This works: ``` Prelude> :set -XNamedWildCards -XPartialTypeSignatures -XPolyKinds Prelude> k :: (Int :: _); k = 42 <interactive>:2:14: warning: [-Wpartial-type-signatures] • Found type wildcard ‘_’ standing for ‘*’ • In the type signature: k :: (Int :: _) ``` And this doesn't: ``` Prelude> k :: (Int :: _t); k = 42 <interactive>:3:7: error: • Expected kind ‘_t’, but ‘Int’ has kind ‘*’ • In the type signature: k :: (Int :: _t) ``` The issue, I suspect, is in `partition_nwcs`, which ignores kind variables for some reason.