Allow arbitrary type casting

[rvcas]

The idea involves allowing expect to let you convert any type to any type and then letting the expect behavior at runtime just behave as it does now. That means that if the shape matches then we can allow it.

type Foo {
  x: Int
}

type Bar {
  y: Int
}


test casting() {
  let thing = Bar { y: 1 }

  let who: Foo = thing

  who.x == thing.y
}

Questions

1. does this mean that since the shapes match we can know that at type check time and so instead we can just use a let in code gen? which leads to 2
2. if we can tell that these are the same shape at compile time anyways why bother injecting the runtime checks? does this mean we should just forget using expect for this and also use aiken level let as well? can let's cast to both Data and anything of the same shape?

[t0anh]

Interesting, so what if the left side contains an opaque type? We will prevent that?

[KtorZ]

Yes.

[rvcas]

Yea but this discussion is totally unrelated to that