diff --git a/src/Codegen/Codegen.hs b/src/Codegen/Codegen.hs
index a9f521f..16ed84f 100644
--- a/src/Codegen/Codegen.hs
+++ b/src/Codegen/Codegen.hs
@@ -74,7 +74,7 @@ getFunctions bs = Map.fromList $ go bs
     go (MIR.DBind (MIR.Bind id args _) : xs) =
         (id, FunctionInfo{numArgs = length args, arguments = args})
             : go xs
-    go (MIR.DData (MIR.Data n cons) : xs) = undefined
+    go (MIR.DData (MIR.Constructor n cons) : xs) = undefined
         {-do map
                 ( \(Constructor id xs) ->
                     ( (id, MIR.TLit n)
@@ -96,8 +96,8 @@ createArgs xs = fst $ foldl (\(acc, l) t -> (acc ++ [(GA.Ident ("arg_" <> show l
 getConstructors :: [MIR.Def] -> Map Ident ConstructorInfo
 getConstructors bs = Map.fromList $ go bs
   where
-    go []                                 = []
-    go (MIR.DData (MIR.Data n cons) : xs) = undefined
+    go []                                        = []
+    go (MIR.DData (MIR.Constructor n cons) : xs) = undefined
         {-do
             fst
                 ( foldl
@@ -117,7 +117,7 @@ getConstructors bs = Map.fromList $ go bs
                     cons
                 )
             <> go xs-}
-    go (_ : xs)                           = go xs
+    go (_ : xs)                                  = go xs
 
 initCodeGenerator :: [MIR.Def] -> CodeGenerator
 initCodeGenerator scs =
@@ -260,7 +260,7 @@ compileScs (MIR.DBind (MIR.Bind (name, _t) args exp) : xs) = do
     emit DefineEnd
     modify $ \s -> s{variableCount = 0}
     compileScs xs
-compileScs (MIR.DData (MIR.Data outer_id ts) : xs) = do
+compileScs (MIR.DData (MIR.Constructor outer_id ts) : xs) = do
     undefined
 --    let biggestVariant = maximum ((\(Constructor _ t) -> sum $ typeByteSize . type2LlvmType <$> t) <$> ts)
 --    emit $ LIR.Type outer_id [I8, Array biggestVariant I8]
diff --git a/src/Monomorphizer/Monomorphizer.hs b/src/Monomorphizer/Monomorphizer.hs
index b0d8c67..c7506cb 100644
--- a/src/Monomorphizer/Monomorphizer.hs
+++ b/src/Monomorphizer/Monomorphizer.hs
@@ -2,53 +2,59 @@
 
 module Monomorphizer.Monomorphizer (monomorphize) where
 
-import           Grammar.Abs                   (Ident (..))
-import           Monomorphizer.MonomorphizerIr
+import           Data.Coerce                   (coerce)
+import           Grammar.Abs                   (Constructor (..), Ident (..),
+                                                Indexed (..))
 import qualified Monomorphizer.MonomorphizerIr as M
 import qualified TypeChecker.TypeCheckerIr     as T
 
-monomorphize :: T.Program -> Program
-monomorphize (T.Program ds) = Program $ monoDefs ds
+monomorphize :: T.Program -> M.Program
+monomorphize (T.Program ds) = M.Program $ monoDefs ds
 
-monoDefs :: [T.Def] -> [Def]
+monoDefs :: [T.Def] -> [M.Def]
 monoDefs = map monoDef
 
-monoDef :: T.Def -> Def
-monoDef (T.DBind bind) = DBind $ monoBind bind
-monoDef (T.DData d)    = DData d
+monoDef :: T.Def -> M.Def
+monoDef (T.DBind bind) = M.DBind $ monoBind bind
+monoDef (T.DData d)    = M.DData $ monoData d
 
