diff --git a/src/main/compile/dune b/src/main/compile/dune
index e59679ba5..7629e3d2b 100644
--- a/src/main/compile/dune
+++ b/src/main/compile/dune
@@ -9,6 +9,7 @@
     interpreter
     ast_simplified
     self_ast_simplified
+    self_ast_typed
     typer_new
     typer
     ast_typed
diff --git a/src/main/compile/of_simplified.ml b/src/main/compile/of_simplified.ml
index 488e809ac..f5271382c 100644
--- a/src/main/compile/of_simplified.ml
+++ b/src/main/compile/of_simplified.ml
@@ -3,12 +3,15 @@ open Trace
 let compile (program : Ast_simplified.program) : (Ast_typed.program * Typer.Solver.state) result =
   let%bind (prog_typed , state) = Typer.type_program program in
   let () = Typer.Solver.discard_state state in
-  ok @@ (prog_typed, state)
+  let%bind prog_typed' = Self_ast_typed.all_program prog_typed in
+  ok @@ (prog_typed', state)
 
 let compile_expression ?(env = Ast_typed.Environment.full_empty) ~(state : Typer.Solver.state) (ae : Ast_simplified.expression)
     : (Ast_typed.expression * Typer.Solver.state) result =
+  let%bind (ae_typed,state) = Typer.type_expression_subst env state ae in
   let () = Typer.Solver.discard_state state in
-  Typer.type_expression_subst env state ae
+  let%bind ae_typed' = Self_ast_typed.all_expression ae_typed in
+  ok @@ (ae_typed',state)
 
 let apply (entry_point : string) (param : Ast_simplified.expression) : Ast_simplified.expression result =
   let name = Var.of_name entry_point in
diff --git a/src/passes/5-self_ast_typed/dune b/src/passes/5-self_ast_typed/dune
new file mode 100644
index 000000000..0fc22a1d3
--- /dev/null
+++ b/src/passes/5-self_ast_typed/dune
@@ -0,0 +1,12 @@
+(library
+  (name self_ast_typed)
+  (public_name ligo.self_ast_typed)
+  (libraries
+    simple-utils
+    ast_typed
+  )
+  (preprocess
+    (pps ppx_let bisect_ppx --conditional)
+  )
+  (flags (:standard -w +1..62-4-9-44-40-42-48-30@39@33 -open Simple_utils ))
+)
diff --git a/src/passes/5-self_ast_typed/helpers.ml b/src/passes/5-self_ast_typed/helpers.ml
new file mode 100644
index 000000000..e65d497d9
--- /dev/null
+++ b/src/passes/5-self_ast_typed/helpers.ml
@@ -0,0 +1,311 @@
+open Ast_typed
+open Trace
+open Stage_common.Helpers
+
+type 'a folder = 'a -> expression -> 'a result
+let rec fold_expression : 'a folder -> 'a -> expression -> 'a result = fun f init e ->
+  let self = fold_expression f in 
+  let%bind init' = f init e in
+  match e.expression_content with
+  | E_literal _ | E_variable _ -> ok init'
+  | E_list lst | E_set lst | E_constant {arguments=lst} -> (
+    let%bind res = bind_fold_list self init' lst in
+    ok res
+  )
+  | E_map lst | E_big_map lst -> (
+    let%bind res = bind_fold_list (bind_fold_pair self) init' lst in
+    ok res
+  )
+  | E_look_up ab ->
+      let%bind res = bind_fold_pair self init' ab in
+      ok res
+  | E_loop {condition;body} ->
+      let ab = (condition,body) in 
+      let%bind res = bind_fold_pair self init' ab in
+      ok res
+  | E_application {expr1;expr2} -> (
+      let ab = (expr1,expr2) in
+      let%bind res = bind_fold_pair self init' ab in
+      ok res
+    )
+  | E_lambda { binder = _ ; result = e }
+  | E_constructor {element=e} -> (
+      let%bind res = self init' e in
+      ok res
+    )
+  | E_matching {matchee=e; cases} -> (
+      let%bind res = self init' e in
+      let%bind res = fold_cases f res cases in
+      ok res
+    )
+  | E_record m -> (
+    let aux init'' _ expr =
+      let%bind res = fold_expression self init'' expr in
+      ok res
+    in
+    let%bind res = bind_fold_lmap aux (ok init') m in
