Generate valid C# for independent external specializations

Signed-off-by: Dimitar Dobrev <dpldobrev@protonmail.com>

src/AST/ClassExtensions.cs

@@ -252,8 +252,19 @@ namespace CppSharp.AST
             if (@class.Fields.Any(f => IsValueDependent(f.Type)))
                 return true;
 
-            return @class.Bases.Where(b => b.IsClass).Select(
-                b => b.Class).Any(HasDependentValueFieldInLayout);
+            if (@class.Bases.Where(b => b.IsClass).Select(
+                b => b.Class).Any(HasDependentValueFieldInLayout))
+                return true;
+
+            // HACK: Clang can't always resolve complex templates such as the base of std::atomic in msvc
+            if (@class.IsTemplate && @class.Specializations.Any(
+                s => s.Layout.Fields.Any(
+                    f => f.QualifiedType.Type.TryGetDeclaration(
+                        out ClassTemplateSpecialization specialization) &&
+                        specialization.TemplatedDecl.TemplatedClass.HasDependentValueFieldInLayout())))
+                return true;
+
+            return false;
         }
 
         public static IEnumerable<Property> GetConstCharFieldProperties(this Class @class) =>

src/Generator/Generators/CodeGenerator.cs

@@ -1322,11 +1322,7 @@ namespace CppSharp.Generators
                     return "_Ptr";
                 return GetSuffixFor(specialization);
             }
-            // HACK: Clang can't always resolve complex templates such as the base of std::atomic in msvc
-            return (from @base in @class.Bases
-                    let suffix = GetSuffixForInternal(@base.Class)
-                    where suffix.Length > 0
-                    select suffix).DefaultIfEmpty(string.Empty).First();
+            return string.Empty;
         }
 
         public static string GetSuffixFor(Declaration decl)

src/Generator/Passes/TrimSpecializationsPass.cs

@@ -138,7 +138,8 @@ namespace CppSharp.Passes
                 template.Specializations.All(s => s.Ignore))
                 template.ExplicitlyIgnore();
 
-            TryMoveExternalSpecializations(template);
+            if (template.Specializations.Any() && template.HasDependentValueFieldInLayout())
+                TryMoveExternalSpecializations(template);
         }
 
         /// <summary>
@@ -174,17 +175,13 @@ namespace CppSharp.Passes
                 {
                     Module module = arg.Type.Type.GetModule();
                     if (module != null)
-                    {
                         modules.Add(module);
-                    }
                 }
                 if (arg.Type.Type.TryGetDeclaration(out ClassTemplateSpecialization nestedSpecialization))
                 {
                     Module module = GetExternalModule(nestedSpecialization);
                     if (module != null)
-                    {
                         modules.Add(module);
-                    }
                 }
             }
             return modules.TopologicalSort(m => m.Dependencies).LastOrDefault();

tests/NamespacesBase/NamespacesBase.h

@@ -71,7 +71,12 @@ void TemplateClass<T>::setField(const T& value)
 }
 
 template <typename T>
-class TemplateWithIndependentFields
+class IndependentFields
+{
+};
+
+template <typename T>
+class DependentFields
 {
 public:
     class Nested
@@ -85,13 +90,13 @@ private:
 };
 
 template <typename T>
-const T& TemplateWithIndependentFields<T>::constField() const
+const T& DependentFields<T>::constField() const
 {
     return *t;
 }
 
 template <typename T>
-typename TemplateWithIndependentFields<T>::Nested TemplateWithIndependentFields<T>::useDependentPointer(const T* t)
+typename DependentFields<T>::Nested DependentFields<T>::useDependentPointer(const T* t)
 {
     return Nested();
 }

tests/NamespacesDerived/Independent.h

@@ -1,3 +1,3 @@
 class Derived;
-template<typename T> class TemplateWithIndependentFields;
-typedef TemplateWithIndependentFields<Derived*> ForwardedInIndependentHeader;
+template<typename T> class DependentFields;
+typedef DependentFields<Derived*> ForwardedInIndependentHeader;

tests/NamespacesDerived/NamespacesDerived.cpp

@@ -62,6 +62,11 @@ TemplateClass<int> Derived2::getTemplate()
     return t;
 }
 
+IndependentFields<int> Derived2::getIndependentSpecialization()
+{
+    return independentSpecialization;
+}
+
 Derived2::LocalTypedefSpecialization Derived2::getLocalTypedefSpecialization()
 {
     return LocalTypedefSpecialization();
@@ -73,13 +78,13 @@ Abstract* Derived2::getAbstract()
 }
 
 DerivedFromExternalSpecialization::DerivedFromExternalSpecialization(int i,
-                                                                     TemplateWithIndependentFields<HasVirtualInDependency> defaultExternalSpecialization)
+                                                                     DependentFields<HasVirtualInDependency> defaultExternalSpecialization)
 {
 }
 
-TemplateWithIndependentFields<Base3> DerivedFromExternalSpecialization::returnExternalSpecialization()
+DependentFields<Base3> DerivedFromExternalSpecialization::returnExternalSpecialization()
 {
-    return TemplateWithIndependentFields<Base3>();
+    return DependentFields<Base3>();
 }
 
 int HasVirtualInDependency::callManagedOverride()

tests/NamespacesDerived/NamespacesDerived.h

@@ -60,13 +60,16 @@ public:
     void defaultEnumValueFromDependency(OverlappingNamespace::ColorsEnum c = OverlappingNamespace::ColorsEnum::black);
 
     TemplateClass<int> getTemplate();
-    typedef TemplateWithIndependentFields<int> LocalTypedefSpecialization;
+    IndependentFields<int> getIndependentSpecialization();
+    typedef DependentFields<int> LocalTypedefSpecialization;
     LocalTypedefSpecialization getLocalTypedefSpecialization();
     Abstract* getAbstract();
 private:
     TemplateClass<int> t;
     TemplateClass<Derived> d;
-    TemplateClass<TemplateWithIndependentFields<Derived>> nestedSpecialization;
+    TemplateClass<DependentFields<Derived>> nestedSpecialization;
+    IndependentFields<int> independentSpecialization;
+    IndependentFields<Derived> independentExternalSpecialization;
 };
 
 class DLL_API HasVirtualInDependency : public HasVirtualInCore
@@ -76,13 +79,13 @@ public:
     int callManagedOverride();
 };
 
-class DLL_API DerivedFromExternalSpecialization : public TemplateWithIndependentFields<Derived>
+class DLL_API DerivedFromExternalSpecialization : public DependentFields<Derived>
 {
 public:
     DerivedFromExternalSpecialization(int i,
-                                      TemplateWithIndependentFields<HasVirtualInDependency> defaultExternalSpecialization =
-                                          TemplateWithIndependentFields<HasVirtualInDependency>());
-    TemplateWithIndependentFields<Base3> returnExternalSpecialization();
+                                      DependentFields<HasVirtualInDependency> defaultExternalSpecialization =
+                                          DependentFields<HasVirtualInDependency>());
+    DependentFields<Base3> returnExternalSpecialization();
 };
 
 class DLL_API DerivedFromSecondaryBaseInDependency : public Derived, public SecondaryBase