diff --git a/app/Commands/Dev/Tree/Read.hs b/app/Commands/Dev/Tree/Read.hs
index eddbe6b02d..1d47a13cba 100644
--- a/app/Commands/Dev/Tree/Read.hs
+++ b/app/Commands/Dev/Tree/Read.hs
@@ -15,10 +15,13 @@ runCommand opts = do
   case Tree.runParser (toFilePath afile) s of
     Left err -> exitJuvixError (JuvixError err)
     Right tab -> do
-      tab' <- Tree.applyTransformations (project opts ^. treeReadTransformations) tab
-      unless (project opts ^. treeReadNoPrint) $
-        renderStdOut (Tree.ppOutDefault tab' tab')
-      doEval tab'
+      r <- runError @JuvixError (Tree.applyTransformations (project opts ^. treeReadTransformations) tab)
+      case r of
+        Left err -> exitJuvixError (JuvixError err)
+        Right tab' -> do
+          unless (project opts ^. treeReadNoPrint) $
+            renderStdOut (Tree.ppOutDefault tab' tab')
+          doEval tab'
   where
     file :: AppPath File
     file = opts ^. treeReadInputFile
diff --git a/src/Juvix/Compiler/Asm/Extra/Memory.hs b/src/Juvix/Compiler/Asm/Extra/Memory.hs
index 6e08f8319d..96aab847dd 100644
--- a/src/Juvix/Compiler/Asm/Extra/Memory.hs
+++ b/src/Juvix/Compiler/Asm/Extra/Memory.hs
@@ -168,11 +168,11 @@ unifyMemory' loc tab mem1 mem2 = do
   unless (length (mem1 ^. memoryValueStack) == length (mem2 ^. memoryValueStack)) $
     throw $
       AsmError loc "value stack height mismatch"
-  vs <- zipWithM (unifyTypes' loc tab) (toList (mem1 ^. memoryValueStack)) (toList (mem2 ^. memoryValueStack))
+  vs <- zipWithM (unifyTypes'' loc tab) (toList (mem1 ^. memoryValueStack)) (toList (mem2 ^. memoryValueStack))
   unless (length (mem1 ^. memoryTempStack) == length (mem2 ^. memoryTempStack)) $
     throw $
       AsmError loc "temporary stack height mismatch"
-  ts <- zipWithM (unifyTypes' loc tab) (toList (mem1 ^. memoryTempStack)) (toList (mem2 ^. memoryTempStack))
+  ts <- zipWithM (unifyTypes'' loc tab) (toList (mem1 ^. memoryTempStack)) (toList (mem2 ^. memoryTempStack))
   unless
     ( length (mem1 ^. memoryArgumentArea) == length (mem2 ^. memoryArgumentArea)
         && mem1 ^. memoryArgsNum == mem2 ^. memoryArgsNum
@@ -183,7 +183,7 @@ unifyMemory' loc tab mem1 mem2 = do
   args <-
     mapM
       ( \off ->
-          unifyTypes'
+          unifyTypes''
             loc
             tab
             (fromJust $ HashMap.lookup off (mem1 ^. memoryArgumentArea))
diff --git a/src/Juvix/Compiler/Asm/Extra/Recursors.hs b/src/Juvix/Compiler/Asm/Extra/Recursors.hs
index 3bf2550030..6f2ce88ddc 100644
--- a/src/Juvix/Compiler/Asm/Extra/Recursors.hs
+++ b/src/Juvix/Compiler/Asm/Extra/Recursors.hs
@@ -130,7 +130,7 @@ recurse' sig = go True
               checkValueStack' loc (sig ^. recursorInfoTable) tyargs mem
               tys <-
                 zipWithM
-                  (\ty idx -> unifyTypes' loc (sig ^. recursorInfoTable) ty (topValueStack' idx mem))
+                  (\ty idx -> unifyTypes'' loc (sig ^. recursorInfoTable) ty (topValueStack' idx mem))
                   tyargs
                   [0 ..]
               return $
@@ -226,7 +226,7 @@ recurse' sig = go True
             checkValueStack' loc (sig ^. recursorInfoTable) (take argsNum (typeArgs ty)) mem'
           let tyargs = topValuesFromValueStack' argsNum mem'
           -- `typeArgs ty` may be shorter than `tyargs` only if `ty` is dynamic
-          zipWithM_ (unifyTypes' loc (sig ^. recursorInfoTable)) tyargs (typeArgs ty)
+          zipWithM_ (unifyTypes'' loc (sig ^. recursorInfoTable)) tyargs (typeArgs ty)
           return $
             pushValueStack (mkTypeFun (drop argsNum (typeArgs ty)) (typeTarget ty)) $
               popValueStack argsNum mem'
diff --git a/src/Juvix/Compiler/Asm/Extra/Type.hs b/src/Juvix/Compiler/Asm/Extra/Type.hs
index c8e040296c..26b94359c5 100644
--- a/src/Juvix/Compiler/Asm/Extra/Type.hs
+++ b/src/Juvix/Compiler/Asm/Extra/Type.hs
@@ -4,84 +4,18 @@ module Juvix.Compiler.Asm.Extra.Type
   )
 where
 
