From 00dc20a00cc18b346730d7e3ea8c714058407c4d Mon Sep 17 00:00:00 2001
From: TurtlePU <sokolov.p64@gmail.com>
Date: Tue, 17 Dec 2024 01:48:44 +0300
Subject: [PATCH] fix ListItem

---
 .../src/ZkFold/Symbolic/Data/List.hs          | 24 +++++++------------
 symbolic-base/test/Tests/List.hs              |  9 +++++--
 2 files changed, 15 insertions(+), 18 deletions(-)

diff --git a/symbolic-base/src/ZkFold/Symbolic/Data/List.hs b/symbolic-base/src/ZkFold/Symbolic/Data/List.hs
index 66252af01..2b8e2b28f 100644
--- a/symbolic-base/src/ZkFold/Symbolic/Data/List.hs
+++ b/symbolic-base/src/ZkFold/Symbolic/Data/List.hs
@@ -29,30 +29,22 @@ import           ZkFold.Symbolic.Data.Payloaded   (Payloaded (Payloaded))
 import           ZkFold.Symbolic.Data.UInt        (UInt)
 import           ZkFold.Symbolic.MonadCircuit
 
-data ListItem x a = ListItem
-  { tailHash    :: Layout x a
-  , headLayout  :: Layout x a
-  , headPayload :: Payload x a
+data ListItem l p a = ListItem
+  { tailHash    :: l a
+  , headLayout  :: l a
+  , headPayload :: p a
   }
-  deriving (Generic1)
+  deriving (Functor, Generic1)
 
-deriving instance
-  (Functor (Layout x), Functor (Payload x)) =>
-  Functor (ListItem x)
-
-instance
-    (Representable (Layout x), Representable (Payload x)) =>
-    Distributive (ListItem x) where
+instance (Representable l, Representable p) => Distributive (ListItem l p) where
   distribute = distributeRep
 
-instance
-  (Representable (Layout x), Representable (Payload x)) =>
-  Representable (ListItem x)
+instance (Representable l, Representable p) => Representable (ListItem l p)
 
 data List c x = List
   { lHash    :: c (Layout x)
   , lSize    :: c Par1
-  , lWitness :: Payloaded (Infinite :.: ListItem x) c
+  , lWitness :: Payloaded (Infinite :.: ListItem (Layout x) (Payload x)) c
   }
   deriving (Generic)
 
diff --git a/symbolic-base/test/Tests/List.hs b/symbolic-base/test/Tests/List.hs
index 884b11bb5..25336c7b3 100644
--- a/symbolic-base/test/Tests/List.hs
+++ b/symbolic-base/test/Tests/List.hs
@@ -16,11 +16,11 @@ import           ZkFold.Base.Algebra.Basic.Class             (one)
 import           ZkFold.Base.Algebra.Basic.Field             (Zp)
 import           ZkFold.Base.Algebra.EllipticCurve.BLS12_381 (BLS12_381_Scalar)
 import           ZkFold.Symbolic.Class                       (Arithmetic, Symbolic)
-import           ZkFold.Symbolic.Compiler                    (compile, eval1)
+import           ZkFold.Symbolic.Compiler                    (acOutput, compile, eval1)
 import           ZkFold.Symbolic.Data.Bool                   (Bool)
 import           ZkFold.Symbolic.Data.Eq                     ((==))
 import           ZkFold.Symbolic.Data.FieldElement           (FieldElement)
-import           ZkFold.Symbolic.Data.List                   (emptyList, head, tail, (.:))
+import           ZkFold.Symbolic.Data.List                   (List, emptyList, head, tail, (.:))
 
 headTest :: Symbolic c => FieldElement c -> FieldElement c -> Bool c
 headTest x y = head (x .: y .: emptyList) == x
@@ -28,8 +28,13 @@ headTest x y = head (x .: y .: emptyList) == x
 tailTest :: Symbolic c => FieldElement c -> FieldElement c -> Bool c
 tailTest x y = head (tail (x .: y .: emptyList)) == y
 
+headFun :: Symbolic c => List c (FieldElement c) -> FieldElement c
+headFun = head
+
 specList' :: forall a. (Arbitrary a, Arithmetic a, Binary a, Show a) => IO ()
 specList' = hspec $ describe "List spec" $ do
+  let _headChecks = -- compile-time test
+                    acOutput (compile @a headFun)
   prop "Head works fine" $ \x y ->
     eval1 (compile @a headTest) (U1 :*: U1 :*: U1) (Par1 x :*: Par1 y :*: U1)
       Haskell.== one