Fixed #638 - incompilable generated C# code when a function takes a protected enum.

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

src/Generator/Generators/CSharp/CSharpTextTemplate.cs

@@ -2885,7 +2885,11 @@ namespace CppSharp.Generators.CSharp
             if (@enum.IsFlags)
                 WriteLine("[Flags]");
 
-            Write("{0}enum {1}", Helpers.GetAccess(@enum.Access), @enum.Name);
+            Write(Helpers.GetAccess(@enum.Access)); 
+            // internal P/Invoke declarations must see protected enums
+            if (@enum.Access == AccessSpecifier.Protected)
+                Write("internal ");
+            Write("enum {0}", @enum.Name);
 
             var typeName = TypePrinter.VisitPrimitiveType(@enum.BuiltinType.Type,
                                                           new TypeQualifiers());

tests/Common/Common.Tests.cs

@@ -25,6 +25,9 @@ public class CommonTests : GeneratorTestFixture
         using (var derivedFromTemplateInstantiationWithVirtual = new DerivedFromTemplateInstantiationWithVirtual())
         {
         }
+        using (var hasProtectedEnum = new HasProtectedEnum())
+        {
+        }
     }
 
     [Test]

tests/Common/Common.cpp

@@ -610,3 +610,11 @@ NonTrivialDtor::~NonTrivialDtor()
 DerivedFromTemplateInstantiationWithVirtual::DerivedFromTemplateInstantiationWithVirtual()
 {
 }
+
+HasProtectedEnum::HasProtectedEnum()
+{
+}
+
+void HasProtectedEnum::function(ProtectedEnum param)
+{
+}

tests/Common/Common.h

@@ -1072,10 +1072,25 @@ public:
     DerivedFromTemplateInstantiationWithVirtual();
 };
 
-typedef DLL_API union {
+typedef DLL_API union
+{
     int c;
 } union_t;
 
-int DLL_API func_union(union_t u) {
+int DLL_API func_union(union_t u)
+{
     return u.c;
 }
+
+class DLL_API HasProtectedEnum
+{
+public:
+    HasProtectedEnum();
+protected:
+    enum class ProtectedEnum
+    {
+        Member1,
+        Member2
+    };
+    void function(ProtectedEnum param);
+};