[Proposal] Keep original Type when calling supertype methods

[texone]

In the current implementation the type you call a function on gets reduced to the supertype the type output of the function should be the same as the input to be able to chain it nicely

As in this image the input of setValue is textureInput but the output is Abstract Input

[gregsn]

A) One way of looking at this request is this:

• The state output of mutable types was invented by VL just to make it easy for the user to chain operation calls and keep side effects in check.
• So it's an artificial pin.
• We could change the target code so that on definition side the pin doesn't really exist. On application side, we could just further operate on the mutated object that we fed into the node.
  
• The vertical line is meant to visualize that the ongoing instance == the outgoing one.
• So for the artificial state output pin it would definitely be type-safe to use the compile-time type of the datahub the state input pin is connected to upstream.

B) Another way of looking at it would be to keep the Stateoutput on definition side and to make everything generic:

class SuperType
{
  public TInstance Foo<TInstance>() where TInstance : SuperType
}

class SubType : SuperType
{
}

---

A) simplifies target code
B) makes target code more complex

so A) would be desirable.
However, we should discuss the record case as well.

[azeno]

A) is a good idea. I think we discussed and rejected B) quite some time ago.

[gregsn]

C) all subtypes have corresponding nodes for all inherited operations from all supertypes. Their state input and output pins are typed with the subtype.

When navigating into an interface e.g. Channel we see all the inherited operations from Channel (Ungeneric): LatestAuthor. Until now, we don't see the inherited operations, which can be very confusing. There are other ways to tackle this (e.g. just make the node browser more clever), but tackling the issue this way by introducing more node definitions - one for each subtype - solves the quest here and in the node browser.