Example in ghc doc for SAKS doesn't work
Not sure if this is a bug or a documentation issue, but an example from the ghc docs on SAKS doesn't compile:
{-# LANGUAGE StandaloneKindSignatures #-}
{-# LANGUAGE KindSignatures #-}
{-# LANGUAGE PolyKinds #-}
{-# LANGUAGE GADTs #-}
{-# LANGUAGE RankNTypes #-}
import Data.Kind
type GProx4 :: k -> Type
data GProx4 :: w where MkGProx4 :: GProx4 a
[nix-shell:~]$ ghci --version
The Glorious Glasgow Haskell Compilation System, version 9.2.2
[nix-shell:~]$ ghci /tmp/asdf.hs
GHCi, version 9.2.2: https://www.haskell.org/ghc/ :? for help
Loaded GHCi configuration from /home/googleson78/.ghci
[1 of 1] Compiling Main ( /tmp/asdf.hs, interpreted )
/tmp/asdf.hs:10:1: error:
• Couldn't match expected kind ‘w’ with actual kind ‘k -> *’
• In the data type declaration for ‘GProx4’
|
10 | data GProx4 :: w where MkGProx4 :: GProx4 a
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Failed, no modules loaded.
>