diff --git a/gitlab-pages/docs/contributors/big-picture/front-end.md b/gitlab-pages/docs/contributors/big-picture/front-end.md
index d4bcfb9e7..d23fe884e 100644
--- a/gitlab-pages/docs/contributors/big-picture/front-end.md
+++ b/gitlab-pages/docs/contributors/big-picture/front-end.md
@@ -10,6 +10,6 @@ Its files are in `parser/parser_name`.
 ## Concrete Syntax Tree
 The CST is the aforementioned structured representation of the program. Is is structurally very close to the source code, and is mostly an intermediary there because manipulating string is not practical.
 Its files are in `parser/parser_name`.
-## Simplifier
-A Simplifier is a function that takes a CST and outputs the corresponding Common AST. This is the actual bridge between a given syntax and LIGO.
+## Sugar_to_core
+A Sugar_to_core is a function that takes a CST and outputs the corresponding Common AST. This is the actual bridge between a given syntax and LIGO.
 Its files are in `simplify/parser_name`.
diff --git a/gitlab-pages/docs/contributors/big-picture/middle-end.md b/gitlab-pages/docs/contributors/big-picture/middle-end.md
index 6dac7f5ec..f7cd04a8b 100644
--- a/gitlab-pages/docs/contributors/big-picture/middle-end.md
+++ b/gitlab-pages/docs/contributors/big-picture/middle-end.md
@@ -6,7 +6,7 @@ title: Middle End
 The Middle-End is the core of LIGO. It is also composed of three parts.
 ## Common AST
 The Common AST is the closest thing to what could be called “LIGO lang”. As such, it should be as simple as possible. Collapsing particular cases in more general constructs is encouraged. Documenting it is crucial for people who’ll write new parsers or editor support for Front-end related things.
-Its files are in `ast_simplified/`, of interest is the definition of the AST itself in `ast_simplified/types.ml`.
+Its files are in `ast_core/`, of interest is the definition of the AST itself in `ast_core/types.ml`.
 ## Type Checker
 The Type Checker, among other things, checks that a given AST is valid with regard to type-safety. It also annotates expressions with their types, free-variables and local environments.
 As time passes, we want to make the type-system stronger, to encode arbitrarily complex properties in an extensible manner.
diff --git a/gitlab-pages/docs/contributors/ligo_test_guide.md b/gitlab-pages/docs/contributors/ligo_test_guide.md
index eea05d77d..f8be06001 100644
--- a/gitlab-pages/docs/contributors/ligo_test_guide.md
+++ b/gitlab-pages/docs/contributors/ligo_test_guide.md
@@ -102,7 +102,7 @@ What's going on is similar to the last program: `expect_eq_evaluate` runs a prog
 
 For example, once the program stops running the value of `address` is `"tz1KqTpEZ7Yob7QbPE4Hy4Wo8fHG8LhKxZSx"`. The *comparison*, however, is made to a constructed expression.  
 
-Remember that we're testing from OCaml, but the program is written and evaluated as LIGO. In order to provide a proper comparison, we convert our expected test values into LIGO expressions and data. Constructors such as `e_list` and `e_address` provide a bridge between LIGO and OCaml. Their definitions can be found in files such as [src/stages/ast_simplified/combinators.ml](https://gitlab.com/ligolang/ligo/blob/dev/src/stages/ast_simplified/combinators.ml), or using [Merlin's definition point finder](https://github.com/ocaml/merlin/wiki). These same functions are used during the simplification stage of LIGO compilation, so becoming familiar with them will help prepare you to work on the [front end](contributors/big-picture/front-end/).
+Remember that we're testing from OCaml, but the program is written and evaluated as LIGO. In order to provide a proper comparison, we convert our expected test values into LIGO expressions and data. Constructors such as `e_list` and `e_address` provide a bridge between LIGO and OCaml. Their definitions can be found in files such as [src/stages/ast_core/combinators.ml](https://gitlab.com/ligolang/ligo/blob/dev/src/stages/ast_core/combinators.ml), or using [Merlin's definition point finder](https://github.com/ocaml/merlin/wiki). These same functions are used during the simplification stage of LIGO compilation, so becoming familiar with them will help prepare you to work on the [front end](contributors/big-picture/front-end/).
 
 ## How To Write A Test For LIGO
 
diff --git a/src/bin/cli.ml b/src/bin/cli.ml
index ad36e987c..1c9a60fe1 100644
--- a/src/bin/cli.ml
+++ b/src/bin/cli.ml
@@ -140,8 +140,7 @@ module Run = Ligo.Run.Of_michelson
 let compile_file =
   let f source_file entry_point syntax display_format disable_typecheck michelson_format =
     toplevel ~display_format @@
-    let%bind simplified = Compile.Of_source.compile source_file (Syntax_name syntax) in
-    let%bind typed,_    = Compile.Of_simplified.compile (Contract entry_point) simplified in
+    let%bind typed,_    = Compile.Utils.type_file source_file syntax (Contract entry_point) in
     let%bind mini_c     = Compile.Of_typed.compile typed in
     let%bind michelson  = Compile.Of_mini_c.aggregate_and_compile_contract mini_c entry_point in
     let%bind contract   = Compile.Of_michelson.build_contract ~disable_typecheck michelson in
@@ -168,8 +167,8 @@ let print_cst =
 let print_ast =
   let f source_file syntax display_format  = (
     toplevel ~display_format @@
-    let%bind simplified = Compile.Of_source.compile source_file (Syntax_name syntax) in
-    ok @@ Format.asprintf "%a\n" Compile.Of_simplified.pretty_print simplified
+    let%bind core = Compile.Utils.to_core source_file syntax in
+    ok @@ Format.asprintf "%a\n" Compile.Of_core.pretty_print core
   )
   in
   let term = Term.(const f $ source_file 0 $ syntax $ display_format) in
@@ -180,8 +179,7 @@ let print_ast =
 let print_typed_ast =
   let f source_file syntax display_format  = (
     toplevel ~display_format @@
-    let%bind simplified = Compile.Of_source.compile source_file (Syntax_name syntax) in
-    let%bind typed,_    = Compile.Of_simplified.compile Env simplified in
+    let%bind typed,_    = Compile.Utils.type_file source_file syntax Env in
     ok @@ Format.asprintf "%a\n" Compile.Of_typed.pretty_print typed
   )
   in
@@ -193,8 +191,7 @@ let print_typed_ast =
 let print_mini_c =
   let f source_file syntax display_format  = (
     toplevel ~display_format @@
-    let%bind simplified = Compile.Of_source.compile source_file (Syntax_name syntax) in
-    let%bind typed,_    = Compile.Of_simplified.compile Env simplified in
+    let%bind typed,_    = Compile.Utils.type_file source_file syntax Env in
     let%bind mini_c     = Compile.Of_typed.compile typed in
     ok @@ Format.asprintf "%a\n" Compile.Of_mini_c.pretty_print mini_c
   )
@@ -207,11 +204,7 @@ let print_mini_c =
 let measure_contract =
   let f source_file entry_point syntax display_format  =
     toplevel ~display_format @@
-    let%bind simplified = Compile.Of_source.compile source_file (Syntax_name syntax) in
-    let%bind typed,_    = Compile.Of_simplified.compile (Contract entry_point) simplified in
-    let%bind mini_c     = Compile.Of_typed.compile typed in
-    let%bind michelson  = Compile.Of_mini_c.aggregate_and_compile_contract mini_c entry_point in
-    let%bind contract   = Compile.Of_michelson.build_contract michelson in
+    let%bind contract   = Compile.Utils.compile_file source_file syntax entry_point in
     let open Tezos_utils in
     ok @@ Format.asprintf "%d bytes\n" (Michelson.measure contract)
   in
@@ -224,8 +217,7 @@ let measure_contract =
 let compile_parameter =
   let f source_file entry_point expression syntax amount balance sender source predecessor_timestamp display_format michelson_format =
     toplevel ~display_format @@
-    let%bind simplified      = Compile.Of_source.compile source_file (Syntax_name syntax) in
-    let%bind typed_prg,state = Compile.Of_simplified.compile (Contract entry_point) simplified in
+    let%bind typed_prg,state = Compile.Utils.type_file source_file syntax (Contract entry_point) in
     let%bind mini_c_prg      = Compile.Of_typed.compile typed_prg in
     let%bind michelson_prg   = Compile.Of_mini_c.aggregate_and_compile_contract mini_c_prg entry_point in
     let      env             = Ast_typed.program_environment typed_prg in
@@ -233,9 +225,7 @@ let compile_parameter =
       (* fails if the given entry point is not a valid contract *)
       Compile.Of_michelson.build_contract michelson_prg in
 
-    let%bind v_syntax         = Helpers.syntax_to_variant (Syntax_name syntax) (Some source_file) in
-    let%bind simplified_param = Compile.Of_source.compile_expression v_syntax expression in
-    let%bind (typed_param,_)  = Compile.Of_simplified.compile_expression ~env ~state simplified_param in
+    let%bind (typed_param,_)  = Compile.Utils.type_expression (Some source_file) syntax expression env state in
     let%bind mini_c_param     = Compile.Of_typed.compile_expression typed_param in
     let%bind compiled_param   = Compile.Of_mini_c.aggregate_and_compile_expression mini_c_prg mini_c_param in
     let%bind ()               = Compile.Of_typed.assert_equal_contract_type Check_parameter entry_point typed_prg typed_param in
@@ -255,16 +245,13 @@ let interpret =
     toplevel ~display_format @@
     let%bind (decl_list,state,env) = match init_file with
       | Some init_file ->
-        let%bind simplified      = Compile.Of_source.compile init_file (Syntax_name syntax) in
-        let%bind typed_prg,state = Compile.Of_simplified.compile Env simplified in
+        let%bind typed_prg,state = Compile.Utils.type_file init_file syntax Env in
         let%bind mini_c_prg      = Compile.Of_typed.compile typed_prg in
         let      env             = Ast_typed.program_environment typed_prg in
         ok (mini_c_prg,state,env)
       | None -> ok ([],Typer.Solver.initial_state,Ast_typed.Environment.full_empty) in
 
-    let%bind v_syntax       = Helpers.syntax_to_variant (Syntax_name syntax) init_file in
-    let%bind simplified_exp = Compile.Of_source.compile_expression v_syntax expression in
-    let%bind (typed_exp,_)  = Compile.Of_simplified.compile_expression ~env ~state simplified_exp in
+    let%bind (typed_exp,_)  = Compile.Utils.type_expression init_file syntax expression env state in
     let%bind mini_c_exp     = Compile.Of_typed.compile_expression typed_exp in
     let%bind compiled_exp   = Compile.Of_mini_c.aggregate_and_compile_expression decl_list mini_c_exp in
     let%bind options        = Run.make_dry_run_options {predecessor_timestamp ; amount ; balance ; sender ; source } in
@@ -274,8 +261,8 @@ let interpret =
         let%bind failstring = Run.failwith_to_string fail_res in
         ok @@ Format.asprintf "%s" failstring
       | Success value' ->
-        let%bind simplified_output = Uncompile.uncompile_expression typed_exp.type_expression value' in
-        ok @@ Format.asprintf "%a\n" Ast_simplified.PP.expression simplified_output
+        let%bind core_output = Uncompile.uncompile_expression typed_exp.type_expression value' in
+        ok @@ Format.asprintf "%a\n" Ast_core.PP.expression core_output
   in
   let term =
     Term.(const f $ expression "EXPRESSION" 0 $ init_file $ syntax $ amount $ balance $ sender $ source $ predecessor_timestamp $ display_format ) in
@@ -286,8 +273,7 @@ let interpret =
 let temp_ligo_interpreter =
   let f source_file syntax display_format =
     toplevel ~display_format @@
-    let%bind simplified = Compile.Of_source.compile source_file (Syntax_name syntax) in
-    let%bind typed,_    = Compile.Of_simplified.compile Env simplified in
+    let%bind typed,_    = Compile.Utils.type_file source_file syntax Env in
     let%bind res = Compile.Of_typed.some_interpret typed in
     ok @@ Format.asprintf "%s\n" res
   in
@@ -300,8 +286,7 @@ let temp_ligo_interpreter =
 let compile_storage =
   let f source_file entry_point expression syntax amount balance sender source predecessor_timestamp display_format michelson_format =
     toplevel ~display_format @@
-    let%bind simplified      = Compile.Of_source.compile source_file (Syntax_name syntax) in
-    let%bind typed_prg,state = Compile.Of_simplified.compile (Contract entry_point) simplified in
+    let%bind typed_prg,state = Compile.Utils.type_file source_file syntax (Contract entry_point) in
     let%bind mini_c_prg      = Compile.Of_typed.compile typed_prg in
     let%bind michelson_prg   = Compile.Of_mini_c.aggregate_and_compile_contract mini_c_prg entry_point in
     let      env             = Ast_typed.program_environment typed_prg in
@@ -309,9 +294,7 @@ let compile_storage =
       (* fails if the given entry point is not a valid contract *)
       Compile.Of_michelson.build_contract michelson_prg in
 
-    let%bind v_syntax         = Helpers.syntax_to_variant (Syntax_name syntax) (Some source_file) in
-    let%bind simplified_param = Compile.Of_source.compile_expression v_syntax expression in
-    let%bind (typed_param,_)  = Compile.Of_simplified.compile_expression ~env ~state simplified_param in
+    let%bind (typed_param,_)  = Compile.Utils.type_expression (Some source_file) syntax expression env state in
     let%bind mini_c_param     = Compile.Of_typed.compile_expression typed_param in
     let%bind compiled_param   = Compile.Of_mini_c.aggregate_and_compile_expression mini_c_prg mini_c_param in
     let%bind ()               = Compile.Of_typed.assert_equal_contract_type Check_storage entry_point typed_prg typed_param in
@@ -329,8 +312,7 @@ let compile_storage =
 let dry_run =
   let f source_file entry_point storage input amount balance sender source predecessor_timestamp syntax display_format =
     toplevel ~display_format @@
-    let%bind simplified      = Compile.Of_source.compile source_file (Syntax_name syntax) in
-    let%bind typed_prg,state = Compile.Of_simplified.compile (Contract entry_point) simplified in
+    let%bind typed_prg,state = Compile.Utils.type_file source_file syntax (Contract entry_point) in
     let      env             = Ast_typed.program_environment typed_prg in
     let%bind mini_c_prg      = Compile.Of_typed.compile typed_prg in
     let%bind michelson_prg   = Compile.Of_mini_c.aggregate_and_compile_contract mini_c_prg entry_point in
@@ -338,11 +320,7 @@ let dry_run =
       (* fails if the given entry point is not a valid contract *)
       Compile.Of_michelson.build_contract michelson_prg in
 
-    let%bind v_syntax          = Helpers.syntax_to_variant (Syntax_name syntax) (Some source_file) in
-    let%bind simplified        = Compile.Of_source.compile_contract_input storage input v_syntax in
-    let%bind typed,_           = Compile.Of_simplified.compile_expression ~env ~state simplified in
-    let%bind mini_c            = Compile.Of_typed.compile_expression typed in
-    let%bind compiled_params   = Compile.Of_mini_c.aggregate_and_compile_expression mini_c_prg mini_c in
+    let%bind compiled_params   = Compile.Utils.compile_storage storage input source_file syntax env state mini_c_prg in
     let%bind args_michelson    = Run.evaluate_expression compiled_params.expr compiled_params.expr_ty in
 
     let%bind options           = Run.make_dry_run_options {predecessor_timestamp ; amount ; balance ; sender ; source } in
@@ -352,8 +330,8 @@ let dry_run =
         let%bind failstring = Run.failwith_to_string fail_res in
         ok @@ Format.asprintf "%s" failstring
       | Success michelson_output ->
-        let%bind simplified_output = Uncompile.uncompile_typed_program_entry_function_result typed_prg entry_point michelson_output in
-        ok @@ Format.asprintf "%a\n" Ast_simplified.PP.expression simplified_output
+        let%bind core_output = Uncompile.uncompile_typed_program_entry_function_result typed_prg entry_point michelson_output in
+        ok @@ Format.asprintf "%a\n" Ast_core.PP.expression core_output
   in
   let term =
     Term.(const f $ source_file 0 $ entry_point 1 $ expression "PARAMETER" 2 $ expression "STORAGE" 3 $ amount $ balance $ sender $ source $ predecessor_timestamp $ syntax $ display_format) in
@@ -364,16 +342,17 @@ let dry_run =
 let run_function =
   let f source_file entry_point parameter amount balance sender source predecessor_timestamp syntax display_format =
     toplevel ~display_format @@
-    let%bind v_syntax        = Helpers.syntax_to_variant (Syntax_name syntax) (Some source_file) in
-    let%bind simplified_prg  = Compile.Of_source.compile source_file (Syntax_name syntax) in
-    let%bind typed_prg,state = Compile.Of_simplified.compile Env simplified_prg in
+    let%bind typed_prg,state = Compile.Utils.type_file source_file syntax Env in
     let      env             = Ast_typed.program_environment typed_prg in
     let%bind mini_c_prg      = Compile.Of_typed.compile typed_prg in
 
 
-    let%bind simplified_param = Compile.Of_source.compile_expression v_syntax parameter in
-    let%bind app              = Compile.Of_simplified.apply entry_point simplified_param in
-    let%bind (typed_app,_)    = Compile.Of_simplified.compile_expression ~env ~state app in
+    let%bind v_syntax         = Helpers.syntax_to_variant (Syntax_name syntax) (Some source_file) in
+    let%bind imperative_param = Compile.Of_source.compile_expression v_syntax parameter in
+    let%bind sugar_param      = Compile.Of_imperative.compile_expression imperative_param in
+    let%bind core_param       = Compile.Of_sugar.compile_expression sugar_param in
+    let%bind app              = Compile.Of_core.apply entry_point core_param in
+    let%bind (typed_app,_)    = Compile.Of_core.compile_expression ~env ~state app in
     let%bind compiled_applied = Compile.Of_typed.compile_expression typed_app in
 
     let%bind michelson        = Compile.Of_mini_c.aggregate_and_compile_expression mini_c_prg compiled_applied in
@@ -384,8 +363,8 @@ let run_function =
         let%bind failstring = Run.failwith_to_string fail_res in
         ok @@ Format.asprintf "%s" failstring
       | Success michelson_output ->
-        let%bind simplified_output = Uncompile.uncompile_typed_program_entry_function_result typed_prg entry_point michelson_output in
-        ok @@ Format.asprintf "%a\n" Ast_simplified.PP.expression simplified_output
+        let%bind core_output = Uncompile.uncompile_typed_program_entry_function_result typed_prg entry_point michelson_output in
+        ok @@ Format.asprintf "%a\n" Ast_core.PP.expression core_output
   in
   let term =
     Term.(const f $ source_file 0 $ entry_point 1 $ expression "PARAMETER" 2 $ amount $ balance $ sender $ source $ predecessor_timestamp $ syntax $ display_format) in
@@ -396,15 +375,14 @@ let run_function =
 let evaluate_value =
   let f source_file entry_point amount balance sender source predecessor_timestamp syntax display_format =
     toplevel ~display_format @@
-    let%bind simplified        = Compile.Of_source.compile source_file (Syntax_name syntax) in
-    let%bind typed_prg,_       = Compile.Of_simplified.compile Env simplified in
+    let%bind typed_prg,_       = Compile.Utils.type_file source_file syntax Env in
     let%bind mini_c            = Compile.Of_typed.compile typed_prg in
     let%bind (exp,_)           = Mini_c.get_entry mini_c entry_point in
     let%bind compiled          = Compile.Of_mini_c.aggregate_and_compile_expression mini_c exp in
     let%bind options           = Run.make_dry_run_options {predecessor_timestamp ; amount ; balance ; sender ; source } in
     let%bind michelson_output  = Run.run_no_failwith ~options compiled.expr compiled.expr_ty in
-    let%bind simplified_output = Uncompile.uncompile_typed_program_entry_expression_result typed_prg entry_point michelson_output in
-    ok @@ Format.asprintf "%a\n" Ast_simplified.PP.expression simplified_output
+    let%bind core_output       = Uncompile.uncompile_typed_program_entry_expression_result typed_prg entry_point michelson_output in
+    ok @@ Format.asprintf "%a\n" Ast_core.PP.expression core_output
   in
   let term =
     Term.(const f $ source_file 0 $ entry_point 1 $ amount $ balance $ sender $ source $ predecessor_timestamp $ syntax $ display_format) in
@@ -415,13 +393,9 @@ let evaluate_value =
 let compile_expression =
   let f expression syntax display_format michelson_format =
     toplevel ~display_format @@
-    let%bind v_syntax = Helpers.syntax_to_variant (Syntax_name syntax) (None) in
     let      env      = Ast_typed.Environment.full_empty in
     let      state    = Typer.Solver.initial_state in
-    let%bind simplified    = Compile.Of_source.compile_expression v_syntax expression in
-    let%bind (typed_exp,_) = Compile.Of_simplified.compile_expression ~env ~state simplified in
-    let%bind mini_c_exp    = Compile.Of_typed.compile_expression typed_exp in
-    let%bind compiled_exp  = Compile.Of_mini_c.compile_expression mini_c_exp in
+    let%bind compiled_exp  = Compile.Utils.compile_expression None syntax expression env state in
     let%bind value         = Run.evaluate_expression compiled_exp.expr compiled_exp.expr_ty in
     ok @@ Format.asprintf "%a\n" (Main.Display.michelson_pp michelson_format) value
   in
@@ -442,8 +416,8 @@ let dump_changelog =
 let list_declarations =
   let f source_file syntax =
     toplevel ~display_format:(`Human_readable) @@
-    let%bind simplified_prg  = Compile.Of_source.compile source_file (Syntax_name syntax) in
-    let json_decl = List.map (fun decl -> `String decl) @@ Compile.Of_simplified.list_declarations simplified_prg in
+    let%bind core_prg  = Compile.Utils.to_core source_file syntax in
+    let json_decl = List.map (fun decl -> `String decl) @@ Compile.Of_core.list_declarations core_prg in
     ok @@ J.to_string @@ `Assoc [ ("source_file", `String source_file) ; ("declarations", `List json_decl) ]
   in
   let term =
diff --git a/src/bin/expect_tests/contract_tests.ml b/src/bin/expect_tests/contract_tests.ml
index 3bcb48aa0..3785881be 100644
--- a/src/bin/expect_tests/contract_tests.ml
+++ b/src/bin/expect_tests/contract_tests.ml
@@ -1174,7 +1174,7 @@ let%expect_test _ =
 let%expect_test _ =
   run_ligo_bad [ "compile-contract" ; bad_contract "create_contract_toplevel.mligo" ; "main" ] ;
   [%expect {|
-ligo: in file "create_contract_toplevel.mligo", line 4, character 35 to line 8, character 8. No free variable allowed in this lambda: variable 'store' {"expression":"CREATE_CONTRACT(lambda (#P:Some(( nat * string ))) : None return let rhs#812 = #P in let p = rhs#812.0 in let s = rhs#812.1 in ( list[] : (TO_list(operation)) , store ) , NONE() : (TO_option(key_hash)) , 300000000mutez , \"un\")","location":"in file \"create_contract_toplevel.mligo\", line 4, character 35 to line 8, character 8"}
+ligo: in file "create_contract_toplevel.mligo", line 4, character 35 to line 8, character 8. No free variable allowed in this lambda: variable 'store' {"expression":"CREATE_CONTRACT(lambda (#P:Some(( nat * string ))) : None return let rhs#654 = #P in let p = rhs#654.0 in let s = rhs#654.1 in ( list[] : (TO_list(operation)) , store ) , NONE() : (TO_option(key_hash)) , 300000000mutez , \"un\")","location":"in file \"create_contract_toplevel.mligo\", line 4, character 35 to line 8, character 8"}
 
 
  If you're not sure how to fix this error, you can
@@ -1187,7 +1187,7 @@ ligo: in file "create_contract_toplevel.mligo", line 4, character 35 to line 8,
 
   run_ligo_bad [ "compile-contract" ; bad_contract "create_contract_var.mligo" ; "main" ] ;
   [%expect {|
-ligo: in file "create_contract_var.mligo", line 6, character 35 to line 10, character 5. No free variable allowed in this lambda: variable 'a' {"expression":"CREATE_CONTRACT(lambda (#P:Some(( nat * int ))) : None return let rhs#815 = #P in let p = rhs#815.0 in let s = rhs#815.1 in ( list[] : (TO_list(operation)) , a ) , NONE() : (TO_option(key_hash)) , 300000000mutez , 1)","location":"in file \"create_contract_var.mligo\", line 6, character 35 to line 10, character 5"}
+ligo: in file "create_contract_var.mligo", line 6, character 35 to line 10, character 5. No free variable allowed in this lambda: variable 'a' {"expression":"CREATE_CONTRACT(lambda (#P:Some(( nat * int ))) : None return let rhs#657 = #P in let p = rhs#657.0 in let s = rhs#657.1 in ( list[] : (TO_list(operation)) , a ) , NONE() : (TO_option(key_hash)) , 300000000mutez , 1)","location":"in file \"create_contract_var.mligo\", line 6, character 35 to line 10, character 5"}
 
 
  If you're not sure how to fix this error, you can
diff --git a/src/main/compile/dune b/src/main/compile/dune
index 98ff34494..6a900909f 100644
--- a/src/main/compile/dune
+++ b/src/main/compile/dune
@@ -5,14 +5,20 @@
     simple-utils
     tezos-utils
     parser
-    simplify
-    interpreter
-    ast_simplified
-    self_ast_simplified
+    concrete_to_imperative
+    ast_imperative
+    self_ast_imperative
+    imperative_to_sugar
+    ast_sugar
+    self_ast_sugar
+    sugar_to_core
+    ast_core
+    self_ast_core
     typer_new
     typer
     ast_typed
     self_ast_typed
+    interpreter
     transpiler
     mini_c
     self_mini_c
diff --git a/src/main/compile/helpers.ml b/src/main/compile/helpers.ml
index 95038a5b9..1b8b390fc 100644
--- a/src/main/compile/helpers.ml
+++ b/src/main/compile/helpers.ml
@@ -23,55 +23,55 @@ let parsify_pascaligo source =
   let%bind raw =
     trace (simple_error "parsing") @@
     Parser.Pascaligo.parse_file source in
-  let%bind simplified =
-    trace (simple_error "simplifying") @@
-      Simplify.Pascaligo.simpl_program raw
-  in ok simplified
+  let%bind imperative =
+    trace (simple_error "abstracting") @@
+      Concrete_to_imperative.Pascaligo.compile_program raw
+  in ok imperative
 
 let parsify_expression_pascaligo source =
   let%bind raw =
     trace (simple_error "parsing expression") @@
     Parser.Pascaligo.parse_expression source in
-  let%bind simplified =
-    trace (simple_error "simplifying expression") @@
-    Simplify.Pascaligo.simpl_expression raw
-  in ok simplified
+  let%bind imperative =
+    trace (simple_error "abstracting expression") @@
+    Concrete_to_imperative.Pascaligo.compile_expression raw
+  in ok imperative
 
 let parsify_cameligo source =
   let%bind raw =
     trace (simple_error "parsing") @@
     Parser.Cameligo.parse_file source in
-  let%bind simplified =
-    trace (simple_error "simplifying") @@
-    Simplify.Cameligo.simpl_program raw
-  in ok simplified
+  let%bind imperative =
+    trace (simple_error "abstracting") @@
+    Concrete_to_imperative.Cameligo.compile_program raw
+  in ok imperative
 
 let parsify_expression_cameligo source =
   let%bind raw =
     trace (simple_error "parsing expression") @@
     Parser.Cameligo.parse_expression source in
-  let%bind simplified =
-    trace (simple_error "simplifying expression") @@
-    Simplify.Cameligo.simpl_expression raw
-  in ok simplified
+  let%bind imperative =
+    trace (simple_error "abstracting expression") @@
+    Concrete_to_imperative.Cameligo.compile_expression raw
+  in ok imperative
 
 let parsify_reasonligo source =
   let%bind raw =
     trace (simple_error "parsing") @@
     Parser.Reasonligo.parse_file source in
-  let%bind simplified =
-    trace (simple_error "simplifying") @@
-    Simplify.Cameligo.simpl_program raw
-  in ok simplified
+  let%bind imperative =
+    trace (simple_error "abstracting") @@
+    Concrete_to_imperative.Cameligo.compile_program raw
+  in ok imperative
 
 let parsify_expression_reasonligo source =
   let%bind raw =
     trace (simple_error "parsing expression") @@
     Parser.Reasonligo.parse_expression source in
-  let%bind simplified =
-    trace (simple_error "simplifying expression") @@
-    Simplify.Cameligo.simpl_expression raw
-  in ok simplified
+  let%bind imperative =
+    trace (simple_error "abstracting expression") @@
+    Concrete_to_imperative.Cameligo.compile_expression raw
+  in ok imperative
 
 let parsify syntax source =
   let%bind parsify =
@@ -80,7 +80,7 @@ let parsify syntax source =
     | CameLIGO   -> ok parsify_cameligo
     | ReasonLIGO -> ok parsify_reasonligo in
   let%bind parsified = parsify source in
-  let%bind applied = Self_ast_simplified.all_program parsified
+  let%bind applied = Self_ast_imperative.all_program parsified
   in ok applied
 
 let parsify_expression syntax source =
@@ -89,35 +89,35 @@ let parsify_expression syntax source =
   | CameLIGO   -> ok parsify_expression_cameligo
   | ReasonLIGO -> ok parsify_expression_reasonligo in
   let%bind parsified = parsify source in
-  let%bind applied = Self_ast_simplified.all_expression parsified
+  let%bind applied = Self_ast_imperative.all_expression parsified
   in ok applied
 
 let parsify_string_reasonligo source =
   let%bind raw =
     trace (simple_error "parsing") @@
     Parser.Reasonligo.parse_string source in
-  let%bind simplified =
-    trace (simple_error "simplifying") @@
-    Simplify.Cameligo.simpl_program raw
-  in ok simplified
+  let%bind imperative =
+    trace (simple_error "abstracting") @@
+    Concrete_to_imperative.Cameligo.compile_program raw
+  in ok imperative
 
 let parsify_string_pascaligo source =
   let%bind raw =
     trace (simple_error "parsing") @@
     Parser.Pascaligo.parse_string source in
-  let%bind simplified =
-    trace (simple_error "simplifying") @@
-    Simplify.Pascaligo.simpl_program raw
-  in ok simplified
+  let%bind imperative =
+    trace (simple_error "abstracting") @@
+    Concrete_to_imperative.Pascaligo.compile_program raw
+  in ok imperative
 
 let parsify_string_cameligo source =
   let%bind raw =
     trace (simple_error "parsing") @@
     Parser.Cameligo.parse_string source in
-  let%bind simplified =
-    trace (simple_error "simplifying") @@
-    Simplify.Cameligo.simpl_program raw
-  in ok simplified
+  let%bind imperative =
+    trace (simple_error "abstracting") @@
+    Concrete_to_imperative.Cameligo.compile_program raw
+  in ok imperative
 
 let parsify_string syntax source =
   let%bind parsify =
@@ -126,7 +126,7 @@ let parsify_string syntax source =
     | CameLIGO   -> ok parsify_string_cameligo
     | ReasonLIGO -> ok parsify_string_reasonligo in
   let%bind parsified = parsify source in
-  let%bind applied = Self_ast_simplified.all_program parsified
+  let%bind applied = Self_ast_imperative.all_program parsified
   in ok applied
 
 let pretty_print_pascaligo source =
diff --git a/src/main/compile/of_simplified.ml b/src/main/compile/of_core.ml
similarity index 59%
rename from src/main/compile/of_simplified.ml
rename to src/main/compile/of_core.ml
index 433321da4..e6f0dfbba 100644
--- a/src/main/compile/of_simplified.ml
+++ b/src/main/compile/of_core.ml
@@ -4,7 +4,7 @@ type form =
   | Contract of string
   | Env
 
-let compile (cform: form) (program : Ast_simplified.program) : (Ast_typed.program * Typer.Solver.state) result =
+let compile (cform: form) (program : Ast_core.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
   let%bind applied = Self_ast_typed.all_program prog_typed in
@@ -13,31 +13,31 @@ let compile (cform: form) (program : Ast_simplified.program) : (Ast_typed.progra
     | Env -> ok applied in
   ok @@ (applied', state)
 
