Fixed the multiple inheritance of nested types.

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

src/Generator/Passes/MultipleInheritancePass.cs

@@ -91,7 +91,7 @@ namespace CppSharp.Passes
 
         public override bool VisitClassDecl(Class @class)
         {
-            if (AlreadyVisited(@class))
+            if (!base.VisitClassDecl(@class))
                 return false;
 
             //CheckNonVirtualInheritedFunctions(@class);
@@ -105,7 +105,7 @@ namespace CppSharp.Passes
                 var @interface = GetInterface(@class, @base, true);
                 @class.Bases[i] = new BaseClassSpecifier { Type = new TagType(@interface) };
             }
-            return base.VisitClassDecl(@class);
+            return true;
         }
 
         private Class GetInterface(Class @class, Class @base, bool addMembers = false)

tests/CSharpTemp/CSharpTemp.h

@@ -70,6 +70,10 @@ Bar::Bar() {}
 class DLL_API Baz : public Foo, public Bar
 {
 public:
+    class NestedBase1 {};
+    class NestedBase2 {};
+    class NestedDerived : public NestedBase1, public NestedBase2 {};
+
     Baz();
 
     int takesQux(const Qux& qux);