Is it possible to cast generic types to Data?

[eddiemundo]

type T<a> {
  a: a
}

let t: T<Int> = T{ a: 1 } 

fn doesnt_work(t: T<Data>) -> Datum { InlineDatum(t.a)  }

fn doesnt_work2(t: T<d>) -> Datum { InlineDatum(t.a) }

Getting the errors

1. I struggled to unify the types of two expressions.
   
2. I am inferring the following type:
   
       Ti<Data>
   
   but I found an expression with a different type:
   
       Ti<Int>
   
   Either, add type-annotation to improve my inference, or adjust the expression to have the expected type.

and

1. I struggled to unify the types of two expressions.
   
2. I am inferring the following type:
   
       Data
   
   but I found an expression with a different type:
   
       d
   
   Either, add type-annotation to improve my inference, or adjust the expression to have the expected type.

I guess this is impossible?

[KtorZ]

It is indeed not possible to cast a non-specialised generic type (e.g. T<a>) to Data. You can only cast types that have a concrete representation. In your example, however, T<Int> is very much concrete, so this would work:

fn t_to_data(t: T<Int>) -> Datum {
  InlineDatum(t.a)
}