diff options
| -rw-r--r-- | haddock-api/src/Haddock/Convert.hs | 25 |
1 files changed, 23 insertions, 2 deletions
diff --git a/haddock-api/src/Haddock/Convert.hs b/haddock-api/src/Haddock/Convert.hs index 9979ebb7..3410c7ba 100644 --- a/haddock-api/src/Haddock/Convert.hs +++ b/haddock-api/src/Haddock/Convert.hs @@ -222,7 +222,7 @@ synifyTyCon coax tc -- CoAxioms, not their TyCons _ -> synifyName tc tyvars = synifyTyVars (tyConVisibleTyVars tc) - kindSig = Just (tyConKind tc) + kindSig = synifyDataTyConReturnKind tc -- The data constructors. -- -- Any data-constructors not exported from the module that *defines* the @@ -248,7 +248,7 @@ synifyTyCon coax tc , dd_ND = alg_nd , dd_ctxt = alg_ctx , dd_cType = Nothing - , dd_kindSig = fmap synifyKindSig kindSig + , dd_kindSig = kindSig , dd_cons = cons , dd_derivs = alg_deriv } in case lefts consRaw of @@ -258,6 +258,27 @@ synifyTyCon coax tc , tcdDExt = DataDeclRn False placeHolderNamesTc } dataConErrs -> Left $ unlines dataConErrs +-- In this module, every TyCon being considered has come from an interface +-- file. This means that when considering a data type constructor such as: +-- +-- data Foo (w :: *) (m :: * -> *) (a :: *) +-- +-- Then its tyConKind will be (* -> (* -> *) -> * -> *). But beware! We are +-- also rendering the type variables of Foo, so if we synify the tyConKind of +-- Foo in full, we will end up displaying this in Haddock: +-- +-- data Foo (w :: *) (m :: * -> *) (a :: *) +-- :: * -> (* -> *) -> * -> * +-- +-- Which is entirely wrong (#548). We only want to display the *return* kind, +-- which this function obtains. +synifyDataTyConReturnKind :: TyCon -> Maybe (LHsKind GhcRn) +synifyDataTyConReturnKind tc + = case splitFunTys (tyConKind tc) of + (_, ret_kind) + | isLiftedTypeKind ret_kind -> Nothing -- Don't bother displaying :: * + | otherwise -> Just (synifyKindSig ret_kind) + synifyInjectivityAnn :: Maybe Name -> [TyVar] -> Injectivity -> Maybe (LInjectivityAnn GhcRn) synifyInjectivityAnn Nothing _ _ = Nothing |