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Diffstat (limited to 'docs/users_guide/8.10.1-notes.rst')
| -rw-r--r-- | docs/users_guide/8.10.1-notes.rst | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/docs/users_guide/8.10.1-notes.rst b/docs/users_guide/8.10.1-notes.rst index cf67246abf..cfe07deb81 100644 --- a/docs/users_guide/8.10.1-notes.rst +++ b/docs/users_guide/8.10.1-notes.rst @@ -16,6 +16,34 @@ Full details Language ~~~~~~~~ +- Kind variables are no longer implicitly quantified when an explicit ``forall`` is used, see + `GHC proposal #24 + <https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0024-no-kind-vars.rst>`__. + :ghc-flag:`-Wimplicit-kind-vars` is now obsolete. + +- Kind variables are no longer implicitly quantified in constructor declarations: :: + + data T a = T1 (S (a :: k) | forall (b::k). T2 (S b) -- no longer accepted + data T (a :: k) = T1 (S (a :: k) | forall (b::k). T2 (S b) -- still accepted + +- Implicitly quantified kind variables are no longer put in front of other variables: :: + + f :: Proxy (a :: k) -> Proxy (b :: j) + + ghci> :t +v f -- old order: + f :: forall k j (a :: k) (b :: j). Proxy a -> Proxy b + + ghci> :t +v f -- new order: + f :: forall k (a :: k) j (b :: j). Proxy a -> Proxy b + + This is a breaking change for users of :extension:`TypeApplications`. + +- In type synonyms and type family equations, free variables on the RHS are no longer + implicitly quantified unless used in an outermost kind annotation: :: + + type T = Just (Nothing :: Maybe a) -- no longer accepted + type T = Just Nothing :: Maybe (Maybe a) -- still accepted + Compiler ~~~~~~~~ |