Refactor protected class member checking in CheckStaticClass.

src/Generator/Passes/CheckStaticClass.cs

@@ -22,11 +22,26 @@ namespace CppSharp.Passes
             if (Options.IsCSharpGenerator)
             {
                 // C# cannot have protected members in static classes.
+                if (IsProtectedClassMember(decl) && decl.IsGenerated)
+                    SetDeclarationAccessToPrivate(decl);
+            }
+
+            return true;
+        }
+
+        static bool IsProtectedClassMember(Declaration decl)
+        {
+            if (decl.Access != AccessSpecifier.Protected)
+                return false;
+            
             var @class = decl.Namespace as Class;
-                if (    decl.Access == AccessSpecifier.Protected && 
+            if (@class == null || !@class.IsStatic)
-                        decl.GenerationKind == GenerationKind.Generate &&
+                return false;
-                        @class != null && 
+
-                        @class.IsStatic)
+            return true;
+        }
+
+        static void SetDeclarationAccessToPrivate(Declaration decl)
         {
             // By setting it to private it will appear
             // as an internal in the final C# wrapper.
@@ -36,10 +51,6 @@ namespace CppSharp.Passes
             // now private declaration will get filtered out later.
             decl.GenerationKind = GenerationKind.Generate;
         }
-            }
-
-            return true;
-        }
 
         static bool ReturnsClassInstance(Function function)
         {