diff options
Diffstat (limited to 'haddock-api/src/Haddock/Interface/Specialize.hs')
| -rw-r--r-- | haddock-api/src/Haddock/Interface/Specialize.hs | 20 |
1 files changed, 10 insertions, 10 deletions
diff --git a/haddock-api/src/Haddock/Interface/Specialize.hs b/haddock-api/src/Haddock/Interface/Specialize.hs index 092a2f4e..2fcb495c 100644 --- a/haddock-api/src/Haddock/Interface/Specialize.hs +++ b/haddock-api/src/Haddock/Interface/Specialize.hs @@ -29,23 +29,23 @@ import qualified Data.Set as Set -- | Instantiate all occurrences of given names with corresponding types. specialize :: Data a => [(Name, HsType GhcRn)] -> a -> a -specialize specs = go +specialize specs = go spec_map0 where - go :: forall x. Data x => x -> x - go = everywhereButType @Name $ mkT $ sugar . strip_kind_sig . specialize_ty_var + go :: forall x. Data x => Map Name (HsType GhcRn) -> x -> x + go spec_map = everywhereButType @Name $ mkT $ sugar . strip_kind_sig . specialize_ty_var spec_map strip_kind_sig :: HsType name -> HsType name strip_kind_sig (HsKindSig _ (L _ t) _) = t strip_kind_sig typ = typ - specialize_ty_var :: HsType GhcRn -> HsType GhcRn - specialize_ty_var (HsTyVar _ _ (L _ name')) + specialize_ty_var :: Map Name (HsType GhcRn) -> HsType GhcRn -> HsType GhcRn + specialize_ty_var spec_map (HsTyVar _ _ (L _ name')) | Just t <- Map.lookup name' spec_map = t - specialize_ty_var typ = typ - -- This is a tricky recursive definition that is guaranteed to terminate - -- because a type binder cannot be instantiated with a type that depends - -- on that binder. i.e. @a -> Maybe a@ is invalid - spec_map = Map.fromList [ (n, go t) | (n, t) <- specs] + specialize_ty_var _ typ = typ + + -- This is a tricky recursive definition. By adding in the specializations + -- one by one, we should avoid infinite loops. + spec_map0 = foldr (\(n,t) acc -> Map.insert n (go acc t) acc) mempty specs -- | Instantiate given binders with corresponding types. |