Fixed VTables.GetVTableIndex to work with base/derived overrides.

src/Generator/AST/VTables.cs

@@ -72,13 +72,21 @@ namespace CppSharp.AST
             throw new NotSupportedException();
         }
 
-        public static int GetVTableIndex(INamedDecl method, Class @class)
+        static bool CanOverride(Method method, Method @override)
+        {
+            return method.OriginalName == @override.OriginalName &&
+                   method.ReturnType == @override.ReturnType &&
+                   method.Parameters.SequenceEqual(@override.Parameters,
+                       new ParameterTypeComparer());
+        }
+
+        public static int GetVTableIndex(Method method, Class @class)
         {
             switch (@class.Layout.ABI)
             {
                 case CppAbi.Microsoft:
                     return (from table in @class.Layout.VFTables
-                            let j = table.Layout.Components.FindIndex(m => m.Method == method)
+                            let j = table.Layout.Components.FindIndex(m => CanOverride(m.Method, method))
                             where j >= 0
                             select j).First();
                 default:

src/Generator/Generators/CSharp/CSharpTextTemplate.cs

@@ -2329,7 +2329,7 @@ namespace CppSharp.Generators.CSharp
             out string delegateId)
         {
             var virtualCallBuilder = new StringBuilder();
-            var i = VTables.GetVTableIndex(function.OriginalFunction, @class);
+            var i = VTables.GetVTableIndex(function.OriginalFunction as Method, @class);
             virtualCallBuilder.AppendFormat("void* slot = *(void**) ((({0}.Internal*) {1})->vfptr0 + {2} * {3});",
                 @class.Name, Helpers.InstanceIdentifier, i, Driver.TargetInfo.PointerWidth / 8);
             virtualCallBuilder.AppendLine();