#16334: Named wildcards in kinds -------------------------------------+------------------------------------- Reporter: int-index | Owner: (none) Type: bug | Status: patch Priority: normal | Milestone: Component: Compiler (Type | Version: 8.4.4 checker) | Keywords: Resolution: | PartialTypeSignatures Operating System: Unknown/Multiple | Architecture: Type of failure: GHC rejects | Unknown/Multiple valid program | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | https://gitlab.haskell.org/ghc/ghc/merge_requests/361 -------------------------------------+------------------------------------- Changes (by int-index): * status: new => patch * differential: => https://gitlab.haskell.org/ghc/ghc/merge_requests/361 Old description:
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. I plan to fix it as part of https://gitlab.haskell.org/ghc/ghc/merge_requests/361
New description: 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. -- -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/16334#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler