Type.Infer: inferExpr: (case -> fmap)

Author: Anton-Latukha

src/Nix/Type/Infer.hs

@@ -257,9 +257,8 @@ inferType env ex = do
 
 -- | Solve for the toplevel type of an expression in a given environment
 inferExpr :: Env -> NExpr -> Either InferError [Scheme]
-inferExpr env ex = case runInfer (inferType env ex) of
-  Left  err -> Left err
-  Right xs  -> Right $ fmap (\(subst, ty) -> closeOver (subst `apply` ty)) xs
+inferExpr env ex =
+  (fmap . fmap) (\(subst, ty) -> closeOver (subst `apply` ty)) $ runInfer $ inferType env ex
 
 -- | Canonicalize and return the polymorphic toplevel type.
 closeOver :: Type -> Scheme