-let compile_expression ?(env = Ast_typed.Environment.full_empty) ~(state : Typer.Solver.state) (ae : Ast_simplified.expression)
+let compile_expression ?(env = Ast_typed.Environment.full_empty) ~(state : Typer.Solver.state) (e : Ast_core.expression)
     : (Ast_typed.expression * Typer.Solver.state) result =
-  let%bind (ae_typed,state) = Typer.type_expression_subst env state ae in
+  let%bind (ae_typed,state) = Typer.type_expression_subst env state e in
   let () = Typer.Solver.discard_state state in
   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 apply (entry_point : string) (param : Ast_core.expression) : Ast_core.expression result =
   let name = Var.of_name entry_point in
-  let entry_point_var : Ast_simplified.expression =
-    { expression_content = Ast_simplified.E_variable name ;
+  let entry_point_var : Ast_core.expression =
+    { expression_content = Ast_core.E_variable name ;
       location = Virtual "generated entry-point variable" } in
-  let applied : Ast_simplified.expression = 
-    { expression_content = Ast_simplified.E_application {expr1=entry_point_var; expr2=param} ;
+  let applied : Ast_core.expression = 
+    { expression_content = Ast_core.E_application {lamb=entry_point_var; args=param} ;
       location = Virtual "generated application" } in
   ok applied
 
-let pretty_print formatter (program : Ast_simplified.program) = 
-  Ast_simplified.PP.program formatter program
+let pretty_print formatter (program : Ast_core.program) = 
+  Ast_core.PP.program formatter program
 
-let list_declarations (program : Ast_simplified.program) : string list =
+let list_declarations (program : Ast_core.program) : string list =
   List.fold_left
     (fun prev el -> 
       let open Location in
-      let open Ast_simplified in
+      let open Ast_core in
       match el.wrap_content with
       | Declaration_constant (var,_,_,_) -> (Var.to_name var)::prev
       | _ -> prev) 
diff --git a/src/main/compile/of_imperative.ml b/src/main/compile/of_imperative.ml
new file mode 100644
index 000000000..ed12a128e
--- /dev/null
+++ b/src/main/compile/of_imperative.ml
@@ -0,0 +1,25 @@
+open Trace
+open Ast_imperative
+open Imperative_to_sugar
+
+type form = 
+  | Contract of string
+  | Env
+
+let compile (program : program) : Ast_sugar.program result =
+  compile_program program
+
+let compile_expression (e : expression) : Ast_sugar.expression result =
+  compile_expression e
+
+let pretty_print formatter (program : program) = 
+  PP.program formatter program
+
+let list_declarations (program : program) : string list =
+  List.fold_left
+    (fun prev el -> 
+      let open Location in
+      match el.wrap_content with
+      | Declaration_constant (var,_,_,_) -> (Var.to_name var)::prev
+      | _ -> prev) 
+    [] program
diff --git a/src/main/compile/of_source.ml b/src/main/compile/of_source.ml
index 3a075ac9e..8b737237b 100644
--- a/src/main/compile/of_source.ml
+++ b/src/main/compile/of_source.ml
@@ -1,23 +1,23 @@
 open Trace
 open Helpers
 
-let compile (source_filename:string) syntax : Ast_simplified.program result =
+let compile (source_filename:string) syntax : Ast_imperative.program result =
   let%bind syntax = syntax_to_variant syntax (Some source_filename) in
-  let%bind simplified = parsify syntax source_filename in
-  ok simplified
+  let%bind abstract = parsify syntax source_filename in
+  ok abstract
 
-let compile_string (source:string) syntax : Ast_simplified.program result =
-  let%bind simplified = parsify_string syntax source in
-  ok simplified
+let compile_string (source:string) syntax : Ast_imperative.program result =
+  let%bind abstract = parsify_string syntax source in
+  ok abstract
 
-let compile_expression : v_syntax -> string -> Ast_simplified.expression result =
+let compile_expression : v_syntax -> string -> Ast_imperative.expression result =
     fun syntax exp ->
   parsify_expression syntax exp
 
-let compile_contract_input : string -> string -> v_syntax -> Ast_simplified.expression result =
+let compile_contract_input : string -> string -> v_syntax -> Ast_imperative.expression result =
     fun storage parameter syntax ->
   let%bind (storage,parameter) = bind_map_pair (compile_expression syntax) (storage,parameter) in
-  ok @@ Ast_simplified.e_pair storage parameter
+  ok @@ Ast_imperative.e_pair storage parameter
 
 let pretty_print source_filename syntax = 
-  Helpers.pretty_print syntax source_filename 
\ No newline at end of file
+  Helpers.pretty_print syntax source_filename 
diff --git a/src/main/compile/of_sugar.ml b/src/main/compile/of_sugar.ml
new file mode 100644
index 000000000..b52607af7
--- /dev/null
+++ b/src/main/compile/of_sugar.ml
@@ -0,0 +1,25 @@
+open Trace
+open Ast_sugar
+open Sugar_to_core
+
+type form = 
+  | Contract of string
+  | Env
+
+let compile (program : program) : Ast_core.program result =
+  compile_program program
+
+let compile_expression (e : expression) : Ast_core.expression result =
+  compile_expression e
+
+let pretty_print formatter (program : program) = 
+  PP.program formatter program
+
+let list_declarations (program : program) : string list =
+  List.fold_left
+    (fun prev el -> 
+      let open Location in
+      match el.wrap_content with
+      | Declaration_constant (var,_,_,_) -> (Var.to_name var)::prev
+      | _ -> prev) 
+    [] program
diff --git a/src/main/compile/utils.ml b/src/main/compile/utils.ml
new file mode 100644
index 000000000..ab8ac6503
--- /dev/null
+++ b/src/main/compile/utils.ml
@@ -0,0 +1,65 @@
+open Trace 
+
+let to_imperatve f stx =
+  let%bind imperative  = Of_source.compile f (Syntax_name stx) in
+  ok @@ imperative
+
+let to_sugar f stx = 
+  let%bind imperative = to_imperatve f stx in 
+  let%bind sugar      = Of_imperative.compile imperative in
+  ok @@ sugar
+
+let to_core f stx = 
+  let%bind sugar  = to_sugar f stx in
+  let%bind core   = Of_sugar.compile sugar in
+  ok @@ core
+
+let type_file f stx env =
+  let%bind core        = to_core f stx in
+  let%bind typed,state = Of_core.compile env core in
+  ok @@ (typed,state)
+
+let to_mini_c f stx env =
+  let%bind typed, _ = type_file f stx env in
+  let%bind mini_c     = Of_typed.compile typed in
+  ok @@ mini_c
+
+let compile_file f stx ep =
+  let%bind typed, _ = type_file f stx @@ Contract ep in
+  let%bind mini_c     = Of_typed.compile typed in
+  let%bind michelson  = Of_mini_c.aggregate_and_compile_contract mini_c ep in
+  let%bind contract   = Of_michelson.build_contract michelson in
+  ok @@ contract
+
+let type_expression source_file syntax expression env state =
+    let%bind v_syntax         = Helpers.syntax_to_variant (Syntax_name syntax) source_file in
+    let%bind imperative_exp    = Of_source.compile_expression v_syntax expression in
+    let%bind sugar_exp         = Of_imperative.compile_expression imperative_exp in
+    let%bind core_exp          = Of_sugar.compile_expression sugar_exp in
+    let%bind (typed_exp,state) = Of_core.compile_expression ~env ~state core_exp in
+    ok @@ (typed_exp,state)
+
+let expression_to_mini_c source_file syntax expression env state =
+    let%bind (typed_exp,_)  = type_expression source_file syntax expression env state in
+    let%bind mini_c_exp     = Of_typed.compile_expression typed_exp in
+    ok @@ mini_c_exp
+
+let compile_expression source_file syntax expression env state =
+    let%bind mini_c_exp = expression_to_mini_c source_file syntax expression env state in
+    let%bind compiled   = Of_mini_c.compile_expression mini_c_exp in
+    ok @@ compiled
+
+let compile_and_aggregate_expression source_file syntax expression env state mini_c_prg =
+    let%bind mini_c_exp = expression_to_mini_c source_file syntax expression env state in
+    let%bind compiled   = Of_mini_c.aggregate_and_compile_expression mini_c_prg mini_c_exp in
+    ok @@ compiled
+
+let compile_storage storage input source_file syntax env state mini_c_prg =
+    let%bind v_syntax   = Helpers.syntax_to_variant (Syntax_name syntax) (Some source_file) in
+    let%bind imperative = Of_source.compile_contract_input storage input v_syntax in
+    let%bind sugar      = Of_imperative.compile_expression imperative in
+    let%bind core       = Of_sugar.compile_expression sugar in
+    let%bind typed,_    = Of_core.compile_expression ~env ~state core in
+    let%bind mini_c     = Of_typed.compile_expression typed in
+    let%bind compiled   = Of_mini_c.aggregate_and_compile_expression mini_c_prg mini_c in
+    ok @@ compiled
diff --git a/src/main/run/dune b/src/main/run/dune
index faaedeab4..c5179a3e6 100644
--- a/src/main/run/dune
+++ b/src/main/run/dune
@@ -5,8 +5,10 @@
     simple-utils
     tezos-utils
     parser
-    simplify
-    ast_simplified
+    concrete_to_imperative
+    self_ast_imperative
+    sugar_to_core
+    ast_core
     typer_new
     typer
     ast_typed
diff --git a/src/main/uncompile/dune b/src/main/uncompile/dune
index bf039deb8..8762c6abf 100644
--- a/src/main/uncompile/dune
+++ b/src/main/uncompile/dune
@@ -4,6 +4,8 @@
   (libraries
     simple-utils
     compiler
+    imperative_to_sugar
+    sugar_to_core
     typer_new
     typer
     ast_typed
diff --git a/src/main/uncompile/uncompile.ml b/src/main/uncompile/uncompile.ml
index 6d43fba15..3adf7445e 100644
--- a/src/main/uncompile/uncompile.ml
+++ b/src/main/uncompile/uncompile.ml
@@ -10,7 +10,8 @@ let uncompile_value func_or_expr program entry ex_ty_value =
       ok output_type in
   let%bind mini_c = Compiler.Uncompiler.translate_value ex_ty_value in
   let%bind typed = Transpiler.untranspile mini_c output_type in
-  Typer.untype_expression typed
+  let%bind core  = Typer.untype_expression typed in
+  ok @@ core
 
 let uncompile_typed_program_entry_expression_result program entry ex_ty_value =
   uncompile_value Expression program entry ex_ty_value
diff --git a/src/passes/6-interpreter/dune b/src/passes/10-interpreter/dune
similarity index 100%
rename from src/passes/6-interpreter/dune
rename to src/passes/10-interpreter/dune
diff --git a/src/passes/6-interpreter/interpreter.ml b/src/passes/10-interpreter/interpreter.ml
similarity index 99%
rename from src/passes/6-interpreter/interpreter.ml
rename to src/passes/10-interpreter/interpreter.ml
index cdbee239c..1a04d35c4 100644
--- a/src/passes/6-interpreter/interpreter.ml
+++ b/src/passes/10-interpreter/interpreter.ml
@@ -270,7 +270,7 @@ and eval_literal : Ast_typed.literal -> value result = function
 and eval : Ast_typed.expression -> env -> value result
   = fun term env ->
     match term.expression_content with
-    | E_application ({expr1 = f; expr2 = args}) -> (
+    | E_application ({lamb = f; args}) -> (
       let%bind f' = eval f env in
       let%bind args' = eval args env in
       match f' with
diff --git a/src/passes/6-interpreter/interpreter.mli b/src/passes/10-interpreter/interpreter.mli
similarity index 100%
rename from src/passes/6-interpreter/interpreter.mli
rename to src/passes/10-interpreter/interpreter.mli
diff --git a/src/passes/6-transpiler/dune b/src/passes/10-transpiler/dune
similarity index 100%
rename from src/passes/6-transpiler/dune
rename to src/passes/10-transpiler/dune
diff --git a/src/passes/6-transpiler/helpers.ml b/src/passes/10-transpiler/helpers.ml
similarity index 100%
rename from src/passes/6-transpiler/helpers.ml
rename to src/passes/10-transpiler/helpers.ml
diff --git a/src/passes/6-transpiler/transpiler.ml b/src/passes/10-transpiler/transpiler.ml
similarity index 99%
rename from src/passes/6-transpiler/transpiler.ml
rename to src/passes/10-transpiler/transpiler.ml
index 3cf73747e..2d726d2df 100644
--- a/src/passes/6-transpiler/transpiler.ml
+++ b/src/passes/10-transpiler/transpiler.ml
@@ -253,9 +253,9 @@ and transpile_annotated_expression (ae:AST.expression) : expression result =
       let%bind tv = transpile_environment_element_type ele in
       return ~tv @@ E_variable (name)
     )
-  | E_application {expr1;expr2} ->
-      let%bind a = transpile_annotated_expression expr1 in
-      let%bind b = transpile_annotated_expression expr2 in
+  | E_application {lamb; args} ->
+      let%bind a = transpile_annotated_expression lamb in
+      let%bind b = transpile_annotated_expression args in
       return @@ E_application (a, b)
   | E_constructor {constructor;element} -> (
       let%bind param' = transpile_annotated_expression element in
@@ -550,10 +550,10 @@ and transpile_recursive {fun_name; fun_type; lambda} =
       E_matching m -> 
         let%bind ty = transpile_type e.type_expression in
         matching fun_name loop_type shadowed m ty |
-      E_application {expr1;expr2} -> (
-        match expr1.expression_content,shadowed with
+      E_application {lamb;args} -> (
+        match lamb.expression_content,shadowed with
         E_variable name, false when Var.equal fun_name name -> 
-          let%bind expr = transpile_annotated_expression expr2 in
+          let%bind expr = transpile_annotated_expression args in
           ok @@ Expression.make (E_constant {cons_name=C_LOOP_CONTINUE;arguments=[expr]}) loop_type |
         _ -> 
           let%bind expr = transpile_annotated_expression e in
diff --git a/src/passes/6-transpiler/transpiler.mli b/src/passes/10-transpiler/transpiler.mli
similarity index 100%
rename from src/passes/6-transpiler/transpiler.mli
rename to src/passes/10-transpiler/transpiler.mli
diff --git a/src/passes/6-transpiler/untranspiler.ml b/src/passes/10-transpiler/untranspiler.ml
similarity index 100%
rename from src/passes/6-transpiler/untranspiler.ml
rename to src/passes/10-transpiler/untranspiler.ml
diff --git a/src/passes/7-self_mini_c/dune b/src/passes/11-self_mini_c/dune
similarity index 100%
rename from src/passes/7-self_mini_c/dune
rename to src/passes/11-self_mini_c/dune
diff --git a/src/passes/7-self_mini_c/helpers.ml b/src/passes/11-self_mini_c/helpers.ml
similarity index 100%
rename from src/passes/7-self_mini_c/helpers.ml
rename to src/passes/11-self_mini_c/helpers.ml
diff --git a/src/passes/7-self_mini_c/michelson_restrictions.ml b/src/passes/11-self_mini_c/michelson_restrictions.ml
similarity index 100%
rename from src/passes/7-self_mini_c/michelson_restrictions.ml
rename to src/passes/11-self_mini_c/michelson_restrictions.ml
diff --git a/src/passes/7-self_mini_c/self_mini_c.ml b/src/passes/11-self_mini_c/self_mini_c.ml
similarity index 100%
rename from src/passes/7-self_mini_c/self_mini_c.ml
rename to src/passes/11-self_mini_c/self_mini_c.ml
diff --git a/src/passes/7-self_mini_c/subst.ml b/src/passes/11-self_mini_c/subst.ml
similarity index 100%
rename from src/passes/7-self_mini_c/subst.ml
rename to src/passes/11-self_mini_c/subst.ml
diff --git a/src/passes/8-compiler/compiler.ml b/src/passes/12-compiler/compiler.ml
similarity index 100%
rename from src/passes/8-compiler/compiler.ml
rename to src/passes/12-compiler/compiler.ml
diff --git a/src/passes/8-compiler/compiler_environment.ml b/src/passes/12-compiler/compiler_environment.ml
similarity index 100%
rename from src/passes/8-compiler/compiler_environment.ml
rename to src/passes/12-compiler/compiler_environment.ml
diff --git a/src/passes/8-compiler/compiler_environment.mli b/src/passes/12-compiler/compiler_environment.mli
similarity index 100%
rename from src/passes/8-compiler/compiler_environment.mli
rename to src/passes/12-compiler/compiler_environment.mli
diff --git a/src/passes/8-compiler/compiler_program.ml b/src/passes/12-compiler/compiler_program.ml
similarity index 100%
rename from src/passes/8-compiler/compiler_program.ml
rename to src/passes/12-compiler/compiler_program.ml
diff --git a/src/passes/8-compiler/compiler_program.mli b/src/passes/12-compiler/compiler_program.mli
similarity index 100%
rename from src/passes/8-compiler/compiler_program.mli
rename to src/passes/12-compiler/compiler_program.mli
diff --git a/src/passes/8-compiler/compiler_type.ml b/src/passes/12-compiler/compiler_type.ml
similarity index 100%
rename from src/passes/8-compiler/compiler_type.ml
rename to src/passes/12-compiler/compiler_type.ml
diff --git a/src/passes/8-compiler/compiler_type.mli b/src/passes/12-compiler/compiler_type.mli
similarity index 100%
rename from src/passes/8-compiler/compiler_type.mli
rename to src/passes/12-compiler/compiler_type.mli
diff --git a/src/passes/8-compiler/dune b/src/passes/12-compiler/dune
similarity index 100%
rename from src/passes/8-compiler/dune
rename to src/passes/12-compiler/dune
diff --git a/src/passes/8-compiler/uncompiler.ml b/src/passes/12-compiler/uncompiler.ml
similarity index 100%
rename from src/passes/8-compiler/uncompiler.ml
rename to src/passes/12-compiler/uncompiler.ml
diff --git a/src/passes/8-compiler/uncompiler.mli b/src/passes/12-compiler/uncompiler.mli
similarity index 100%
rename from src/passes/8-compiler/uncompiler.mli
rename to src/passes/12-compiler/uncompiler.mli
diff --git a/src/passes/9-self_michelson/dune b/src/passes/13-self_michelson/dune
similarity index 100%
rename from src/passes/9-self_michelson/dune
rename to src/passes/13-self_michelson/dune
diff --git a/src/passes/9-self_michelson/helpers.ml b/src/passes/13-self_michelson/helpers.ml
similarity index 100%
rename from src/passes/9-self_michelson/helpers.ml
rename to src/passes/13-self_michelson/helpers.ml
diff --git a/src/passes/3-self_ast_simplified/main.ml b/src/passes/13-self_michelson/main.ml
similarity index 100%
rename from src/passes/3-self_ast_simplified/main.ml
rename to src/passes/13-self_michelson/main.ml
diff --git a/src/passes/9-self_michelson/self_michelson.ml b/src/passes/13-self_michelson/self_michelson.ml
similarity index 100%
rename from src/passes/9-self_michelson/self_michelson.ml
rename to src/passes/13-self_michelson/self_michelson.ml
diff --git a/src/passes/2-simplify/cameligo.ml b/src/passes/2-concrete_to_imperative/cameligo.ml
similarity index 86%
rename from src/passes/2-simplify/cameligo.ml
rename to src/passes/2-concrete_to_imperative/cameligo.ml
index 4e82b9d11..f6b2ef165 100644
--- a/src/passes/2-simplify/cameligo.ml
+++ b/src/passes/2-concrete_to_imperative/cameligo.ml
@@ -1,7 +1,7 @@
 [@@@warning "-45"]
 
 open Trace
-open Ast_simplified
+open Ast_imperative
 
 module Raw = Parser.Cameligo.AST
 module SMap = Map.String
@@ -114,8 +114,8 @@ module Errors = struct
     ] in
     error ~data title message
 
-  let simplifying_expr t =
-    let title () = "Simplifying expression" in
+  let abstracting_expr t =
+    let title () = "abstracting expression" in
     let message () = "" in
     let data = [
         ("expression" ,
@@ -156,7 +156,7 @@ end
 
 open Errors
 
-open Operators.Simplify.Cameligo
+open Operators.Concrete_to_imperative.Cameligo
 
 let r_split = Location.r_split
 
@@ -205,7 +205,7 @@ let rec typed_pattern_to_typed_vars : Raw.pattern -> _ = fun pattern ->
   | Raw.PTyped pt ->
      let (p,t) = pt.value.pattern,pt.value.type_expr in
      let%bind p = tuple_pattern_to_vars p in 
-     let%bind t = simpl_type_expression t in
+     let%bind t = compile_type_expression t in
      ok @@ (p,t)
   | other -> (fail @@ wrong_pattern "parenthetical or type annotation" other)
 
@@ -213,10 +213,10 @@ and unpar_pattern : Raw.pattern -> Raw.pattern = function
   | PPar p -> unpar_pattern p.value.inside
   | _ as p -> p
 
-and simpl_type_expression : Raw.type_expr -> type_expression result = fun te ->
-  trace (simple_info "simplifying this type expression...") @@
+and compile_type_expression : Raw.type_expr -> type_expression result = fun te ->
+  trace (simple_info "abstracting this type expression...") @@
   match te with
-    TPar x -> simpl_type_expression x.value.inside
+    TPar x -> compile_type_expression x.value.inside
   | TVar v -> (
       match type_constants v.value with
       | Ok (s,_) -> ok @@ make_t @@ T_constant s
@@ -225,8 +225,8 @@ and simpl_type_expression : Raw.type_expr -> type_expression result = fun te ->
   | TFun x -> (
       let%bind (type1 , type2) =
         let (a , _ , b) = x.value in
-        let%bind a = simpl_type_expression a in
-        let%bind b = simpl_type_expression b in
+        let%bind a = compile_type_expression a in
+        let%bind b = compile_type_expression b in
         ok (a , b)
       in
       ok @@ make_t @@ T_arrow {type1;type2}
@@ -234,18 +234,18 @@ and simpl_type_expression : Raw.type_expr -> type_expression result = fun te ->
   | TApp x -> (
       let (name, tuple) = x.value in
       let lst = npseq_to_list tuple.value.inside in
-      let%bind lst' = bind_map_list simpl_type_expression lst in
+      let%bind lst' = bind_map_list compile_type_expression lst in
       let%bind cst =
         trace (unknown_predefined_type name) @@
         type_operators name.value in
       t_operator cst lst'
     )
   | TProd p -> (
-      let%bind tpl = simpl_list_type_expression  @@ npseq_to_list p.value in
+      let%bind tpl = compile_list_type_expression  @@ npseq_to_list p.value in
       ok tpl
     )
   | TRecord r ->
-      let aux = fun (x, y) -> let%bind y = simpl_type_expression y in ok (x, y) in
+      let aux = fun (x, y) -> let%bind y = compile_type_expression y in ok (x, y) in
       let apply (x:Raw.field_decl Raw.reg) =
         (x.value.field_name.value, x.value.field_type) in
       let%bind lst =
@@ -262,7 +262,7 @@ and simpl_type_expression : Raw.type_expr -> type_expression result = fun te ->
             None -> []
           | Some (_, TProd product) -> npseq_to_list product.value
           | Some (_, t_expr) -> [t_expr] in
-        let%bind te = simpl_list_type_expression @@ args in
+        let%bind te = compile_list_type_expression @@ args in
         ok (v.value.constr.value, te) in
       let%bind lst = bind_list
         @@ List.map aux
@@ -270,18 +270,18 @@ and simpl_type_expression : Raw.type_expr -> type_expression result = fun te ->
       let m = List.fold_left (fun m (x, y) -> CMap.add (Constructor x) y m) CMap.empty lst in
       ok @@ make_t @@ T_sum m
 
-and simpl_list_type_expression (lst:Raw.type_expr list) : type_expression result =
+and compile_list_type_expression (lst:Raw.type_expr list) : type_expression result =
   match lst with
   | [] -> ok @@ t_unit
-  | [hd] -> simpl_type_expression hd
+  | [hd] -> compile_type_expression hd
   | lst ->
-      let%bind lst = bind_map_list simpl_type_expression lst in
+      let%bind lst = bind_map_list compile_type_expression lst in
       ok @@ t_tuple lst
 
-let rec simpl_expression :
+let rec compile_expression :
   Raw.expr -> expr result = fun t ->
   let return x = ok x in
-  let simpl_projection = fun (p:Raw.projection Region.reg) ->
+  let compile_projection = fun (p:Raw.projection Region.reg) ->
     let (p , loc) = r_split p in
     let var =
       let name = Var.of_name p.struct_name.value in
@@ -296,7 +296,7 @@ let rec simpl_expression :
       List.map aux @@ npseq_to_list path in
     return @@ List.fold_left (e_accessor ~loc ) var path'
   in
-  let simpl_path : Raw.path -> string * label list = fun p ->
+  let compile_path : Raw.path -> string * label list = fun p ->
     match p with
     | Raw.Name v -> (v.value , [])
     | Raw.Path p -> (
@@ -313,9 +313,9 @@ let rec simpl_expression :
         (var , path')
       )
   in
-  let simpl_update = fun (u:Raw.update Region.reg) ->
+  let compile_update = fun (u:Raw.update Region.reg) ->
     let (u, loc) = r_split u in
-    let (name, path) = simpl_path u.record in
+    let (name, path) = compile_path u.record in
     let record = match path with
     | [] -> e_variable (Var.of_name name)
     | _ ->
@@ -325,7 +325,7 @@ let rec simpl_expression :
     let%bind updates' =
       let aux (f:Raw.field_path_assign Raw.reg) =
         let (f,_) = r_split f in
-        let%bind expr = simpl_expression f.field_expr in
+        let%bind expr = compile_expression f.field_expr in
         ok ( List.map (fun (x: _ Raw.reg) -> x.value) (npseq_to_list f.field_path), expr)
       in
       bind_map_list aux @@ npseq_to_list updates
@@ -342,7 +342,7 @@ let rec simpl_expression :
     bind_fold_list aux record updates'
   in
 
-  trace (simplifying_expr t) @@
+  trace (abstracting_expr t) @@
   match t with
     Raw.ELetIn e ->
       let Raw.{kwd_rec; binding; body; attributes; _} = e.value in
@@ -352,20 +352,20 @@ let rec simpl_expression :
       | (p, []) ->
       let%bind variables = tuple_pattern_to_typed_vars p in
       let%bind ty_opt =
-        bind_map_option (fun (_,te) -> simpl_type_expression te) lhs_type in
-      let%bind rhs = simpl_expression let_rhs in
+        bind_map_option (fun (_,te) -> compile_type_expression te) lhs_type in
+      let%bind rhs = compile_expression let_rhs in
       let rhs_b = Var.fresh ~name: "rhs" () in
       let rhs',rhs_b_expr =
         match ty_opt with
           None -> rhs, e_variable rhs_b
         | Some ty -> (e_annotation rhs ty), e_annotation (e_variable rhs_b) ty in
-      let%bind body = simpl_expression body in
+      let%bind body = compile_expression body in
       let prepare_variable (ty_var: Raw.variable * Raw.type_expr option) =
         let variable, ty_opt = ty_var in
         let var_expr = Var.of_name variable.value in
         let%bind ty_expr_opt =
           match ty_opt with
-          | Some ty -> bind_map_option simpl_type_expression (Some ty)
+          | Some ty -> bind_map_option compile_type_expression (Some ty)
           | None -> ok None
         in ok (var_expr, ty_expr_opt)
       in
@@ -397,7 +397,7 @@ let rec simpl_expression :
       | None -> (match let_rhs with 
         | EFun {value={binders;lhs_type}} -> 
           let f_args = nseq_to_list (binders) in
-          let%bind lhs_type' = bind_map_option (fun x -> simpl_type_expression (snd x)) lhs_type in
+          let%bind lhs_type' = bind_map_option (fun x -> compile_type_expression (snd x)) lhs_type in
           let%bind ty = bind_map_list typed_pattern_to_typed_vars f_args in
           let aux acc ty = Option.map (t_function (snd ty)) acc in
           ok @@ (List.fold_right' aux lhs_type' ty)
@@ -444,8 +444,8 @@ let rec simpl_expression :
       end
   | Raw.EAnnot a ->
       let Raw.{inside=expr, _, type_expr; _}, loc = r_split a in
-      let%bind expr' = simpl_expression expr in
-      let%bind type_expr' = simpl_type_expression type_expr in
+      let%bind expr' = compile_expression expr in
+      let%bind type_expr' = compile_type_expression type_expr in
       return @@ e_annotation ~loc expr' type_expr'
   | EVar c ->
       let (c',loc) = r_split c in
@@ -454,7 +454,7 @@ let rec simpl_expression :
        | Ok (s,_) -> return @@ e_constant s [])
   | ECall x -> (
       let ((e1 , e2) , loc) = r_split x in
-      let%bind args = bind_map_list simpl_expression (nseq_to_list e2) in
+      let%bind args = bind_map_list compile_expression (nseq_to_list e2) in
       let rec chain_application (f: expression) (args: expression list) =
         match args with
         | hd :: tl ->  chain_application (e_application ~loc f hd) tl
@@ -468,29 +468,29 @@ let rec simpl_expression :
           | Ok (s, _) -> return @@ e_constant ~loc s args
               )
       | e1 ->
-          let%bind e1' = simpl_expression e1 in
+          let%bind e1' = compile_expression e1 in
           return @@ chain_application e1' args
   )
-  | EPar x -> simpl_expression x.value.inside
+  | EPar x -> compile_expression x.value.inside
   | EUnit reg ->
       let (_ , loc) = r_split reg in
       return @@ e_literal ~loc Literal_unit
   | EBytes x ->
       let (x , loc) = r_split x in
       return @@ e_literal ~loc (Literal_bytes (Hex.to_bytes @@ snd x))
-  | ETuple tpl -> simpl_tuple_expression @@ (npseq_to_list tpl.value)
+  | ETuple tpl -> compile_tuple_expression @@ (npseq_to_list tpl.value)
   | ERecord r ->
       let (r , loc) = r_split r in
       let%bind fields = bind_list
-        @@ List.map (fun ((k : _ Raw.reg), v) -> let%bind v = simpl_expression v in ok (k.value, v))
+        @@ List.map (fun ((k : _ Raw.reg), v) -> let%bind v = compile_expression v in ok (k.value, v))
         @@ List.map (fun (x:Raw.field_assign Raw.reg) -> (x.value.field_name, x.value.field_expr))
         @@ npseq_to_list r.ne_elements in
       return @@ e_record_ez ~loc fields
-  | EProj p -> simpl_projection p
-  | EUpdate u -> simpl_update u
+  | EProj p -> compile_projection p
+  | EUpdate u -> compile_update u
   | EConstr (ESomeApp a) ->
       let (_, args), loc = r_split a in
-      let%bind arg = simpl_expression args in
+      let%bind arg = compile_expression args in
       return @@ e_constant ~loc C_SOME [arg]
   | EConstr (ENone reg) ->
       let loc = Location.lift reg in
@@ -502,18 +502,18 @@ let rec simpl_expression :
         match args with
           None -> []
         | Some arg -> [arg] in
-      let%bind arg = simpl_tuple_expression @@ args
+      let%bind arg = compile_tuple_expression @@ args
       in return @@ e_constructor ~loc c_name arg
   | EArith (Add c) ->
-      simpl_binop "ADD" c
+      compile_binop "ADD" c
   | EArith (Sub c) ->
-      simpl_binop "SUB" c
+      compile_binop "SUB" c
   | EArith (Mult c) ->
-      simpl_binop "TIMES" c
+      compile_binop "TIMES" c
   | EArith (Div c) ->
-      simpl_binop "DIV" c
+      compile_binop "DIV" c
   | EArith (Mod c) ->
-      simpl_binop "MOD" c
+      compile_binop "MOD" c
   | EArith (Int n) -> (
       let (n , loc) = r_split n in
       let n = Z.to_int @@ snd @@ n in
@@ -529,7 +529,7 @@ let rec simpl_expression :
       let n = Z.to_int @@ snd @@ n in
       return @@ e_literal ~loc (Literal_mutez n)
     )
-  | EArith (Neg e) -> simpl_unop "NEG" e
+  | EArith (Neg e) -> compile_unop "NEG" e
   | EString (String s) -> (
       let (s , loc) = r_split s in
       let s' =
@@ -540,24 +540,24 @@ let rec simpl_expression :
     )
   | EString (Cat c) ->
     let (c, loc) = r_split c in
-    let%bind string_left = simpl_expression c.arg1 in
-    let%bind string_right = simpl_expression c.arg2 in
+    let%bind string_left = compile_expression c.arg1 in
+    let%bind string_right = compile_expression c.arg2 in
     return @@ e_string_cat ~loc string_left string_right
-  | ELogic l -> simpl_logic_expression l
-  | EList l -> simpl_list_expression l
+  | ELogic l -> compile_logic_expression l
+  | EList l -> compile_list_expression l
   | ECase c -> (
       let (c , loc) = r_split c in
-      let%bind e = simpl_expression c.expr in
+      let%bind e = compile_expression c.expr in
       let%bind lst =
         let aux (x : Raw.expr Raw.case_clause) =
-          let%bind expr = simpl_expression x.rhs in
+          let%bind expr = compile_expression x.rhs in
           ok (x.pattern, expr) in
         bind_list
         @@ List.map aux
         @@ List.map get_value
         @@ npseq_to_list c.cases.value in
       let default_action () =
-        let%bind cases = simpl_cases lst in
+        let%bind cases = compile_cases lst in
         return @@ e_matching ~loc e  cases in
       (* Hack to take care of patterns introduced by `parser/cameligo/Parser.mly` in "norm_fun_expr". TODO: Still needed? *)
       match lst with
@@ -571,7 +571,7 @@ let rec simpl_expression :
                   match x'.pattern with
                   | Raw.PVar y ->
                     let var_name = Var.of_name y.value in
-                    let%bind type_expr = simpl_type_expression x'.type_expr in
+                    let%bind type_expr = compile_type_expression x'.type_expr in
                     return @@ e_let_in (var_name , Some type_expr) false false e rhs
                   | _ -> default_action ()
                 )
@@ -581,29 +581,29 @@ let rec simpl_expression :
         )
       | _ -> default_action ()
     )
-  | EFun lamb -> simpl_fun lamb
+  | EFun lamb -> compile_fun lamb
   | ESeq s -> (
       let (s , loc) = r_split s in
       let items : Raw.expr list = pseq_to_list s.elements in
       (match items with
          [] -> return @@ e_skip ~loc ()
        | expr::more ->
-          let expr' = simpl_expression expr in
+          let expr' = compile_expression expr in
           let apply (e1: Raw.expr) (e2: expression Trace.result) =
-            let%bind a = simpl_expression e1 in
+            let%bind a = compile_expression e1 in
             let%bind e2' = e2 in
             return @@ e_sequence a e2'
           in List.fold_right apply more expr')
     )
   | ECond c -> (
       let (c , loc) = r_split c in
-      let%bind expr = simpl_expression c.test in
-      let%bind match_true = simpl_expression c.ifso in
-      let%bind match_false = simpl_expression c.ifnot in
+      let%bind expr = compile_expression c.test in
+      let%bind match_true = compile_expression c.ifso in
+      let%bind match_false = compile_expression c.ifnot in
       return @@ e_matching ~loc expr (Match_bool {match_true; match_false})
     )
 