-monoBind :: T.Bind -> Bind
-monoBind (T.Bind name args (e, t)) = Bind (monoId name) (map monoId args) (monoExpr e, monoType t)
+monoBind :: T.Bind -> M.Bind
+monoBind (T.Bind name args (e, t)) = M.Bind (monoId name) (map monoId args) (monoExpr e, monoType t)
+
+monoData :: T.Data -> M.Constructor
+monoData (T.Data (Indexed n _) cons) = undefined-- M.Constructor n (map (\(Constructor n t) -> (n, monoType t)) cons)
 
 monoExpr :: T.Exp -> M.Exp
 monoExpr = \case
-    T.EId (Ident i) -> EId (Ident i)
-    T.ELit lit -> ELit $ monoLit lit
-    T.ELet bind expt -> ELet (monoBind bind) (monoexpt expt)
-    T.EApp expt1 expt2 -> EApp (monoexpt expt1) (monoexpt expt2)
-    T.EAdd expt1 expt2 -> EAdd (monoexpt expt1) (monoexpt expt2)
+    T.EId (Ident i) -> M.EId (Ident i)
+    T.ELit lit -> M.ELit $ monoLit lit
+    T.ELet bind expt -> M.ELet (monoBind bind) (monoexpt expt)
+    T.EApp expt1 expt2 -> M.EApp (monoexpt expt1) (monoexpt expt2)
+    T.EAdd expt1 expt2 -> M.EAdd (monoexpt expt1) (monoexpt expt2)
     T.EAbs i expt -> error "BUG"
-    T.ECase expt injs -> ECase (monoexpt expt) (monoInjs injs)
+    T.ECase expt injs -> M.ECase (monoexpt expt) (monoInjs injs)
 
-monoType :: T.Type -> Type
+monoType :: T.Type -> M.Type
 monoType (T.TAll _ t)          = monoType t
 monoType (T.TVar (T.MkTVar i)) = error "NOT POLYMORPHIC TYPES"
-monoType (T.TLit i)            = TLit i
-monoType (T.TFun t1 t2)        = TFun (monoType t1) (monoType t2)
+monoType (T.TLit i)            = M.TLit i
+monoType (T.TFun t1 t2)        = M.TFun (monoType t1) (monoType t2)
 
 monoexpt :: T.ExpT -> M.ExpT
 monoexpt (e, t) = (monoExpr e, monoType t)
 
-monoId :: T.Id -> Id
+monoId :: T.Id -> M.Id
 monoId (n,t) = (n, monoType t)
 
-monoLit :: T.Lit -> Lit
-monoLit (T.LInt i)  = LInt i
-monoLit (T.LChar c) = LChar c
+monoLit :: T.Lit -> M.Lit
+monoLit (T.LInt i)  = M.LInt i
+monoLit (T.LChar c) = M.LChar c
 
+monoInjs :: [T.Inj] -> [M.Injection]
 monoInjs = map monoInj
 
-monoInj (T.Inj (init, t) expt) = Injection (monoInit init, monoType t) (monoexpt expt)
+monoInj :: T.Inj -> M.Injection
+monoInj (T.Inj (init, t) expt) = M.Injection (monoInit init, monoType t) (monoexpt expt)
 
-monoInit :: T.Init -> Init
+monoInit :: T.Init -> M.Init
 monoInit = id
diff --git a/src/Monomorphizer/MonomorphizerIr.hs b/src/Monomorphizer/MonomorphizerIr.hs
index 65d0c4b..18f29ed 100644
--- a/src/Monomorphizer/MonomorphizerIr.hs
+++ b/src/Monomorphizer/MonomorphizerIr.hs
@@ -1,8 +1,7 @@
 module Monomorphizer.MonomorphizerIr (module Monomorphizer.MonomorphizerIr, module RE, module GA) where
 
-import           Grammar.Abs               (Data (..), Ident (..), Init (..))
-import qualified Grammar.Abs               as GA (Data (..), Ident (..),
-                                                  Init (..))
+import           Grammar.Abs               (Ident (..), Init (..), UIdent)
+import qualified Grammar.Abs               as GA (Ident (..), Init (..))
 import qualified TypeChecker.TypeCheckerIr as RE (Indexed)
 import           TypeChecker.TypeCheckerIr (Indexed)
 
@@ -11,7 +10,7 @@ type Id = (Ident, Type)
 newtype Program = Program [Def]
     deriving (Show, Ord, Eq)
 
-data Def = DBind Bind | DData Data
+data Def = DBind Bind | DData Constructor
     deriving (Show, Ord, Eq)
 
 data Bind = Bind Id [Id] ExpT
@@ -31,7 +30,7 @@ data Injection = Injection (Init, Type) ExpT
 
 type ExpT = (Exp, Type)
 
-data Constructor = Constructor Ident [Type]
+data Constructor = Constructor UIdent [(UIdent, Type)]
     deriving (Show, Ord, Eq)
 
 data Lit