[C++] Interfacewrapper.cpp compilation failure (string cache)

Given a function with a class / optionalclass argument, the generated code ends up looking something like this:

interfacewrapper.cpp
```c++
std::string sName("");
IBase* pBaseThisResult(nullptr);
IFoo* pIFoo = dynamic_cast(pIBaseClass);
if (!pIFoo)
throw EMyComponentInterfaceException(MYCOMPONENT_ERROR_INVALIDCAST);
bool isCacheCall = (pNameBuffer == nullptr);
if (isCacheCall) {
pBaseThisResult = pIFoo->GetProperties(sName, *pBar);
pIFoo->_setCache (new ParameterCache_3 (sName, *pBar, pBaseThisResult));
}
else {
auto cache = dynamic_cast*> (pIFoo->_getCache ());
if (cache == nullptr)
throw EMyComponentInterfaceException(MYCOMPONENT_ERROR_INVALIDCAST);
cache->retrieveData (sName, *pBar, pBaseThisResult);
pIFoo->_setCache (nullptr);
}
```

Since ` CMyComponentFoo` is a binding class, this won't compile. Also, the pointer `pBaseThisResult` is actually of type `IBase *`.

I've hacked a fix to get it to work by generating `IBase *` instead, but as I don't know how this parameter caching is supposed to work I can't say if it's the right way to fix it.

Start with the generated interfacewrapper.cpp example and inspect how parameter caching handles class or optionalclass arguments. Trace the types used for pBaseThisResult, ParameterCache_3, and the binding class CMyComponentFoo, then verify the generated wrapper compiles and that the cache path still behaves correctly.

Scritto dal modello di indicizzazione a partire dal testo della issue.