-and simpl_fun lamb' : expr result =
+and compile_fun lamb' : expr result =
   let return x = ok x in
   let (lamb , loc) = r_split lamb' in
   let%bind params' =
@@ -649,7 +649,7 @@ and simpl_fun lamb' : expr result =
       | _ , None ->
           fail @@ untyped_fun_param var
       | _ , Some ty -> (
-        let%bind ty' = simpl_type_expression ty in
+        let%bind ty' = compile_type_expression ty in
         ok (var , ty')
       )
     in
@@ -700,8 +700,8 @@ and simpl_fun lamb' : expr result =
   in
   let%bind (body , body_type) = expr_to_typed_expr body in
   let%bind output_type =
-    bind_map_option simpl_type_expression body_type in
-  let%bind body = simpl_expression body in
+    bind_map_option compile_type_expression body_type in
+  let%bind body = compile_expression body in
   let rec layer_arguments (arguments: (Raw.variable * type_expression) list) =
     match arguments with
     | hd :: tl ->
@@ -714,7 +714,7 @@ and simpl_fun lamb' : expr result =
   return @@ ret_lamb
 
 
-and simpl_logic_expression ?te_annot (t:Raw.logic_expr) : expr result =
+and compile_logic_expression ?te_annot (t:Raw.logic_expr) : expr result =
   let return x = ok @@ make_option_typed x te_annot in
   match t with
   | BoolExpr (False reg) -> (
@@ -726,61 +726,61 @@ and simpl_logic_expression ?te_annot (t:Raw.logic_expr) : expr result =
       return @@ e_literal ~loc (Literal_bool true)
     )
   | BoolExpr (Or b) ->
-      simpl_binop "OR" b
+      compile_binop "OR" b
   | BoolExpr (And b) ->
-      simpl_binop "AND" b
+      compile_binop "AND" b
   | BoolExpr (Not b) ->
-      simpl_unop "NOT" b
+      compile_unop "NOT" b
   | CompExpr (Lt c) ->
-      simpl_binop "LT" c
+      compile_binop "LT" c
   | CompExpr (Gt c) ->
-      simpl_binop "GT" c
+      compile_binop "GT" c
   | CompExpr (Leq c) ->
-      simpl_binop "LE" c
+      compile_binop "LE" c
   | CompExpr (Geq c) ->
-      simpl_binop "GE" c
+      compile_binop "GE" c
   | CompExpr (Equal c) ->
-      simpl_binop "EQ" c
+      compile_binop "EQ" c
   | CompExpr (Neq c) ->
-      simpl_binop "NEQ" c
+      compile_binop "NEQ" c
 
-and simpl_list_expression (t:Raw.list_expr) : expression result =
+and compile_list_expression (t:Raw.list_expr) : expression result =
   let return x = ok @@ x in
   match t with
-    ECons c -> simpl_binop "CONS" c
+    ECons c -> compile_binop "CONS" c
   | EListComp lst -> (
       let (lst , loc) = r_split lst in
       let%bind lst' =
-        bind_map_list simpl_expression @@
+        bind_map_list compile_expression @@
         pseq_to_list lst.elements in
       return @@ e_list ~loc lst'
     )
 
-and simpl_binop (name:string) (t:_ Raw.bin_op Region.reg) : expression result =
+and compile_binop (name:string) (t:_ Raw.bin_op Region.reg) : expression result =
   let return x = ok @@ x in
   let (args , loc) = r_split t in
-  let%bind a = simpl_expression args.arg1 in
-  let%bind b = simpl_expression args.arg2 in
+  let%bind a = compile_expression args.arg1 in
+  let%bind b = compile_expression args.arg2 in
   let%bind name = constants name in
   return @@ e_constant ~loc name [ a ; b ]
 
-and simpl_unop (name:string) (t:_ Raw.un_op Region.reg) : expression result =
+and compile_unop (name:string) (t:_ Raw.un_op Region.reg) : expression result =
   let return x = ok @@ x in
   let (t , loc) = r_split t in
-  let%bind a = simpl_expression t.arg in
+  let%bind a = compile_expression t.arg in
   let%bind name = constants name in
   return @@ e_constant ~loc name [ a ]
 
-and simpl_tuple_expression ?loc (lst:Raw.expr list) : expression result =
+and compile_tuple_expression ?loc (lst:Raw.expr list) : expression result =
   let return x = ok @@ x in
   match lst with
   | [] -> return @@ e_literal ?loc Literal_unit
-  | [hd] -> simpl_expression hd
+  | [hd] -> compile_expression hd
   | lst ->
-      let%bind lst = bind_list @@ List.map simpl_expression lst in
+      let%bind lst = bind_list @@ List.map compile_expression lst in
       return @@ e_tuple ?loc lst
 
-and simpl_declaration : Raw.declaration -> declaration Location.wrap list result =
+and compile_declaration : Raw.declaration -> declaration Location.wrap list result =
   fun t ->
   let open! Raw in
   let loc : 'a . 'a Raw.reg -> _ -> _ =
@@ -788,7 +788,7 @@ and simpl_declaration : Raw.declaration -> declaration Location.wrap list result
   match t with
   | TypeDecl x ->
       let {name;type_expr} : Raw.type_decl = x.value in
-      let%bind type_expression = simpl_type_expression type_expr in
+      let%bind type_expression = compile_type_expression type_expr in
       ok @@ [loc x @@ Declaration_type (Var.of_name name.value , type_expression)]
   | Let x -> (
       let (_, recursive, let_binding, attributes), _ = r_split x in
@@ -798,17 +798,16 @@ and simpl_declaration : Raw.declaration -> declaration Location.wrap list result
       let (hd, _) = binders in
         match hd with
         | PTuple pt ->
-          let process_variable (var_pair: pattern * Raw.expr) :
-            Ast_simplified.declaration Location.wrap result =
+          let process_variable (var_pair: pattern * Raw.expr) =
            (let (par_var, rhs_expr) = var_pair in
             let%bind (v, v_type) = pattern_to_typed_var par_var in
             let%bind v_type_expression =
               match v_type with
-              | Some v_type -> ok (to_option (simpl_type_expression v_type))
+              | Some v_type -> ok (to_option (compile_type_expression v_type))
               | None -> ok None
             in
-            let%bind simpl_rhs_expr = simpl_expression rhs_expr in
-              ok @@ loc x @@ Declaration_constant (Var.of_name v.value, v_type_expression, inline, simpl_rhs_expr) )
+            let%bind compile_rhs_expr = compile_expression rhs_expr in
+              ok @@ loc x @@ Declaration_constant (Var.of_name v.value, v_type_expression, inline, compile_rhs_expr) )
           in let%bind variables = ok @@ npseq_to_list pt.value
           in let%bind expr_bind_lst =
                match let_rhs with
@@ -840,7 +839,7 @@ and simpl_declaration : Raw.declaration -> declaration Location.wrap list result
                      gen_access_tuple name ~i: (i + 1) ~accesses
                  in ok (gen_access_tuple name)
                (* TODO: Improve this error message *)
-               | other -> fail @@ simplifying_expr other
+               | other -> fail @@ abstracting_expr other
           in let%bind decls =
                (* TODO: Rewrite the gen_access_tuple so there's no List.rev *)
                bind_map_list process_variable (List.combine variables (List.rev expr_bind_lst))
@@ -848,7 +847,7 @@ and simpl_declaration : Raw.declaration -> declaration Location.wrap list result
         | PPar {region = _ ; value = { lpar = _ ; inside = pt; rpar = _; } } ->
           (* Extract parenthetical multi-bind *)
           let (wild, recursive, _, attributes) = fst @@ r_split x in
-          simpl_declaration
+          compile_declaration
             (Let {
                 region = x.region;
                 value = (wild, recursive, {binders = (pt, []);
@@ -863,7 +862,7 @@ and simpl_declaration : Raw.declaration -> declaration Location.wrap list result
         let%bind var = pattern_to_var hd in
         ok (var , tl)
       in
-      let%bind lhs_type' = bind_map_option (fun x -> simpl_type_expression (snd x)) lhs_type in
+      let%bind lhs_type' = bind_map_option (fun x -> compile_type_expression (snd x)) lhs_type in
       let%bind let_rhs,lhs_type = match args with
       | [] -> ok (let_rhs, lhs_type')
       | param1::others ->
@@ -879,12 +878,12 @@ and simpl_declaration : Raw.declaration -> declaration Location.wrap list result
           let aux acc ty = Option.map (t_function (snd ty)) acc in
           ok (Raw.EFun {region=Region.ghost ; value=fun_},List.fold_right' aux lhs_type' ty)
       in
-      let%bind rhs' = simpl_expression let_rhs in
+      let%bind rhs' = compile_expression let_rhs in
       let%bind lhs_type = match lhs_type with 
       | None -> (match let_rhs with 
         | EFun {value={binders;lhs_type}} -> 
           let f_args = nseq_to_list (binders) in
-          let%bind lhs_type' = bind_map_option (fun x -> simpl_type_expression (snd x)) lhs_type in
+          let%bind lhs_type' = bind_map_option (fun x -> compile_type_expression (snd x)) lhs_type in
           let%bind ty = bind_map_list typed_pattern_to_typed_vars f_args in
           let aux acc ty = Option.map (t_function (snd ty)) acc in
           ok @@ (List.fold_right' aux lhs_type' ty)
@@ -907,7 +906,7 @@ and simpl_declaration : Raw.declaration -> declaration Location.wrap list result
       ok @@ [loc x @@ (Declaration_constant (Var.of_name var.value , lhs_type , inline, rhs'))]
     )
 
-and simpl_cases : type a . (Raw.pattern * a) list -> (a, unit) matching_content result =
+and compile_cases : type a . (Raw.pattern * a) list -> (a, unit) matching_content result =
   fun t ->
   let open Raw in
   let rec get_var (t:Raw.pattern) =
@@ -1027,6 +1026,6 @@ and simpl_cases : type a . (Raw.pattern * a) list -> (a, unit) matching_content
         | _ -> simple_fail "bad option pattern"
       in bind_or (as_option () , as_variant ())
 
-let simpl_program : Raw.ast -> program result = fun t ->
-  let%bind decls = bind_map_list simpl_declaration @@ nseq_to_list t.decl in
+let compile_program : Raw.ast -> program result = fun t ->
+  let%bind decls = bind_map_list compile_declaration @@ nseq_to_list t.decl in
   ok @@ List.concat @@ decls
diff --git a/src/passes/2-simplify/cameligo.mli b/src/passes/2-concrete_to_imperative/cameligo.mli
similarity index 63%
rename from src/passes/2-simplify/cameligo.mli
rename to src/passes/2-concrete_to_imperative/cameligo.mli
index a69583d73..f9e4b852a 100644
--- a/src/passes/2-simplify/cameligo.mli
+++ b/src/passes/2-concrete_to_imperative/cameligo.mli
@@ -1,8 +1,7 @@
 [@@@warning "-45"]
 
 open Trace
-
-open Ast_simplified
+open Ast_imperative
 
 module Raw = Parser.Cameligo.AST
 module SMap = Map.String
@@ -29,7 +28,7 @@ module Errors : sig
   val unsupported_tuple_pattern : Raw.pattern -> unit -> error
   val unsupported_cst_constr : Raw.pattern -> unit -> error
   val unsupported_non_var_pattern : Raw.pattern -> unit -> error
-  val simplifying_expr : Raw.expr -> unit -> error
+  val abstracting_expr : Raw.expr -> unit -> error
   val only_constructors : Raw.pattern -> unit -> error
   val unsupported_sugared_lists : Raw.wild -> unit -> error
   val bad_set_definition : unit -> error
@@ -46,18 +45,18 @@ val pattern_to_var : Raw.pattern -> Raw.variable result
 val pattern_to_typed_var : Raw.pattern -> ( Raw.variable * Raw.type_expr option ) result
 val expr_to_typed_expr : Raw.expr -> ( Raw.expr * Raw.type_expr option ) result
 val patterns_to_var : Raw.pattern list -> Raw.variable result
-val simpl_type_expression : Raw.type_expr -> type_expression result
-val simpl_list_type_expression : Raw.type_expr list -> type_expression result
+val compile_type_expression : Raw.type_expr -> type_expression result
+val compile_list_type_expression : Raw.type_expr list -> type_expression result
 *)
-val simpl_expression : Raw.expr -> expr result
+val compile_expression : Raw.expr -> expr result
 (*
-val simpl_fun : Raw.fun_expr Raw.reg -> expr result 
-val simpl_logic_expression : ?te_annot:type_expression -> Raw.logic_expr -> expr result
-val simpl_list_expression : Raw.list_expr -> expression result
-val simpl_binop : string -> Raw.wild Raw.bin_op Region.reg -> expression result 
-val simpl_unop : string -> Raw.wild Raw.un_op Region.reg -> expression result
-val simpl_tuple_expression : ?loc:Location.t -> Raw.expr list -> expression result
-val simpl_declaration : Raw.declaration -> declaration Location.wrap result
-val simpl_cases : (Raw.pattern * 'a) list -> 'a matching result
+val compile_fun : Raw.fun_expr Raw.reg -> expr result 
+val compile_logic_expression : ?te_annot:type_expression -> Raw.logic_expr -> expr result
+val compile_list_expression : Raw.list_expr -> expression result
+val compile_binop : string -> Raw.wild Raw.bin_op Region.reg -> expression result 
+val compile_unop : string -> Raw.wild Raw.un_op Region.reg -> expression result
+val compile_tuple_expression : ?loc:Location.t -> Raw.expr list -> expression result
+val compile_declaration : Raw.declaration -> declaration Location.wrap result
+val compile_cases : (Raw.pattern * 'a) list -> 'a matching result
 *)
-val simpl_program : Raw.ast -> program result
+val compile_program : Raw.ast -> program result
diff --git a/src/passes/2-simplify/camligo.ml.old b/src/passes/2-concrete_to_imperative/camligo.ml.old
similarity index 99%
rename from src/passes/2-simplify/camligo.ml.old
rename to src/passes/2-concrete_to_imperative/camligo.ml.old
index 64c0ebd10..7789d796d 100644
--- a/src/passes/2-simplify/camligo.ml.old
+++ b/src/passes/2-concrete_to_imperative/camligo.ml.old
@@ -1,7 +1,7 @@
 open Trace
 open Function
 module I = Parser.Cameligo.Ast
-module O = Ast_simplified
+module O = Ast_core
 open O.Combinators
 
 let unwrap : type a . a Location.wrap -> a = Location.unwrap
@@ -252,7 +252,7 @@ and expression_main : I.expression_main Location.wrap -> O.expression result = f
     let%bind (a' , b') = bind_map_pair expression_main ab in
     return @@ e_binop name a' b' in
   let error_main =
-    let title () = "simplifying main_expression" in
+    let title () = "abstracting main_expression" in
     let content () = Format.asprintf "%a" I.pp_expression_main (unwrap em) in
     error title content
   in
diff --git a/src/passes/2-simplify/simplify.ml b/src/passes/2-concrete_to_imperative/concrete_to_imperative.ml
similarity index 100%
rename from src/passes/2-simplify/simplify.ml
rename to src/passes/2-concrete_to_imperative/concrete_to_imperative.ml
diff --git a/src/passes/2-simplify/dune b/src/passes/2-concrete_to_imperative/dune
similarity index 56%
rename from src/passes/2-simplify/dune
rename to src/passes/2-concrete_to_imperative/dune
index 8e506cebc..c3f316ce4 100644
--- a/src/passes/2-simplify/dune
+++ b/src/passes/2-concrete_to_imperative/dune
@@ -1,14 +1,14 @@
 (library
-  (name simplify)
-  (public_name ligo.simplify)
+  (name concrete_to_imperative)
+  (public_name ligo.concrete_to_imperative)
   (libraries
     simple-utils
     tezos-utils
     parser
-    ast_simplified
-    self_ast_simplified
+    ast_imperative
+    self_ast_imperative
     operators)
-  (modules cameligo pascaligo simplify)
+  (modules cameligo pascaligo concrete_to_imperative)
   (preprocess
     (pps
       ppx_let
diff --git a/src/passes/2-simplify/pascaligo.ml b/src/passes/2-concrete_to_imperative/pascaligo.ml
similarity index 82%
rename from src/passes/2-simplify/pascaligo.ml
rename to src/passes/2-concrete_to_imperative/pascaligo.ml
index a0c051f28..7823cfb4e 100644
--- a/src/passes/2-simplify/pascaligo.ml
+++ b/src/passes/2-concrete_to_imperative/pascaligo.ml
@@ -1,5 +1,5 @@
 open Trace
-open Ast_simplified
+open Ast_imperative
 
 module Raw = Parser.Pascaligo.AST
 module SMap = Map.String
@@ -15,7 +15,7 @@ let pseq_to_list = function
 let get_value : 'a Raw.reg -> 'a = fun x -> x.value
 
 and repair_mutable_variable_in_matching (for_body : expression) (element_names : expression_variable list) (env : expression_variable) =
-  let%bind captured_names = Self_ast_simplified.fold_map_expression
+  let%bind captured_names = Self_ast_imperative.fold_map_expression
     (* TODO : these should use Variables sets *)
     (fun (decl_var,free_var : expression_variable list * expression_variable list) (ass_exp : expression) ->
       match ass_exp.expression_content with
@@ -47,7 +47,7 @@ and repair_mutable_variable_in_matching (for_body : expression) (element_names :
   ok @@ captured_names
 
 and repair_mutable_variable_in_loops (for_body : expression) (element_names : expression_variable list) (env : expression_variable) =
-  let%bind captured_names = Self_ast_simplified.fold_map_expression
+  let%bind captured_names = Self_ast_imperative.fold_map_expression
     (* TODO : these should use Variables sets *)
     (fun (decl_var,free_var : expression_variable list * expression_variable list) (ass_exp : expression) ->
       match ass_exp.expression_content with
@@ -186,7 +186,7 @@ module Errors = struct
 
   (* Logging *)
 
-  let simplifying_instruction t =
+  let abstracting_instruction t =
     let title () = "\nSimplifiying instruction" in
     let message () = "" in
     (** TODO: The labelled arguments should be flowing from the CLI. *)
@@ -199,14 +199,14 @@ module Errors = struct
 end
 
 open Errors
-open Operators.Simplify.Pascaligo
+open Operators.Concrete_to_imperative.Pascaligo
 
 let r_split = Location.r_split
 
 (* Statements can't be simplified in isolation. [a ; b ; c] can get
    simplified either as [let x = expr in (b ; c)] if [a] is a [const x
    = expr] declaration or as [sequence(a, sequence(b, c))] for
-   everything else.  Because of this, simplifying sequences depend on
+   everything else.  Because of this, abstracting sequences depend on
    their contents. To avoid peeking in their contents, we instead
    simplify sequences elements as functions from their next elements
    to the actual result.
@@ -229,9 +229,9 @@ let return_statement expr = ok @@ fun expr'_opt ->
   | Some expr' -> ok @@ e_sequence expr expr'
 
 
-let rec simpl_type_expression (t:Raw.type_expr) : type_expression result =
+let rec compile_type_expression (t:Raw.type_expr) : type_expression result =
   match t with
-    TPar x -> simpl_type_expression x.value.inside
+    TPar x -> compile_type_expression x.value.inside
   | TVar v -> (
       match type_constants v.value with
       | Ok (s,_) -> ok @@ make_t @@ T_constant s
@@ -240,25 +240,25 @@ let rec simpl_type_expression (t:Raw.type_expr) : type_expression result =
   | TFun x -> (
       let%bind (a , b) =
         let (a , _ , b) = x.value in
-        bind_map_pair simpl_type_expression (a , b) in
+        bind_map_pair compile_type_expression (a , b) in
       ok @@ make_t @@ T_arrow {type1=a;type2=b}
     )
   | TApp x ->
       let (name, tuple) = x.value in
       let lst = npseq_to_list tuple.value.inside in
       let%bind lst =
-        bind_list @@ List.map simpl_type_expression lst in (** TODO: fix constant and operator*)
+        bind_list @@ List.map compile_type_expression lst in (** TODO: fix constant and operator*)
       let%bind cst =
         trace (unknown_predefined_type name) @@
         type_operators name.value in
       t_operator cst lst
   | TProd p ->
-      let%bind tpl = simpl_list_type_expression
+      let%bind tpl = compile_list_type_expression
     @@ npseq_to_list p.value in
       ok tpl
   | TRecord r ->
       let aux = fun (x, y) ->
-        let%bind y = simpl_type_expression y in
+        let%bind y = compile_type_expression y in
         ok (x, y)
       in
       let apply =
@@ -276,7 +276,7 @@ let rec simpl_type_expression (t:Raw.type_expr) : type_expression result =
             None -> []
           | Some (_, TProd product) -> npseq_to_list product.value
           | Some (_, t_expr) -> [t_expr] in
-        let%bind te = simpl_list_type_expression @@ args in
+        let%bind te = compile_list_type_expression @@ args in
         ok (v.value.constr.value, te)
       in
       let%bind lst = bind_list
@@ -285,15 +285,15 @@ let rec simpl_type_expression (t:Raw.type_expr) : type_expression result =
       let m = List.fold_left (fun m (x, y) -> CMap.add (Constructor x) y m) CMap.empty lst in
       ok @@ make_t @@ T_sum m
 
-and simpl_list_type_expression (lst:Raw.type_expr list) : type_expression result =
+and compile_list_type_expression (lst:Raw.type_expr list) : type_expression result =
   match lst with
   | [] -> ok @@ t_unit
-  | [hd] -> simpl_type_expression hd
+  | [hd] -> compile_type_expression hd
   | lst ->
-      let%bind lst = bind_list @@ List.map simpl_type_expression lst in
+      let%bind lst = bind_list @@ List.map compile_type_expression lst in
       ok @@ t_tuple lst
 
-let simpl_projection : Raw.projection Region.reg -> _ = fun p ->
+let compile_projection : Raw.projection Region.reg -> _ = fun p ->
   let (p' , loc) = r_split p in
   let var =
     let name = Var.of_name p'.struct_name.value in
@@ -309,13 +309,13 @@ let simpl_projection : Raw.projection Region.reg -> _ = fun p ->
   ok @@ List.fold_left (e_accessor ~loc) var path'
 
 
-let rec simpl_expression (t:Raw.expr) : expr result =
+let rec compile_expression (t:Raw.expr) : expr result =
   let return x = ok x in
   match t with
   | EAnnot a -> (
       let ((expr , type_expr) , loc) = r_split a in
-      let%bind expr' = simpl_expression expr in
-      let%bind type_expr' = simpl_type_expression type_expr in
+      let%bind expr' = compile_expression expr in
+      let%bind type_expr' = compile_type_expression type_expr in
       return @@ e_annotation ~loc expr' type_expr'
     )
   | EVar c -> (
@@ -333,19 +333,19 @@ let rec simpl_expression (t:Raw.expr) : expr result =
         let (f_name , f_loc) = r_split name in
         match constants f_name with
         | Error _ ->
-           let%bind arg = simpl_tuple_expression ~loc:args_loc args' in
+           let%bind arg = compile_tuple_expression ~loc:args_loc args' in
            return @@ e_application ~loc (e_variable ~loc:f_loc (Var.of_name f_name)) arg
         | Ok (s,_) ->
-           let%bind lst = bind_map_list simpl_expression args' in
+           let%bind lst = bind_map_list compile_expression args' in
            return @@ e_constant ~loc s lst
       )
       | f -> (
-        let%bind f' = simpl_expression f in
-        let%bind arg = simpl_tuple_expression ~loc:args_loc args' in
+        let%bind f' = compile_expression f in
+        let%bind arg = compile_tuple_expression ~loc:args_loc args' in
         return @@ e_application ~loc f' arg
       )
     )
-  | EPar x -> simpl_expression x.value.inside
+  | EPar x -> compile_expression x.value.inside
   | EUnit reg ->
     let loc = Location.lift reg in
     return @@ e_literal ~loc Literal_unit
@@ -354,16 +354,16 @@ let rec simpl_expression (t:Raw.expr) : expr result =
     return @@ e_literal ~loc (Literal_bytes (Hex.to_bytes @@ snd x'))
   | ETuple tpl ->
       let (tpl' , loc) = r_split tpl in
-      simpl_tuple_expression ~loc @@ npseq_to_list tpl'.inside
+      compile_tuple_expression ~loc @@ npseq_to_list tpl'.inside
   | ERecord r ->
       let%bind fields = bind_list
-        @@ List.map (fun ((k : _ Raw.reg), v) -> let%bind v = simpl_expression v in ok (k.value, v))
+        @@ List.map (fun ((k : _ Raw.reg), v) -> let%bind v = compile_expression v in ok (k.value, v))
         @@ List.map (fun (x:Raw.field_assign Raw.reg) -> (x.value.field_name, x.value.field_expr))
         @@ npseq_to_list r.value.ne_elements in
       let aux prev (k, v) = SMap.add k v prev in
       return @@ e_record (List.fold_left aux SMap.empty fields)
-  | EProj p -> simpl_projection p
-  | EUpdate u -> simpl_update u
+  | EProj p -> compile_projection p
+  | EUpdate u -> compile_update u
   | EConstr (ConstrApp c) -> (
       let ((c, args) , loc) = r_split c in
       match args with
@@ -372,7 +372,7 @@ let rec simpl_expression (t:Raw.expr) : expr result =
       | Some args ->
           let args, args_loc = r_split args in
           let%bind arg =
-            simpl_tuple_expression ~loc:args_loc
+            compile_tuple_expression ~loc:args_loc
             @@ npseq_to_list args.inside in
           return @@ e_constructor ~loc c.value arg
     )
@@ -380,7 +380,7 @@ let rec simpl_expression (t:Raw.expr) : expr result =
       let ((_, args) , loc) = r_split a in
       let (args , args_loc) = r_split args in
       let%bind arg =
-        simpl_tuple_expression ~loc:args_loc
+        compile_tuple_expression ~loc:args_loc
         @@ npseq_to_list args.inside in
       return @@ e_constant ~loc C_SOME [arg]
   | EConstr (NoneExpr reg) -> (
@@ -388,15 +388,15 @@ let rec simpl_expression (t:Raw.expr) : expr result =
       return @@ e_none ~loc ()
     )
   | EArith (Add c) ->
-      simpl_binop "ADD" c
+      compile_binop "ADD" c
   | EArith (Sub c) ->
-      simpl_binop "SUB" c
+      compile_binop "SUB" c
   | EArith (Mult c) ->
-      simpl_binop "TIMES" c
+      compile_binop "TIMES" c
   | EArith (Div c) ->
-      simpl_binop "DIV" c
+      compile_binop "DIV" c
   | EArith (Mod c) ->
-      simpl_binop "MOD" c
+      compile_binop "MOD" c
   | EArith (Int n) -> (
       let (n , loc) = r_split n in
       let n = Z.to_int @@ snd n in
@@ -412,7 +412,7 @@ let rec simpl_expression (t:Raw.expr) : expr result =
     let n = Z.to_int @@ snd @@ n in
     return @@ e_literal ~loc (Literal_mutez n)
   )
-  | EArith (Neg e) -> simpl_unop "NEG" e
+  | EArith (Neg e) -> compile_unop "NEG" e
   | EString (String s) ->
     let (s , loc) = r_split s in
       let s' =
@@ -422,17 +422,17 @@ let rec simpl_expression (t:Raw.expr) : expr result =
       return @@ e_literal ~loc (Literal_string s')
   | EString (Cat bo) ->
     let (bo , loc) = r_split bo in
-    let%bind sl = simpl_expression bo.arg1 in
-    let%bind sr = simpl_expression bo.arg2 in
+    let%bind sl = compile_expression bo.arg1 in
+    let%bind sr = compile_expression bo.arg2 in
     return @@ e_string_cat ~loc sl sr
-  | ELogic l -> simpl_logic_expression l
-  | EList l -> simpl_list_expression l
-  | ESet s -> simpl_set_expression s
+  | ELogic l -> compile_logic_expression l
+  | EList l -> compile_list_expression l
+  | ESet s -> compile_set_expression s
   | ECond c ->
       let (c , loc) = r_split c in
-      let%bind expr = simpl_expression c.test in
-      let%bind match_true = simpl_expression c.ifso in
-      let%bind match_false = simpl_expression c.ifnot in
+      let%bind expr = compile_expression c.test in
+      let%bind match_true = compile_expression c.ifso in
+      let%bind match_false = compile_expression c.ifnot in
       let match_expr = e_matching expr ~loc (Match_bool {match_true; match_false}) in
       let env = Var.fresh () in
       let%bind (_, match_expr) = repair_mutable_variable_in_matching match_expr [] env in
@@ -440,16 +440,16 @@ let rec simpl_expression (t:Raw.expr) : expr result =
 
   | ECase c -> (
       let (c , loc) = r_split c in
-      let%bind e = simpl_expression c.expr in
+      let%bind e = compile_expression c.expr in
       let%bind lst =
         let aux (x : Raw.expr Raw.case_clause) =
-          let%bind expr = simpl_expression x.rhs in
+          let%bind expr = compile_expression x.rhs in
           ok (x.pattern, expr) in
         bind_list
         @@ List.map aux
         @@ List.map get_value
         @@ npseq_to_list c.cases.value in
-      let%bind cases = simpl_cases lst in
+      let%bind cases = compile_cases lst in
       let match_expr = e_matching ~loc e cases in
       let env = Var.fresh () in
       let%bind (_, match_expr) = repair_mutable_variable_in_matching match_expr [] env in
@@ -461,8 +461,8 @@ let rec simpl_expression (t:Raw.expr) : expr result =
         let lst = List.map get_value @@ pseq_to_list mi.elements in
         let aux : Raw.binding -> (expression * expression) result =
           fun b ->
-            let%bind src = simpl_expression b.source in
-            let%bind dst = simpl_expression b.image in
+            let%bind src = compile_expression b.source in
+            let%bind dst = compile_expression b.image in
             ok (src, dst) in
         bind_map_list aux lst in
       return @@ e_map ~loc lst
@@ -473,8 +473,8 @@ let rec simpl_expression (t:Raw.expr) : expr result =
         let lst = List.map get_value @@ pseq_to_list mi.elements in
         let aux : Raw.binding -> (expression * expression) result =
           fun b ->
-            let%bind src = simpl_expression b.source in
-            let%bind dst = simpl_expression b.image in
+            let%bind src = compile_expression b.source in
+            let%bind dst = compile_expression b.image in
             ok (src, dst) in
         bind_map_list aux lst in
       return @@ e_big_map ~loc lst
@@ -486,20 +486,20 @@ let rec simpl_expression (t:Raw.expr) : expr result =
             let (v , loc) = r_split v in
             return @@ e_variable ~loc (Var.of_name v)
           )
-        | Path p -> simpl_projection p
+        | Path p -> compile_projection p
       in
-      let%bind index = simpl_expression lu.index.value.inside in
+      let%bind index = compile_expression lu.index.value.inside in
       return @@ e_look_up ~loc path index
     )
   | EFun f ->
     let (f , loc) = r_split f in
-    let%bind (_ty_opt, f') = simpl_fun_expression ~loc f
+    let%bind (_ty_opt, f') = compile_fun_expression ~loc f
     in return @@ f'
 
 
-and simpl_update = fun (u:Raw.update Region.reg) ->
+and compile_update = fun (u:Raw.update Region.reg) ->
   let (u, loc) = r_split u in
-  let (name, path) = simpl_path u.record in
+  let (name, path) = compile_path u.record in
   let record = match path with
   | [] -> e_variable (Var.of_name name)
   | _ -> e_accessor_list (e_variable (Var.of_name name)) path in 
@@ -507,7 +507,7 @@ and simpl_update = fun (u:Raw.update Region.reg) ->
   let%bind updates' =
     let aux (f:Raw.field_path_assign Raw.reg) =
       let (f,_) = r_split f in
-      let%bind expr = simpl_expression f.field_expr in
+      let%bind expr = compile_expression f.field_expr in
         ok ( List.map (fun (x: _ Raw.reg) -> x.value) (npseq_to_list f.field_path), expr)
     in
     bind_map_list aux @@ npseq_to_list updates
@@ -523,7 +523,7 @@ and simpl_update = fun (u:Raw.update Region.reg) ->
     aux ur path in
   bind_fold_list aux record updates'
 
-and simpl_logic_expression (t:Raw.logic_expr) : expression result =
+and compile_logic_expression (t:Raw.logic_expr) : expression result =
   let return x = ok x in
   match t with
   | BoolExpr (False reg) -> (
@@ -535,92 +535,92 @@ and simpl_logic_expression (t:Raw.logic_expr) : expression result =
       return @@ e_literal ~loc (Literal_bool true)
     )
   | BoolExpr (Or b) ->
-      simpl_binop "OR" b
+      compile_binop "OR" b
   | BoolExpr (And b) ->
-      simpl_binop "AND" b
+      compile_binop "AND" b
   | BoolExpr (Not b) ->
-      simpl_unop "NOT" b
+      compile_unop "NOT" b
   | CompExpr (Lt c) ->
-      simpl_binop "LT" c
+      compile_binop "LT" c
   | CompExpr (Gt c) ->
-      simpl_binop "GT" c
+      compile_binop "GT" c
   | CompExpr (Leq c) ->
-      simpl_binop "LE" c
+      compile_binop "LE" c
   | CompExpr (Geq c) ->
-      simpl_binop "GE" c
+      compile_binop "GE" c
   | CompExpr (Equal c) ->
-      simpl_binop "EQ" c
+      compile_binop "EQ" c
   | CompExpr (Neq c) ->
-      simpl_binop "NEQ" c
+      compile_binop "NEQ" c
 
-and simpl_list_expression (t:Raw.list_expr) : expression result =
+and compile_list_expression (t:Raw.list_expr) : expression result =
   let return x = ok x in
   match t with
     ECons c ->
-      simpl_binop "CONS" c
+      compile_binop "CONS" c
   | EListComp lst ->
       let (lst , loc) = r_split lst in
       let%bind lst' =
-        bind_map_list simpl_expression @@
+        bind_map_list compile_expression @@
         pseq_to_list lst.elements in
       return @@ e_list ~loc lst'
   | ENil reg ->
       let loc = Location.lift reg in
       return @@ e_list ~loc []
 
-and simpl_set_expression (t:Raw.set_expr) : expression result =
+and compile_set_expression (t:Raw.set_expr) : expression result =
   match t with
   | SetMem x -> (
     let (x' , loc) = r_split x in
-    let%bind set' = simpl_expression x'.set in
-    let%bind element' = simpl_expression x'.element in
+    let%bind set' = compile_expression x'.set in
+    let%bind element' = compile_expression x'.element in
     ok @@ e_constant ~loc C_SET_MEM [ element' ; set' ]
   )
   | SetInj x -> (
     let (x' , loc) = r_split x in
     let elements = pseq_to_list x'.elements in
-    let%bind elements' = bind_map_list simpl_expression elements in
+    let%bind elements' = bind_map_list compile_expression elements in
     ok @@ e_set ~loc elements'
   )
 
-and simpl_binop (name:string) (t:_ Raw.bin_op Region.reg) : expression result =
+and compile_binop (name:string) (t:_ Raw.bin_op Region.reg) : expression result =
   let return x = ok x in
   let (t , loc) = r_split t in
-  let%bind a = simpl_expression t.arg1 in
-  let%bind b = simpl_expression t.arg2 in
+  let%bind a = compile_expression t.arg1 in
+  let%bind b = compile_expression t.arg2 in
   let%bind name = constants name in
   return @@ e_constant ~loc name [ a ; b ]
 
-and simpl_unop (name:string) (t:_ Raw.un_op Region.reg) : expression result =
+and compile_unop (name:string) (t:_ Raw.un_op Region.reg) : expression result =
   let return x = ok x in
   let (t , loc) = r_split t in
-  let%bind a = simpl_expression t.arg in
+  let%bind a = compile_expression t.arg in
   let%bind name = constants name in
   return @@ e_constant ~loc name [ a ]
 
-and simpl_tuple_expression ?loc (lst:Raw.expr list) : expression result =
+and compile_tuple_expression ?loc (lst:Raw.expr list) : expression result =
   let return x = ok x in
   match lst with
   | [] -> return @@ e_literal Literal_unit
-  | [hd] -> simpl_expression hd
+  | [hd] -> compile_expression hd
   | lst ->
-      let%bind lst = bind_list @@ List.map simpl_expression lst
+      let%bind lst = bind_list @@ List.map compile_expression lst
       in return @@ e_tuple ?loc lst
 
-and simpl_data_declaration : Raw.data_decl -> _ result =
+and compile_data_declaration : Raw.data_decl -> _ result =
   fun t ->
   match t with
   | LocalVar x ->
       let (x , loc) = r_split x in
       let name = x.name.value in
-      let%bind t = simpl_type_expression x.var_type in
-      let%bind expression = simpl_expression x.init in
+      let%bind t = compile_type_expression x.var_type in
+      let%bind expression = compile_expression x.init in
       return_let_in ~loc (Var.of_name name, Some t) false false expression
   | LocalConst x ->
       let (x , loc) = r_split x in
       let name = x.name.value in
-      let%bind t = simpl_type_expression x.const_type in
-      let%bind expression = simpl_expression x.init in
+      let%bind t = compile_type_expression x.const_type in
+      let%bind expression = compile_expression x.init in
       let inline =
         match x.attributes with
           None -> false
@@ -630,7 +630,7 @@ and simpl_data_declaration : Raw.data_decl -> _ result =
       in return_let_in ~loc (Var.of_name name, Some t) false inline expression
   | LocalFun f  ->
       let (f , loc) = r_split f in
-      let%bind (binder, expr) = simpl_fun_decl ~loc f in
+      let%bind (binder, expr) = compile_fun_decl ~loc f in
       let inline =
         match f.attributes with
           None -> false
@@ -639,22 +639,22 @@ and simpl_data_declaration : Raw.data_decl -> _ result =
            |> List.exists (fun Region.{value; _} -> value = "\"inline\"")
       in return_let_in ~loc binder false inline expr
 
-and simpl_param :
+and compile_param :
       Raw.param_decl -> (string * type_expression) result =
   fun t ->
   match t with
   | ParamConst c ->
       let c = c.value in
       let param_name = c.var.value in
-      let%bind type_expression = simpl_type_expression c.param_type in
+      let%bind type_expression = compile_type_expression c.param_type in
       ok (param_name , type_expression)
   | ParamVar v ->
       let c = v.value in
       let param_name = c.var.value in
-      let%bind type_expression = simpl_type_expression c.param_type in
+      let%bind type_expression = compile_type_expression c.param_type in
       ok (param_name , type_expression)
 
-and simpl_fun_decl :
+and compile_fun_decl :
       loc:_ -> Raw.fun_decl ->
       ((expression_variable * type_expression option) * expression) result =
   fun ~loc x ->
@@ -674,11 +674,11 @@ and simpl_fun_decl :
   in
   (match param.value.inside with
      a, [] -> (
-       let%bind input = simpl_param a in
+       let%bind input = compile_param a in
        let (binder , input_type) = input in
-       let%bind instructions = simpl_statement_list statements in
-       let%bind result = simpl_expression return in
-       let%bind output_type = simpl_type_expression ret_type in
+       let%bind instructions = compile_statement_list statements in
+       let%bind result = compile_expression return in
+       let%bind output_type = compile_type_expression ret_type in
        let body = instructions in
        let%bind result =
          let aux prec cur = cur (Some prec) in
@@ -699,7 +699,7 @@ and simpl_fun_decl :
        let lst = npseq_to_list lst in
        (* TODO wrong, should be fresh? *)
        let arguments_name = Var.of_name "arguments" in
-       let%bind params = bind_map_list simpl_param lst in
+       let%bind params = bind_map_list compile_param lst in
        let (binder , input_type) =
          let type_expression = t_tuple (List.map snd params) in
          (arguments_name , type_expression) in
@@ -712,9 +712,9 @@ and simpl_fun_decl :
            ass
          in
          bind_list @@ List.mapi aux params in
-       let%bind instructions = simpl_statement_list statements in
-       let%bind result = simpl_expression return in
-       let%bind output_type = simpl_type_expression ret_type in
+       let%bind instructions = compile_statement_list statements in
+       let%bind result = compile_expression return in
+       let%bind output_type = compile_type_expression ret_type in
        let body = tpl_declarations @ instructions in
        let%bind result =
          let aux prec cur = cur (Some prec) in
@@ -732,7 +732,7 @@ and simpl_fun_decl :
      )
   )
 
-and simpl_fun_expression :
+and compile_fun_expression :
   loc:_ -> Raw.fun_expr -> (type_expression option * expression) result =
   fun ~loc x ->
   let open! Raw in
@@ -740,11 +740,12 @@ and simpl_fun_expression :
   let statements = [] in
   (match param.value.inside with
     a, [] -> (
-        let%bind input = simpl_param a in
+        let%bind input = compile_param a in
         let (binder , input_type) = input in
-        let%bind instructions = simpl_statement_list statements in
-        let%bind result = simpl_expression return in
-        let%bind output_type = simpl_type_expression ret_type in
+        let%bind instructions = compile_statement_list statements in
+        let%bind result = compile_expression return in
+        let%bind output_type = compile_type_expression ret_type in
+
         let body = instructions in
         let%bind result =
           let aux prec cur = cur (Some prec) in
@@ -762,7 +763,7 @@ and simpl_fun_expression :
        let lst = npseq_to_list lst in
        (* TODO wrong, should be fresh? *)
        let arguments_name = Var.of_name "arguments" in
-       let%bind params = bind_map_list simpl_param lst in
+       let%bind params = bind_map_list compile_param lst in
        let (binder , input_type) =
          let type_expression = t_tuple (List.map snd params) in
          (arguments_name , type_expression) in
@@ -774,9 +775,9 @@ and simpl_fun_expression :
            ass
          in
          bind_list @@ List.mapi aux params in
-       let%bind instructions = simpl_statement_list statements in
-       let%bind result = simpl_expression return in
-       let%bind output_type = simpl_type_expression ret_type in
+       let%bind instructions = compile_statement_list statements in
+       let%bind result = compile_expression return in
+       let%bind output_type = compile_type_expression ret_type in
        let body = tpl_declarations @ instructions in
        let%bind result =
          let aux prec cur = cur (Some prec) in
@@ -791,7 +792,7 @@ and simpl_fun_expression :
      )
   )
 
-and simpl_statement_list statements =
+and compile_statement_list statements =
   let open Raw in
   let rec hook acc = function
     [] -> acc
@@ -813,9 +814,9 @@ and simpl_statement_list statements =
       (* Detached attributes are erased. TODO: Warning. *)
       hook acc statements
   | Instr i :: statements ->
-      hook (simpl_instruction i :: acc) statements
+      hook (compile_instruction i :: acc) statements
   | Data d :: statements ->
-      hook (simpl_data_declaration d :: acc) statements
+      hook (compile_data_declaration d :: acc) statements
   in bind_list @@ hook [] (List.rev statements)
 
 and get_case_variables (t:Raw.pattern) : expression_variable list result = 
@@ -847,7 +848,7 @@ and get_case_variables (t:Raw.pattern) : expression_variable list result =
     | PVar  v -> ok @@ [Var.of_name v.value] 
     | p -> fail @@ unsupported_cst_constr p
 
-and simpl_single_instruction : Raw.instruction -> (_ -> expression result) result =
+and compile_single_instruction : Raw.instruction -> (_ -> expression result) result =
   fun t ->
   match t with
   | ProcCall x -> (
@@ -859,15 +860,15 @@ and simpl_single_instruction : Raw.instruction -> (_ -> expression result) resul
       let (f_name , f_loc) = r_split name in
       match constants f_name with
       | Error _  ->
-         let%bind arg = simpl_tuple_expression ~loc:args_loc args' in
+         let%bind arg = compile_tuple_expression ~loc:args_loc args' in
          return_statement @@ e_application ~loc (e_variable ~loc:f_loc (Var.of_name f_name)) arg
       | Ok (s,_) ->
-         let%bind lst = bind_map_list simpl_expression args' in
+         let%bind lst = bind_map_list compile_expression args' in
          return_statement @@ e_constant ~loc s lst
     )
     | f -> (
-      let%bind f' = simpl_expression f in
-      let%bind arg = simpl_tuple_expression ~loc:args_loc args' in
+      let%bind f' = compile_expression f in
+      let%bind arg = compile_tuple_expression ~loc:args_loc args' in
       return_statement @@ e_application ~loc f' arg
     )
   )
@@ -876,35 +877,35 @@ and simpl_single_instruction : Raw.instruction -> (_ -> expression result) resul
       return_statement @@ e_skip ~loc ()
     )
   | Loop (While l) ->
-      simpl_while_loop l.value
+      compile_while_loop l.value
   | Loop (For (ForInt fi)) -> (
-      let%bind loop = simpl_for_int fi.value in
+      let%bind loop = compile_for_int fi.value in
       ok loop
   )
   | Loop (For (ForCollect fc)) ->
-      let%bind loop = simpl_for_collect fc.value in
+      let%bind loop = compile_for_collect fc.value in
       ok loop
   | Cond c -> (
       let (c , loc) = r_split c in
-      let%bind expr = simpl_expression c.test in
+      let%bind expr = compile_expression c.test in
       let%bind match_true = match c.ifso with
           ClauseInstr i ->
-            simpl_single_instruction i
+            compile_single_instruction i
         | ClauseBlock b ->
             match b with
               LongBlock {value; _} ->
-                simpl_block value
+                compile_block value
             | ShortBlock {value; _} ->
-                simpl_statements @@ fst value.inside in
+                compile_statements @@ fst value.inside in
       let%bind match_false = match c.ifnot with
           ClauseInstr i ->
-            simpl_single_instruction i
+            compile_single_instruction i
         | ClauseBlock b ->
             match b with
               LongBlock {value; _} ->
-                simpl_block value
+                compile_block value
             | ShortBlock {value; _} ->
-                simpl_statements @@ fst value.inside in
+                compile_statements @@ fst value.inside in
       let env = Var.fresh () in
       
       let%bind match_true' = match_true None in
@@ -928,10 +929,10 @@ and simpl_single_instruction : Raw.instruction -> (_ -> expression result) resul
     )
   | Assign a -> (
       let (a , loc) = r_split a in
-      let%bind value_expr = simpl_expression a.rhs in
+      let%bind value_expr = compile_expression a.rhs in
       match a.lhs with
         | Path path -> (
-            let (name , path') = simpl_path path in
+            let (name , path') = compile_path path in
             let (let_binder, mut, rhs, inline) = e_assign_with_let ~loc name path' value_expr in
             return_let_in let_binder mut inline rhs
           )
@@ -940,11 +941,11 @@ and simpl_single_instruction : Raw.instruction -> (_ -> expression result) resul
             let%bind (varname,map,path) = match v'.path with
               | Name name -> ok (name.value , e_variable (Var.of_name name.value), [])
               | Path p ->
-                let (name,p') = simpl_path v'.path in
-                let%bind accessor = simpl_projection p in
+                let (name,p') = compile_path v'.path in
+                let%bind accessor = compile_projection p in
                 ok @@ (name , accessor , p')
             in
-            let%bind key_expr = simpl_expression v'.index.value.inside in
+            let%bind key_expr = compile_expression v'.index.value.inside in
             let expr' = e_map_add key_expr value_expr map in
             let (let_binder, mut, rhs, inline) = e_assign_with_let ~loc varname path expr' in
             return_let_in let_binder mut inline rhs  
@@ -952,20 +953,20 @@ and simpl_single_instruction : Raw.instruction -> (_ -> expression result) resul
     )
   | CaseInstr c -> (
       let (c , loc) = r_split c in
-      let%bind expr = simpl_expression c.expr in
+      let%bind expr = compile_expression c.expr in
       let env = Var.fresh () in
       let%bind (fv,cases) =
         let aux fv (x : Raw.if_clause Raw.case_clause Raw.reg) =
           let%bind case_clause =
             match x.value.rhs with
               ClauseInstr i ->
-                simpl_single_instruction i
+                compile_single_instruction i
             | ClauseBlock b ->
                 match b with
                   LongBlock {value; _} ->
-                    simpl_block value
+                    compile_block value
                 | ShortBlock {value; _} ->
-                  simpl_statements @@ fst value.inside in
+                  compile_statements @@ fst value.inside in
           let%bind case_clause'= case_clause @@ None in
           let%bind case_clause = case_clause @@ Some(e_variable env) in
           let%bind case_vars   = get_case_variables x.value.pattern in
@@ -975,11 +976,11 @@ and simpl_single_instruction : Raw.instruction -> (_ -> expression result) resul
       let free_vars = List.concat fv in
       if (List.length free_vars == 0) then (
         let cases = List.map (fun case -> let (a,_,b) = case in (a,b)) cases in
-        let%bind m = simpl_cases cases in
+        let%bind m = compile_cases cases in
         return_statement @@ e_matching ~loc expr m
       ) else (
         let cases = List.map (fun case -> let (a,b,_) = case in (a,b)) cases in
-        let%bind m = simpl_cases cases in
+        let%bind m = compile_cases cases in
         let match_expr = e_matching ~loc expr m in
         let return_expr = fun expr ->
           e_let_in (env,None) false false (store_mutable_variable free_vars) @@
@@ -1001,8 +1002,8 @@ and simpl_single_instruction : Raw.instruction -> (_ -> expression result) resul
         region=r.record_inj.region
         } in
       let u : Raw.update = {record=r.path;kwd_with=r.kwd_with; updates=update} in
-      let%bind expr = simpl_update {value=u;region=reg} in
-      let (name , access_path) = simpl_path r.path in
+      let%bind expr = compile_update {value=u;region=reg} in
+      let (name , access_path) = compile_path r.path in
       let loc = Some loc in
       let (binder, mut, rhs, inline) = e_assign_with_let ?loc name access_path expr in
       return_let_in binder mut inline rhs
@@ -1010,13 +1011,13 @@ and simpl_single_instruction : Raw.instruction -> (_ -> expression result) resul
   )
   | MapPatch patch -> (
       let (map_p, loc) = r_split patch in
-      let (name, access_path) = simpl_path map_p.path in
+      let (name, access_path) = compile_path map_p.path in
       let%bind inj = bind_list
           @@ List.map (fun (x:Raw.binding Region.reg) ->
             let x = x.value in
             let (key, value) = x.source, x.image in
-            let%bind key' = simpl_expression key in
-            let%bind value' = simpl_expression value
+            let%bind key' = compile_expression key in
+            let%bind value' = compile_expression value
             in ok @@ (key', value')
           )
         @@ npseq_to_list map_p.map_inj.value.ne_elements in
@@ -1033,10 +1034,10 @@ and simpl_single_instruction : Raw.instruction -> (_ -> expression result) resul
     )
   | SetPatch patch -> (
       let (setp, loc) = r_split patch in
-      let (name , access_path) = simpl_path setp.path in
+      let (name , access_path) = compile_path setp.path in
       let%bind inj =
         bind_list @@
-        List.map simpl_expression @@
+        List.map compile_expression @@
         npseq_to_list setp.set_inj.value.ne_elements in
       match inj with
       | [] -> return_statement @@ e_skip ~loc ()
@@ -1053,11 +1054,11 @@ and simpl_single_instruction : Raw.instruction -> (_ -> expression result) resul
       let%bind (varname,map,path) = match v.map with
         | Name v -> ok (v.value , e_variable (Var.of_name v.value) , [])
         | Path p ->
-          let (name,p') = simpl_path v.map in
-          let%bind accessor = simpl_projection p in
+          let (name,p') = compile_path v.map in
+          let%bind accessor = compile_projection p in
           ok @@ (name , accessor , p')
       in
-      let%bind key' = simpl_expression key in
+      let%bind key' = compile_expression key in
       let expr = e_constant ~loc C_MAP_REMOVE [key' ; map] in
       let (binder, mut, rhs, inline) = e_assign_with_let ~loc varname path expr in
       return_let_in binder mut inline rhs
@@ -1067,17 +1068,17 @@ and simpl_single_instruction : Raw.instruction -> (_ -> expression result) resul
       let%bind (varname, set, path) = match set_rm.set with
         | Name v -> ok (v.value, e_variable (Var.of_name v.value), [])
         | Path path ->
-          let(name, p') = simpl_path set_rm.set in
-          let%bind accessor = simpl_projection path in
+          let(name, p') = compile_path set_rm.set in
+          let%bind accessor = compile_projection path in
           ok @@ (name, accessor, p')
       in
-      let%bind removed' = simpl_expression set_rm.element in
+      let%bind removed' = compile_expression set_rm.element in
       let expr = e_constant ~loc C_SET_REMOVE [removed' ; set] in
       let (binder, mut, rhs, inline) = e_assign_with_let ~loc varname path expr in
       return_let_in binder mut inline rhs
     )
 
-and simpl_path : Raw.path -> string * string list = fun p ->
+and compile_path : Raw.path -> string * string list = fun p ->
   match p with
   | Raw.Name v -> (v.value , [])
   | Raw.Path p -> (
@@ -1094,7 +1095,7 @@ and simpl_path : Raw.path -> string * string list = fun p ->
       (var , path')
     )
 
-and simpl_cases : (Raw.pattern * expression) list -> matching_expr result = fun t ->
+and compile_cases : (Raw.pattern * expression) list -> matching_expr result = fun t ->
   let open Raw in
   let get_var (t:Raw.pattern) =
     match t with
@@ -1185,13 +1186,13 @@ and simpl_cases : (Raw.pattern * expression) list -> matching_expr result = fun
         bind_map_list aux lst in
       ok @@ ez_match_variant constrs
 
-and simpl_instruction : Raw.instruction -> (_ -> expression result) result =
-  fun t -> trace (simplifying_instruction t) @@ simpl_single_instruction t
+and compile_instruction : Raw.instruction -> (_ -> expression result) result =
+  fun t -> trace (abstracting_instruction t) @@ compile_single_instruction t
 
-and simpl_statements : Raw.statements -> (_ -> expression result) result =
+and compile_statements : Raw.statements -> (_ -> expression result) result =
   fun statements ->
     let lst = npseq_to_list statements in
-    let%bind fs = simpl_statement_list lst in
+    let%bind fs = compile_statement_list lst in
     let aux : _ -> (expression option -> expression result) -> _ =
       fun prec cur ->
         let%bind res = cur prec
@@ -1200,19 +1201,19 @@ and simpl_statements : Raw.statements -> (_ -> expression result) result =
            let%bind ret = bind_fold_right_list aux expr' fs in
            ok @@ Option.unopt_exn ret
 
-and simpl_block : Raw.block -> (_ -> expression result) result =
-  fun t -> simpl_statements t.statements
+and compile_block : Raw.block -> (_ -> expression result) result =
+  fun t -> compile_statements t.statements
 
-and simpl_while_loop : Raw.while_loop -> (_ -> expression result) result = fun wl ->
+and compile_while_loop : Raw.while_loop -> (_ -> expression result) result = fun wl ->
   let env_rec = Var.fresh () in
   let binder  = Var.fresh () in
 
-  let%bind cond = simpl_expression wl.cond in
+  let%bind cond = compile_expression wl.cond in
   let ctrl = 
     (e_variable binder)
   in
 
-  let%bind for_body = simpl_block wl.block.value in
+  let%bind for_body = compile_block wl.block.value in
   let%bind for_body = for_body @@ Some( ctrl ) in
   let%bind ((_,captured_name_list),for_body) = repair_mutable_variable_in_loops for_body [] binder in
 
@@ -1237,15 +1238,15 @@ and simpl_while_loop : Raw.while_loop -> (_ -> expression result) result = fun w
   restore_mutable_variable return_expr captured_name_list env_rec 
 
 
-and simpl_for_int : Raw.for_int -> (_ -> expression result) result = fun fi ->
+and compile_for_int : Raw.for_int -> (_ -> expression result) result = fun fi ->
   let env_rec = Var.fresh () in
   let binder  = Var.fresh () in
   let name = fi.assign.value.name.value in
   let it = Var.of_name name in
   let var = e_variable it in
   (*Make the cond and the step *)
-  let%bind value = simpl_expression fi.assign.value.expr in
-  let%bind bound = simpl_expression fi.bound in
+  let%bind value = compile_expression fi.assign.value.expr in
+  let%bind bound = compile_expression fi.bound in
   let cond = e_annotation (e_constant C_LE [var ; bound]) t_bool in
   let step = e_int 1 in
   let continue_expr = e_constant C_FOLD_CONTINUE [(e_variable binder)] in
@@ -1255,7 +1256,7 @@ and simpl_for_int : Raw.for_int -> (_ -> expression result) result = fun fi ->
     continue_expr
   in
   (* Modify the body loop*)
-  let%bind for_body = simpl_block fi.block.value in
+  let%bind for_body = compile_block fi.block.value in
   let%bind for_body = for_body @@ Some ctrl in
   let%bind ((_,captured_name_list),for_body) = repair_mutable_variable_in_loops for_body [it] binder in
 
@@ -1285,19 +1286,19 @@ and simpl_for_int : Raw.for_int -> (_ -> expression result) result = fun fi ->
   in
   restore_mutable_variable return_expr captured_name_list env_rec 
 
-and simpl_for_collect : Raw.for_collect -> (_ -> expression result) result = fun fc ->
+and compile_for_collect : Raw.for_collect -> (_ -> expression result) result = fun fc ->
   let binder = Var.of_name "arguments" in
   let%bind element_names = ok @@ match fc.bind_to with
     | Some v -> [Var.of_name fc.var.value;Var.of_name (snd v).value]
     | None -> [Var.of_name fc.var.value] in
   
   let env = Var.fresh () in
-  let%bind for_body = simpl_block fc.block.value in
+  let%bind for_body = compile_block fc.block.value in
   let%bind for_body = for_body @@ Some (e_accessor (e_variable binder) "0") in
   let%bind ((_,free_vars), for_body) = repair_mutable_variable_in_loops for_body element_names binder in
 
   let init_record = store_mutable_variable free_vars in
-  let%bind collect = simpl_expression fc.expr in
+  let%bind collect = compile_expression fc.expr in
   let aux name expr=
     e_let_in (name,None) false false (e_accessor (e_accessor (e_variable binder) "0") (Var.to_name name)) expr
   in
@@ -1319,8 +1320,7 @@ and simpl_for_collect : Raw.for_collect -> (_ -> expression result) result = fun
   in
   restore_mutable_variable fold free_vars env
 
-and simpl_declaration_list declarations :
-  Ast_simplified.declaration Location.wrap list result =
+and compile_declaration_list declarations : declaration Location.wrap list result =
   let open Raw in
   let rec hook acc = function
     [] -> acc
@@ -1344,16 +1344,16 @@ and simpl_declaration_list declarations :
   | TypeDecl decl :: declarations ->
       let decl, loc = r_split decl in
       let {name; type_expr} : Raw.type_decl = decl in
-      let%bind type_expression = simpl_type_expression type_expr in
+      let%bind type_expression = compile_type_expression type_expr in
       let new_decl =
         Declaration_type (Var.of_name name.value, type_expression) in
       let res = Location.wrap ~loc new_decl in
       hook (bind_list_cons res acc) declarations
   | ConstDecl decl :: declarations ->
-      let simpl_const_decl =
+      let compile_const_decl =
         fun {name;const_type; init; attributes} ->
-          let%bind expression = simpl_expression init in
-          let%bind t = simpl_type_expression const_type in
+          let%bind expression = compile_expression init in
+          let%bind t = compile_type_expression const_type in
           let type_annotation = Some t in
           let inline =
             match attributes with
@@ -1366,11 +1366,11 @@ and simpl_declaration_list declarations :
               (Var.of_name name.value, type_annotation, inline, expression)
           in ok new_decl in
       let%bind res =
-        bind_map_location simpl_const_decl (Location.lift_region decl)
+        bind_map_location compile_const_decl (Location.lift_region decl)
       in hook (bind_list_cons res acc) declarations
   | FunDecl fun_decl :: declarations ->
       let decl, loc = r_split fun_decl in
-      let%bind ((name, ty_opt), expr) = simpl_fun_decl ~loc decl in
+      let%bind ((name, ty_opt), expr) = compile_fun_decl ~loc decl in
       let inline =
         match fun_decl.value.attributes with
           None -> false
@@ -1383,5 +1383,5 @@ and simpl_declaration_list declarations :
       hook (bind_list_cons res acc) declarations
   in hook (ok @@ []) (List.rev declarations)
 
-let simpl_program : Raw.ast -> program result =
-  fun t -> simpl_declaration_list @@ nseq_to_list t.decl
+let compile_program : Raw.ast -> program result =
+  fun t -> compile_declaration_list @@ nseq_to_list t.decl
diff --git a/src/passes/2-concrete_to_imperative/pascaligo.mli b/src/passes/2-concrete_to_imperative/pascaligo.mli
new file mode 100644
index 000000000..cfa945fb9
--- /dev/null
+++ b/src/passes/2-concrete_to_imperative/pascaligo.mli
@@ -0,0 +1,15 @@
+(** Converts PascaLIGO programs to the Simplified Abstract Syntax Tree. *)
+
+open Trace
+open Ast_imperative
+
+module Raw = Parser.Pascaligo.AST
+module SMap = Map.String
+
+(** Convert a concrete PascaLIGO expression AST to the imperative
+    expression AST used by the compiler. *)
+val compile_expression : Raw.expr -> expr result
+
+(** Convert a concrete PascaLIGO program AST to the miperative program
+    AST used by the compiler. *)
+val compile_program : Raw.ast -> program result
diff --git a/src/passes/2-simplify/pascaligo.mli b/src/passes/2-simplify/pascaligo.mli
deleted file mode 100644
index 42e5e4afe..000000000
--- a/src/passes/2-simplify/pascaligo.mli
+++ /dev/null
@@ -1,15 +0,0 @@
-(** Converts PascaLIGO programs to the Simplified Abstract Syntax Tree. *)
-
-open Trace
-open Ast_simplified
-
-module Raw = Parser.Pascaligo.AST
-module SMap = Map.String
-
-(** Convert a concrete PascaLIGO expression AST to the simplified
-    expression AST used by the compiler. *)
-val simpl_expression : Raw.expr -> expr result
-
-(** Convert a concrete PascaLIGO program AST to the simplified program
-    AST used by the compiler. *)
-val simpl_program : Raw.ast -> program result
diff --git a/src/passes/3-self_ast_simplified/dune b/src/passes/3-self_ast_imperative/dune
similarity index 69%
rename from src/passes/3-self_ast_simplified/dune
rename to src/passes/3-self_ast_imperative/dune
index aef575249..2b1e5f8b5 100644
--- a/src/passes/3-self_ast_simplified/dune
+++ b/src/passes/3-self_ast_imperative/dune
@@ -1,9 +1,9 @@
 (library
-  (name self_ast_simplified)
-  (public_name ligo.self_ast_simplified)
+  (name self_ast_imperative)
+  (public_name ligo.self_ast_imperative)
   (libraries
     simple-utils
-    ast_simplified
+    ast_imperative
     proto-alpha-utils
   )
   (preprocess
diff --git a/src/passes/3-self_ast_simplified/entrypoints_lenght_limit.ml b/src/passes/3-self_ast_imperative/entrypoints_lenght_limit.ml
similarity index 97%
rename from src/passes/3-self_ast_simplified/entrypoints_lenght_limit.ml
rename to src/passes/3-self_ast_imperative/entrypoints_lenght_limit.ml
index a64007b4a..f2d5fc202 100644
--- a/src/passes/3-self_ast_simplified/entrypoints_lenght_limit.ml
+++ b/src/passes/3-self_ast_imperative/entrypoints_lenght_limit.ml
@@ -1,4 +1,4 @@
-open Ast_simplified
+open Ast_imperative
 open Trace
 open Stage_common.Helpers
 
diff --git a/src/passes/3-self_ast_simplified/helpers.ml b/src/passes/3-self_ast_imperative/helpers.ml
similarity index 93%
rename from src/passes/3-self_ast_simplified/helpers.ml
rename to src/passes/3-self_ast_imperative/helpers.ml
index 101f8d9ab..fc15f29e1 100644
--- a/src/passes/3-self_ast_simplified/helpers.ml
+++ b/src/passes/3-self_ast_imperative/helpers.ml
@@ -1,4 +1,4 @@
-open Ast_simplified
+open Ast_imperative
 open Trace
 open Stage_common.Helpers
 
@@ -19,8 +19,8 @@ let rec fold_expression : 'a folder -> 'a -> expression -> 'a result = fun f ini
   | E_look_up ab ->
       let%bind res = bind_fold_pair self init' ab in
       ok res
-  | E_application {expr1;expr2} -> (
-      let ab = (expr1,expr2) in
+  | E_application {lamb;args} -> (
+      let ab = (lamb,args) in
       let%bind res = bind_fold_pair self init' ab in
       ok res
     )
@@ -59,6 +59,11 @@ let rec fold_expression : 'a folder -> 'a -> expression -> 'a result = fun f ini
   | E_recursive { lambda={result=e;_}; _} ->
       let%bind res = self init' e in
       ok res
+  | E_sequence {expr1;expr2} ->
+      let ab = (expr1,expr2) in
+      let%bind res = bind_fold_pair self init' ab in
+      ok res
+     
 
 and fold_cases : 'a folder -> 'a -> matching_expr -> 'a result = fun f init m ->
   match m with
@@ -145,10 +150,10 @@ let rec map_expression : exp_mapper -> expression -> expression result = fun f e
       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_application {lamb;args} -> (
+      let ab = (lamb,args) in
+      let%bind (lamb,args) = bind_map_pair self ab in
+      return @@ E_application {lamb;args}
     )
   | E_let_in { let_binder ; mut; rhs ; let_result; inline } -> (
       let%bind rhs = self rhs in
@@ -167,6 +172,10 @@ let rec map_expression : exp_mapper -> expression -> expression result = fun f e
       let%bind args = bind_map_list self c.arguments in
       return @@ E_constant {c with arguments=args}
     )
+  | E_sequence {expr1;expr2} -> (
+      let%bind (expr1,expr2) = bind_map_pair self (expr1,expr2) in
+      return @@ E_sequence {expr1;expr2}
+    )
   | E_literal _ | E_variable _ | E_skip as e' -> return e'
 
 and map_type_expression : ty_exp_mapper -> type_expression -> type_expression result = fun f te ->
@@ -288,10 +297,10 @@ let rec fold_map_expression : 'a fold_mapper -> 'a -> expression -> ('a * expres
       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
+  | E_application {lamb;args} -> (
+      let ab = (lamb,args) in
       let%bind (res,(a,b)) = bind_fold_map_pair self init' ab in
-      ok (res, return @@ E_application {expr1=a;expr2=b})
+      ok (res, return @@ E_application {lamb=a;args=b})
     )
   | E_let_in { let_binder ; mut; rhs ; let_result; inline } -> (
       let%bind (res,rhs) = self init' rhs in
@@ -310,6 +319,10 @@ let rec fold_map_expression : 'a fold_mapper -> 'a -> expression -> ('a * expres
       let%bind (res,args) = bind_fold_map_list self init' c.arguments in
       ok (res, return @@ E_constant {c with arguments=args})
     )
+  | E_sequence {expr1;expr2} -> (
+      let%bind (res,(expr1,expr2)) = bind_fold_map_pair self init' (expr1,expr2) in
+      ok (res, return @@ E_sequence {expr1;expr2})
+    )
   | E_literal _ | E_variable _ | E_skip as e' -> ok (init', return e')
 
 and fold_map_cases : 'a fold_mapper -> 'a -> matching_expr -> ('a * matching_expr) result = fun f init m ->
diff --git a/src/passes/3-self_ast_simplified/literals.ml b/src/passes/3-self_ast_imperative/literals.ml
similarity index 98%
rename from src/passes/3-self_ast_simplified/literals.ml
rename to src/passes/3-self_ast_imperative/literals.ml
index 367e9787f..96914359a 100644
--- a/src/passes/3-self_ast_simplified/literals.ml
+++ b/src/passes/3-self_ast_imperative/literals.ml
@@ -1,4 +1,4 @@
-open Ast_simplified
+open Ast_imperative
 open Trace
 open Proto_alpha_utils
 
@@ -6,7 +6,7 @@ module Errors = struct
 
   let bad_format e () =
     let title = (thunk ("Badly formatted literal")) in
-    let message () = Format.asprintf "%a" Ast_simplified.PP.expression e in
+    let message () = Format.asprintf "%a" PP.expression e in
     let data = [
       ("location" , fun () -> Format.asprintf "%a" Location.pp e.location)
     ] in
diff --git a/src/passes/3-self_ast_simplified/none_variant.ml b/src/passes/3-self_ast_imperative/none_variant.ml
similarity index 95%
rename from src/passes/3-self_ast_simplified/none_variant.ml
rename to src/passes/3-self_ast_imperative/none_variant.ml
index 416142f0f..894d55830 100644
--- a/src/passes/3-self_ast_simplified/none_variant.ml
+++ b/src/passes/3-self_ast_imperative/none_variant.ml
@@ -1,4 +1,4 @@
-open Ast_simplified
+open Ast_imperative
 open Trace
 
 let peephole_expression : expression -> expression result = fun e ->
diff --git a/src/passes/3-self_ast_simplified/self_ast_simplified.ml b/src/passes/3-self_ast_imperative/self_ast_imperative.ml
similarity index 100%
rename from src/passes/3-self_ast_simplified/self_ast_simplified.ml
rename to src/passes/3-self_ast_imperative/self_ast_imperative.ml
diff --git a/src/passes/3-self_ast_simplified/tezos_type_annotation.ml b/src/passes/3-self_ast_imperative/tezos_type_annotation.ml
similarity index 98%
rename from src/passes/3-self_ast_simplified/tezos_type_annotation.ml
rename to src/passes/3-self_ast_imperative/tezos_type_annotation.ml
index cc6557ae2..19118f125 100644
--- a/src/passes/3-self_ast_simplified/tezos_type_annotation.ml
+++ b/src/passes/3-self_ast_imperative/tezos_type_annotation.ml
@@ -1,4 +1,4 @@
-open Ast_simplified
+open Ast_imperative
 open Trace
 
 module Errors = struct
diff --git a/src/passes/4-imperative_to_sugar/dune b/src/passes/4-imperative_to_sugar/dune
new file mode 100644
index 000000000..445998b90
--- /dev/null
+++ b/src/passes/4-imperative_to_sugar/dune
@@ -0,0 +1,14 @@
+(library
+  (name imperative_to_sugar)
+  (public_name ligo.imperative_to_sugar)
+  (libraries
+    simple-utils
+    ast_imperative
+    ast_sugar
+    proto-alpha-utils
+  )
+  (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/4-imperative_to_sugar/imperative_to_sugar.ml b/src/passes/4-imperative_to_sugar/imperative_to_sugar.ml
new file mode 100644
index 000000000..9cdfed78e
--- /dev/null
+++ b/src/passes/4-imperative_to_sugar/imperative_to_sugar.ml
@@ -0,0 +1,363 @@
+module I = Ast_imperative
+module O = Ast_sugar
+open Trace
+
+let rec compile_type_expression : I.type_expression -> O.type_expression result =
+  fun te ->
+  let return te = ok @@ O.make_t te in
+  match te.type_content with
+    | I.T_sum sum -> 
+      let sum = I.CMap.to_kv_list sum in
+      let%bind sum = 
+        bind_map_list (fun (k,v) ->
+          let%bind v = compile_type_expression v in
+          ok @@ (k,v)
+        ) sum
+      in
+      return @@ O.T_sum (O.CMap.of_list sum)
+    | I.T_record record -> 
+      let record = I.LMap.to_kv_list record in
+      let%bind record = 
+        bind_map_list (fun (k,v) ->
+          let%bind v = compile_type_expression v in
+          ok @@ (k,v)
+        ) record
+      in
+      return @@ O.T_record (O.LMap.of_list record)
+    | I.T_arrow {type1;type2} ->
+      let%bind type1 = compile_type_expression type1 in
+      let%bind type2 = compile_type_expression type2 in
+      return @@ T_arrow {type1;type2}
+    | I.T_variable type_variable -> return @@ T_variable type_variable 
+    | I.T_constant type_constant -> return @@ T_constant type_constant
+    | I.T_operator type_operator ->
+      let%bind type_operator = compile_type_operator type_operator in
+      return @@ T_operator type_operator
+
+and compile_type_operator : I.type_operator -> O.type_operator result =
+  fun t_o ->
+  match t_o with
+    | TC_contract c -> 
+      let%bind c = compile_type_expression c in
+      ok @@ O.TC_contract c
+    | TC_option o ->
+      let%bind o = compile_type_expression o in
+      ok @@ O.TC_option o
+    | TC_list l ->
+      let%bind l = compile_type_expression l in
+      ok @@ O.TC_list l
+    | TC_set s ->
+      let%bind s = compile_type_expression s in
+      ok @@ O.TC_set s
+    | TC_map (k,v) ->
+      let%bind (k,v) = bind_map_pair compile_type_expression (k,v) in
+      ok @@ O.TC_map (k,v)
+    | TC_big_map (k,v) ->
+      let%bind (k,v) = bind_map_pair compile_type_expression (k,v) in
+      ok @@ O.TC_big_map (k,v)
+    | TC_arrow (i,o) ->
+      let%bind (i,o) = bind_map_pair compile_type_expression (i,o) in
+      ok @@ O.TC_arrow (i,o)
+
+let rec compile_expression : I.expression -> O.expression result =
+  fun e ->
+  let return expr = ok @@ O.make_expr ~loc:e.location expr in
+  match e.expression_content with
+    | I.E_literal literal   -> return @@ O.E_literal literal
+    | I.E_constant {cons_name;arguments} -> 
+      let%bind arguments = bind_map_list compile_expression arguments in
+      return @@ O.E_constant {cons_name;arguments}
+    | I.E_variable name     -> return @@ O.E_variable name
+    | I.E_application {lamb;args} -> 
+      let%bind lamb = compile_expression lamb in
+      let%bind args = compile_expression args in
+      return @@ O.E_application {lamb;args}
+    | I.E_lambda lambda ->
+      let%bind lambda = compile_lambda lambda in
+      return @@ O.E_lambda lambda
+    | I.E_recursive {fun_name;fun_type;lambda} ->
+      let%bind fun_type = compile_type_expression fun_type in
+      let%bind lambda = compile_lambda lambda in
+      return @@ O.E_recursive {fun_name;fun_type;lambda}
+    | I.E_let_in {let_binder;mut=_;inline;rhs;let_result} ->
+      let (binder,ty_opt) = let_binder in
+      let%bind ty_opt = bind_map_option compile_type_expression ty_opt in
+      let%bind rhs = compile_expression rhs in
+      let%bind let_result = compile_expression let_result in
+      return @@ O.E_let_in {let_binder=(binder,ty_opt);inline;rhs;let_result}
+    | I.E_constructor {constructor;element} ->
+      let%bind element = compile_expression element in
+      return @@ O.E_constructor {constructor;element}
+    | I.E_matching {matchee; cases} ->
+      let%bind matchee = compile_expression matchee in
+      let%bind cases   = compile_matching cases in
+      return @@ O.E_matching {matchee;cases}
+    | I.E_record record ->
+      let record = I.LMap.to_kv_list record in
+      let%bind record = 
+        bind_map_list (fun (k,v) ->
+          let%bind v =compile_expression v in
+          ok @@ (k,v)
+        ) record
+      in
+      return @@ O.E_record (O.LMap.of_list record)
+    | I.E_record_accessor {expr;label} ->
+      let%bind expr = compile_expression expr in
+      return @@ O.E_record_accessor {expr;label}
+    | I.E_record_update {record;path;update} ->
+      let%bind record = compile_expression record in
+      let%bind update = compile_expression update in
+      return @@ O.E_record_update {record;path;update}
+    | I.E_map map ->
+      let%bind map = bind_map_list (
+        bind_map_pair compile_expression
+      ) map
+      in
+      return @@ O.E_map map
+    | I.E_big_map big_map ->
+      let%bind big_map = bind_map_list (
+        bind_map_pair compile_expression
+      ) big_map
+      in
+      return @@ O.E_big_map big_map
+    | I.E_list lst ->
+      let%bind lst = bind_map_list compile_expression lst in
+      return @@ O.E_list lst
+    | I.E_set set ->
+      let%bind set = bind_map_list compile_expression set in
+      return @@ O.E_set set 
+    | I.E_look_up look_up ->
+      let%bind look_up = bind_map_pair compile_expression look_up in
+      return @@ O.E_look_up look_up
+    | I.E_ascription {anno_expr; type_annotation} ->
+      let%bind anno_expr = compile_expression anno_expr in
+      let%bind type_annotation = compile_type_expression type_annotation in
+      return @@ O.E_ascription {anno_expr; type_annotation}
+    | I.E_sequence {expr1; expr2} ->
+      let%bind expr1 = compile_expression expr1 in
+      let%bind expr2 = compile_expression expr2 in
+      return @@ O.E_sequence {expr1; expr2}
+    | I.E_skip -> return @@ O.E_skip
+and compile_lambda : I.lambda -> O.lambda result =
+  fun {binder;input_type;output_type;result}->
+    let%bind input_type = bind_map_option compile_type_expression input_type in
+    let%bind output_type = bind_map_option compile_type_expression output_type in
+    let%bind result = compile_expression result in
+    ok @@ O.{binder;input_type;output_type;result}
+and compile_matching : I.matching_expr -> O.matching_expr result =
+  fun m -> 
+  match m with 
+    | I.Match_bool {match_true;match_false} ->
+      let%bind match_true = compile_expression match_true in
+      let%bind match_false = compile_expression match_false in
+      ok @@ O.Match_bool {match_true;match_false}
+    | I.Match_list {match_nil;match_cons} ->
+      let%bind match_nil = compile_expression match_nil in
+      let (hd,tl,expr,tv) = match_cons in
+      let%bind expr = compile_expression expr in
+      ok @@ O.Match_list {match_nil; match_cons=(hd,tl,expr,tv)}
+    | I.Match_option {match_none;match_some} ->
+      let%bind match_none = compile_expression match_none in
+      let (n,expr,tv) = match_some in
+      let%bind expr = compile_expression expr in
+      ok @@ O.Match_option {match_none; match_some=(n,expr,tv)}
+    | I.Match_tuple ((lst,expr), tv) ->
+      let%bind expr = compile_expression expr in
+      ok @@ O.Match_tuple ((lst,expr), tv)
+    | I.Match_variant (lst,tv) ->
+      let%bind lst = bind_map_list (
+        fun ((c,n),expr) ->
+          let%bind expr = compile_expression expr in
+          ok @@ ((c,n),expr)
+      ) lst 
+      in
+      ok @@ O.Match_variant (lst,tv)
+ 
+let compile_declaration : I.declaration Location.wrap -> _ =
+  fun {wrap_content=declaration;location} ->
+  let return decl = ok @@ Location.wrap ~loc:location decl in
+  match declaration with 
+  | I.Declaration_constant (n, te_opt, inline, expr) ->
+    let%bind expr = compile_expression expr in
+    let%bind te_opt = bind_map_option compile_type_expression te_opt in
+    return @@ O.Declaration_constant (n, te_opt, inline, expr)
+  | I.Declaration_type (n, te) ->
+    let%bind te = compile_type_expression te in
+    return @@ O.Declaration_type (n,te)
+
+let compile_program : I.program -> O.program result =
+  fun p ->
+  bind_map_list compile_declaration p
+
+(* uncompiling *)
+let rec uncompile_type_expression : O.type_expression -> I.type_expression result =
+  fun te ->
+  let return te = ok @@ I.make_t te in
+  match te.type_content with
+    | O.T_sum sum -> 
+      let sum = I.CMap.to_kv_list sum in
+      let%bind sum = 
+        bind_map_list (fun (k,v) ->
+          let%bind v = uncompile_type_expression v in
+          ok @@ (k,v)
+        ) sum
+      in
+      return @@ I.T_sum (O.CMap.of_list sum)
+    | O.T_record record -> 
+      let record = I.LMap.to_kv_list record in
+      let%bind record = 
+        bind_map_list (fun (k,v) ->
+          let%bind v = uncompile_type_expression v in
+          ok @@ (k,v)
+        ) record
+      in
+      return @@ I.T_record (O.LMap.of_list record)
+    | O.T_arrow {type1;type2} ->
+      let%bind type1 = uncompile_type_expression type1 in
+      let%bind type2 = uncompile_type_expression type2 in
+      return @@ T_arrow {type1;type2}
+    | O.T_variable type_variable -> return @@ T_variable type_variable 
+    | O.T_constant type_constant -> return @@ T_constant type_constant
+    | O.T_operator type_operator ->
+      let%bind type_operator = uncompile_type_operator type_operator in
+      return @@ T_operator type_operator
+
+and uncompile_type_operator : O.type_operator -> I.type_operator result =
+  fun t_o ->
+  match t_o with
+    | TC_contract c -> 
+      let%bind c = uncompile_type_expression c in
+      ok @@ I.TC_contract c
+    | TC_option o ->
+      let%bind o = uncompile_type_expression o in
+      ok @@ I.TC_option o
+    | TC_list l ->
+      let%bind l = uncompile_type_expression l in
+      ok @@ I.TC_list l
+    | TC_set s ->
+      let%bind s = uncompile_type_expression s in
+      ok @@ I.TC_set s
+    | TC_map (k,v) ->
+      let%bind (k,v) = bind_map_pair uncompile_type_expression (k,v) in
+      ok @@ I.TC_map (k,v)
+    | TC_big_map (k,v) ->
+      let%bind (k,v) = bind_map_pair uncompile_type_expression (k,v) in
+      ok @@ I.TC_big_map (k,v)
+    | TC_arrow (i,o) ->
+      let%bind (i,o) = bind_map_pair uncompile_type_expression (i,o) in
+      ok @@ I.TC_arrow (i,o)
+
+let rec uncompile_expression : O.expression -> I.expression result =
+  fun e ->
+  let return expr = ok @@ I.make_expr ~loc:e.location expr in
+  match e.expression_content with 
+    O.E_literal lit -> return @@ I.E_literal lit
+  | O.E_constant {cons_name;arguments} -> 
+    let%bind arguments = bind_map_list uncompile_expression arguments in
+    return @@ I.E_constant {cons_name;arguments}
+  | O.E_variable name     -> return @@ I.E_variable name
+  | O.E_application {lamb; args} -> 
+    let%bind lamb = uncompile_expression lamb in
+    let%bind args = uncompile_expression args in
+    return @@ I.E_application {lamb; args}
+  | O.E_lambda lambda ->
+    let%bind lambda = uncompile_lambda lambda in
+    return @@ I.E_lambda lambda
+  | O.E_recursive {fun_name;fun_type;lambda} ->
+    let%bind fun_type = uncompile_type_expression fun_type in
+    let%bind lambda = uncompile_lambda lambda in
+    return @@ I.E_recursive {fun_name;fun_type;lambda}
+  | O.E_let_in {let_binder;inline;rhs;let_result} ->
+    let (binder,ty_opt) = let_binder in
+    let%bind ty_opt = bind_map_option uncompile_type_expression ty_opt in
+    let%bind rhs = uncompile_expression rhs in
+    let%bind let_result = uncompile_expression let_result in
+    return @@ I.E_let_in {let_binder=(binder,ty_opt);mut=false;inline;rhs;let_result}
+  | O.E_constructor {constructor;element} ->
+    let%bind element = uncompile_expression element in
+    return @@ I.E_constructor {constructor;element}
+  | O.E_matching {matchee; cases} ->
+    let%bind matchee = uncompile_expression matchee in
+    let%bind cases   = uncompile_matching cases in
+    return @@ I.E_matching {matchee;cases}
+  | O.E_record record ->
+    let record = I.LMap.to_kv_list record in
+    let%bind record = 
+      bind_map_list (fun (k,v) ->
+        let%bind v = uncompile_expression v in
+        ok @@ (k,v)
+      ) record
+    in
+    return @@ I.E_record (O.LMap.of_list record)
+  | O.E_record_accessor {expr;label} ->
+    let%bind expr = uncompile_expression expr in
+    return @@ I.E_record_accessor {expr;label}
+  | O.E_record_update {record;path;update} ->
+    let%bind record = uncompile_expression record in
+    let%bind update = uncompile_expression update in
+    return @@ I.E_record_update {record;path;update}
+  | O.E_map map ->
+    let%bind map = bind_map_list (
+      bind_map_pair uncompile_expression
+    ) map
+    in
+    return @@ I.E_map map
+  | O.E_big_map big_map ->
+    let%bind big_map = bind_map_list (
+      bind_map_pair uncompile_expression
+    ) big_map
+    in
+    return @@ I.E_big_map big_map
+  | O.E_list lst ->
+    let%bind lst = bind_map_list uncompile_expression lst in
+    return @@ I.E_list lst
+  | O.E_set set ->
+    let%bind set = bind_map_list uncompile_expression set in
+    return @@ I.E_set set 
+  | O.E_look_up look_up ->
+    let%bind look_up = bind_map_pair uncompile_expression look_up in
+    return @@ I.E_look_up look_up
+  | O.E_ascription {anno_expr; type_annotation} ->
+    let%bind anno_expr = uncompile_expression anno_expr in
+    let%bind type_annotation = uncompile_type_expression type_annotation in
+    return @@ I.E_ascription {anno_expr; type_annotation}
+  | O.E_sequence {expr1; expr2} ->
+    let%bind expr1 = uncompile_expression expr1 in
+    let%bind expr2 = uncompile_expression expr2 in
+    return @@ I.E_sequence {expr1; expr2}
+  | O.E_skip -> return @@ I.E_skip
+
+and uncompile_lambda : O.lambda -> I.lambda result =
+  fun {binder;input_type;output_type;result}->
+    let%bind input_type = bind_map_option uncompile_type_expression input_type in
+    let%bind output_type = bind_map_option uncompile_type_expression output_type in
+    let%bind result = uncompile_expression result in
+    ok @@ I.{binder;input_type;output_type;result}
+and uncompile_matching : O.matching_expr -> I.matching_expr result =
+  fun m -> 
+  match m with 
+    | O.Match_bool {match_true;match_false} ->
+      let%bind match_true = uncompile_expression match_true in
+      let%bind match_false = uncompile_expression match_false in
+      ok @@ I.Match_bool {match_true;match_false}
+    | O.Match_list {match_nil;match_cons} ->
+      let%bind match_nil = uncompile_expression match_nil in
+      let (hd,tl,expr,tv) = match_cons in
+      let%bind expr = uncompile_expression expr in
+      ok @@ I.Match_list {match_nil; match_cons=(hd,tl,expr,tv)}
+    | O.Match_option {match_none;match_some} ->
+      let%bind match_none = uncompile_expression match_none in
+      let (n,expr,tv) = match_some in
+      let%bind expr = uncompile_expression expr in
+      ok @@ I.Match_option {match_none; match_some=(n,expr,tv)}
+    | O.Match_tuple ((lst,expr), tv) ->
+      let%bind expr = uncompile_expression expr in
+      ok @@ O.Match_tuple ((lst,expr), tv)
+    | O.Match_variant (lst,tv) ->
+      let%bind lst = bind_map_list (
+        fun ((c,n),expr) ->
+          let%bind expr = uncompile_expression expr in
+          ok @@ ((c,n),expr)
+      ) lst 
+      in
+      ok @@ I.Match_variant (lst,tv)
diff --git a/src/passes/5-self_ast_sugar/dune b/src/passes/5-self_ast_sugar/dune
new file mode 100644
index 000000000..33b51be08
--- /dev/null
+++ b/src/passes/5-self_ast_sugar/dune
@@ -0,0 +1,13 @@
+(library
+  (name self_ast_sugar)
+  (public_name ligo.self_ast_sugar)
+  (libraries
+    simple-utils
+    ast_sugar
+    proto-alpha-utils
+  )
+  (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/main.ml b/src/passes/5-self_ast_typed/main.ml
deleted file mode 100644
index e69de29bb..000000000
diff --git a/src/passes/6-sugar_to_core/dune b/src/passes/6-sugar_to_core/dune
new file mode 100644
index 000000000..4f4bb92e9
--- /dev/null
+++ b/src/passes/6-sugar_to_core/dune
@@ -0,0 +1,14 @@
+(library
+  (name sugar_to_core)
+  (public_name ligo.sugar_to_core)
+  (libraries
+    simple-utils
+    ast_sugar
+    ast_core
+    proto-alpha-utils
+  )
+  (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/6-sugar_to_core/sugar_to_core.ml b/src/passes/6-sugar_to_core/sugar_to_core.ml
new file mode 100644
index 000000000..261bb1e81
--- /dev/null
+++ b/src/passes/6-sugar_to_core/sugar_to_core.ml
@@ -0,0 +1,363 @@
+module I = Ast_sugar
+module O = Ast_core
+open Trace
+
+let rec idle_type_expression : I.type_expression -> O.type_expression result =
+  fun te ->
+  let return te = ok @@ O.make_t te in
+  match te.type_content with
+    | I.T_sum sum -> 
+      let sum = I.CMap.to_kv_list sum in
+      let%bind sum = 
+        bind_map_list (fun (k,v) ->
+          let%bind v = idle_type_expression v in
+          ok @@ (k,v)
+        ) sum
+      in
+      return @@ O.T_sum (O.CMap.of_list sum)
+    | I.T_record record -> 
+      let record = I.LMap.to_kv_list record in
+      let%bind record = 
+        bind_map_list (fun (k,v) ->
+          let%bind v = idle_type_expression v in
+          ok @@ (k,v)
+        ) record
+      in
+      return @@ O.T_record (O.LMap.of_list record)
+    | I.T_arrow {type1;type2} ->
+      let%bind type1 = idle_type_expression type1 in
+      let%bind type2 = idle_type_expression type2 in
+      return @@ T_arrow {type1;type2}
+    | I.T_variable type_variable -> return @@ T_variable type_variable 
+    | I.T_constant type_constant -> return @@ T_constant type_constant
+    | I.T_operator type_operator ->
+      let%bind type_operator = idle_type_operator type_operator in
+      return @@ T_operator type_operator
+
+and idle_type_operator : I.type_operator -> O.type_operator result =
+  fun t_o ->
+  match t_o with
+    | TC_contract c -> 
+      let%bind c = idle_type_expression c in
+      ok @@ O.TC_contract c
+    | TC_option o ->
+      let%bind o = idle_type_expression o in
+      ok @@ O.TC_option o
+    | TC_list l ->
+      let%bind l = idle_type_expression l in
+      ok @@ O.TC_list l
+    | TC_set s ->
+      let%bind s = idle_type_expression s in
+      ok @@ O.TC_set s
+    | TC_map (k,v) ->
+      let%bind (k,v) = bind_map_pair idle_type_expression (k,v) in
+      ok @@ O.TC_map (k,v)
+    | TC_big_map (k,v) ->
+      let%bind (k,v) = bind_map_pair idle_type_expression (k,v) in
+      ok @@ O.TC_big_map (k,v)
+    | TC_arrow (i,o) ->
+      let%bind (i,o) = bind_map_pair idle_type_expression (i,o) in
+      ok @@ O.TC_arrow (i,o)
+
+let rec compile_expression : I.expression -> O.expression result =
+  fun e ->
+  let return expr = ok @@ O.make_expr ~loc:e.location expr in
+  match e.expression_content with
+    | I.E_literal literal   -> return @@ O.E_literal literal
+    | I.E_constant {cons_name;arguments} -> 
+      let%bind arguments = bind_map_list compile_expression arguments in
+      return @@ O.E_constant {cons_name;arguments}
+    | I.E_variable name     -> return @@ O.E_variable name
+    | I.E_application {lamb;args} -> 
+      let%bind lamb = compile_expression lamb in
+      let%bind args = compile_expression args in
+      return @@ O.E_application {lamb; args}
+    | I.E_lambda lambda ->
+      let%bind lambda = compile_lambda lambda in
+      return @@ O.E_lambda lambda
+    | I.E_recursive {fun_name;fun_type;lambda} ->
+      let%bind fun_type = idle_type_expression fun_type in
+      let%bind lambda = compile_lambda lambda in
+      return @@ O.E_recursive {fun_name;fun_type;lambda}
+    | I.E_let_in {let_binder;inline;rhs;let_result} ->
+      let (binder,ty_opt) = let_binder in
+      let%bind ty_opt = bind_map_option idle_type_expression ty_opt in
+      let%bind rhs = compile_expression rhs in
+      let%bind let_result = compile_expression let_result in
+      return @@ O.E_let_in {let_binder=(binder,ty_opt);inline;rhs;let_result}
+    | I.E_constructor {constructor;element} ->
+      let%bind element = compile_expression element in
+      return @@ O.E_constructor {constructor;element}
+    | I.E_matching {matchee; cases} ->
+      let%bind matchee = compile_expression matchee in
+      let%bind cases   = compile_matching cases in
+      return @@ O.E_matching {matchee;cases}
+    | I.E_record record ->
+      let record = I.LMap.to_kv_list record in
+      let%bind record = 
+        bind_map_list (fun (k,v) ->
+          let%bind v =compile_expression v in
+          ok @@ (k,v)
+        ) record
+      in
+      return @@ O.E_record (O.LMap.of_list record)
+    | I.E_record_accessor {expr;label} ->
+      let%bind expr = compile_expression expr in
+      return @@ O.E_record_accessor {expr;label}
+    | I.E_record_update {record;path;update} ->
+      let%bind record = compile_expression record in
+      let%bind update = compile_expression update in
+      return @@ O.E_record_update {record;path;update}
+    | I.E_map map ->
+      let%bind map = bind_map_list (
+        bind_map_pair compile_expression
+      ) map
+      in
+      return @@ O.E_map map
+    | I.E_big_map big_map ->
+      let%bind big_map = bind_map_list (
+        bind_map_pair compile_expression
+      ) big_map
+      in
+      return @@ O.E_big_map big_map
+    | I.E_list lst ->
+      let%bind lst = bind_map_list compile_expression lst in
+      return @@ O.E_list lst
+    | I.E_set set ->
+      let%bind set = bind_map_list compile_expression set in
+      return @@ O.E_set set 
+    | I.E_look_up look_up ->
+      let%bind look_up = bind_map_pair compile_expression look_up in
+      return @@ O.E_look_up look_up
+    | I.E_ascription {anno_expr; type_annotation} ->
+      let%bind anno_expr = compile_expression anno_expr in
+      let%bind type_annotation = idle_type_expression type_annotation in
+      return @@ O.E_ascription {anno_expr; type_annotation}
+    | I.E_sequence {expr1; expr2} ->
+      let%bind expr1 = compile_expression expr1 in
+      let%bind expr2 = compile_expression expr2 in
+      return @@ O.E_let_in {let_binder=(Var.of_name "_", Some O.t_unit); rhs=expr1;let_result=expr2; inline=false}
+    | I.E_skip -> ok @@ O.e_unit ~loc:e.location ()
+
+and compile_lambda : I.lambda -> O.lambda result =
+  fun {binder;input_type;output_type;result}->
+    let%bind input_type = bind_map_option idle_type_expression input_type in
+    let%bind output_type = bind_map_option idle_type_expression output_type in
+    let%bind result = compile_expression result in
+    ok @@ O.{binder;input_type;output_type;result}
+and compile_matching : I.matching_expr -> O.matching_expr result =
+  fun m -> 
+  match m with 
+    | I.Match_bool {match_true;match_false} ->
+      let%bind match_true = compile_expression match_true in
+      let%bind match_false = compile_expression match_false in
+      ok @@ O.Match_bool {match_true;match_false}
+    | I.Match_list {match_nil;match_cons} ->
+      let%bind match_nil = compile_expression match_nil in
+      let (hd,tl,expr,tv) = match_cons in
+      let%bind expr = compile_expression expr in
+      ok @@ O.Match_list {match_nil; match_cons=(hd,tl,expr,tv)}
+    | I.Match_option {match_none;match_some} ->
+      let%bind match_none = compile_expression match_none in
+      let (n,expr,tv) = match_some in
+      let%bind expr = compile_expression expr in
+      ok @@ O.Match_option {match_none; match_some=(n,expr,tv)}
+    | I.Match_tuple ((lst,expr), tv) ->
+      let%bind expr = compile_expression expr in
+      ok @@ O.Match_tuple ((lst,expr), tv)
+    | I.Match_variant (lst,tv) ->
+      let%bind lst = bind_map_list (
+        fun ((c,n),expr) ->
+          let%bind expr = compile_expression expr in
+          ok @@ ((c,n),expr)
+      ) lst 
+      in
+      ok @@ O.Match_variant (lst,tv)
+ 
+let compile_declaration : I.declaration Location.wrap -> _ =
+  fun {wrap_content=declaration;location} ->
+  let return decl = ok @@ Location.wrap ~loc:location decl in
+  match declaration with 
+  | I.Declaration_constant (n, te_opt, inline, expr) ->
+    let%bind expr = compile_expression expr in
+    let%bind te_opt = bind_map_option idle_type_expression te_opt in
+    return @@ O.Declaration_constant (n, te_opt, inline, expr)
+  | I.Declaration_type (n, te) ->
+    let%bind te = idle_type_expression te in
+    return @@ O.Declaration_type (n,te)
+
+let compile_program : I.program -> O.program result =
+  fun p ->
+  bind_map_list compile_declaration p
+
+(* uncompiling *)
+let rec uncompile_type_expression : O.type_expression -> I.type_expression result =
+  fun te ->
+  let return te = ok @@ I.make_t te in
+  match te.type_content with
+    | O.T_sum sum -> 
+      let sum = I.CMap.to_kv_list sum in
+      let%bind sum = 
+        bind_map_list (fun (k,v) ->
+          let%bind v = uncompile_type_expression v in
+          ok @@ (k,v)
+        ) sum
+      in
+      return @@ I.T_sum (O.CMap.of_list sum)
+    | O.T_record record -> 
+      let record = I.LMap.to_kv_list record in
+      let%bind record = 
+        bind_map_list (fun (k,v) ->
+          let%bind v = uncompile_type_expression v in
+          ok @@ (k,v)
+        ) record
+      in
+      return @@ I.T_record (O.LMap.of_list record)
+    | O.T_arrow {type1;type2} ->
+      let%bind type1 = uncompile_type_expression type1 in
+      let%bind type2 = uncompile_type_expression type2 in
+      return @@ T_arrow {type1;type2}
+    | O.T_variable type_variable -> return @@ T_variable type_variable 
+    | O.T_constant type_constant -> return @@ T_constant type_constant
+    | O.T_operator type_operator ->
+      let%bind type_operator = uncompile_type_operator type_operator in
+      return @@ T_operator type_operator
+
+and uncompile_type_operator : O.type_operator -> I.type_operator result =
+  fun t_o ->
+  match t_o with
+    | TC_contract c -> 
+      let%bind c = uncompile_type_expression c in
+      ok @@ I.TC_contract c
+    | TC_option o ->
+      let%bind o = uncompile_type_expression o in
+      ok @@ I.TC_option o
+    | TC_list l ->
+      let%bind l = uncompile_type_expression l in
+      ok @@ I.TC_list l
+    | TC_set s ->
+      let%bind s = uncompile_type_expression s in
+      ok @@ I.TC_set s
+    | TC_map (k,v) ->
+      let%bind (k,v) = bind_map_pair uncompile_type_expression (k,v) in
+      ok @@ I.TC_map (k,v)
+    | TC_big_map (k,v) ->
+      let%bind (k,v) = bind_map_pair uncompile_type_expression (k,v) in
+      ok @@ I.TC_big_map (k,v)
+    | TC_arrow (i,o) ->
+      let%bind (i,o) = bind_map_pair uncompile_type_expression (i,o) in
+      ok @@ I.TC_arrow (i,o)
+
+let rec uncompile_expression : O.expression -> I.expression result =
+  fun e ->
+  let return expr = ok @@ I.make_expr ~loc:e.location expr in
+  match e.expression_content with 
+    O.E_literal lit -> return @@ I.E_literal lit
+  | O.E_constant {cons_name;arguments} -> 
+    let%bind arguments = bind_map_list uncompile_expression arguments in
+    return @@ I.E_constant {cons_name;arguments}
+  | O.E_variable name     -> return @@ I.E_variable name
+  | O.E_application {lamb; args} -> 
+    let%bind lamb = uncompile_expression lamb in
+    let%bind args = uncompile_expression args in
+    return @@ I.E_application {lamb; args}
+  | O.E_lambda lambda ->
+    let%bind lambda = uncompile_lambda lambda in
+    return @@ I.E_lambda lambda
+  | O.E_recursive {fun_name;fun_type;lambda} ->
+    let%bind fun_type = uncompile_type_expression fun_type in
+    let%bind lambda = uncompile_lambda lambda in
+    return @@ I.E_recursive {fun_name;fun_type;lambda}
+  | O.E_let_in {let_binder;inline=false;rhs=expr1;let_result=expr2} when let_binder = (Var.of_name "_", Some O.t_unit) ->
+    let%bind expr1 = uncompile_expression expr1 in
+    let%bind expr2 = uncompile_expression expr2 in
+    return @@ I.E_sequence {expr1;expr2}
+  | O.E_let_in {let_binder;inline;rhs;let_result} ->
+    let (binder,ty_opt) = let_binder in
+    let%bind ty_opt = bind_map_option uncompile_type_expression ty_opt in
+    let%bind rhs = uncompile_expression rhs in
+    let%bind let_result = uncompile_expression let_result in
+    return @@ I.E_let_in {let_binder=(binder,ty_opt);inline;rhs;let_result}
+  | O.E_constructor {constructor;element} ->
+    let%bind element = uncompile_expression element in
+    return @@ I.E_constructor {constructor;element}
+  | O.E_matching {matchee; cases} ->
+    let%bind matchee = uncompile_expression matchee in
+    let%bind cases   = uncompile_matching cases in
+    return @@ I.E_matching {matchee;cases}
+  | O.E_record record ->
+    let record = I.LMap.to_kv_list record in
+    let%bind record = 
+      bind_map_list (fun (k,v) ->
+        let%bind v = uncompile_expression v in
+        ok @@ (k,v)
+      ) record
+    in
+    return @@ I.E_record (O.LMap.of_list record)
+  | O.E_record_accessor {expr;label} ->
+    let%bind expr = uncompile_expression expr in
+    return @@ I.E_record_accessor {expr;label}
+  | O.E_record_update {record;path;update} ->
+    let%bind record = uncompile_expression record in
+    let%bind update = uncompile_expression update in
+    return @@ I.E_record_update {record;path;update}
+  | O.E_map map ->
+    let%bind map = bind_map_list (
+      bind_map_pair uncompile_expression
+    ) map
+    in
+    return @@ I.E_map map
+  | O.E_big_map big_map ->
+    let%bind big_map = bind_map_list (
+      bind_map_pair uncompile_expression
+    ) big_map
+    in
+    return @@ I.E_big_map big_map
+  | O.E_list lst ->
+    let%bind lst = bind_map_list uncompile_expression lst in
+    return @@ I.E_list lst
+  | O.E_set set ->
+    let%bind set = bind_map_list uncompile_expression set in
+    return @@ I.E_set set 
+  | O.E_look_up look_up ->
+    let%bind look_up = bind_map_pair uncompile_expression look_up in
+    return @@ I.E_look_up look_up
+  | O.E_ascription {anno_expr; type_annotation} ->
+    let%bind anno_expr = uncompile_expression anno_expr in
+    let%bind type_annotation = uncompile_type_expression type_annotation in
+    return @@ I.E_ascription {anno_expr; type_annotation}
+
+and uncompile_lambda : O.lambda -> I.lambda result =
+  fun {binder;input_type;output_type;result}->
+    let%bind input_type = bind_map_option uncompile_type_expression input_type in
+    let%bind output_type = bind_map_option uncompile_type_expression output_type in
+    let%bind result = uncompile_expression result in
+    ok @@ I.{binder;input_type;output_type;result}
+and uncompile_matching : O.matching_expr -> I.matching_expr result =
+  fun m -> 
+  match m with 
+    | O.Match_bool {match_true;match_false} ->
+      let%bind match_true = uncompile_expression match_true in
+      let%bind match_false = uncompile_expression match_false in
+      ok @@ I.Match_bool {match_true;match_false}
+    | O.Match_list {match_nil;match_cons} ->
+      let%bind match_nil = uncompile_expression match_nil in
+      let (hd,tl,expr,tv) = match_cons in
+      let%bind expr = uncompile_expression expr in
+      ok @@ I.Match_list {match_nil; match_cons=(hd,tl,expr,tv)}
+    | O.Match_option {match_none;match_some} ->
+      let%bind match_none = uncompile_expression match_none in
+      let (n,expr,tv) = match_some in
+      let%bind expr = uncompile_expression expr in
+      ok @@ I.Match_option {match_none; match_some=(n,expr,tv)}
+    | O.Match_tuple ((lst,expr), tv) ->
+      let%bind expr = uncompile_expression expr in
+      ok @@ O.Match_tuple ((lst,expr), tv)
+    | O.Match_variant (lst,tv) ->
+      let%bind lst = bind_map_list (
+        fun ((c,n),expr) ->
+          let%bind expr = uncompile_expression expr in
+          ok @@ ((c,n),expr)
+      ) lst 
+      in
+      ok @@ I.Match_variant (lst,tv)
diff --git a/src/passes/7-self_ast_core/dune b/src/passes/7-self_ast_core/dune
new file mode 100644
index 000000000..e51afd86e
--- /dev/null
+++ b/src/passes/7-self_ast_core/dune
@@ -0,0 +1,13 @@
+(library
+  (name self_ast_core)
+  (public_name ligo.self_ast_core)
+  (libraries
+    simple-utils
+    ast_core
+    proto-alpha-utils
+  )
+  (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/4-typer-new/PP.ml b/src/passes/8-typer-new/PP.ml
similarity index 100%
rename from src/passes/4-typer-new/PP.ml
rename to src/passes/8-typer-new/PP.ml
diff --git a/src/passes/4-typer-new/dune b/src/passes/8-typer-new/dune
similarity index 93%
rename from src/passes/4-typer-new/dune
rename to src/passes/8-typer-new/dune
index 645a7053f..b7bbee5f4 100644
--- a/src/passes/4-typer-new/dune
+++ b/src/passes/8-typer-new/dune
@@ -4,7 +4,7 @@
   (libraries
     simple-utils
     tezos-utils
-    ast_simplified
+    ast_core
     ast_typed
     operators
     UnionFind
diff --git a/src/passes/4-typer-new/solver.ml b/src/passes/8-typer-new/solver.ml
similarity index 99%
rename from src/passes/4-typer-new/solver.ml
rename to src/passes/8-typer-new/solver.ml
index aad418cb5..328cfe015 100644
--- a/src/passes/4-typer-new/solver.ml
+++ b/src/passes/8-typer-new/solver.ml
@@ -3,7 +3,7 @@ open Trace
 module Core = Typesystem.Core
 
