
 {
     if (!index.isValid())
-        return nullptr;
+        return Qt::NoItemFlags;
     return Qt::ItemIsEnabled | Qt::ItemIsSelectable;
 }