+    ok res
+  )
+  | E_record_update {record;update} -> (
+    let%bind res = self init' record in
+    let%bind res = fold_expression self res update in
+    ok res 
+  )
+  | E_record_accessor {expr} -> (
+     let%bind res = self init' expr in
+     ok res
+    )
+  | E_let_in { let_binder = _ ; rhs ; let_result } -> (
+      let%bind res = self init' rhs in
+      let%bind res = self res let_result in
+      ok res
+    )
+
+and fold_cases : 'a folder -> 'a -> matching_expr -> 'a result = fun f init m ->
+  match m with
+  | Match_bool { match_true ; match_false } -> (
+      let%bind res = fold_expression f init match_true in
+      let%bind res = fold_expression f res match_false in
+      ok res
+    )
+  | Match_list { match_nil ; match_cons = (_ , _ , cons, _) } -> (
+      let%bind res = fold_expression f init match_nil in
+      let%bind res = fold_expression f res cons in
+      ok res
+    )
+  | Match_option { match_none ; match_some = (_ , some, _) } -> (
+      let%bind res = fold_expression f init match_none in
+      let%bind res = fold_expression f res some in
+      ok res
+    )
+  | Match_tuple ((_ , e), _) -> (
+      let%bind res = fold_expression f init e in
+      ok res
+    )
+  | Match_variant (lst, _) -> (
+      let aux init' ((_ , _) , e) =
+        let%bind res' = fold_expression f init' e in
+        ok res' in
+      let%bind res = bind_fold_list aux init lst in
+      ok res
+    )
+
+type mapper = expression -> expression result
+let rec map_expression : mapper -> expression -> expression result = fun f e ->
+  let self = map_expression f in
+  let%bind e' = f e in
+  let return expression_content = ok { e' with expression_content } in
+  match e'.expression_content with
+  | E_list lst -> (
+    let%bind lst' = bind_map_list self lst in
+    return @@ E_list lst'
+  )
+  | E_set lst -> (
+    let%bind lst' = bind_map_list self lst in
+    return @@ E_set lst'
+  )
+  | E_map lst -> (
+    let%bind lst' = bind_map_list (bind_map_pair self) lst in
+    return @@ E_map lst'
+  )
+  | E_big_map lst -> (
+    let%bind lst' = bind_map_list (bind_map_pair self) lst in
+    return @@ E_big_map lst'
+  )
+  | E_look_up ab -> (
+      let%bind ab' = bind_map_pair self ab in
+      return @@ E_look_up ab'
+    )
+  | E_loop {condition;body} -> (
+      let ab = (condition,body) in
+      let%bind (a,b) = bind_map_pair self ab in
+      return @@ E_loop {condition = a; body = b}
+    )
+  | E_matching {matchee=e;cases} -> (
+      let%bind e' = self e in
+      let%bind cases' = map_cases f cases in
+      return @@ E_matching {matchee=e';cases=cases'}
+    )
+  | E_record_accessor acc -> (
+      let%bind e' = self acc.expr in
+      return @@ E_record_accessor {acc with expr = e'}
+    )
+  | E_record m -> (
+    let%bind m' = bind_map_lmap self m in
+    return @@ E_record m'
+  )
+  | E_record_update {record; path; update} -> (
+    let%bind record = self record in
+    let%bind update = self update in
+    return @@ E_record_update {record;path;update}
+  )
+  | E_constructor c -> (
+      let%bind e' = self c.element in
+      return @@ E_constructor {c with element = e'}
+  )
+  | E_application {expr1;expr2} -> (
+      let ab = (expr1,expr2) in
+      let%bind (a,b) = bind_map_pair self ab in
+      return @@ E_application {expr1=a;expr2=b}
+    )
+  | E_let_in { let_binder ; rhs ; let_result; inline } -> (
+      let%bind rhs = self rhs in
+      let%bind let_result = self let_result in
+      return @@ E_let_in { let_binder ; rhs ; let_result; inline }
