Incorrect handling of virtual methods

[tritao]

Consider this case:

C++:
static Base getBase() { return Derived(); }

C#:
Base b = Base.getBase(); b.virtual();

Since we're not generating code to go through the virtual table in Base we'll not have the expected polymorphic behaviour.

[genuinelucifer]

@tritao I tried to reproduce it but could not because probably I didn't quite understand it. Please explain this a bit...

[ddobrev]

@genuinelucifer imagine that in the Base of the example you have a virtual function defined as follows:

int Base::virtualFunction()
{
    return 1;
}

Then in the Derived from the example you override this function:

int Derived::virtualFunction()
{
    return 2;
}

At present, when you call b.virtualFunction() - as in the definition of the issue - you'll get 1. However, this is wrong - you should get 2 because the real C++ type that is returned is Derived.

[ddobrev]

@genuinelucifer You need to use the same code we use for calls in abstract implementations:

https://github.com/mono/CppSharp/blob/master/src/Generator/Generators/CSharp/CSharpTextTemplate.cs#L2202

[genuinelucifer]

@ddobrev Thanks. Will try to implement it.

[genuinelucifer]

@ddobrev Please see #496. I have tried but the test is failing at one instance. It feels a bit weird to me.