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authorSimon Peyton Jones <simonpj@microsoft.com>2019-02-21 15:27:17 +0000
committerMarge Bot <ben+marge-bot@smart-cactus.org>2019-03-09 02:07:53 -0500
commit1f5cc9dc8aeeafa439d6d12c3c4565ada524b926 (patch)
treea83c219447dc397524535f408368437422178cba /utils
parent2762f94dc27cc065dded7755f99c66cba26683dd (diff)
downloadhaskell-1f5cc9dc8aeeafa439d6d12c3c4565ada524b926.tar.gz
Stop inferring over-polymorphic kinds
Before this patch GHC was trying to be too clever (Trac #16344); it succeeded in kind-checking this polymorphic-recursive declaration data T ka (a::ka) b = MkT (T Type Int Bool) (T (Type -> Type) Maybe Bool) As Note [No polymorphic recursion] discusses, the "solution" was horribly fragile. So this patch deletes the key lines in TcHsType, and a wodge of supporting stuff in the renamer. There were two regressions, both the same: a closed type family decl like this (T12785b) does not have a CUSK: type family Payload (n :: Peano) (s :: HTree n x) where Payload Z (Point a) = a Payload (S n) (a `Branch` stru) = a To kind-check the equations we need a dependent kind for Payload, and we don't get that any more. Solution: make it a CUSK by giving the result kind -- probably a good thing anyway. The other case (T12442) was very similar: a close type family declaration without a CUSK.
Diffstat (limited to 'utils')
m---------utils/haddock0
1 files changed, 0 insertions, 0 deletions
diff --git a/utils/haddock b/utils/haddock
-Subproject e7586f005aa89a45b0fc4f3564f0f17ab9f79d3
+Subproject 65bbdfb6dc1b08f893187e1847985aad4505fcd