-import Data.List.NonEmpty qualified as NonEmpty
 import Juvix.Compiler.Asm.Data.InfoTable
 import Juvix.Compiler.Asm.Error
 import Juvix.Compiler.Asm.Language
-import Juvix.Compiler.Asm.Pretty
+import Juvix.Compiler.Tree.Error
 import Juvix.Compiler.Tree.Extra.Type
 
-unifyTypes :: forall r. (Members '[Error AsmError, Reader (Maybe Location), Reader InfoTable] r) => Type -> Type -> Sem r Type
-unifyTypes ty1 ty2 = case (ty1, ty2) of
-  (TyDynamic, x) -> return x
-  (x, TyDynamic) -> return x
-  (TyInductive TypeInductive {..}, TyConstr TypeConstr {..})
-    | _typeInductiveSymbol == _typeConstrInductive ->
-        return ty1
-  (TyConstr {}, TyInductive {}) -> unifyTypes ty2 ty1
-  (TyConstr c1, TyConstr c2)
-    | c1 ^. typeConstrInductive == c2 ^. typeConstrInductive
-        && c1 ^. typeConstrTag == c2 ^. typeConstrTag -> do
-        flds <- zipWithM unifyTypes (c1 ^. typeConstrFields) (c2 ^. typeConstrFields)
-        return $ TyConstr (set typeConstrFields flds c1)
-  (TyConstr c1, TyConstr c2)
-    | c1 ^. typeConstrInductive == c2 ^. typeConstrInductive ->
-        return $ TyInductive (TypeInductive (c1 ^. typeConstrInductive))
-  (TyFun t1, TyFun t2)
-    | length (t1 ^. typeFunArgs) == length (t2 ^. typeFunArgs) -> do
-        let args1 = toList (t1 ^. typeFunArgs)
-            args2 = toList (t2 ^. typeFunArgs)
-            tgt1 = t1 ^. typeFunTarget
-            tgt2 = t2 ^. typeFunTarget
-        args <- zipWithM unifyTypes args1 args2
-        tgt <- unifyTypes tgt1 tgt2
-        return $ TyFun (TypeFun (NonEmpty.fromList args) tgt)
-  (TyInteger (TypeInteger l1 u1), TyInteger (TypeInteger l2 u2)) ->
-    return $ TyInteger (TypeInteger (unifyBounds min l1 l2) (unifyBounds max u1 u2))
-    where
-      unifyBounds :: (Integer -> Integer -> Integer) -> Maybe Integer -> Maybe Integer -> Maybe Integer
-      unifyBounds _ Nothing _ = Nothing
-      unifyBounds _ _ Nothing = Nothing
-      unifyBounds f (Just x) (Just y) = Just (f x y)
-  (TyBool {}, TyBool {})
-    | ty1 == ty2 -> return ty1
-  (TyString, TyString) -> return TyString
-  (TyUnit, TyUnit) -> return TyUnit
-  (TyVoid, TyVoid) -> return TyVoid
-  (TyInductive {}, TyInductive {})
-    | ty1 == ty2 -> return ty1
-  (TyUnit, _) -> err
-  (_, TyUnit) -> err
-  (TyVoid, _) -> err
-  (_, TyVoid) -> err
-  (TyInteger {}, _) -> err
-  (_, TyInteger {}) -> err
-  (TyString, _) -> err
-  (_, TyString) -> err
-  (TyBool {}, _) -> err
-  (_, TyBool {}) -> err
-  (TyFun {}, _) -> err
-  (_, TyFun {}) -> err
-  (TyInductive {}, _) -> err
-  (_, TyConstr {}) -> err
+unifyTypes'' :: forall t e r. (Member (Error AsmError) r) => Maybe Location -> InfoTable' t e -> Type -> Type -> Sem r Type
+unifyTypes'' loc tab ty1 ty2 = mapError toAsmError $ unifyTypes' loc tab ty1 ty2
   where
-    err :: Sem r a
-    err = do
-      loc <- ask
-      tab <- ask
-      throw $ AsmError loc ("not unifiable: " <> ppTrace tab ty1 <> ", " <> ppTrace tab ty2)
-
-unifyTypes' :: (Member (Error AsmError) r) => Maybe Location -> InfoTable -> Type -> Type -> Sem r Type
-unifyTypes' loc tab ty1 ty2 =
-  runReader loc $
-    runReader tab $
-      -- The `if` is to ensure correct behaviour with dynamic type targets. E.g.
-      -- `(A, B) -> *` should unify with `A -> B -> C -> D`.
-      if
-          | tgt1 == TyDynamic || tgt2 == TyDynamic ->
-              unifyTypes (curryType ty1) (curryType ty2)
-          | otherwise ->
-              unifyTypes ty1 ty2
-  where
-    tgt1 = typeTarget (uncurryType ty1)
-    tgt2 = typeTarget (uncurryType ty2)
+    toAsmError :: TreeError -> AsmError
+    toAsmError TreeError {..} =
+      AsmError
+        { _asmErrorLoc = _treeErrorLoc,
+          _asmErrorMsg = _treeErrorMsg
+        }
diff --git a/src/Juvix/Compiler/Pipeline.hs b/src/Juvix/Compiler/Pipeline.hs
index 28e2ec550f..bdba8ab49b 100644
--- a/src/Juvix/Compiler/Pipeline.hs
+++ b/src/Juvix/Compiler/Pipeline.hs
@@ -176,7 +176,7 @@ coreToVampIR' = Core.toStored' >=> storedCoreToVampIR'
 -- Other workflows
 --------------------------------------------------------------------------------
 