 module Wrap = struct
-  module I = Ast_simplified
+  module I = Ast_core
   module T = Ast_typed
   module O = Core
 
diff --git a/src/passes/4-typer-new/typer.ml b/src/passes/8-typer-new/typer.ml
similarity index 97%
rename from src/passes/4-typer-new/typer.ml
rename to src/passes/8-typer-new/typer.ml
index decd197fc..0dcae68d0 100644
--- a/src/passes/4-typer-new/typer.ml
+++ b/src/passes/8-typer-new/typer.ml
@@ -1,6 +1,6 @@
 open Trace
 
-module I = Ast_simplified
+module I = Ast_core
 module O = Ast_typed
 open O.Combinators
 
@@ -446,10 +446,6 @@ and type_expression : environment -> Solver.state -> ?tv_opt:O.type_expression -
   | E_literal (Literal_void) -> (
       failwith "TODO: missing implementation for literal void"
     )
-  | E_skip -> (
-    (* E_skip just returns unit *)
-    return_wrapped (e_unit ()) state @@ Wrap.literal (t_unit ())
-    )
   (* | E_literal (Literal_string s) -> (
    *     L.log (Format.asprintf "literal_string option type: %a" PP_helpers.(option O.PP.type_expression) tv_opt) ;
    *     match Option.map Ast_typed.get_type' tv_opt with
@@ -683,11 +679,11 @@ and type_expression : environment -> Solver.state -> ?tv_opt:O.type_expression -
    *   let%bind (name', tv) =
    *     type_constant name tv_lst tv_opt ae.location in
    *   return (E_constant (name' , lst')) tv *)
-  | E_application {expr1;expr2} ->
-    let%bind (f' , state') = type_expression e state expr1 in
-    let%bind (arg , state'') = type_expression e state' expr2 in
-    let wrapped = Wrap.application f'.type_expression arg.type_expression in
-    return_wrapped (E_application {expr1=f';expr2=arg}) state'' wrapped
+  | E_application {lamb;args} ->
+    let%bind (f' , state') = type_expression e state lamb in
+    let%bind (args , state'') = type_expression e state' args in
+    let wrapped = Wrap.application f'.type_expression args.type_expression in
+    return_wrapped (E_application {lamb=f';args}) state'' wrapped
 
   (* | E_look_up dsi ->
    *   let%bind (ds, ind) = bind_map_pair (type_expression e) dsi in
@@ -872,7 +868,7 @@ let untype_type_value (t:O.type_expression) : (I.type_expression) result =
 (* TODO: we ended up with two versions of type_program… ??? *)
 
 (*
-Apply type_declaration on all the node of the AST_simplified from the root p
+Apply type_declaration on all the node of the AST_core from the root p
 *)
 let type_program_returns_state ((env, state, p) : environment * Solver.state * I.program) : (environment * Solver.state * O.program) result =
   let aux ((e : environment), (s : Solver.state) , (ds : O.declaration Location.wrap list)) (d:I.declaration Location.wrap) =
@@ -950,10 +946,10 @@ let type_program' : I.program -> O.program result = fun p ->
   ok p'
 
 (*
-  Tranform a Ast_typed type_expression into an ast_simplified type_expression
+  Tranform a Ast_typed type_expression into an ast_core type_expression
 *)
 let rec untype_type_expression (t:O.type_expression) : (I.type_expression) result =
-  (* TODO: or should we use t.simplified if present? *)
+  (* TODO: or should we use t.core if present? *)
   let%bind t = match t.type_content with
   | O.T_sum x ->
     let%bind x' = Stage_common.Helpers.bind_map_cmap untype_type_expression x in
@@ -999,13 +995,13 @@ let rec untype_type_expression (t:O.type_expression) : (I.type_expression) resul
     in
   ok @@ I.make_t t
 
-(* match t.simplified with *)
+(* match t.core with *)
 (* | Some s -> ok s *)
 (* | _ -> fail @@ internal_assertion_failure "trying to untype generated type" *)
 
 
 (*
-  Tranform a Ast_typed literal into an ast_simplified literal
+  Tranform a Ast_typed literal into an ast_core literal
 *)
 let untype_literal (l:O.literal) : I.literal result =
   let open I in
@@ -1027,7 +1023,7 @@ let untype_literal (l:O.literal) : I.literal result =
   | Literal_operation s -> ok (Literal_operation s)
 
 (*
-  Tranform a Ast_typed expression into an ast_simplified matching
+  Tranform a Ast_typed expression into an ast_core matching
 *)
 let rec untype_expression (e:O.expression) : (I.expression) result =
   let open I in
@@ -1041,9 +1037,9 @@ let rec untype_expression (e:O.expression) : (I.expression) result =
       return (e_constant cons_name lst')
   | E_variable (n) ->
     return (e_variable (n))
-  | E_application {expr1;expr2} ->
-      let%bind f' = untype_expression expr1 in
-      let%bind arg' = untype_expression expr2 in
+  | E_application {lamb;args} ->
+      let%bind f' = untype_expression lamb in
+      let%bind arg' = untype_expression args in
       return (e_application f' arg')
   | E_lambda lambda ->
       let%bind lambda = untype_lambda e.type_expression lambda in
@@ -1094,7 +1090,7 @@ let rec untype_expression (e:O.expression) : (I.expression) result =
     let%bind tv = untype_type_value rhs.type_expression in
     let%bind rhs = untype_expression rhs in
     let%bind result = untype_expression let_result in
-    return (e_let_in (let_binder , (Some tv)) false inline rhs result)
+    return (e_let_in (let_binder , (Some tv)) inline rhs result)
   | E_recursive {fun_name; fun_type; lambda} ->
       let%bind lambda = untype_lambda fun_type lambda in
       let%bind fun_type = untype_type_expression fun_type in
@@ -1107,7 +1103,7 @@ and untype_lambda ty {binder; result} : I.lambda result =
       ok ({binder;input_type = Some input_type; output_type = Some output_type; result}: I.lambda)
 
 (*
-  Tranform a Ast_typed matching into an ast_simplified matching
+  Tranform a Ast_typed matching into an ast_core matching
 *)
 and untype_matching : (O.expression -> I.expression result) -> O.matching_expr -> I.matching_expr result = fun f m ->
   let open I in
diff --git a/src/passes/4-typer-new/typer.ml.old b/src/passes/8-typer-new/typer.ml.old
similarity index 99%
rename from src/passes/4-typer-new/typer.ml.old
rename to src/passes/8-typer-new/typer.ml.old
index db842716a..66b918235 100644
--- a/src/passes/4-typer-new/typer.ml.old
+++ b/src/passes/8-typer-new/typer.ml.old
@@ -1,6 +1,6 @@
 open Trace
 
-module I = Ast_simplified
+module I = Ast_core
 module O = Ast_typed
 open O.Combinators
 
@@ -736,7 +736,7 @@ and type_constant (name:string) (lst:O.type_expression list) (tv_opt:O.type_expr
   typer lst tv_opt
 
 let untype_type_expression (t:O.type_expression) : (I.type_expression) result =
-  match t.simplified with
+  match t.core with
   | Some s -> ok s
   | _ -> fail @@ internal_assertion_failure "trying to untype generated type"
 
diff --git a/src/passes/4-typer-new/typer.mli b/src/passes/8-typer-new/typer.mli
similarity index 99%
rename from src/passes/4-typer-new/typer.mli
rename to src/passes/8-typer-new/typer.mli
index 29b7cad08..6e24e7359 100644
--- a/src/passes/4-typer-new/typer.mli
+++ b/src/passes/8-typer-new/typer.mli
@@ -1,6 +1,6 @@
 open Trace
 
-module I = Ast_simplified
+module I = Ast_core
 module O = Ast_typed
 
 module Environment = O.Environment
diff --git a/src/passes/4-typer-new/typer_new.ml b/src/passes/8-typer-new/typer_new.ml
similarity index 100%
rename from src/passes/4-typer-new/typer_new.ml
rename to src/passes/8-typer-new/typer_new.ml
diff --git a/src/passes/4-typer-old/dune b/src/passes/8-typer-old/dune
similarity index 93%
rename from src/passes/4-typer-old/dune
rename to src/passes/8-typer-old/dune
index 29e48c79e..faec4e901 100644
--- a/src/passes/4-typer-old/dune
+++ b/src/passes/8-typer-old/dune
@@ -4,7 +4,7 @@
   (libraries
     simple-utils
     tezos-utils
-    ast_simplified
+    ast_core
     ast_typed
     typer_new
     operators
diff --git a/src/passes/4-typer-old/typer.ml b/src/passes/8-typer-old/typer.ml
similarity index 98%
rename from src/passes/4-typer-old/typer.ml
rename to src/passes/8-typer-old/typer.ml
index 448f7be08..5a11d6184 100644
--- a/src/passes/4-typer-old/typer.ml
+++ b/src/passes/8-typer-old/typer.ml
@@ -1,6 +1,6 @@
 open Trace
 
-module I = Ast_simplified
+module I = Ast_core
 module O = Ast_typed
 open O.Combinators
 
@@ -423,7 +423,7 @@ and type_expression' : environment -> ?tv_opt:O.type_expression -> I.expression
       return (E_variable name) tv'.type_value
   | E_literal (Literal_bool b) ->
       return (E_literal (Literal_bool b)) (t_bool ())
-  | E_literal Literal_unit | E_skip ->
+  | E_literal Literal_unit ->
       return (E_literal (Literal_unit)) (t_unit ())
   | E_literal Literal_void -> return (E_literal (Literal_void)) (t_unit ()) (* TODO : IS this really a t_unit ?*)
   | E_literal (Literal_string s) ->
@@ -688,21 +688,21 @@ and type_expression' : environment -> ?tv_opt:O.type_expression -> I.expression
       let%bind (name', tv) =
         type_constant cons_name tv_lst tv_opt in
       return (E_constant {cons_name=name';arguments=lst'}) tv
-  | E_application {expr1;expr2} ->
-      let%bind expr1' = type_expression' e expr1 in
-      let%bind expr2 = type_expression' e expr2 in
-      let%bind tv = match expr1'.type_expression.type_content with
+  | E_application {lamb; args} ->
+      let%bind lamb' = type_expression' e lamb in
+      let%bind args' = type_expression' e args in
+      let%bind tv = match lamb'.type_expression.type_content with
         | T_arrow {type1;type2} ->
-            let%bind _ = O.assert_type_expression_eq (type1, expr2.type_expression) in
+            let%bind _ = O.assert_type_expression_eq (type1, args'.type_expression) in
             ok type2
         | _ ->
           fail @@ type_error_approximate
             ~expected:"should be a function type"
-            ~expression:expr1
-            ~actual:expr1'.type_expression
-            expr1'.location
+            ~expression:lamb
+            ~actual:lamb'.type_expression
+            lamb'.location
       in
-      return (E_application {expr1=expr1';expr2}) tv
+      return (E_application {lamb=lamb'; args=args'}) tv
   | E_look_up dsi ->
       let%bind (ds, ind) = bind_map_pair (type_expression' e) dsi in
       let%bind (src, dst) = bind_map_or (get_t_map , get_t_big_map) ds.type_expression in
@@ -841,9 +841,9 @@ let rec untype_expression (e:O.expression) : (I.expression) result =
       return (e_constant cons_name lst')
   | E_variable n ->
       return (e_variable (n))
-  | E_application {expr1;expr2} ->
-      let%bind f' = untype_expression expr1 in
-      let%bind arg' = untype_expression expr2 in
+  | E_application {lamb;args} ->
+      let%bind f' = untype_expression lamb in
+      let%bind arg' = untype_expression args in
       return (e_application f' arg')
   | E_lambda {binder ; result} -> (
       let%bind io = get_t_function ty in
@@ -893,7 +893,7 @@ let rec untype_expression (e:O.expression) : (I.expression) result =
       let%bind tv = untype_type_expression rhs.type_expression in
       let%bind rhs = untype_expression rhs in
       let%bind result = untype_expression let_result in
-      return (e_let_in (let_binder , (Some tv)) false inline rhs result)
+      return (e_let_in (let_binder , (Some tv)) inline rhs result)
   | E_recursive {fun_name;fun_type; lambda} ->
       let%bind fun_type = untype_type_expression fun_type in
       let%bind unty_expr= untype_expression_content ty @@ E_lambda lambda in
diff --git a/src/passes/4-typer-old/typer.mli b/src/passes/8-typer-old/typer.mli
similarity index 99%
rename from src/passes/4-typer-old/typer.mli
rename to src/passes/8-typer-old/typer.mli
index 9b1e986da..d1bf21393 100644
--- a/src/passes/4-typer-old/typer.mli
+++ b/src/passes/8-typer-old/typer.mli
@@ -1,6 +1,6 @@
 open Trace
 
-module I = Ast_simplified
+module I = Ast_core
 module O = Ast_typed
 
 module Environment = O.Environment
diff --git a/src/passes/4-typer-old/typer_old.ml b/src/passes/8-typer-old/typer_old.ml
similarity index 100%
rename from src/passes/4-typer-old/typer_old.ml
rename to src/passes/8-typer-old/typer_old.ml
diff --git a/src/passes/4-typer/dune b/src/passes/8-typer/dune
similarity index 93%
rename from src/passes/4-typer/dune
rename to src/passes/8-typer/dune
index 35c5e807d..f6072da39 100644
--- a/src/passes/4-typer/dune
+++ b/src/passes/8-typer/dune
@@ -4,7 +4,7 @@
   (libraries
     simple-utils
     tezos-utils
-    ast_simplified
+    ast_core
     ast_typed
     typer_old
     typer_new
diff --git a/src/passes/4-typer/typer.ml b/src/passes/8-typer/typer.ml
similarity index 96%
rename from src/passes/4-typer/typer.ml
rename to src/passes/8-typer/typer.ml
index 8ab5576a0..48f1ac011 100644
--- a/src/passes/4-typer/typer.ml
+++ b/src/passes/8-typer/typer.ml
@@ -1,6 +1,6 @@
 let use_new_typer = false
 
-module I = Ast_simplified
+module I = Ast_core
 module O = Ast_typed
 
 module Environment = O.Environment
diff --git a/src/passes/4-typer/typer.mli b/src/passes/8-typer/typer.mli
similarity index 94%
rename from src/passes/4-typer/typer.mli
rename to src/passes/8-typer/typer.mli
index bb8ac3094..bf4c11f4d 100644
--- a/src/passes/4-typer/typer.mli
+++ b/src/passes/8-typer/typer.mli
@@ -2,7 +2,7 @@ val use_new_typer : bool
 
 open Trace
 
-module I = Ast_simplified
+module I = Ast_core
 module O = Ast_typed
 
 module Environment = O.Environment
diff --git a/src/passes/5-self_ast_typed/contract_passes.ml b/src/passes/9-self_ast_typed/contract_passes.ml
similarity index 100%
rename from src/passes/5-self_ast_typed/contract_passes.ml
rename to src/passes/9-self_ast_typed/contract_passes.ml
diff --git a/src/passes/5-self_ast_typed/dune b/src/passes/9-self_ast_typed/dune
similarity index 100%
rename from src/passes/5-self_ast_typed/dune
rename to src/passes/9-self_ast_typed/dune
diff --git a/src/passes/5-self_ast_typed/helpers.ml b/src/passes/9-self_ast_typed/helpers.ml
similarity index 97%
rename from src/passes/5-self_ast_typed/helpers.ml
rename to src/passes/9-self_ast_typed/helpers.ml
index 818cdccf5..2da8a766e 100644
--- a/src/passes/5-self_ast_typed/helpers.ml
+++ b/src/passes/9-self_ast_typed/helpers.ml
@@ -19,8 +19,8 @@ let rec fold_expression : 'a folder -> 'a -> expression -> 'a result = fun f ini
   | E_look_up ab ->
       let%bind res = bind_fold_pair self init' ab in
       ok res
-  | E_application {expr1;expr2} -> (
-      let ab = (expr1,expr2) in
+  | E_application {lamb; args} -> (
+      let ab = (lamb, args) in
       let%bind res = bind_fold_pair self init' ab in
       ok res
     )
@@ -135,10 +135,10 @@ let rec map_expression : mapper -> expression -> expression result = fun f e ->
       let%bind e' = self c.element in
       return @@ E_constructor {c with element = e'}
   )
-  | E_application {expr1;expr2} -> (
-      let ab = (expr1,expr2) in
+  | E_application {lamb; args} -> (
+      let ab = (lamb, args) in
       let%bind (a,b) = bind_map_pair self ab in
-      return @@ E_application {expr1=a;expr2=b}
+      return @@ E_application {lamb=a;args=b}
     )
   | E_let_in { let_binder ; rhs ; let_result; inline } -> (
       let%bind rhs = self rhs in
@@ -251,10 +251,10 @@ let rec fold_map_expression : 'a fold_mapper -> 'a -> expression -> ('a * expres
       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
+  | E_application {lamb;args} -> (
+      let ab = (lamb, args) in
       let%bind (res,(a,b)) = bind_fold_map_pair self init' ab in
-      ok (res, return @@ E_application {expr1=a;expr2=b})
+      ok (res, return @@ E_application {lamb=a;args=b})
     )
   | E_let_in { let_binder ; rhs ; let_result; inline } -> (
       let%bind (res,rhs) = self init' rhs in
diff --git a/src/passes/5-self_ast_typed/self_ast_typed.ml b/src/passes/9-self_ast_typed/self_ast_typed.ml
similarity index 100%
rename from src/passes/5-self_ast_typed/self_ast_typed.ml
rename to src/passes/9-self_ast_typed/self_ast_typed.ml
diff --git a/src/passes/5-self_ast_typed/tail_recursion.ml b/src/passes/9-self_ast_typed/tail_recursion.ml
similarity index 96%
rename from src/passes/5-self_ast_typed/tail_recursion.ml
rename to src/passes/9-self_ast_typed/tail_recursion.ml
index 3e971c79e..610484a38 100644
--- a/src/passes/5-self_ast_typed/tail_recursion.ml
+++ b/src/passes/9-self_ast_typed/tail_recursion.ml
@@ -24,9 +24,9 @@ let rec check_recursive_call : expression_variable -> bool -> expression -> unit
     Assert.assert_true (final_path || n <> v) in
     ok ()
     )
-  | E_application {expr1;expr2} ->
-    let%bind _ = check_recursive_call n final_path expr1 in
-    let%bind _ = check_recursive_call n false expr2 in
+  | E_application {lamb;args} ->
+    let%bind _ = check_recursive_call n final_path lamb in
+    let%bind _ = check_recursive_call n false args in
     ok ()
   | E_lambda {result;_} ->
     let%bind _ = check_recursive_call n final_path result in
diff --git a/src/passes/9-self_michelson/main.ml b/src/passes/9-self_michelson/main.ml
deleted file mode 100644
index e69de29bb..000000000
diff --git a/src/passes/operators/dune b/src/passes/operators/dune
index 64222a117..fa69f6257 100644
--- a/src/passes/operators/dune
+++ b/src/passes/operators/dune
@@ -4,6 +4,9 @@
   (libraries
     simple-utils
     tezos-utils
+    ast_imperative
+    ast_sugar
+    ast_core
     ast_typed
     typesystem
     mini_c
diff --git a/src/passes/operators/operators.ml b/src/passes/operators/operators.ml
index deb541216..472b67506 100644
--- a/src/passes/operators/operators.ml
+++ b/src/passes/operators/operators.ml
@@ -9,15 +9,15 @@ open Trace
   a new constructor at all those places.
 *)
 
-module Simplify = struct
+module Concrete_to_imperative = struct
 
-  open Ast_simplified
+  open Ast_imperative
   (*
     Each front-end has its owns constants.
 