+    )
+  | E_lambda { binder ; result } -> (
+      let%bind result = self result in
+      return @@ E_lambda { binder ; result }
+    )
+  | E_constant c -> (
+      let%bind args = bind_map_list self c.arguments in
+      return @@ E_constant {c with arguments=args}
+    )
+  | E_literal _ | E_variable _ as e' -> return e'
+
+
+and map_cases : mapper -> matching_expr -> matching_expr result = fun f m ->
+  match m with
+  | Match_bool { match_true ; match_false } -> (
+      let%bind match_true = map_expression f match_true in
+      let%bind match_false = map_expression f match_false in
+      ok @@ Match_bool { match_true ; match_false }
+    )
+  | Match_list { match_nil ; match_cons = (hd , tl , cons, te) } -> (
+      let%bind match_nil = map_expression f match_nil in
+      let%bind cons = map_expression f cons in
+      ok @@ Match_list { match_nil ; match_cons = (hd , tl , cons, te) }
+    )
+  | Match_option { match_none ; match_some = (name , some, te) } -> (
+      let%bind match_none = map_expression f match_none in
+      let%bind some = map_expression f some in
+      ok @@ Match_option { match_none ; match_some = (name , some, te) }
+    )
+  | Match_tuple ((names , e), _) -> (
+      let%bind e' = map_expression f e in
+      ok @@ Match_tuple ((names , e'), [])
+    )
+  | Match_variant (lst, te) -> (
+      let aux ((a , b) , e) =
+        let%bind e' = map_expression f e in
+        ok ((a , b) , e')
+      in
+      let%bind lst' = bind_map_list aux lst in
+      ok @@ Match_variant (lst', te)
+    )
+
+and map_program : mapper -> program -> program result = fun m p ->
+  let aux = fun (x : declaration) ->
+    match x with
+    | Declaration_constant (v , e , i, env) -> (
+        let%bind e' = map_expression m e in
+        ok (Declaration_constant (v , e' , i, env))
+      )
+  in
+  bind_map_list (bind_map_location aux) p
+
+type 'a fold_mapper = 'a -> expression -> (bool * 'a * expression) result
+let rec fold_map_expression : 'a fold_mapper -> 'a -> expression -> ('a * expression) result = fun f a e ->
+  let self = fold_map_expression f in
+  let%bind (continue, init',e') = f a e in
+  if (not continue) then ok(init',e')
+  else
+  let return expression_content = { e' with expression_content } in
+  match e'.expression_content with
+  | E_list lst -> (
+    let%bind (res, lst') = bind_fold_map_list self init' lst in
+    ok (res, return @@ E_list lst')
+  )
+  | E_set lst -> (
+    let%bind (res, lst') = bind_fold_map_list self init' lst in
+    ok (res, return @@ E_set lst')
+  )
+  | E_map lst -> (
+    let%bind (res, lst') = bind_fold_map_list (bind_fold_map_pair self) init' lst in
+    ok (res, return @@ E_map lst')
+  )
+  | E_big_map lst -> (
+    let%bind (res, lst') = bind_fold_map_list (bind_fold_map_pair self) init' lst in
+    ok (res, return @@ E_big_map lst')
+  )
+  | E_look_up ab -> (
+      let%bind (res, ab') = bind_fold_map_pair self init' ab in
+      ok (res, return @@ E_look_up ab')
+    )
+  | E_loop {condition;body} -> (
+      let ab = (condition,body) in
+      let%bind (res,(a,b)) = bind_fold_map_pair self init' ab in
+      ok (res, return @@ E_loop {condition = a; body = b})
+    )
+  | E_matching {matchee=e;cases} -> (
+      let%bind (res, e') = self init' e in
+      let%bind (res,cases') = fold_map_cases f res cases in
+      ok (res, return @@ E_matching {matchee=e';cases=cases'})
+    )
+  | E_record_accessor acc -> (
+      let%bind (res, e') = self init' acc.expr in
+      ok (res, return @@ E_record_accessor {acc with expr = e'})
+    )
+  | E_record m -> (
+    let%bind (res, lst') = bind_fold_map_list (fun res (k,e) -> let%bind (res,e) = self res e in ok (res,(k,e))) init' (LMap.to_kv_list m) in
+    let m' = LMap.of_list lst' in
+    ok (res, return @@ E_record m')
+  )
+  | E_record_update {record; path; update} -> (
+    let%bind (res, record) = self init' record in
+    let%bind (res, update) = self res update in
+    ok (res, return @@ E_record_update {record;path;update})
+  )
+  | E_constructor c -> (
+      let%bind (res,e') = self init' c.element in
+      ok (res, return @@ E_constructor {c with element = e'})
+  )
+  | E_application {expr1;expr2} -> (
+      let ab = (expr1,expr2) in
+      let%bind (res,(a,b)) = bind_fold_map_pair self init' ab in
+      ok (res, return @@ E_application {expr1=a;expr2=b})
+    )
+  | E_let_in { let_binder ; rhs ; let_result; inline } -> (
+      let%bind (res,rhs) = self init' rhs in
+      let%bind (res,let_result) = self res let_result in
+      ok (res, return @@ E_let_in { let_binder ; rhs ; let_result ; inline })
+    )
+  | E_lambda { binder ; result } -> (
+      let%bind (res,result) = self init' result in
+      ok ( res, return @@ E_lambda { binder ; result })
+    )
+  | E_constant c -> (
+      let%bind (res,args) = bind_fold_map_list self init' c.arguments in
+      ok (res, return @@ E_constant {c with arguments=args})
+    )
+  | E_literal _ | E_variable _ as e' -> ok (init', return e')
+
+and fold_map_cases : 'a fold_mapper -> 'a -> matching_expr -> ('a * matching_expr) result = fun f init m ->
+  match m with
+  | Match_bool { match_true ; match_false } -> (
+      let%bind (init, match_true) = fold_map_expression f init match_true in
+      let%bind (init, match_false) = fold_map_expression f init match_false in
+      ok @@ (init, Match_bool { match_true ; match_false })
+    )
+  | Match_list { match_nil ; match_cons = (hd , tl , cons, te) } -> (
+      let%bind (init, match_nil) = fold_map_expression f init match_nil in
+      let%bind (init, cons) = fold_map_expression f init cons in
+      ok @@ (init, Match_list { match_nil ; match_cons = (hd , tl , cons, te) })
+    )
+  | Match_option { match_none ; match_some = (name , some, te) } -> (
+      let%bind (init, match_none) = fold_map_expression f init match_none in
+      let%bind (init, some) = fold_map_expression f init some in
+      ok @@ (init, Match_option { match_none ; match_some = (name , some, te) })
+    )
+  | Match_tuple ((names , e), _) -> (
+      let%bind (init, e') = fold_map_expression f init e in
+      ok @@ (init, Match_tuple ((names , e'), []))
+    )
+  | Match_variant (lst, te) -> (
+      let aux init ((a , b) , e) =
+        let%bind (init,e') = fold_map_expression f init e in
+        ok (init, ((a , b) , e'))
+      in
+      let%bind (init,lst') = bind_fold_map_list aux init lst in
+      ok @@ (init, Match_variant (lst', te))
+    )  
diff --git a/src/passes/5-self_ast_typed/self_ast_typed.ml b/src/passes/5-self_ast_typed/self_ast_typed.ml
new file mode 100644
index 000000000..bfe730244
--- /dev/null
+++ b/src/passes/5-self_ast_typed/self_ast_typed.ml
@@ -0,0 +1,17 @@
+open Trace
+
+let all = []
+
+let all_program =
+  let all_p = List.map Helpers.map_program all in
+  bind_chain all_p
+
+let all_expression =
+  let all_p = List.map Helpers.map_expression all in
+  bind_chain all_p
+
+let map_expression = Helpers.map_expression
+
+let fold_expression = Helpers.fold_expression
+
+let fold_map_expression = Helpers.fold_map_expression