-treeToAsm :: Tree.InfoTable -> Sem r Asm.InfoTable
+treeToAsm :: (Member (Error JuvixError) r) => Tree.InfoTable -> Sem r Asm.InfoTable
 treeToAsm = Tree.toAsm >=> return . Asm.fromTree
 
 treeToNockma :: (Members '[Error JuvixError, Reader EntryPoint] r) => Tree.InfoTable -> Sem r (Nockma.Cell Natural)
diff --git a/src/Juvix/Compiler/Tree/Data/TransformationId.hs b/src/Juvix/Compiler/Tree/Data/TransformationId.hs
index e001e0535a..6cd45861d5 100644
--- a/src/Juvix/Compiler/Tree/Data/TransformationId.hs
+++ b/src/Juvix/Compiler/Tree/Data/TransformationId.hs
@@ -11,6 +11,7 @@ data TransformationId
   | Apply
   | TempHeight
   | FilterUnreachable
+  | Validate
   deriving stock (Data, Bounded, Enum, Show)
 
 data PipelineId
@@ -21,10 +22,10 @@ data PipelineId
 type TransformationLikeId = TransformationLikeId' TransformationId PipelineId
 
 toNockmaTransformations :: [TransformationId]
-toNockmaTransformations = [Apply, FilterUnreachable, TempHeight]
+toNockmaTransformations = [Validate, Apply, FilterUnreachable, TempHeight]
 
 toAsmTransformations :: [TransformationId]
-toAsmTransformations = []
+toAsmTransformations = [Validate]
 
 instance TransformationId' TransformationId where
   transformationText :: TransformationId -> Text
@@ -35,6 +36,7 @@ instance TransformationId' TransformationId where
     Apply -> strApply
     TempHeight -> strTempHeight
     FilterUnreachable -> strFilterUnreachable
+    Validate -> strValidate
 
 instance PipelineId' TransformationId PipelineId where
   pipelineText :: PipelineId -> Text
diff --git a/src/Juvix/Compiler/Tree/Data/TransformationId/Strings.hs b/src/Juvix/Compiler/Tree/Data/TransformationId/Strings.hs
index 7e454ccbdc..41ed6a3974 100644
--- a/src/Juvix/Compiler/Tree/Data/TransformationId/Strings.hs
+++ b/src/Juvix/Compiler/Tree/Data/TransformationId/Strings.hs
@@ -25,3 +25,6 @@ strTempHeight = "temp-height"
 
 strFilterUnreachable :: Text
 strFilterUnreachable = "filter-unreachable"
+
+strValidate :: Text
+strValidate = "validate"
diff --git a/src/Juvix/Compiler/Tree/Extra/Type.hs b/src/Juvix/Compiler/Tree/Extra/Type.hs
index 9e25042770..f3382f12d8 100644
--- a/src/Juvix/Compiler/Tree/Extra/Type.hs
+++ b/src/Juvix/Compiler/Tree/Extra/Type.hs
@@ -1,7 +1,15 @@
+{-# LANGUAGE AllowAmbiguousTypes #-}
+{-# OPTIONS_GHC -Wno-unrecognised-pragmas #-}
+
+{-# HLINT ignore "Avoid restricted extensions" #-}
+{-# HLINT ignore "Avoid restricted flags" #-}
+
 module Juvix.Compiler.Tree.Extra.Type where
 
+import Juvix.Compiler.Tree.Data.InfoTable.Base
+import Juvix.Compiler.Tree.Error
 import Juvix.Compiler.Tree.Language.Base
-import Juvix.Compiler.Tree.Language.Type
+import Juvix.Compiler.Tree.Pretty
 
 mkTypeInteger :: Type
 mkTypeInteger = TyInteger (TypeInteger Nothing Nothing)
@@ -98,3 +106,78 @@ isSubtype' ty1 ty2
     tgt2 = typeTarget (uncurryType ty2)
 isSubtype' ty1 ty2 =
   isSubtype ty1 ty2
+
+unifyTypes :: forall t e r. (Members '[Error TreeError, Reader (Maybe Location), Reader (InfoTable' t e)] r) => Type -> Type -> Sem r Type
+unifyTypes ty1 ty2 = case (ty1, ty2) of
+  (TyDynamic, x) -> return x
+  (x, TyDynamic) -> return x
+  (TyInductive TypeInductive {..}, TyConstr TypeConstr {..})
+    | _typeInductiveSymbol == _typeConstrInductive ->
+        return ty1
+  (TyConstr {}, TyInductive {}) -> unifyTypes @t @e ty2 ty1
+  (TyConstr c1, TyConstr c2)
+    | c1 ^. typeConstrInductive == c2 ^. typeConstrInductive
+        && c1 ^. typeConstrTag == c2 ^. typeConstrTag -> do
+        flds <- zipWithM (unifyTypes @t @e) (c1 ^. typeConstrFields) (c2 ^. typeConstrFields)
+        return $ TyConstr (set typeConstrFields flds c1)
+  (TyConstr c1, TyConstr c2)
+    | c1 ^. typeConstrInductive == c2 ^. typeConstrInductive ->
+        return $ TyInductive (TypeInductive (c1 ^. typeConstrInductive))
+  (TyFun t1, TyFun t2)
+    | length (t1 ^. typeFunArgs) == length (t2 ^. typeFunArgs) -> do
+        let args1 = toList (t1 ^. typeFunArgs)
+            args2 = toList (t2 ^. typeFunArgs)
+            tgt1 = t1 ^. typeFunTarget
+            tgt2 = t2 ^. typeFunTarget
+        args <- zipWithM (unifyTypes @t @e) args1 args2
+        tgt <- unifyTypes @t @e tgt1 tgt2
+        return $ TyFun (TypeFun (nonEmpty' args) tgt)
+  (TyInteger (TypeInteger l1 u1), TyInteger (TypeInteger l2 u2)) ->
+    return $ TyInteger (TypeInteger (unifyBounds min l1 l2) (unifyBounds max u1 u2))
+    where
+      unifyBounds :: (Integer -> Integer -> Integer) -> Maybe Integer -> Maybe Integer -> Maybe Integer
+      unifyBounds _ Nothing _ = Nothing
+      unifyBounds _ _ Nothing = Nothing
+      unifyBounds f (Just x) (Just y) = Just (f x y)
+  (TyBool {}, TyBool {})
+    | ty1 == ty2 -> return ty1
+  (TyString, TyString) -> return TyString
+  (TyUnit, TyUnit) -> return TyUnit
+  (TyVoid, TyVoid) -> return TyVoid
+  (TyInductive {}, TyInductive {})
+    | ty1 == ty2 -> return ty1
+  (TyUnit, _) -> err
+  (_, TyUnit) -> err
+  (TyVoid, _) -> err
+  (_, TyVoid) -> err
+  (TyInteger {}, _) -> err
+  (_, TyInteger {}) -> err
+  (TyString, _) -> err
+  (_, TyString) -> err
+  (TyBool {}, _) -> err
+  (_, TyBool {}) -> err
+  (TyFun {}, _) -> err
+  (_, TyFun {}) -> err
+  (TyInductive {}, _) -> err
+  (_, TyConstr {}) -> err
+  where
+    err :: Sem r a
+    err = do
+      loc <- ask
+      tab <- ask @(InfoTable' t e)
+      throw $ TreeError loc ("not unifiable: " <> ppTrace' (defaultOptions tab) ty1 <> ", " <> ppTrace' (defaultOptions tab) ty2)
+
+unifyTypes' :: forall t e r. (Member (Error TreeError) r) => Maybe Location -> InfoTable' t e -> Type -> Type -> Sem r Type
+unifyTypes' loc tab ty1 ty2 =
+  runReader loc $
+    runReader tab $
+      -- The `if` is to ensure correct behaviour with dynamic type targets. E.g.
+      -- `(A, B) -> *` should unify with `A -> B -> C -> D`.
+      if
+          | tgt1 == TyDynamic || tgt2 == TyDynamic ->
+              unifyTypes @t @e (curryType ty1) (curryType ty2)
+          | otherwise ->
+              unifyTypes @t @e ty1 ty2
+  where
+    tgt1 = typeTarget (uncurryType ty1)
+    tgt2 = typeTarget (uncurryType ty2)
diff --git a/src/Juvix/Compiler/Tree/Pipeline.hs b/src/Juvix/Compiler/Tree/Pipeline.hs
index 001b92bc50..96ce8becac 100644
--- a/src/Juvix/Compiler/Tree/Pipeline.hs
+++ b/src/Juvix/Compiler/Tree/Pipeline.hs
@@ -7,8 +7,8 @@ where
 import Juvix.Compiler.Tree.Data.InfoTable
 import Juvix.Compiler.Tree.Transformation
 
-toNockma :: InfoTable -> Sem r InfoTable
+toNockma :: (Member (Error JuvixError) r) => InfoTable -> Sem r InfoTable
 toNockma = applyTransformations toNockmaTransformations
 
-toAsm :: InfoTable -> Sem r InfoTable
+toAsm :: (Member (Error JuvixError) r) => InfoTable -> Sem r InfoTable
 toAsm = applyTransformations toAsmTransformations
diff --git a/src/Juvix/Compiler/Tree/Transformation.hs b/src/Juvix/Compiler/Tree/Transformation.hs
index c16456c838..3f2e078e3d 100644
--- a/src/Juvix/Compiler/Tree/Transformation.hs
+++ b/src/Juvix/Compiler/Tree/Transformation.hs
@@ -6,13 +6,15 @@ module Juvix.Compiler.Tree.Transformation
 where
 
 import Juvix.Compiler.Tree.Data.TransformationId
+import Juvix.Compiler.Tree.Error
 import Juvix.Compiler.Tree.Transformation.Apply
 import Juvix.Compiler.Tree.Transformation.Base
 import Juvix.Compiler.Tree.Transformation.FilterUnreachable
 import Juvix.Compiler.Tree.Transformation.Identity
 import Juvix.Compiler.Tree.Transformation.TempHeight
+import Juvix.Compiler.Tree.Transformation.Validate
 
-applyTransformations :: forall r. [TransformationId] -> InfoTable -> Sem r InfoTable
+applyTransformations :: forall r. (Member (Error JuvixError) r) => [TransformationId] -> InfoTable -> Sem r InfoTable
 applyTransformations ts tbl = foldM (flip appTrans) tbl ts
   where
     appTrans :: TransformationId -> InfoTable -> Sem r InfoTable
@@ -23,3 +25,4 @@ applyTransformations ts tbl = foldM (flip appTrans) tbl ts
       Apply -> return . computeApply
       TempHeight -> return . computeTempHeight
       FilterUnreachable -> return . filterUnreachable
+      Validate -> mapError (JuvixError @TreeError) . validate
diff --git a/src/Juvix/Compiler/Tree/Transformation/Validate.hs b/src/Juvix/Compiler/Tree/Transformation/Validate.hs
new file mode 100644
index 0000000000..0fc486768d
--- /dev/null
+++ b/src/Juvix/Compiler/Tree/Transformation/Validate.hs
@@ -0,0 +1,266 @@
+module Juvix.Compiler.Tree.Transformation.Validate where
+
+import Juvix.Compiler.Core.Data.BinderList qualified as BL
+import Juvix.Compiler.Tree.Error
+import Juvix.Compiler.Tree.Extra.Base (getNodeLocation)
+import Juvix.Compiler.Tree.Extra.Recursors
+import Juvix.Compiler.Tree.Extra.Type
+import Juvix.Compiler.Tree.Transformation.Base
+
+inferType :: forall r. (Member (Error TreeError) r) => InfoTable -> FunctionInfo -> Node -> Sem r Type
+inferType tab funInfo = goInfer mempty
+  where
+    goInfer :: BinderList Type -> Node -> Sem r Type
+    goInfer bl = \case
+      Binop x -> goBinop bl x
+      Unop x -> goUnop bl x
+      Const x -> goConst bl x
+      MemRef x -> goMemRef bl x
+      AllocConstr x -> goAllocConstr bl x
+      AllocClosure x -> goAllocClosure bl x
+      ExtendClosure x -> goExtendClosure bl x
+      Call x -> goCall bl x
+      CallClosures x -> goCallClosures bl x
+      Branch x -> goBranch bl x
+      Case x -> goCase bl x
+      Save x -> goSave bl x
+
+    goBinop :: BinderList Type -> NodeBinop -> Sem r Type
+    goBinop bl NodeBinop {..} = case _nodeBinopOpcode of
+      IntAdd -> checkBinop mkTypeInteger mkTypeInteger mkTypeInteger
+      IntSub -> checkBinop mkTypeInteger mkTypeInteger mkTypeInteger
+      IntMul -> checkBinop mkTypeInteger mkTypeInteger mkTypeInteger
+      IntDiv -> checkBinop mkTypeInteger mkTypeInteger mkTypeInteger
+      IntMod -> checkBinop mkTypeInteger mkTypeInteger mkTypeInteger
+      IntLt -> checkBinop mkTypeInteger mkTypeInteger mkTypeBool
+      IntLe -> checkBinop mkTypeInteger mkTypeInteger mkTypeBool
+      ValEq -> checkBinop TyDynamic TyDynamic mkTypeBool
+      StrConcat -> checkBinop TyString TyString TyString
+      OpSeq -> do
+        checkType bl _nodeBinopArg1 TyDynamic
+        goInfer bl _nodeBinopArg2
+      where
+        loc = _nodeBinopInfo ^. nodeInfoLocation
+
+        checkBinop :: Type -> Type -> Type -> Sem r Type
+        checkBinop ty1' ty2' rty = do
+          ty1 <- goInfer bl _nodeBinopArg1
+          ty2 <- goInfer bl _nodeBinopArg2
+          void $ unifyTypes' loc tab ty1 ty1'
+          void $ unifyTypes' loc tab ty2 ty2'
+          return rty
+
+    goUnop :: BinderList Type -> NodeUnop -> Sem r Type
+    goUnop bl NodeUnop {..} = case _nodeUnopOpcode of
+      OpShow -> checkUnop TyDynamic TyString
+      OpStrToInt -> checkUnop TyString mkTypeInteger
+      OpTrace -> goInfer bl _nodeUnopArg
+      OpFail -> checkUnop TyDynamic TyDynamic
+      OpArgsNum -> checkUnop TyDynamic mkTypeInteger
+      where
+        loc = _nodeUnopInfo ^. nodeInfoLocation
+
+        checkUnop :: Type -> Type -> Sem r Type
+        checkUnop ty rty = do
+          ty' <- goInfer bl _nodeUnopArg
+          void $ unifyTypes' loc tab ty ty'
+          return rty
+
+    goConst :: BinderList Type -> NodeConstant -> Sem r Type
+    goConst _ NodeConstant {..} = case _nodeConstant of
+      ConstInt {} -> return mkTypeInteger
+      ConstBool {} -> return mkTypeBool
+      ConstString {} -> return TyString
+      ConstUnit {} -> return TyUnit
+      ConstVoid {} -> return TyVoid
+
+    goMemRef :: BinderList Type -> NodeMemRef -> Sem r Type
+    goMemRef bl NodeMemRef {..} = case _nodeMemRef of
+      DRef d -> goDirectRef (_nodeMemRefInfo ^. nodeInfoLocation) bl d
+      ConstrRef x -> goField bl x
+
+    goDirectRef :: Maybe Location -> BinderList Type -> DirectRef -> Sem r Type
+    goDirectRef loc bl = \case
+      ArgRef x -> goArgRef loc bl x
+      TempRef RefTemp {..} -> goTempRef bl _refTempOffsetRef
+
+    goArgRef :: Maybe Location -> BinderList Type -> OffsetRef -> Sem r Type
+    goArgRef loc _ OffsetRef {..}
+      | _offsetRefOffset < length tys = return $ tys !! _offsetRefOffset
+      | typeTarget (funInfo ^. functionType) == TyDynamic = return TyDynamic
+      | otherwise =
+          throw $
+            TreeError
+              { _treeErrorLoc = loc,
+                _treeErrorMsg = "Wrong target type"
+              }
+      where
+        tys = typeArgs (funInfo ^. functionType)
+
+    goTempRef :: BinderList Type -> OffsetRef -> Sem r Type
+    goTempRef bl OffsetRef {..} = return $ BL.lookupLevel _offsetRefOffset bl
+
+    goField :: BinderList Type -> Field -> Sem r Type
+    goField _ Field {..}
+      | _fieldOffset < length tys = return $ tys !! _fieldOffset
+      | otherwise = return TyDynamic
+      where
+        ci = lookupConstrInfo tab _fieldTag
+        tys = typeArgs (ci ^. constructorType)
+
+    goAllocConstr :: BinderList Type -> NodeAllocConstr -> Sem r Type
+    goAllocConstr bl NodeAllocConstr {..}
+      | length _nodeAllocConstrArgs == length tys = do
+          forM_ (zipExact _nodeAllocConstrArgs tys) (uncurry (checkType bl))
+          return $ typeTarget (ci ^. constructorType)
+      | otherwise =
+          throw $
+            TreeError
+              { _treeErrorLoc = _nodeAllocConstrInfo ^. nodeInfoLocation,
+                _treeErrorMsg = ""
+              }
+      where
+        ci = lookupConstrInfo tab _nodeAllocConstrTag
+        tys = typeArgs (ci ^. constructorType)
+
+    goAllocClosure :: BinderList Type -> NodeAllocClosure -> Sem r Type
+    goAllocClosure bl NodeAllocClosure {..}
+      | n <= fi ^. functionArgsNum = do
+          forM_ (zipExact _nodeAllocClosureArgs (take n tys)) (uncurry (checkType bl))
+          return $ mkTypeFun (drop n tys) (typeTarget (fi ^. functionType))
+      | otherwise =
+          throw $
+            TreeError
+              { _treeErrorLoc = _nodeAllocClosureInfo ^. nodeInfoLocation,
+                _treeErrorMsg = "Wrong number of arguments"
+              }
+      where
+        n = length _nodeAllocClosureArgs
+        fi = lookupFunInfo tab _nodeAllocClosureFunSymbol
+        tys = typeArgs (fi ^. functionType)
+
+    goExtendClosure :: BinderList Type -> NodeExtendClosure -> Sem r Type
+    goExtendClosure bl NodeExtendClosure {..} = do
+      ty <- goInfer bl _nodeExtendClosureFun
+      let tys = typeArgs ty
+          m = length tys
+          n = length _nodeExtendClosureArgs
+      if
+          | n < m -> do
+              forM_ (zipExact (toList _nodeExtendClosureArgs) (take n tys)) (uncurry (checkType bl))
+              return $ mkTypeFun (drop n tys) (typeTarget ty)
+          | typeTarget ty == TyDynamic -> do
+              let tys' = tys ++ replicate (n - m) TyDynamic
+              forM_ (zipExact (toList _nodeExtendClosureArgs) tys') (uncurry (checkType bl))
+              return $ typeTarget ty
+          | otherwise ->
+              throw $
+                TreeError
+                  { _treeErrorLoc = _nodeExtendClosureInfo ^. nodeInfoLocation,
+                    _treeErrorMsg = "Too many arguments"
+                  }
+
+    goCall :: BinderList Type -> NodeCall -> Sem r Type
+    goCall bl NodeCall {..} = case _nodeCallType of
+      CallFun sym
+        | n == fi ^. functionArgsNum -> do
+            unless (n == 0) $
+              forM_ (zipExact _nodeCallArgs tys) (uncurry (checkType bl))
+            return $ mkTypeFun (drop n tys) (typeTarget (fi ^. functionType))
+        | otherwise ->
+            throw $
+              TreeError
+                { _treeErrorLoc = _nodeCallInfo ^. nodeInfoLocation,
+                  _treeErrorMsg = "Wrong number of arguments"
+                }
+        where
+          n = length _nodeCallArgs
+          fi = lookupFunInfo tab sym
+          tys = typeArgs (fi ^. functionType)
+      CallClosure cl -> do
+        ty <- goInfer bl cl
+        let tys = typeArgs ty
+            n = length _nodeCallArgs
+        when (length tys > n) $
+          throw $
+            TreeError
+              { _treeErrorLoc = _nodeCallInfo ^. nodeInfoLocation,
+                _treeErrorMsg = "Too few arguments"
+              }
+        when (length tys < n && typeTarget ty /= TyDynamic) $
+          throw $
+            TreeError
+              { _treeErrorLoc = _nodeCallInfo ^. nodeInfoLocation,
+                _treeErrorMsg = "Too many arguments"
+              }
+        let tys' = tys ++ replicate (n - length tys) TyDynamic
+        forM_ (zipExact _nodeCallArgs tys') (uncurry (checkType bl))
+        return $ typeTarget ty
+
+    goCallClosures :: BinderList Type -> NodeCallClosures -> Sem r Type
+    goCallClosures bl NodeCallClosures {..} = do
+      ty <- goInfer bl _nodeCallClosuresFun
+      go ty (toList _nodeCallClosuresArgs)
+      where
+        go :: Type -> [Node] -> Sem r Type
+        go ty args
+          | m == 0 =
+              return ty
+          | m <= n = do
+              forM_ (zipExact (take m args) tys) (uncurry (checkType bl))
+              go (typeTarget ty) (drop m args)
+          | otherwise = do
+              forM_ (zipExact args (take n tys)) (uncurry (checkType bl))
+              return $ mkTypeFun (drop n tys) (typeTarget ty)
+          where
+            tys = typeArgs ty
+            m = length tys
+            n = length args
+
+    goBranch :: BinderList Type -> NodeBranch -> Sem r Type
+    goBranch bl NodeBranch {..} = do
+      checkType bl _nodeBranchArg mkTypeBool
+      ty1 <- goInfer bl _nodeBranchTrue
+      ty2 <- goInfer bl _nodeBranchFalse
+      unifyTypes' (_nodeBranchInfo ^. nodeInfoLocation) tab ty1 ty2
+
+    goCase :: BinderList Type -> NodeCase -> Sem r Type
+    goCase bl NodeCase {..} = do
+      ity <- goInfer bl _nodeCaseArg
+      unless (ity == mkTypeInductive _nodeCaseInductive || ity == TyDynamic) $
+        throw $
+          TreeError
+            { _treeErrorLoc = _nodeCaseInfo ^. nodeInfoLocation,
+              _treeErrorMsg = "Inductive type mismatch"
+            }
+      ty <- maybe (return TyDynamic) (goInfer bl) _nodeCaseDefault
+      go ity ty _nodeCaseBranches
+      where
+        go :: Type -> Type -> [CaseBranch] -> Sem r Type
+        go ity ty = \case
+          [] -> return ty
+          CaseBranch {..} : brs -> do
+            let bl' = if _caseBranchSave then BL.cons ity bl else bl
+            ty' <- goInfer bl' _caseBranchBody
+            ty'' <- unifyTypes' (_nodeCaseInfo ^. nodeInfoLocation) tab ty ty'
+            go ity ty'' brs
+
+    goSave :: BinderList Type -> NodeSave -> Sem r Type
+    goSave bl NodeSave {..} = do
+      ty <- goInfer bl _nodeSaveArg
+      goInfer (BL.cons ty bl) _nodeSaveBody
+
+    checkType :: BinderList Type -> Node -> Type -> Sem r ()
+    checkType bl node ty = do
+      ty' <- goInfer bl node
+      void $ unifyTypes' (getNodeLocation node) tab ty ty'
+
+validateFunction :: (Member (Error TreeError) r) => InfoTable -> FunctionInfo -> Sem r FunctionInfo
+validateFunction tab funInfo = do
+  ty <- inferType tab funInfo (funInfo ^. functionCode)
+  let ty' = if funInfo ^. functionArgsNum == 0 then funInfo ^. functionType else typeTarget (funInfo ^. functionType)
+  void $ unifyTypes' (funInfo ^. functionLocation) tab ty ty'
+  return funInfo
+
+validate :: (Member (Error TreeError) r) => InfoTable -> Sem r InfoTable
+validate tab = mapFunctionsM (validateFunction tab) tab
diff --git a/test/Tree/Eval/Base.hs b/test/Tree/Eval/Base.hs
index 4c2d93cfa7..6f98965f7d 100644
--- a/test/Tree/Eval/Base.hs
+++ b/test/Tree/Eval/Base.hs
@@ -35,25 +35,31 @@ treeEvalAssertionParam evalParam mainFile expectedFile trans testTrans step = do
   case runParser (toFilePath mainFile) s of
     Left err -> assertFailure (show (pretty err))
     Right tab0 -> do
-      unless (null trans) $
-        step "Transform"
-      let tab = run $ applyTransformations trans tab0
-      testTrans tab
-      case tab ^. infoMainFunction of
-        Just sym -> do
-          withTempDir'
-            ( \dirPath -> do
-                let outputFile = dirPath <//> $(mkRelFile "out.out")
-                hout <- openFile (toFilePath outputFile) WriteMode
-                step "Evaluate"
-                evalParam hout sym tab
-                hClose hout
-                actualOutput <- readFile (toFilePath outputFile)
-                step "Compare expected and actual program output"
-                expected <- readFile (toFilePath expectedFile)
-                assertEqDiffText ("Check: RUN output = " <> toFilePath expectedFile) actualOutput expected
-            )
-        Nothing -> assertFailure "no 'main' function"
+      step "Validate"
+      case run $ runError @JuvixError $ applyTransformations [Validate] tab0 of
+        Left err -> assertFailure (show (pretty (fromJuvixError @GenericError err)))
+        Right tab1 -> do
+          unless (null trans) $
+            step "Transform"
+          case run $ runError @JuvixError $ applyTransformations trans tab1 of
+            Left err -> assertFailure (show (pretty (fromJuvixError @GenericError err)))
+            Right tab -> do
+              testTrans tab
+              case tab ^. infoMainFunction of
+                Just sym -> do
+                  withTempDir'
+                    ( \dirPath -> do
+                        let outputFile = dirPath <//> $(mkRelFile "out.out")
+                        hout <- openFile (toFilePath outputFile) WriteMode
+                        step "Evaluate"
+                        evalParam hout sym tab
+                        hClose hout
+                        actualOutput <- readFile (toFilePath outputFile)
+                        step "Compare expected and actual program output"
+                        expected <- readFile (toFilePath expectedFile)
+                        assertEqDiffText ("Check: RUN output = " <> toFilePath expectedFile) actualOutput expected
+                    )
+                Nothing -> assertFailure "no 'main' function"
 
 evalAssertion :: Handle -> Symbol -> InfoTable -> IO ()
 evalAssertion hout sym tab = do
diff --git a/tests/Asm/positive/test032.jva b/tests/Asm/positive/test032.jva
index d0d08b3368..4449224805 100644
--- a/tests/Asm/positive/test032.jva
+++ b/tests/Asm/positive/test032.jva
@@ -99,7 +99,7 @@ function uncurry(*, * -> *, *) {
   tccall 2;
 }
 
-function pred_step(Pair) : (* -> *, *) -> * {
+function pred_step(Pair) : Pair {
   push arg[0].pair[1];
   call isZero;
   br {
diff --git a/tests/Tree/positive/test032.jvt b/tests/Tree/positive/test032.jvt
index 41e99ffb64..4a4c50b650 100644
--- a/tests/Tree/positive/test032.jvt
+++ b/tests/Tree/positive/test032.jvt
@@ -101,7 +101,7 @@ function uncurry(*, * → *, *) : * {
   ccall(arg[0], arg[1], arg[2])
 }
 
-function pred_step(Pair) : (* → *, *) → * {
+function pred_step(Pair) : Pair {
   br(call[isZero](arg[0].pair[1])) {
     true: alloc[pair](arg[0].pair[0], calloc[uncurry](calloc[succ](arg[0].pair[1])))
     false: alloc[pair](calloc[uncurry](calloc[succ](arg[0].pair[0])), calloc[uncurry](calloc[succ](arg[0].pair[1])))