     Constants are special names that have their own case in the AST. E_constant
     for regular constants, and T_constant for type constants. Both types are
-    defined in `Ast_simplified/types.ml`.
+    defined in `Ast_core/types.ml`.
     For instance, "2 + 2" in Pascaligo is translated to `E_constant ("ADD" , [
       E_literal (Literal_int 2) ;
       E_literal (Literal_int 2) ;
diff --git a/src/passes/operators/operators.mli b/src/passes/operators/operators.mli
index 77ce53196..15176ff8c 100644
--- a/src/passes/operators/operators.mli
+++ b/src/passes/operators/operators.mli
@@ -1,6 +1,6 @@
 
-module Simplify : sig
- open Ast_simplified
+module Concrete_to_imperative : sig
+ open Ast_imperative
  open Trace
 
   module Pascaligo : sig
diff --git a/src/stages/ast_simplified/PP.ml b/src/stages/1-ast_imperative/PP.ml
similarity index 95%
rename from src/stages/ast_simplified/PP.ml
rename to src/stages/1-ast_imperative/PP.ml
index f27d9ed70..ebb4bd83e 100644
--- a/src/stages/ast_simplified/PP.ml
+++ b/src/stages/1-ast_imperative/PP.ml
@@ -4,7 +4,7 @@ open Format
 open PP_helpers
 
 include Stage_common.PP
-include Ast_PP_type(Ast_simplified_parameter)
+include Ast_PP_type(Ast_imperative_parameter)
 
 let expression_variable ppf (ev : expression_variable) : unit =
   fprintf ppf "%a" Var.pp ev
@@ -18,8 +18,8 @@ and expression_content ppf (ec : expression_content) =
       literal ppf l
   | E_variable n ->
       fprintf ppf "%a" expression_variable n
-  | E_application app ->
-      fprintf ppf "(%a)@(%a)" expression app.expr1 expression app.expr2
+  | E_application {lamb;args} ->
+      fprintf ppf "(%a)@(%a)" expression lamb expression args
   | E_constructor c ->
       fprintf ppf "%a(%a)" constructor c.constructor expression c.element
   | E_constant c ->
@@ -52,18 +52,20 @@ and expression_content ppf (ec : expression_content) =
       fprintf ppf "match %a with %a"
         expression matchee (matching expression)
         cases
-  | E_let_in { let_binder ; mut; rhs ; let_result; inline } ->    
-      fprintf ppf "let %a%a = %a%a in %a" option_mut mut option_type_name let_binder expression rhs option_inline inline expression let_result
   | E_recursive { fun_name; fun_type; lambda} ->
       fprintf ppf "rec (%a:%a => %a )" 
         expression_variable fun_name 
         type_expression fun_type
         expression_content (E_lambda lambda)
-  | E_skip ->
-      fprintf ppf "skip"
+  | E_let_in { let_binder ; mut; rhs ; let_result; inline } ->    
+      fprintf ppf "let %a%a = %a%a in %a" option_mut mut option_type_name let_binder expression rhs option_inline inline expression let_result
   | E_ascription {anno_expr; type_annotation} ->
       fprintf ppf "%a : %a" expression anno_expr type_expression
         type_annotation
+  | E_sequence {expr1;expr2} ->
+      fprintf ppf "%a;\n%a" expression expr1 expression expr2
+  | E_skip ->
+      fprintf ppf "skip"
 
 and option_type_name ppf
     ((n, ty_opt) : expression_variable * type_expression option) =
diff --git a/src/stages/ast_simplified/ast_simplified.ml b/src/stages/1-ast_imperative/ast_imperative.ml
similarity index 100%
rename from src/stages/ast_simplified/ast_simplified.ml
rename to src/stages/1-ast_imperative/ast_imperative.ml
diff --git a/src/stages/ast_simplified/combinators.ml b/src/stages/1-ast_imperative/combinators.ml
similarity index 69%
rename from src/stages/ast_simplified/combinators.ml
rename to src/stages/1-ast_imperative/combinators.ml
index 24b292c4f..92a1dbe73 100644
--- a/src/stages/ast_simplified/combinators.ml
+++ b/src/stages/1-ast_imperative/combinators.ml
@@ -79,57 +79,57 @@ let t_operator op lst: type_expression result =
   | TC_contract _    , [t] -> ok @@ t_contract t
   | _ , _ -> fail @@ bad_type_operator op
 
-let location_wrap ?(loc = Location.generated) expression_content =
+let make_expr ?(loc = Location.generated) expression_content =
   let location = loc in
   { expression_content; location }
 
-let e_var ?loc (n: string) : expression = location_wrap ?loc @@ E_variable (Var.of_name n)
-let e_literal ?loc l : expression = location_wrap ?loc @@ E_literal l
-let e_unit ?loc () : expression = location_wrap ?loc @@ E_literal (Literal_unit)
-let e_int ?loc n : expression = location_wrap ?loc @@ E_literal (Literal_int n)
-let e_nat ?loc n : expression = location_wrap ?loc @@ E_literal (Literal_nat n)
-let e_timestamp ?loc n : expression = location_wrap ?loc @@ E_literal (Literal_timestamp n)
-let e_bool ?loc   b : expression = location_wrap ?loc @@ E_literal (Literal_bool b)
-let e_string ?loc s : expression = location_wrap ?loc @@ E_literal (Literal_string s)
-let e_address ?loc s : expression = location_wrap ?loc @@ E_literal (Literal_address s)
-let e_mutez ?loc s : expression = location_wrap ?loc @@ E_literal (Literal_mutez s)
-let e_signature ?loc s : expression = location_wrap ?loc @@ E_literal (Literal_signature s)
-let e_key ?loc s : expression = location_wrap ?loc @@ E_literal (Literal_key s)
-let e_key_hash ?loc s : expression = location_wrap ?loc @@ E_literal (Literal_key_hash s)
-let e_chain_id ?loc s : expression = location_wrap ?loc @@ E_literal (Literal_chain_id s)
+let e_var ?loc (n: string) : expression = make_expr ?loc @@ E_variable (Var.of_name n)
+let e_literal ?loc l : expression = make_expr ?loc @@ E_literal l
+let e_unit ?loc () : expression = make_expr ?loc @@ E_literal (Literal_unit)
+let e_int ?loc n : expression = make_expr ?loc @@ E_literal (Literal_int n)
+let e_nat ?loc n : expression = make_expr ?loc @@ E_literal (Literal_nat n)
+let e_timestamp ?loc n : expression = make_expr ?loc @@ E_literal (Literal_timestamp n)
+let e_bool ?loc   b : expression = make_expr ?loc @@ E_literal (Literal_bool b)
+let e_string ?loc s : expression = make_expr ?loc @@ E_literal (Literal_string s)
+let e_address ?loc s : expression = make_expr ?loc @@ E_literal (Literal_address s)
+let e_mutez ?loc s : expression = make_expr ?loc @@ E_literal (Literal_mutez s)
+let e_signature ?loc s : expression = make_expr ?loc @@ E_literal (Literal_signature s)
+let e_key ?loc s : expression = make_expr ?loc @@ E_literal (Literal_key s)
+let e_key_hash ?loc s : expression = make_expr ?loc @@ E_literal (Literal_key_hash s)
+let e_chain_id ?loc s : expression = make_expr ?loc @@ E_literal (Literal_chain_id s)
 let e'_bytes b : expression_content result =
   let%bind bytes = generic_try (simple_error "bad hex to bytes") (fun () -> Hex.to_bytes (`Hex b)) in
   ok @@ E_literal (Literal_bytes bytes)
 let e_bytes_hex ?loc b : expression result =
   let%bind e' = e'_bytes b in
-  ok @@ location_wrap ?loc e'
+  ok @@ make_expr ?loc e'
 let e_bytes_raw ?loc (b: bytes) : expression =
-  location_wrap ?loc @@ E_literal (Literal_bytes b)
+  make_expr ?loc @@ E_literal (Literal_bytes b)
 let e_bytes_string ?loc (s: string) : expression =
-  location_wrap ?loc @@ E_literal (Literal_bytes (Hex.to_bytes (Hex.of_string s)))
-let e_big_map ?loc lst : expression = location_wrap ?loc @@ E_big_map lst
-let e_some ?loc s  : expression = location_wrap ?loc @@ E_constant {cons_name = C_SOME; arguments = [s]}
-let e_none ?loc () : expression = location_wrap ?loc @@ E_constant {cons_name = C_NONE; arguments = []}
-let e_string_cat ?loc sl sr : expression = location_wrap ?loc @@ E_constant {cons_name = C_CONCAT; arguments = [sl ; sr ]}
-let e_map_add ?loc k v old  : expression = location_wrap ?loc @@ E_constant {cons_name = C_MAP_ADD; arguments = [k ; v ; old]}
-let e_map ?loc lst : expression = location_wrap ?loc @@ E_map lst
-let e_set ?loc lst : expression = location_wrap ?loc @@ E_set lst
-let e_list ?loc lst : expression = location_wrap ?loc @@ E_list lst
-let e_constructor ?loc s a : expression = location_wrap ?loc @@ E_constructor { constructor = Constructor s; element = a}
-let e_matching ?loc a b : expression = location_wrap ?loc @@ E_matching {matchee=a;cases=b}
+  make_expr ?loc @@ E_literal (Literal_bytes (Hex.to_bytes (Hex.of_string s)))
+let e_big_map ?loc lst : expression = make_expr ?loc @@ E_big_map lst
+let e_some ?loc s  : expression = make_expr ?loc @@ E_constant {cons_name = C_SOME; arguments = [s]}
+let e_none ?loc () : expression = make_expr ?loc @@ E_constant {cons_name = C_NONE; arguments = []}
+let e_string_cat ?loc sl sr : expression = make_expr ?loc @@ E_constant {cons_name = C_CONCAT; arguments = [sl ; sr ]}
+let e_map_add ?loc k v old  : expression = make_expr ?loc @@ E_constant {cons_name = C_MAP_ADD; arguments = [k ; v ; old]}
+let e_map ?loc lst : expression = make_expr ?loc @@ E_map lst
+let e_set ?loc lst : expression = make_expr ?loc @@ E_set lst
+let e_list ?loc lst : expression = make_expr ?loc @@ E_list lst
+let e_constructor ?loc s a : expression = make_expr ?loc @@ E_constructor { constructor = Constructor s; element = a}
+let e_matching ?loc a b : expression = make_expr ?loc @@ E_matching {matchee=a;cases=b}
 let e_matching_bool ?loc a b c : expression = e_matching ?loc a (Match_bool {match_true = b ; match_false = c})
-let e_accessor ?loc a b = location_wrap ?loc @@ E_record_accessor {expr = a; label= Label b}
+let e_accessor ?loc a b = make_expr ?loc @@ E_record_accessor {expr = a; label= Label b}
 let e_accessor_list ?loc a b  = List.fold_left (fun a b -> e_accessor ?loc a b) a b
-let e_variable ?loc v = location_wrap ?loc @@ E_variable v
-let e_skip ?loc () = location_wrap ?loc @@ E_skip
+let e_variable ?loc v = make_expr ?loc @@ E_variable v
+let e_skip ?loc () = make_expr ?loc @@ E_skip
 let e_let_in ?loc (binder, ascr) mut inline rhs let_result = 
-  location_wrap ?loc @@ E_let_in { let_binder = (binder, ascr) ; mut; rhs ; let_result; inline }
-let e_annotation ?loc anno_expr ty = location_wrap ?loc @@ E_ascription {anno_expr; type_annotation = ty}
-let e_application ?loc a b = location_wrap ?loc @@ E_application {expr1=a ; expr2=b}
-let e_binop ?loc name a b  = location_wrap ?loc @@ E_constant {cons_name = name ; arguments = [a ; b]}
-let e_constant ?loc name lst = location_wrap ?loc @@ E_constant {cons_name=name ; arguments = lst}
-let e_look_up ?loc x y = location_wrap ?loc @@ E_look_up (x , y)
-let e_sequence ?loc expr1 expr2 = e_let_in ?loc (Var.fresh (), Some t_unit) false false expr1 expr2
+  make_expr ?loc @@ E_let_in { let_binder = (binder, ascr) ; mut; rhs ; let_result; inline }
+let e_annotation ?loc anno_expr ty = make_expr ?loc @@ E_ascription {anno_expr; type_annotation = ty}
+let e_application ?loc a b = make_expr ?loc @@ E_application {lamb=a ; args=b}
+let e_binop ?loc name a b  = make_expr ?loc @@ E_constant {cons_name = name ; arguments = [a ; b]}
+let e_constant ?loc name lst = make_expr ?loc @@ E_constant {cons_name=name ; arguments = lst}
+let e_look_up ?loc x y = make_expr ?loc @@ E_look_up (x , y)
+let e_sequence ?loc expr1 expr2 = make_expr ?loc @@ E_sequence {expr1; expr2}
 let e_cond ?loc expr match_true match_false = e_matching expr ?loc (Match_bool {match_true; match_false})
 (*
 let e_assign ?loc a b c = location_wrap ?loc @@ E_assign (Var.of_name a , b , c) (* TODO handlethat*)
@@ -141,14 +141,14 @@ let e_matching_variant ?loc a (lst : ((string * string)* 'a) list) =
   e_matching ?loc a (ez_match_variant lst)
 let e_record_ez ?loc (lst : (string * expr) list) : expression =
   let map = List.fold_left (fun m (x, y) -> LMap.add (Label x) y m) LMap.empty lst in
-  location_wrap ?loc @@ E_record map
+  make_expr ?loc @@ E_record map
 let e_record ?loc map =
   let lst = Map.String.to_kv_list map in
   e_record_ez ?loc lst 
 
 let e_update ?loc record path update = 
   let path = Label path in
-  location_wrap ?loc @@ E_record_update {record; path; update}
+  make_expr ?loc @@ E_record_update {record; path; update}
 
 let e_tuple ?loc lst : expression = e_record_ez ?loc (tuple_to_record lst)
 let e_pair ?loc a b  : expression = e_tuple ?loc [a;b]
@@ -177,13 +177,13 @@ let e_lambda ?loc (binder : expression_variable)
     (output_type : type_expression option)
     (result : expression)
   : expression =
-  location_wrap ?loc @@ E_lambda {
-    binder = binder;
+  make_expr ?loc @@ E_lambda {
+    binder = binder ;
     input_type = input_type ;
     output_type = output_type ;
     result ;
   }
-let e_recursive ?loc fun_name fun_type lambda = location_wrap ?loc @@ E_recursive {fun_name; fun_type; lambda}
+let e_recursive ?loc fun_name fun_type lambda = make_expr ?loc @@ E_recursive {fun_name; fun_type; lambda}
 
 
 let e_assign_with_let ?loc var access_path expr = 
@@ -237,7 +237,7 @@ let tuple_of_record (m: _ LMap.t) =
 let get_e_tuple = fun t ->
   match t with
   | E_record r -> ok @@ tuple_of_record r
-  | _ -> simple_fail "ast_simplified: get_e_tuple: not a tuple"
+  | _ -> simple_fail "ast_core: get_e_tuple: not a tuple"
 
 (* Same as get_e_pair *)
 let extract_pair : expression -> (expression * expression) result = fun e ->
diff --git a/src/stages/ast_simplified/combinators.mli b/src/stages/1-ast_imperative/combinators.mli
similarity index 98%
rename from src/stages/ast_simplified/combinators.mli
rename to src/stages/1-ast_imperative/combinators.mli
index 5dc0af74c..ca2f2d552 100644
--- a/src/stages/ast_simplified/combinators.mli
+++ b/src/stages/1-ast_imperative/combinators.mli
@@ -46,6 +46,7 @@ val t_map : type_expression -> type_expression -> type_expression
 val t_operator : type_operator -> type_expression list -> type_expression result
 val t_set : type_expression -> type_expression
 
