diff --git a/src/Codegen/Codegen.hs b/src/Codegen/Codegen.hs
index 4e95102..ec20273 100644
--- a/src/Codegen/Codegen.hs
+++ b/src/Codegen/Codegen.hs
@@ -317,7 +317,7 @@ compileExp (MIR.ECase e cs,t)   = emitECased t e (map (t,) cs)
 -- go (EMod e1 e2)  = emitMod e1 e2
 
 --- aux functions ---
-emitECased :: MIR.Type -> ExpT -> [(MIR.Type, Injection)] -> CompilerState ()
+emitECased :: MIR.Type -> ExpT -> [(MIR.Type, Branch)] -> CompilerState ()
 emitECased t e cases = do
     let cs = snd <$> cases
     let ty = type2LlvmType t
@@ -332,8 +332,8 @@ emitECased t e cases = do
     res <- getNewVar
     emit $ SetVariable res (Load ty Ptr stackPtr)
   where
-    emitCases :: LLVMType -> LLVMType -> GA.Ident -> GA.Ident -> LLVMValue -> Injection -> CompilerState ()
-    emitCases rt ty label stackPtr vs (Injection (MIR.InitConstructor consId cs, t) exp) = do
+    emitCases :: LLVMType -> LLVMType -> GA.Ident -> GA.Ident -> LLVMValue -> Branch -> CompilerState ()
+    emitCases rt ty label stackPtr vs (Branch (MIR.PInj consId cs, t) exp) = do
         cons <- gets constructors
         let r = fromJust $ Map.lookup (coerce consId, t) cons
 
@@ -380,10 +380,10 @@ emitECased t e cases = do
         -- emit $ Store ty val Ptr stackPtr
         emit $ Br label
         emit $ Label lbl_failPos
-    emitCases rt ty label stackPtr vs (Injection (MIR.InitLit i, _) exp) = do
+    emitCases rt ty label stackPtr vs (Branch (MIR.PLit i, _) exp) = do
         let i' = case i of
-                GA.LInt i  -> VInteger i
-                GA.LChar i -> VChar i
+                (MIR.LInt i, _)  -> VInteger i
+                (MIR.LChar i, _) -> VChar i
         ns <- getNewVar
         lbl_failPos <- (\x -> GA.Ident $ "failed_" <> show x) <$> getNewLabel
         lbl_succPos <- (\x -> GA.Ident $ "success_" <> show x) <$> getNewLabel
@@ -404,7 +404,7 @@ emitECased t e cases = do
 --         val <- exprToValue (fst exp)
 --         emit $ Store ty val Ptr stackPtr
 --         emit $ Br label
-    emitCases _ ty label stackPtr _ (Injection (MIR.InitCatch, _) exp) = do
+    emitCases _ ty label stackPtr _ (Branch (MIR.PCatch, _) exp) = do
         val <- exprToValue exp
         emit $ Store ty val Ptr stackPtr
         emit $ Br label
diff --git a/src/Monomorphizer/Monomorphizer.hs b/src/Monomorphizer/Monomorphizer.hs
index a4b92e1..70483ad 100644
--- a/src/Monomorphizer/Monomorphizer.hs
+++ b/src/Monomorphizer/Monomorphizer.hs
@@ -25,7 +25,7 @@ monoBind (T.Bind name args (e, t)) = M.Bind (monoId name) (map monoId args) (mon
 
 monoExpr :: T.Exp -> M.Exp
 monoExpr = \case
-    T.EId (Ident i) -> M.EId (Ident i)
+    T.EId (T.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)
@@ -44,7 +44,7 @@ monoAbsType (GA.TIndexed _) = error "NOT INDEXED TYPES"
 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)            = M.TLit i
+monoType (T.TLit (T.Ident i))  = M.TLit (Ident i)
 monoType (T.TFun t1 t2)        = M.TFun (monoType t1) (monoType t2)
 monoType (T.TData _ _)         = error "Not sure what this is"
 
@@ -52,17 +52,20 @@ monoexpt :: T.ExpT -> M.ExpT
 monoexpt (e, t) = (monoExpr e, monoType t)
 
 monoId :: T.Id -> M.Id
-monoId (n, t) = (n, monoType t)
+monoId (n, t) = (coerce n, monoType t)
 
 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 :: [T.Branch] -> [M.Branch]
 monoInjs = map monoInj
 
-monoInj :: T.Inj -> M.Injection
-monoInj (T.Inj (init, t) expt) = M.Injection (monoInit init, monoType t) (monoexpt expt)
+monoInj :: T.Branch -> M.Branch
+monoInj (T.Branch (init, t) expt) = M.Branch (monoInit init, monoType t) (monoexpt expt)
 
-monoInit :: T.Init -> M.Init
-monoInit = id
+monoInit :: T.Pattern -> M.Pattern
+monoInit (T.PVar (id, t))  = M.PVar (coerce id, monoType t)
+monoInit (T.PLit (lit, t)) = M.PLit (monoLit lit, monoType t)
+monoInit (T.PInj id ps)    = M.PInj (coerce id) (monoInit <$> ps)
+monoInit T.PCatch          = M.PCatch
diff --git a/src/Monomorphizer/MonomorphizerIr.hs b/src/Monomorphizer/MonomorphizerIr.hs
index 4d71363..e4c4bad 100644
--- a/src/Monomorphizer/MonomorphizerIr.hs
+++ b/src/Monomorphizer/MonomorphizerIr.hs
@@ -24,10 +24,13 @@ data Exp
     | ELet Bind ExpT
     | EApp ExpT ExpT
     | EAdd ExpT ExpT
-    | ECase ExpT [Injection]
+    | ECase ExpT [Branch]
     deriving (Show, Ord, Eq)
 
-data Injection = Injection (Init, Type) ExpT
+data Pattern = PVar Id | PLit (Lit, Type) | PInj Ident [Pattern] | PCatch
+    deriving (Eq, Ord, Show)
+
+data Branch = Branch (Pattern, Type) ExpT
     deriving (Eq, Ord, Show)
 
 type ExpT = (Exp, Type)