c++ virtual functions not working

I'm trying to use virtual functions with emscripten like the following :

```
IGameAssembly* asm = Application::GetGameAssembly();
auto scripts = asm ->GetScripts();

for (auto it : scripts)
{
std::cout << it << std::endl;
}
```

the above doesn't work when calling the class interface pointer
it gives an error like ```indirect call to null```
but if I do it like this it works :

```
WebGameAssembly* asm = (WebGameAssembly*)Application::GetGameAssembly();
auto scripts = asm->GetScripts();

for (auto it : scripts)
{
std::cout << it << std::endl;
}
```

any idea on how I can debug this ?