Promotion of newtypes
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE KindSignatures #-}
{-# LANGUAGE GADTs #-}
newtype A = A Int
data B (x :: A)The program above raises the error: A of kind * is not promotable. The program compiles fine if we declare A using data instead of newtype. Is there a good reason to prevent promotion of newtypes?
Trac metadata
| Trac field | Value |
|---|---|
| Version | 7.7 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Compiler |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | |
| Operating system | |
| Architecture |