diff --git a/src/App/DocumentObserverPython.h b/src/App/DocumentObserverPython.h
index 95aee29b98..ce57626ddf 100644
--- a/src/App/DocumentObserverPython.h
+++ b/src/App/DocumentObserverPython.h
@@ -24,10 +24,20 @@
 #ifndef APP_DOCUMENTOBSERVERPYTHON_H
 #define APP_DOCUMENTOBSERVERPYTHON_H
 
+#include <FCGlobal.h>
+#include <boost/signals2.hpp>
+#include <CXX/Objects.hxx>
+#include <string>
+#include <vector>
 
 namespace App
 {
 
+class Document;
+class DocumentObject;
+class ExtensionContainer;
+class Property;
+
 /**
  * The DocumentObserverPython class is used to notify registered Python instances
  * whenever something happens to a document, like creation, destruction, adding or
@@ -111,13 +121,13 @@ private:
     Py::Object inst;
     static std::vector<DocumentObserverPython*> _instances;
 
-    typedef struct PythonObject {
+    using Connection = struct PythonObject {
        boost::signals2::scoped_connection slot;
        Py::Object py;
        PyObject* ptr() {
            return py.ptr();
        }
-    } Connection;
+    };
 
     Connection pyCreatedDocument;
     Connection pyDeletedDocument;
diff --git a/src/App/ElementMap.h b/src/App/ElementMap.h
index fb49da4cdc..a617e0c59c 100644
--- a/src/App/ElementMap.h
+++ b/src/App/ElementMap.h
@@ -43,7 +43,7 @@ namespace Data
 {
 
 class ElementMap;
-typedef std::shared_ptr<ElementMap> ElementMapPtr;
+using ElementMapPtr = std::shared_ptr<ElementMap>;
 
 /* This class provides for ComplexGeoData's ability to provide proper naming.
  * Specifically, ComplexGeoData uses this class for it's `_id` property.
diff --git a/src/Base/Writer.cpp b/src/Base/Writer.cpp
index f6a12bb15e..b1d592f787 100644
--- a/src/Base/Writer.cpp
+++ b/src/Base/Writer.cpp
@@ -45,8 +45,8 @@ using namespace zipios;
 // It does not check if the character is valid utf8 or not.
 struct cdata_filter {
 
-    typedef char char_type;
-    typedef boost::iostreams::output_filter_tag category;
+    using char_type = char;
+    using category = boost::iostreams::output_filter_tag;
 
     template<typename Device>
     inline bool put(Device& dev, char c) {
diff --git a/src/Gui/DocumentObserverPython.h b/src/Gui/DocumentObserverPython.h
index 15424c9838..6d7ea31a60 100644
--- a/src/Gui/DocumentObserverPython.h
+++ b/src/Gui/DocumentObserverPython.h
@@ -24,10 +24,23 @@
 #ifndef GUI_DOCUMENTOBSERVERPYTHON_H
 #define GUI_DOCUMENTOBSERVERPYTHON_H
 
+#include <FCGlobal.h>
+#include <boost/signals2.hpp>
+#include <CXX/Objects.hxx>
+#include <string>
+#include <vector>
+
+namespace App {
+class Property;
+}
 
 namespace Gui
 {
 
+class Document;
+class ViewProvider;
+class ViewProviderDocumentObject;
+
 /**
  * The DocumentObserverPython class is used to notify registered Python instances
  * whenever something happens to a document, like creation, destruction, adding or
@@ -73,13 +86,13 @@ private:
     Py::Object inst;
     static std::vector<DocumentObserverPython*> _instances;
 
-    typedef struct PythonObject {
+    using Connection = struct PythonObject {
        boost::signals2::scoped_connection slot;
        Py::Object py;
        PyObject* ptr() {
            return py.ptr();
        }
-    } Connection;
+    };
 
     Connection pyCreatedDocument;
     Connection pyDeletedDocument;
diff --git a/src/Gui/Quarter/SoQTQuarterAdaptor.h b/src/Gui/Quarter/SoQTQuarterAdaptor.h
index d5e883fe80..f9f46a25ee 100644
--- a/src/Gui/Quarter/SoQTQuarterAdaptor.h
+++ b/src/Gui/Quarter/SoQTQuarterAdaptor.h
@@ -40,7 +40,7 @@ namespace Coin3D {
 namespace Quarter {
 
 class SoQTQuarterAdaptor;
-typedef void SoQTQuarterAdaptorCB(void* data, SoQTQuarterAdaptor* viewer);
+using SoQTQuarterAdaptorCB = void (void* data, SoQTQuarterAdaptor* viewer);
 
 class QUARTER_DLL_API SoQTQuarterAdaptor :  public QuarterWidget {
 
diff --git a/src/Gui/SoFCSelectionContext.h b/src/Gui/SoFCSelectionContext.h
index 293fc77196..68ee2d2720 100644
--- a/src/Gui/SoFCSelectionContext.h
+++ b/src/Gui/SoFCSelectionContext.h
@@ -41,8 +41,10 @@ using SoFCSelectionContextBasePtr = std::shared_ptr<SoFCSelectionContextBase>;
 
 struct GuiExport SoFCSelectionContextBase {
     virtual ~SoFCSelectionContextBase() {}
-    typedef int MergeFunc(int status, SoFCSelectionContextBasePtr &output,
-            SoFCSelectionContextBasePtr input, SoFCSelectionRoot *node);
+    using MergeFunc = int (int status,
+                           SoFCSelectionContextBasePtr &output,
+                           SoFCSelectionContextBasePtr input,
+                           SoFCSelectionRoot *node);
 };
 
 struct SoFCSelectionContext;
diff --git a/src/Gui/SoFCUnifiedSelection.cpp b/src/Gui/SoFCUnifiedSelection.cpp
index 4238cc2d52..2bc0581b17 100644
--- a/src/Gui/SoFCUnifiedSelection.cpp
+++ b/src/Gui/SoFCUnifiedSelection.cpp
@@ -1030,11 +1030,11 @@ void SoFCSeparator::finish()
 // Thread local data for bounding box rendering
 //
 // The code is inspred by Coin SoLevelOfDetails.cpp.
-typedef struct {
+using SoFCBBoxRenderInfo = struct {
     SoGetBoundingBoxAction * bboxaction;
     SoCube *cube;
     SoColorPacker *packer;
-} SoFCBBoxRenderInfo;
+};
 
 static void so_bbox_construct_data(void * closure)
 {
diff --git a/src/Mod/PartDesign/App/FeatureHole.h b/src/Mod/PartDesign/App/FeatureHole.h
index acf56a7e31..fa51e14ee0 100644
--- a/src/Mod/PartDesign/App/FeatureHole.h
+++ b/src/Mod/PartDesign/App/FeatureHole.h
@@ -86,22 +86,22 @@ public:
     //@}
     short mustExecute() const override;
 
-    typedef struct {
+    using ThreadDescription = struct {
         const char * designation;
         double diameter;
         double pitch;
         double CoreHole;
-    } ThreadDescription;
+    };
     static const ThreadDescription threadDescription[][171];
 
     static const double metricHoleDiameters[36][4];
 
-    typedef struct {
+    using UTSClearanceDefinition = struct {
         std::string designation;
         double close;
         double normal;
         double loose;
-    } UTSClearanceDefinition;
+    };
     static const UTSClearanceDefinition UTSHoleDiameters[22];
 
     void Restore(Base::XMLReader & reader) override;