diff --git a/generator/abstractmetalang.cpp b/generator/abstractmetalang.cpp
index d565e7266..c15d80106 100644
--- a/generator/abstractmetalang.cpp
+++ b/generator/abstractmetalang.cpp
@@ -1066,7 +1066,7 @@ void AbstractMetaClass::setFunctions(const AbstractMetaFunctionList& functions)
 bool AbstractMetaClass::hasFieldAccessors() const
 {
   for (const AbstractMetaField* field : fields()) {
-    if (field->getter() || field->setter())
+    if (field->isPublic() && (field->getter() || field->setter()))
       return true;
   }
 
@@ -1154,8 +1154,10 @@ bool AbstractMetaClass::hasProtectedFunctions() const
 bool AbstractMetaClass::generateShellClass() const
 {
   return typeEntry()->shouldCreateShell()
+         // require that classes that get a shell have a virtual destructor
+         // (required for proper working of derived class)
          && (m_force_shell_class
-             || (!isFinal() && (hasVirtualFunctions() || hasProtectedFunctions() || hasFieldAccessors())));
+             || (!isFinal() && hasVirtualDestructor() && (hasVirtualFunctions() || hasProtectedConstructors())));
 }
 
 QPropertySpec* AbstractMetaClass::propertySpecForRead(const QString& name) const
@@ -1315,6 +1317,11 @@ bool AbstractMetaClass::hasConstructors() const
   return queryFunctions(Constructors).size() != 0;
 }
 
+bool AbstractMetaClass::hasProtectedConstructors() const
+{
+  return queryFunctions(Constructors | WasProtected).size() != 0;
+}
+
 void AbstractMetaClass::addDefaultConstructor()
 {
   AbstractMetaFunction* f = new AbstractMetaFunction;
diff --git a/generator/abstractmetalang.h b/generator/abstractmetalang.h
index 6e62499b7..59a2ad321 100644
--- a/generator/abstractmetalang.h
+++ b/generator/abstractmetalang.h
@@ -697,6 +697,7 @@ class AbstractMetaClass : public AbstractMetaAttributes
   bool hasSignal(const AbstractMetaFunction* f) const;
 
   bool hasConstructors() const;
+  bool hasProtectedConstructors() const;
 
   void addDefaultConstructor();
 
diff --git a/generator/shellheadergenerator.cpp b/generator/shellheadergenerator.cpp
index ce8fb6448..d0ef5a7a7 100644
--- a/generator/shellheadergenerator.cpp
+++ b/generator/shellheadergenerator.cpp
@@ -135,7 +135,8 @@ void ShellHeaderGenerator::write(QTextStream& s, const AbstractMetaClass* meta_c
   }
 
   // Shell-------------------------------------------------------------------
-  if (meta_class->generateShellClass() && !ctors.isEmpty()) {
+  bool generateShell = meta_class->generateShellClass() && !ctors.isEmpty();
+  if (generateShell) {
 
     AbstractMetaFunctionList virtualsForShell = getVirtualFunctionsForShell(meta_class);
 
@@ -348,12 +349,12 @@ void ShellHeaderGenerator::write(QTextStream& s, const AbstractMetaClass* meta_c
     }
   }
   s << "public Q_SLOTS:" << Qt::endl;
-  if (meta_class->generateShellClass() || !meta_class->isAbstract()) {
+  if (generateShell || !meta_class->isAbstract()) {
 
     bool copyConstructorSeen = false;
     bool defaultConstructorSeen = false;
     for (const AbstractMetaFunction* fun : ctors) {
-      if (fun->isAbstract() || (!meta_class->generateShellClass() && !fun->isPublic())) {
+      if (fun->isAbstract() || (!generateShell && !fun->isPublic())) {
         continue;
       }
 
@@ -373,8 +374,7 @@ void ShellHeaderGenerator::write(QTextStream& s, const AbstractMetaClass* meta_c
     if (meta_class->typeEntry()->isValue() && !copyConstructorSeen && defaultConstructorSeen
         && !meta_class->typeEntry()->hasNoCopy())
     {
-      QString className =
-        meta_class->generateShellClass() ? shellClassName(meta_class) : meta_class->qualifiedCppName();
+      QString className = generateShell ? shellClassName(meta_class) : meta_class->qualifiedCppName();
       s << meta_class->qualifiedCppName() << "* new_" << meta_class->name() << "(const "
         << meta_class->qualifiedCppName() << "& other) {" << Qt::endl;
       s << className << "* a = new " << className << "();" << Qt::endl;
diff --git a/generator/shellimplgenerator.cpp b/generator/shellimplgenerator.cpp
index 38d18d3c1..f3d8c3f66 100644
--- a/generator/shellimplgenerator.cpp
+++ b/generator/shellimplgenerator.cpp
@@ -228,11 +228,11 @@ void ShellImplGenerator::write(QTextStream& s, const AbstractMetaClass* meta_cla
     }
   }
 
-  if (meta_class->generateShellClass() || !meta_class->isAbstract()) {
+  if (generateShell || !meta_class->isAbstract()) {
 
     // write constructors
     for (const AbstractMetaFunction* ctor : ctors) {
-      if (ctor->isAbstract() || (!meta_class->generateShellClass() && !ctor->isPublic())) {
+      if (ctor->isAbstract() || (!generateShell && !ctor->isPublic())) {
         continue;
       }
 
@@ -241,8 +241,7 @@ void ShellImplGenerator::write(QTextStream& s, const AbstractMetaClass* meta_cla
       writeFunctionSignature(s, ctor, 0, "new_", Option(AddOwnershipTemplates | ShowStatic));
       s << Qt::endl;
       s << "{ " << Qt::endl;
-      s << "return new "
-        << (meta_class->generateShellClass() ? shellClassName(meta_class) : meta_class->qualifiedCppName()) << "(";
+      s << "return new " << (generateShell ? shellClassName(meta_class) : meta_class->qualifiedCppName()) << "(";
       AbstractMetaArgumentList args = ctor->arguments();
       for (int i = 0; i < args.size(); ++i) {
         if (i > 0)
@@ -333,7 +332,6 @@ void ShellImplGenerator::write(QTextStream& s, const AbstractMetaClass* meta_cla
           }
         } else {
           if (fun->wasProtected()) {
-            //|| (fun->isVirtual() && meta_class->typeEntry()->shouldCreatePromoter())) {
             s << " ((" << promoterClassName(meta_class) << "*)theWrappedObject)->promoted_";
           } else {
             s << " theWrappedObject->";