+val make_expr : ?loc:Location.t -> expression_content -> expression
 val e_var : ?loc:Location.t -> string -> expression
 val e_literal : ?loc:Location.t -> literal -> expression
 val e_unit : ?loc:Location.t -> unit -> expression
diff --git a/src/stages/1-ast_imperative/dune b/src/stages/1-ast_imperative/dune
new file mode 100644
index 000000000..8966ca542
--- /dev/null
+++ b/src/stages/1-ast_imperative/dune
@@ -0,0 +1,13 @@
+(library
+  (name ast_imperative)
+  (public_name ligo.ast_impretative)
+  (libraries
+    simple-utils
+    tezos-utils
+    stage_common
+  )
+  (preprocess
+    (pps ppx_let bisect_ppx --conditional)
+  )
+  (flags (:standard -open Simple_utils ))
+)
diff --git a/src/stages/1-ast_imperative/misc.ml b/src/stages/1-ast_imperative/misc.ml
new file mode 100644
index 000000000..324529525
--- /dev/null
+++ b/src/stages/1-ast_imperative/misc.ml
@@ -0,0 +1,331 @@
+open Trace
+open Types
+
+open Stage_common.Helpers
+module Errors = struct
+  let different_literals_because_different_types name a b () =
+    let title () = "literals have different types: " ^ name in
+    let message () = "" in
+    let data = [
+      ("a" , fun () -> Format.asprintf "%a" PP.literal a) ;
+      ("b" , fun () -> Format.asprintf "%a" PP.literal b )
+    ] in
+    error ~data title message ()
+
+  let different_literals name a b () =
+    let title () = name ^ " are different" in
+    let message () = "" in
+    let data = [
+      ("a" , fun () -> Format.asprintf "%a" PP.literal a) ;
+      ("b" , fun () -> Format.asprintf "%a" PP.literal b )
+    ] in
+    error ~data title message ()
+
+  let error_uncomparable_literals name a b () =
+    let title () = name ^ " are not comparable" in
+    let message () = "" in
+    let data = [
+      ("a" , fun () -> Format.asprintf "%a" PP.literal a) ;
+      ("b" , fun () -> Format.asprintf "%a" PP.literal b )
+    ] in
+    error ~data title message ()
+end
+open Errors
+
+let assert_literal_eq (a, b : literal * literal) : unit result =
+  match (a, b) with
+  | Literal_bool a, Literal_bool b when a = b -> ok ()
+  | Literal_bool _, Literal_bool _ -> fail @@ different_literals "different bools" a b
+  | Literal_bool _, _ -> fail @@ different_literals_because_different_types "bool vs non-bool" a b
+  | Literal_int a, Literal_int b when a = b -> ok ()
+  | Literal_int _, Literal_int _ -> fail @@ different_literals "different ints" a b
+  | Literal_int _, _ -> fail @@ different_literals_because_different_types "int vs non-int" a b
+  | Literal_nat a, Literal_nat b when a = b -> ok ()
+  | Literal_nat _, Literal_nat _ -> fail @@ different_literals "different nats" a b
+  | Literal_nat _, _ -> fail @@ different_literals_because_different_types "nat vs non-nat" a b
+  | Literal_timestamp a, Literal_timestamp b when a = b -> ok ()
+  | Literal_timestamp _, Literal_timestamp _ -> fail @@ different_literals "different timestamps" a b
+  | Literal_timestamp _, _ -> fail @@ different_literals_because_different_types "timestamp vs non-timestamp" a b
+  | Literal_mutez a, Literal_mutez b when a = b -> ok ()
+  | Literal_mutez _, Literal_mutez _ -> fail @@ different_literals "different tezs" a b
+  | Literal_mutez _, _ -> fail @@ different_literals_because_different_types "tez vs non-tez" a b
+  | Literal_string a, Literal_string b when a = b -> ok ()
+  | Literal_string _, Literal_string _ -> fail @@ different_literals "different strings" a b
+  | Literal_string _, _ -> fail @@ different_literals_because_different_types "string vs non-string" a b
+  | Literal_bytes a, Literal_bytes b when a = b -> ok ()
+  | Literal_bytes _, Literal_bytes _ -> fail @@ different_literals "different bytess" a b
+  | Literal_bytes _, _ -> fail @@ different_literals_because_different_types "bytes vs non-bytes" a b
+  | Literal_void, Literal_void -> ok ()
+  | Literal_void, _ -> fail @@ different_literals_because_different_types "void vs non-void" a b
+  | Literal_unit, Literal_unit -> ok ()
+  | Literal_unit, _ -> fail @@ different_literals_because_different_types "unit vs non-unit" a b
+  | Literal_address a, Literal_address b when a = b -> ok ()
+  | Literal_address _, Literal_address _ -> fail @@ different_literals "different addresss" a b
+  | Literal_address _, _ -> fail @@ different_literals_because_different_types "address vs non-address" a b
+  | Literal_operation _, Literal_operation _ -> fail @@ error_uncomparable_literals "can't compare operations" a b
+  | Literal_operation _, _ -> fail @@ different_literals_because_different_types "operation vs non-operation" a b
+  | Literal_signature a, Literal_signature b when a = b -> ok ()
+  | Literal_signature _, Literal_signature _ -> fail @@ different_literals "different signature" a b
+  | Literal_signature _, _ -> fail @@ different_literals_because_different_types "signature vs non-signature" a b
+  | Literal_key a, Literal_key b when a = b -> ok ()
+  | Literal_key _, Literal_key _ -> fail @@ different_literals "different key" a b
+  | Literal_key _, _ -> fail @@ different_literals_because_different_types "key vs non-key" a b
+  | Literal_key_hash a, Literal_key_hash b when a = b -> ok ()
+  | Literal_key_hash _, Literal_key_hash _ -> fail @@ different_literals "different key_hash" a b
+  | Literal_key_hash _, _ -> fail @@ different_literals_because_different_types "key_hash vs non-key_hash" a b
+  | Literal_chain_id a, Literal_chain_id b when a = b -> ok ()
+  | Literal_chain_id _, Literal_chain_id _ -> fail @@ different_literals "different chain_id" a b
+  | Literal_chain_id _, _ -> fail @@ different_literals_because_different_types "chain_id vs non-chain_id" a b
+
+let rec assert_value_eq (a, b: (expression * expression )) : unit result =
+  Format.printf "in assert_value_eq %a %a\n%!" PP.expression a PP.expression b;
+  let error_content () =
+    Format.asprintf "\n@[<v>- %a@;- %a]" PP.expression a PP.expression b
+  in
+  trace (fun () -> error (thunk "not equal") error_content ()) @@
+  match (a.expression_content , b.expression_content) with
+  | E_literal a , E_literal b ->
+      assert_literal_eq (a, b)
+  | E_literal _ , _ ->
+    simple_fail "comparing a literal with not a literal"
+  | E_constant (ca) , E_constant (cb) when ca.cons_name = cb.cons_name -> (
+      let%bind lst =
+        generic_try (simple_error "constants with different number of elements")
+          (fun () -> List.combine ca.arguments cb.arguments) in
+      let%bind _all = bind_list @@ List.map assert_value_eq lst in
+      ok ()
+    )
+  | E_constant _ , E_constant _ ->
+      simple_fail "different constants"
+  | E_constant _ , _ ->
+      let error_content () =
+        Format.asprintf "%a vs %a"
+          PP.expression a
+          PP.expression b
+      in
+      fail @@ (fun () -> error (thunk "comparing constant with other expression") error_content ())
+
+  | E_constructor (ca), E_constructor (cb) when ca.constructor = cb.constructor -> (
+      let%bind _eq = assert_value_eq (ca.element, cb.element) in
+      ok ()
+    )
+  | E_constructor _, E_constructor _ ->
+      simple_fail "different constructors"
+  | E_constructor _, _ ->
+      simple_fail "comparing constructor with other expression"
+
+
+  | E_record sma, E_record smb -> (
+      let aux _ a b =
+        match a, b with
+        | Some a, Some b -> Some (assert_value_eq (a, b))
+        | _ -> Some (simple_fail "different record keys")
+      in
+      let%bind _all = bind_lmap @@ LMap.merge aux sma smb in
+      ok ()
+    )
+  | E_record _, _ ->
+      simple_fail "comparing record with other expression"
+  
+  | E_record_update ura, E_record_update urb ->
+    let _ = 
+      generic_try (simple_error "Updating different record") @@ 
+      fun () -> assert_value_eq (ura.record, urb.record) in
+    let aux (Label a,Label b) =
+      assert (String.equal a b)
+    in
+    let () = aux (ura.path, urb.path) in
+    let%bind () = assert_value_eq (ura.update,urb.update) in
+    ok ()
+  | E_record_update _, _ ->
+     simple_fail "comparing record update with other expression"
+
+  | (E_map lsta, E_map lstb | E_big_map lsta, E_big_map lstb) -> (
+      let%bind lst = generic_try (simple_error "maps of different lengths")
+          (fun () ->
+             let lsta' = List.sort compare lsta in
+             let lstb' = List.sort compare lstb in
+             List.combine lsta' lstb') in
+      let aux = fun ((ka, va), (kb, vb)) ->
+        let%bind _ = assert_value_eq (ka, kb) in
+        let%bind _ = assert_value_eq (va, vb) in
+        ok () in
+      let%bind _all = bind_map_list aux lst in
+      ok ()
+    )
+  | (E_map _ | E_big_map _), _ ->
+      simple_fail "comparing map with other expression"
+
+  | E_list lsta, E_list lstb -> (
+      let%bind lst =
+        generic_try (simple_error "list of different lengths")
+          (fun () -> List.combine lsta lstb) in
+      let%bind _all = bind_map_list assert_value_eq lst in
+      ok ()
+    )
+  | E_list _, _ ->
+      simple_fail "comparing list with other expression"
+
+  | E_set lsta, E_set lstb -> (
+      let lsta' = List.sort (compare) lsta in
+      let lstb' = List.sort (compare) lstb in
+      let%bind lst =
+        generic_try (simple_error "set of different lengths")
+          (fun () -> List.combine lsta' lstb') in
+      let%bind _all = bind_map_list assert_value_eq lst in
+      ok ()
+    )
+  | E_set _, _ ->
+      simple_fail "comparing set with other expression"
+
+  | (E_ascription a ,  _b') -> assert_value_eq (a.anno_expr , b)
+  | (_a' , E_ascription b) -> assert_value_eq (a , b.anno_expr)
+  | (E_variable _, _) | (E_lambda _, _)
+  | (E_application _, _) | (E_let_in _, _)
+  | (E_recursive _,_) | (E_record_accessor _, _)
+  | (E_look_up _, _) | (E_matching _, _)
+  | (E_sequence _, _) | (E_skip, _) -> simple_fail "comparing not a value"
+
+let is_value_eq (a , b) = to_bool @@ assert_value_eq (a , b)
+
+(* module Rename = struct
+ *   open Trace
+ *
+ *   module Type = struct
+ *     (\* Type renaming, not needed. Yet. *\)
+ *   end
+ * 
+ *   module Value = struct
+ *     type renaming = string * (string * access_path) (\* src -> dst *\)
+ *     type renamings = renaming list
+ *     let filter (r:renamings) (s:string) : renamings =
+ *       List.filter (fun (x, _) -> not (x = s)) r
+ *     let filters (r:renamings) (ss:string list) : renamings =
+ *       List.filter (fun (x, _) -> not (List.mem x ss)) r
+ * 
+ *     let rec rename_instruction (r:renamings) (i:instruction) : instruction result =
+ *       match i with
+ *       | I_assignment ({name;annotated_expression = e} as a) -> (
+ *           match List.assoc_opt name r with
+ *           | None ->
+ *               let%bind annotated_expression = rename_annotated_expression (filter r name) e in
+ *               ok (I_assignment {a with annotated_expression})
+ *           | Some (name', lst) -> (
+ *               let%bind annotated_expression = rename_annotated_expression r e in
+ *               match lst with
+ *               | [] -> ok (I_assignment {name = name' ; annotated_expression})
+ *               | lst ->
+ *                   let (hds, tl) =
+ *                     let open List in
+ *                     let r = rev lst in
+ *                     rev @@ tl r, hd r
+ *                   in
+ *                   let%bind tl' = match tl with
+ *                     | Access_record n -> ok n
+ *                     | Access_tuple _ -> simple_fail "no support for renaming into tuples yet" in
+ *                   ok (I_record_patch (name', hds, [tl', annotated_expression]))
+ *             )
+ *         )
+ *       | I_skip -> ok I_skip
+ *       | I_fail e ->
+ *           let%bind e' = rename_annotated_expression r e in
+ *           ok (I_fail e')
+ *       | I_loop (cond, body) ->
+ *           let%bind cond' = rename_annotated_expression r cond in
+ *           let%bind body' = rename_block r body in
+ *           ok (I_loop (cond', body'))
+ *       | I_matching (ae, m) ->
+ *           let%bind ae' = rename_annotated_expression r ae in
+ *           let%bind m' = rename_matching rename_block r m in
+ *           ok (I_matching (ae', m'))
+ *       | I_record_patch (v, path, lst) ->
+ *           let aux (x, y) =
+ *             let%bind y' = rename_annotated_expression (filter r v) y in
+ *             ok (x, y') in
+ *           let%bind lst' = bind_map_list aux lst in
+ *           match List.assoc_opt v r with
+ *           | None -> (
+ *               ok (I_record_patch (v, path, lst'))
+ *             )
+ *           | Some (v', path') -> (
+ *               ok (I_record_patch (v', path' @ path, lst'))
+ *             )
+ *     and rename_block (r:renamings) (bl:block) : block result =
+ *       bind_map_list (rename_instruction r) bl
+ * 
+ *     and rename_matching : type a . (renamings -> a -> a result) -> renamings -> a matching -> a matching result =
+ *       fun f r m ->
+ *       match m with
+ *       | Match_bool { match_true = mt ; match_false = mf } ->
+ *           let%bind match_true = f r mt in
+ *           let%bind match_false = f r mf in
+ *           ok (Match_bool {match_true ; match_false})
+ *       | Match_option { match_none = mn ; match_some = (some, ms) } ->
+ *           let%bind match_none = f r mn in
+ *           let%bind ms' = f (filter r some) ms in
+ *           ok (Match_option {match_none ; match_some = (some, ms')})
+ *       | Match_list { match_nil = mn ; match_cons = (hd, tl, mc) } ->
+ *           let%bind match_nil = f r mn in
+ *           let%bind mc' = f (filters r [hd;tl]) mc in
+ *           ok (Match_list {match_nil ; match_cons = (hd, tl, mc')})
+ *       | Match_tuple (lst, body) ->
+ *           let%bind body' = f (filters r lst) body in
+ *           ok (Match_tuple (lst, body'))
+ * 
+ *     and rename_matching_instruction = fun x -> rename_matching rename_block x
+ * 
+ *     and rename_matching_expr = fun x -> rename_matching rename_expression x
+ * 
+ *     and rename_annotated_expression (r:renamings) (ae:annotated_expression) : annotated_expression result =
+ *       let%bind expression = rename_expression r ae.expression in
+ *       ok {ae with expression}
+ * 
+ *     and rename_expression : renamings -> expression -> expression result = fun r e ->
+ *       match e with
+ *       | E_literal _ as l -> ok l
+ *       | E_constant (name, lst) ->
+ *           let%bind lst' = bind_map_list (rename_annotated_expression r) lst in
+ *           ok (E_constant (name, lst'))
+ *       | E_constructor (name, ae) ->
+ *           let%bind ae' = rename_annotated_expression r ae in
+ *           ok (E_constructor (name, ae'))
+ *       | E_variable v -> (
+ *           match List.assoc_opt v r with
+ *           | None -> ok (E_variable v)
+ *           | Some (name, path) -> ok (E_accessor (ae (E_variable (name)), path))
+ *         )
+ *       | E_lambda ({binder;body;result} as l) ->
+ *           let r' = filter r binder in
+ *           let%bind body = rename_block r' body in
+ *           let%bind result = rename_annotated_expression r' result in
+ *           ok (E_lambda {l with body ; result})
+ *       | E_application (f, arg) ->
+ *           let%bind f' = rename_annotated_expression r f in
+ *           let%bind arg' = rename_annotated_expression r arg in
+ *           ok (E_application (f', arg'))
+ *       | E_tuple lst ->
+ *           let%bind lst' = bind_map_list (rename_annotated_expression r) lst in
+ *           ok (E_tuple lst')
+ *       | E_accessor (ae, p) ->
+ *           let%bind ae' = rename_annotated_expression r ae in
+ *           ok (E_accessor (ae', p))
+ *       | E_record sm ->
+ *           let%bind sm' = bind_smap
+ *             @@ SMap.map (rename_annotated_expression r) sm in
+ *           ok (E_record sm')
+ *       | E_map m ->
+ *           let%bind m' = bind_map_list
+ *             (fun (x, y) -> bind_map_pair (rename_annotated_expression r) (x, y)) m in
+ *           ok (E_map m')
+ *       | E_list lst ->
+ *           let%bind lst' = bind_map_list (rename_annotated_expression r) lst in
+ *           ok (E_list lst')
+ *       | E_look_up m ->
+ *           let%bind m' = bind_map_pair (rename_annotated_expression r) m in
+ *           ok (E_look_up m')
+ *       | E_matching (ae, m) ->
+ *           let%bind ae' = rename_annotated_expression r ae in
+ *           let%bind m' = rename_matching rename_annotated_expression r m in
+ *           ok (E_matching (ae', m'))
+ *   end
+ * end *)
diff --git a/src/stages/ast_simplified/misc.mli b/src/stages/1-ast_imperative/misc.mli
similarity index 100%
rename from src/stages/ast_simplified/misc.mli
rename to src/stages/1-ast_imperative/misc.mli
diff --git a/src/stages/1-ast_imperative/types.ml b/src/stages/1-ast_imperative/types.ml
new file mode 100644
index 000000000..4d0d0bd68
--- /dev/null
+++ b/src/stages/1-ast_imperative/types.ml
@@ -0,0 +1,126 @@
+[@@@warning "-30"]
+
+module Location = Simple_utils.Location
+
+module Ast_imperative_parameter = struct
+  type type_meta = unit
+end
+
+include Stage_common.Types
+
+(*include Ast_generic_type(Ast_core_parameter)
+*)
+include Ast_generic_type (Ast_imperative_parameter)
+
+type inline = bool 
+type program = declaration Location.wrap list
+and declaration =
+  | Declaration_type of (type_variable * type_expression)
+
+  (* A Declaration_constant is described by
+   *   a name
+   *   an optional type annotation
+   *   a boolean indicating whether it should be inlined
+   *   an expression *)
+  | Declaration_constant of (expression_variable * type_expression option * inline * expression)
+
+(* | Macro_declaration of macro_declaration *)
+and expression = {expression_content: expression_content; location: Location.t}
+
+and expression_content =
+  (* Base *)
+  | E_literal of literal
+  | E_constant of constant (* For language constants, like (Cons hd tl) or (plus i j) *)
+  | E_variable of expression_variable
+  | E_application of application
+  | E_lambda of lambda
+  | E_recursive of recursive
+  | E_let_in of let_in
+  (* Variant *)
+  | E_constructor of constructor (* For user defined constructors *)
+  | E_matching of matching
+  (* Record *)
+  | E_record of expression label_map
+  | E_record_accessor of accessor
+  | E_record_update of update
+  (* Advanced *)
+  | E_ascription of ascription
+  (* Sugar *)
+  | E_sequence of sequence
+  | E_skip
+  (* Data Structures *)
+  | E_map of (expression * expression) list 
+  | E_big_map of (expression * expression) list
+  | E_list of expression list
+  | E_set of expression list
+  | E_look_up of (expression * expression)
+
+and constant =
+  { cons_name: constant' (* this is at the end because it is huge *)
+  ; arguments: expression list }
+
+and application = {
+  lamb: expression ; 
+  args: expression ;
+  }
+
+and lambda =
+  { binder: expression_variable
+  ; input_type: type_expression option
+  ; output_type: type_expression option
+  ; result: expression }
+
+and recursive = {
+  fun_name :  expression_variable;
+  fun_type : type_expression;
+  lambda : lambda;
+}
+
+and let_in =
+  { let_binder: expression_variable * type_expression option
+  ; mut: bool
+  ; rhs: expression
+  ; let_result: expression
+  ; inline: bool }
+
+and constructor = {constructor: constructor'; element: expression}
+
+and accessor = {expr: expression; label: label}
+
+and update = {record: expression; path: label ; update: expression}
+
+and matching_expr = (expr,unit) matching_content
+and matching =
+  { matchee: expression
+  ; cases: matching_expr
+  }
+
+and ascription = {anno_expr: expression; type_annotation: type_expression}
+and sequence = {
+  expr1: expression ;
+  expr2: expression ;
+  }
+
+and environment_element_definition =
+  | ED_binder
+  | ED_declaration of (expression * free_variables)
+
+and free_variables = expression_variable list
+
+and environment_element =
+  { type_value: type_expression
+  ; source_environment: full_environment
+  ; definition: environment_element_definition }
+
+and environment = (expression_variable * environment_element) list
+
+and type_environment = (type_variable * type_expression) list
+
+(* SUBST ??? *)
+and small_environment = environment * type_environment
+
+and full_environment = small_environment List.Ne.t
+
+and expr = expression
+
+and texpr = type_expression
diff --git a/src/stages/2-ast_sugar/PP.ml b/src/stages/2-ast_sugar/PP.ml
new file mode 100644
index 000000000..d4a4ead08
--- /dev/null
+++ b/src/stages/2-ast_sugar/PP.ml
@@ -0,0 +1,139 @@
+[@@@coverage exclude_file]
+open Types
+open Format
+open PP_helpers
+
+include Stage_common.PP
+include Ast_PP_type(Ast_sugar_parameter)
+
+let expression_variable ppf (ev : expression_variable) : unit =
+  fprintf ppf "%a" Var.pp ev
+
+
+let rec expression ppf (e : expression) =
+  expression_content ppf e.expression_content
+and expression_content ppf (ec : expression_content) =
+  match ec with
+  | E_literal l ->
+      literal ppf l
+  | E_variable n ->
+      fprintf ppf "%a" expression_variable n
+  | E_application {lamb;args} ->
+      fprintf ppf "(%a)@(%a)" expression lamb expression args
+  | E_constructor c ->
+      fprintf ppf "%a(%a)" constructor c.constructor expression c.element
+  | E_constant c ->
+      fprintf ppf "%a(%a)" constant c.cons_name (list_sep_d expression)
+        c.arguments
+  | E_record m ->
+      fprintf ppf "%a" (tuple_or_record_sep_expr expression) m
+  | E_record_accessor ra ->
+      fprintf ppf "%a.%a" expression ra.expr label ra.label
+  | E_record_update {record; path; update} ->
+      fprintf ppf "{ %a with { %a = %a } }" expression record label path expression update
+  | E_map m ->
+      fprintf ppf "map[%a]" (list_sep_d assoc_expression) m
+  | E_big_map m ->
+      fprintf ppf "big_map[%a]" (list_sep_d assoc_expression) m
+  | E_list lst ->
+      fprintf ppf "list[%a]" (list_sep_d expression) lst
+  | E_set lst ->
+      fprintf ppf "set[%a]" (list_sep_d expression) lst
+  | E_look_up (ds, ind) ->
+      fprintf ppf "(%a)[%a]" expression ds expression ind
+  | E_lambda {binder; input_type; output_type; result} ->
+      fprintf ppf "lambda (%a:%a) : %a return %a" 
+        expression_variable binder
+        (PP_helpers.option type_expression)
+        input_type
+        (PP_helpers.option type_expression)
+        output_type expression result
+  | E_recursive { fun_name; fun_type; lambda} ->
+      fprintf ppf "rec (%a:%a => %a )" 
+        expression_variable fun_name 
+        type_expression fun_type
+        expression_content (E_lambda lambda)
+  | E_matching {matchee; cases; _} ->
+      fprintf ppf "match %a with %a" expression matchee (matching expression)
+        cases
+  | E_let_in { let_binder ; rhs ; let_result; inline } ->    
+    fprintf ppf "let %a = %a%a in %a" option_type_name let_binder expression rhs option_inline inline expression let_result
+  | E_sequence {expr1;expr2} ->
+      fprintf ppf "%a;\n%a" expression expr1 expression expr2
+  | E_ascription {anno_expr; type_annotation} ->
+      fprintf ppf "%a : %a" expression anno_expr type_expression type_annotation
+  | E_skip ->
+      fprintf ppf "skip"
+
+and option_type_name ppf
+    ((n, ty_opt) : expression_variable * type_expression option) =
+  match ty_opt with
+  | None ->
+      fprintf ppf "%a" expression_variable n
+  | Some ty ->
+      fprintf ppf "%a : %a" expression_variable n type_expression ty
+
+and assoc_expression ppf : expr * expr -> unit =
+ fun (a, b) -> fprintf ppf "%a -> %a" expression a expression b
+
+and single_record_patch ppf ((p, expr) : label * expr) =
+  fprintf ppf "%a <- %a" label p expression expr
+
+and matching_variant_case : type a . (_ -> a -> unit) -> _ -> (constructor' * expression_variable) * a -> unit =
+  fun f ppf ((c,n),a) ->
+  fprintf ppf "| %a %a -> %a" constructor c expression_variable n f a
+
+and matching : type a . (formatter -> a -> unit) -> formatter -> (a,unit) matching_content -> unit =
+  fun f ppf m -> match m with
+    | Match_tuple ((lst, b), _) ->
+        fprintf ppf "let (%a) = %a" (list_sep_d expression_variable) lst f b
+    | Match_variant (lst, _) ->
+        fprintf ppf "%a" (list_sep (matching_variant_case f) (tag "@.")) lst
+    | Match_bool {match_true ; match_false} ->
+        fprintf ppf "| True -> %a @.| False -> %a" f match_true f match_false
+    | Match_list {match_nil ; match_cons = (hd, tl, match_cons, _)} ->
+        fprintf ppf "| Nil -> %a @.| %a :: %a -> %a" f match_nil expression_variable hd expression_variable tl f match_cons
+    | Match_option {match_none ; match_some = (some, match_some, _)} ->
+        fprintf ppf "| None -> %a @.| Some %a -> %a" f match_none expression_variable some f match_some
+
+(* Shows the type expected for the matched value *)
+and matching_type ppf m = match m with
+  | Match_tuple _ ->
+      fprintf ppf "tuple"
+  | Match_variant (lst, _) ->
+      fprintf ppf "variant %a" (list_sep matching_variant_case_type (tag "@.")) lst
+  | Match_bool _ ->
+      fprintf ppf "boolean"
+  | Match_list _ ->
+      fprintf ppf "list"
+  | Match_option _ ->
+      fprintf ppf "option"
+
+and matching_variant_case_type ppf ((c,n),_a) =
+  fprintf ppf "| %a %a" constructor c expression_variable n
+
+and option_mut ppf mut = 
+  if mut then 
+    fprintf ppf "[@mut]"
+  else
+    fprintf ppf ""
+
+and option_inline ppf inline = 
+  if inline then 
+    fprintf ppf "[@inline]"
+  else
+    fprintf ppf ""
+
+let declaration ppf (d : declaration) =
+  match d with
+  | Declaration_type (type_name, te) ->
+      fprintf ppf "type %a = %a" type_variable type_name type_expression te
+  | Declaration_constant (name, ty_opt, i, expr) ->
+      fprintf ppf "const %a = %a%a" option_type_name (name, ty_opt) expression
+        expr
+        option_inline i
+
+let program ppf (p : program) =
+  fprintf ppf "@[<v>%a@]"
+    (list_sep declaration (tag "@;"))
+    (List.map Location.unwrap p)
diff --git a/src/stages/2-ast_sugar/ast_sugar.ml b/src/stages/2-ast_sugar/ast_sugar.ml
new file mode 100644
index 000000000..e9614490a
--- /dev/null
+++ b/src/stages/2-ast_sugar/ast_sugar.ml
@@ -0,0 +1,8 @@
+include Types
+
+(* include Misc *)
+include Combinators
+module Types = Types
+module Misc = Misc
+module PP=PP
+module Combinators = Combinators
diff --git a/src/stages/2-ast_sugar/combinators.ml b/src/stages/2-ast_sugar/combinators.ml
new file mode 100644
index 000000000..759d6fc55
--- /dev/null
+++ b/src/stages/2-ast_sugar/combinators.ml
@@ -0,0 +1,268 @@
+open Types
+open Simple_utils.Trace
+module Option = Simple_utils.Option
+
+module SMap = Map.String
+
+module Errors = struct
+  let bad_kind expected location =
+    let title () = Format.asprintf "a %s was expected" expected in
+    let message () = "" in
+    let data = [
+      ("location" , fun () -> Format.asprintf "%a" Location.pp location) ;
+    ] in
+    error ~data title message
+  let bad_type_operator type_op =
+    let title () = Format.asprintf "bad type operator %a" (PP.type_operator PP.type_expression) type_op in
+    let message () = "" in
+    error title message
+end
+open Errors
+
+let make_t type_content = {type_content; type_meta = ()}
+
+  
+let tuple_to_record lst =
+  let aux (i,acc) el = (i+1,(string_of_int i, el)::acc) in
+  let (_, lst ) = List.fold_left aux (0,[]) lst in
+  lst
+
+let t_bool         : type_expression = make_t @@ T_constant (TC_bool)
+let t_string       : type_expression = make_t @@ T_constant (TC_string)
+let t_bytes        : type_expression = make_t @@ T_constant (TC_bytes)
+let t_int          : type_expression = make_t @@ T_constant (TC_int)
+let t_operation    : type_expression = make_t @@ T_constant (TC_operation)
+let t_nat          : type_expression = make_t @@ T_constant (TC_nat)
+let t_tez          : type_expression = make_t @@ T_constant (TC_mutez)
+let t_unit         : type_expression = make_t @@ T_constant (TC_unit)
+let t_address      : type_expression = make_t @@ T_constant (TC_address)
+let t_signature    : type_expression = make_t @@ T_constant (TC_signature)
+let t_key          : type_expression = make_t @@ T_constant (TC_key)
+let t_key_hash     : type_expression = make_t @@ T_constant (TC_key_hash)
+let t_timestamp    : type_expression = make_t @@ T_constant (TC_timestamp)
+let t_option  o    : type_expression = make_t @@ T_operator (TC_option o)
+let t_list  t      : type_expression = make_t @@ T_operator (TC_list t)
+let t_variable n   : type_expression = make_t @@ T_variable (Var.of_name n)
+let t_record_ez lst =
+  let lst = List.map (fun (k, v) -> (Label k, v)) lst in
+  let m = LMap.of_list lst in
+  make_t @@ T_record m
+let t_record m  : type_expression =
+  let lst = Map.String.to_kv_list m in
+  t_record_ez lst
+
+let t_pair (a , b) : type_expression = t_record_ez [("0",a) ; ("1",b)]
+let t_tuple lst    : type_expression = t_record_ez (tuple_to_record lst)
+
+let ez_t_sum (lst:(string * type_expression) list) : type_expression =
+  let aux prev (k, v) = CMap.add (Constructor k) v prev in
+  let map = List.fold_left aux CMap.empty lst in
+  make_t @@ T_sum map
+let t_sum m : type_expression =
+  let lst = Map.String.to_kv_list m in
+  ez_t_sum lst
+
+let t_function type1 type2  : type_expression = make_t @@ T_arrow {type1; type2}
+let t_map key value         : type_expression = make_t @@ T_operator (TC_map (key, value))
+let t_big_map key value     : type_expression = make_t @@ T_operator (TC_big_map (key , value))
+let t_set key               : type_expression = make_t @@ T_operator (TC_set key)
+let t_contract contract     : type_expression = make_t @@ T_operator (TC_contract contract)
+
+(* TODO find a better way than using list*)
+let t_operator op lst: type_expression result =
+  match op,lst with 
+  | TC_set _         , [t] -> ok @@ t_set t
+  | TC_list _        , [t] -> ok @@ t_list t
+  | TC_option _      , [t] -> ok @@ t_option t
+  | TC_map (_,_)     , [kt;vt] -> ok @@ t_map kt vt
+  | TC_big_map (_,_) , [kt;vt] -> ok @@ t_big_map kt vt
+  | TC_contract _    , [t] -> ok @@ t_contract t
+  | _ , _ -> fail @@ bad_type_operator op
+
+let make_expr ?(loc = Location.generated) expression_content =
+  let location = loc in
+  { expression_content; location }
+
+let e_var ?loc (n: string) : expression = make_expr ?loc @@ E_variable (Var.of_name n)
+let e_literal ?loc l : expression = make_expr ?loc @@ E_literal l
+let e_unit ?loc () : expression = make_expr ?loc @@ E_literal (Literal_unit)
+let e_int ?loc n : expression = make_expr ?loc @@ E_literal (Literal_int n)
+let e_nat ?loc n : expression = make_expr ?loc @@ E_literal (Literal_nat n)
+let e_timestamp ?loc n : expression = make_expr ?loc @@ E_literal (Literal_timestamp n)
+let e_bool ?loc   b : expression = make_expr ?loc @@ E_literal (Literal_bool b)
+let e_string ?loc s : expression = make_expr ?loc @@ E_literal (Literal_string s)
+let e_address ?loc s : expression = make_expr ?loc @@ E_literal (Literal_address s)
+let e_mutez ?loc s : expression = make_expr ?loc @@ E_literal (Literal_mutez s)
+let e_signature ?loc s : expression = make_expr ?loc @@ E_literal (Literal_signature s)
+let e_key ?loc s : expression = make_expr ?loc @@ E_literal (Literal_key s)
+let e_key_hash ?loc s : expression = make_expr ?loc @@ E_literal (Literal_key_hash s)
+let e_chain_id ?loc s : expression = make_expr ?loc @@ E_literal (Literal_chain_id s)
+let e'_bytes b : expression_content result =
+  let%bind bytes = generic_try (simple_error "bad hex to bytes") (fun () -> Hex.to_bytes (`Hex b)) in
+  ok @@ E_literal (Literal_bytes bytes)
+let e_bytes_hex ?loc b : expression result =
+  let%bind e' = e'_bytes b in
+  ok @@ make_expr ?loc e'
+let e_bytes_raw ?loc (b: bytes) : expression =
+  make_expr ?loc @@ E_literal (Literal_bytes b)
+let e_bytes_string ?loc (s: string) : expression =
+  make_expr ?loc @@ E_literal (Literal_bytes (Hex.to_bytes (Hex.of_string s)))
+let e_big_map ?loc lst : expression = make_expr ?loc @@ E_big_map lst
+let e_some ?loc s  : expression = make_expr ?loc @@ E_constant {cons_name = C_SOME; arguments = [s]}
+let e_none ?loc () : expression = make_expr ?loc @@ E_constant {cons_name = C_NONE; arguments = []}
+let e_string_cat ?loc sl sr : expression = make_expr ?loc @@ E_constant {cons_name = C_CONCAT; arguments = [sl ; sr ]}
+let e_map_add ?loc k v old  : expression = make_expr ?loc @@ E_constant {cons_name = C_MAP_ADD; arguments = [k ; v ; old]}
+let e_map ?loc lst : expression = make_expr ?loc @@ E_map lst
+let e_set ?loc lst : expression = make_expr ?loc @@ E_set lst
+let e_list ?loc lst : expression = make_expr ?loc @@ E_list lst
+let e_constructor ?loc s a : expression = make_expr ?loc @@ E_constructor { constructor = Constructor s; element = a}
+let e_matching ?loc a b : expression = make_expr ?loc @@ E_matching {matchee=a;cases=b}
+let e_matching_bool ?loc a b c : expression = e_matching ?loc a (Match_bool {match_true = b ; match_false = c})
+let e_accessor ?loc a b = make_expr ?loc @@ E_record_accessor {expr = a; label= Label b}
+let e_accessor_list ?loc a b  = List.fold_left (fun a b -> e_accessor ?loc a b) a b
+let e_variable ?loc v = make_expr ?loc @@ E_variable v
+let e_skip ?loc () = make_expr ?loc @@ E_skip
+let e_let_in ?loc (binder, ascr) inline rhs let_result = 
+  make_expr ?loc @@ E_let_in { let_binder = (binder, ascr) ; rhs ; let_result; inline }
+let e_annotation ?loc anno_expr ty = make_expr ?loc @@ E_ascription {anno_expr; type_annotation = ty}
+let e_application ?loc a b = make_expr ?loc @@ E_application {lamb=a ; args=b}
+let e_binop ?loc name a b  = make_expr ?loc @@ E_constant {cons_name = name ; arguments = [a ; b]}
+let e_constant ?loc name lst = make_expr ?loc @@ E_constant {cons_name=name ; arguments = lst}
+let e_look_up ?loc x y = make_expr ?loc @@ E_look_up (x , y)
+let e_sequence ?loc expr1 expr2 = make_expr ?loc @@ E_sequence {expr1; expr2}
+let e_cond ?loc expr match_true match_false = e_matching expr ?loc (Match_bool {match_true; match_false})
+(*
+let e_assign ?loc a b c = location_wrap ?loc @@ E_assign (Var.of_name a , b , c) (* TODO handlethat*)
+*)
+let ez_match_variant (lst : ((string * string) * 'a) list) =
+  let lst = List.map (fun ((c,n),a) -> ((Constructor c, Var.of_name n), a) ) lst in
+  Match_variant (lst,())
+let e_matching_variant ?loc a (lst : ((string * string)* 'a) list) =
+  e_matching ?loc a (ez_match_variant lst)
+let e_record_ez ?loc (lst : (string * expr) list) : expression =
+  let map = List.fold_left (fun m (x, y) -> LMap.add (Label x) y m) LMap.empty lst in
+  make_expr ?loc @@ E_record map
+let e_record ?loc map =
+  let lst = Map.String.to_kv_list map in
+  e_record_ez ?loc lst 
+
+let e_update ?loc record path update = 
+  let path = Label path in
+  make_expr ?loc @@ E_record_update {record; path; update}
+
+let e_tuple ?loc lst : expression = e_record_ez ?loc (tuple_to_record lst)
+let e_pair ?loc a b  : expression = e_tuple ?loc [a;b]
+
+let make_option_typed ?loc e t_opt =
+  match t_opt with
+  | None -> e
+  | Some t -> e_annotation ?loc e t
+
+
+let e_typed_none ?loc t_opt =
+  let type_annotation = t_option t_opt in
+  e_annotation ?loc (e_none ?loc ()) type_annotation
+
+let e_typed_list ?loc lst t =
+  e_annotation ?loc (e_list lst) (t_list t)
+
+let e_typed_map ?loc lst k v = e_annotation ?loc (e_map lst) (t_map k v)
+let e_typed_big_map ?loc lst k v = e_annotation ?loc (e_big_map lst) (t_big_map k v)
+
+let e_typed_set ?loc lst k = e_annotation ?loc (e_set lst) (t_set k)
+
+
+let e_lambda ?loc (binder : expression_variable)
+    (input_type : type_expression option)
+    (output_type : type_expression option)
+    (result : expression)
+  : expression =
+  make_expr ?loc @@ E_lambda {
+    binder = binder ;
+    input_type = input_type ;
+    output_type = output_type ;
+    result ;
+  }
+let e_recursive ?loc fun_name fun_type lambda = make_expr ?loc @@ E_recursive {fun_name; fun_type; lambda}
+
+
+let e_assign_with_let ?loc var access_path expr = 
+  let var = Var.of_name (var) in
+  match access_path with 
+  | [] -> (var, None), true, expr, false
+
+  | lst -> 
+    let rec aux path record= match path with 
+    | [] -> failwith "acces_path cannot be empty"
+    | [e] -> e_update ?loc record e expr
+    | elem::tail -> 
+      let next_record = e_accessor record elem in
+      e_update ?loc record elem (aux tail next_record )
+    in 
+    (var, None), true, (aux lst (e_variable var)), false
+
+let get_e_accessor = fun t ->
+  match t with
+  | E_record_accessor {expr; label} -> ok (expr , label)
+  | _ -> simple_fail "not an accessor"
+
+let assert_e_accessor = fun t ->
+  let%bind _ = get_e_accessor t in
+  ok ()
+
+let get_e_pair = fun t ->
+  match t with
+  | E_record r -> ( 
+  let lst = LMap.to_kv_list r in
+    match lst with 
+    | [(Label "O",a);(Label "1",b)]
+    | [(Label "1",b);(Label "0",a)] -> 
+        ok (a , b)
+    | _ -> simple_fail "not a pair"
+    )
+  | _ -> simple_fail "not a pair"
+
+let get_e_list = fun t ->
+  match t with
+  | E_list lst -> ok lst
+  | _ -> simple_fail "not a list"
+
+let tuple_of_record (m: _ LMap.t) =
+  let aux i = 
+    let opt = LMap.find_opt (Label (string_of_int i)) m in
+    Option.bind (fun opt -> Some (opt,i+1)) opt
+  in
+  Base.Sequence.to_list @@ Base.Sequence.unfold ~init:0 ~f:aux
+
+let get_e_tuple = fun t ->
+  match t with
+  | E_record r -> ok @@ tuple_of_record r
+  | _ -> simple_fail "ast_core: get_e_tuple: not a tuple"
+
+(* Same as get_e_pair *)
+let extract_pair : expression -> (expression * expression) result = fun e ->
+  match e.expression_content with
+  | E_record r -> ( 
+  let lst = LMap.to_kv_list r in
+    match lst with 
+    | [(Label "O",a);(Label "1",b)]
+    | [(Label "1",b);(Label "0",a)] -> 
+        ok (a , b)
+    | _ -> fail @@ bad_kind "pair" e.location
+    )
+  | _ -> fail @@ bad_kind "pair" e.location
+
+let extract_list : expression -> (expression list) result = fun e ->
+  match e.expression_content with
+  | E_list lst -> ok lst
+  | _ -> fail @@ bad_kind "list" e.location
+
+let extract_record : expression -> (label * expression) list result = fun e ->
+  match e.expression_content with
+  | E_record lst -> ok @@ LMap.to_kv_list lst
+  | _ -> fail @@ bad_kind "record" e.location
+
+let extract_map : expression -> (expression * expression) list result = fun e ->
+  match e.expression_content with
+  | E_map lst -> ok lst
+  | _ -> fail @@ bad_kind "map" e.location
diff --git a/src/stages/2-ast_sugar/combinators.mli b/src/stages/2-ast_sugar/combinators.mli
new file mode 100644
index 000000000..e9d3dd144
--- /dev/null
+++ b/src/stages/2-ast_sugar/combinators.mli
@@ -0,0 +1,135 @@
+open Types
+open Simple_utils.Trace
+(*
+module Option = Simple_utils.Option
+
+module SMap = Map.String
+
+module Errors : sig
+  val bad_kind : name -> Location.t -> unit -> error
+end
+*)
+val make_t      : type_content -> type_expression
+val t_bool      : type_expression
+val t_string    : type_expression
+val t_bytes     : type_expression
+val t_int       : type_expression
+val t_operation : type_expression
+val t_nat       : type_expression
+val t_tez       : type_expression
+val t_unit      : type_expression
+val t_address   : type_expression
+val t_key       : type_expression
+val t_key_hash  : type_expression
+val t_timestamp : type_expression
+val t_signature : type_expression
+(*
+val t_option    : type_expression -> type_expression
+*)
+val t_list      : type_expression -> type_expression
+val t_variable  : string -> type_expression
+(*
+val t_record    : te_map -> type_expression
+*)
+val t_pair : ( type_expression * type_expression ) -> type_expression
+val t_tuple     : type_expression list -> type_expression
+
+val t_record : type_expression Map.String.t -> type_expression
+val t_record_ez : (string * type_expression) list -> type_expression
+
+val t_sum : type_expression Map.String.t -> type_expression
+val ez_t_sum : ( string * type_expression ) list -> type_expression
+
+val t_function : type_expression -> type_expression -> type_expression
+val t_map : type_expression -> type_expression -> type_expression
+
+val t_operator : type_operator -> type_expression list -> type_expression result
+val t_set : type_expression -> type_expression
+
+val make_expr : ?loc:Location.t -> expression_content -> expression
+val e_var : ?loc:Location.t -> string -> expression
+val e_literal : ?loc:Location.t -> literal -> expression
+val e_unit : ?loc:Location.t -> unit -> expression
+val e_int : ?loc:Location.t -> int -> expression 
+val e_nat : ?loc:Location.t -> int -> expression
+val e_timestamp : ?loc:Location.t -> int -> expression
+val e_bool : ?loc:Location.t -> bool -> expression
+val e_string : ?loc:Location.t -> string -> expression
+val e_address : ?loc:Location.t -> string -> expression 
+val e_signature : ?loc:Location.t -> string -> expression 
+val e_key : ?loc:Location.t -> string -> expression 
+val e_key_hash : ?loc:Location.t -> string -> expression 
+val e_chain_id : ?loc:Location.t -> string -> expression 
+val e_mutez : ?loc:Location.t -> int -> expression
+val e'_bytes : string -> expression_content result
+val e_bytes_hex : ?loc:Location.t -> string -> expression result
+val e_bytes_raw : ?loc:Location.t -> bytes -> expression
+val e_bytes_string : ?loc:Location.t -> string -> expression
+val e_big_map : ?loc:Location.t -> ( expr * expr ) list -> expression
+
+val e_record_ez  : ?loc:Location.t -> ( string * expr ) list -> expression
+val e_tuple : ?loc:Location.t -> expression list -> expression
+val e_some : ?loc:Location.t -> expression -> expression
+val e_none : ?loc:Location.t -> unit -> expression
+val e_string_cat : ?loc:Location.t -> expression -> expression -> expression
+val e_map_add : ?loc:Location.t -> expression -> expression ->  expression -> expression
+val e_map : ?loc:Location.t -> ( expression * expression ) list -> expression
+val e_set : ?loc:Location.t -> expression list -> expression
+val e_list : ?loc:Location.t -> expression list -> expression
+val e_pair : ?loc:Location.t -> expression -> expression -> expression
+val e_constructor : ?loc:Location.t -> string -> expression -> expression
+val e_matching : ?loc:Location.t -> expression -> matching_expr -> expression
+val e_matching_bool : ?loc:Location.t -> expression -> expression -> expression -> expression
+val e_accessor : ?loc:Location.t -> expression -> string -> expression
+val e_accessor_list : ?loc:Location.t -> expression -> string list -> expression
+val e_variable : ?loc:Location.t -> expression_variable -> expression
+val e_skip : ?loc:Location.t -> unit -> expression
+val e_sequence : ?loc:Location.t -> expression -> expression -> expression
+val e_cond: ?loc:Location.t -> expression -> expression -> expression -> expression
+val e_let_in : ?loc:Location.t -> ( expression_variable * type_expression option ) -> bool -> expression -> expression -> expression
+val e_annotation : ?loc:Location.t -> expression -> type_expression -> expression
+val e_application : ?loc:Location.t -> expression -> expression -> expression
+val e_binop    : ?loc:Location.t -> constant' -> expression -> expression -> expression
+val e_constant : ?loc:Location.t -> constant' -> expression list -> expression
+val e_look_up : ?loc:Location.t -> expression -> expression -> expression
+val ez_match_variant : ((string * string ) * 'a ) list -> ('a,unit) matching_content
+val e_matching_variant : ?loc:Location.t -> expression -> ((string * string) * expression) list -> expression
+
+val make_option_typed : ?loc:Location.t -> expression -> type_expression option -> expression
+
+val e_typed_none : ?loc:Location.t -> type_expression -> expression
+
+val e_typed_list : ?loc:Location.t -> expression list -> type_expression -> expression
+
+val e_typed_map : ?loc:Location.t -> ( expression * expression ) list  -> type_expression -> type_expression -> expression
+val e_typed_big_map : ?loc:Location.t -> ( expression * expression ) list  -> type_expression -> type_expression -> expression
+
+val e_typed_set : ?loc:Location.t -> expression list -> type_expression -> expression
+
+val e_lambda : ?loc:Location.t -> expression_variable -> type_expression option -> type_expression option -> expression -> expression
+val e_recursive : ?loc:Location.t -> expression_variable -> type_expression -> lambda -> expression
+val e_record : ?loc:Location.t -> expr Map.String.t -> expression
+val e_update : ?loc:Location.t -> expression -> string -> expression -> expression
+val e_assign_with_let : ?loc:Location.t -> string -> string list -> expression -> ((expression_variable*type_expression option)*bool*expression*bool)
+
+(*
+val get_e_accessor : expression' -> ( expression * access_path ) result
+*)
+
+val assert_e_accessor : expression_content -> unit result
+
+val get_e_pair : expression_content -> ( expression * expression ) result
+
+val get_e_list : expression_content -> ( expression list ) result
+val get_e_tuple : expression_content -> ( expression list ) result
+(*
+val get_e_failwith : expression -> expression result 
+val is_e_failwith : expression -> bool
+*)
+val extract_pair : expression -> ( expression * expression ) result 
+
+val extract_list : expression -> (expression list) result
+
+val extract_record : expression -> (label * expression) list result
+
+val extract_map : expression -> (expression * expression) list result
diff --git a/src/stages/ast_simplified/dune b/src/stages/2-ast_sugar/dune
similarity index 75%
rename from src/stages/ast_simplified/dune
rename to src/stages/2-ast_sugar/dune
index f6c961536..6f1ca6fef 100644
--- a/src/stages/ast_simplified/dune
+++ b/src/stages/2-ast_sugar/dune
@@ -1,6 +1,6 @@
 (library
-  (name ast_simplified)
-  (public_name ligo.ast_simplified)
+  (name ast_sugar)
+  (public_name ligo.ast_sugar)
   (libraries
     simple-utils
     tezos-utils
diff --git a/src/stages/2-ast_sugar/misc.ml b/src/stages/2-ast_sugar/misc.ml
new file mode 100644
index 000000000..324529525
--- /dev/null
+++ b/src/stages/2-ast_sugar/misc.ml
@@ -0,0 +1,331 @@
+open Trace
+open Types
+
+open Stage_common.Helpers
+module Errors = struct
+  let different_literals_because_different_types name a b () =
+    let title () = "literals have different types: " ^ name in
+    let message () = "" in
+    let data = [
+      ("a" , fun () -> Format.asprintf "%a" PP.literal a) ;
+      ("b" , fun () -> Format.asprintf "%a" PP.literal b )
+    ] in
+    error ~data title message ()
+
+  let different_literals name a b () =
+    let title () = name ^ " are different" in
+    let message () = "" in
+    let data = [
+      ("a" , fun () -> Format.asprintf "%a" PP.literal a) ;
+      ("b" , fun () -> Format.asprintf "%a" PP.literal b )
+    ] in
+    error ~data title message ()
+
+  let error_uncomparable_literals name a b () =
+    let title () = name ^ " are not comparable" in
+    let message () = "" in
+    let data = [
+      ("a" , fun () -> Format.asprintf "%a" PP.literal a) ;
+      ("b" , fun () -> Format.asprintf "%a" PP.literal b )
+    ] in
+    error ~data title message ()
+end
+open Errors
+
+let assert_literal_eq (a, b : literal * literal) : unit result =
+  match (a, b) with
+  | Literal_bool a, Literal_bool b when a = b -> ok ()
+  | Literal_bool _, Literal_bool _ -> fail @@ different_literals "different bools" a b
+  | Literal_bool _, _ -> fail @@ different_literals_because_different_types "bool vs non-bool" a b
+  | Literal_int a, Literal_int b when a = b -> ok ()
+  | Literal_int _, Literal_int _ -> fail @@ different_literals "different ints" a b
+  | Literal_int _, _ -> fail @@ different_literals_because_different_types "int vs non-int" a b
+  | Literal_nat a, Literal_nat b when a = b -> ok ()
+  | Literal_nat _, Literal_nat _ -> fail @@ different_literals "different nats" a b
+  | Literal_nat _, _ -> fail @@ different_literals_because_different_types "nat vs non-nat" a b
+  | Literal_timestamp a, Literal_timestamp b when a = b -> ok ()
+  | Literal_timestamp _, Literal_timestamp _ -> fail @@ different_literals "different timestamps" a b
+  | Literal_timestamp _, _ -> fail @@ different_literals_because_different_types "timestamp vs non-timestamp" a b
+  | Literal_mutez a, Literal_mutez b when a = b -> ok ()
+  | Literal_mutez _, Literal_mutez _ -> fail @@ different_literals "different tezs" a b
+  | Literal_mutez _, _ -> fail @@ different_literals_because_different_types "tez vs non-tez" a b
+  | Literal_string a, Literal_string b when a = b -> ok ()
+  | Literal_string _, Literal_string _ -> fail @@ different_literals "different strings" a b
+  | Literal_string _, _ -> fail @@ different_literals_because_different_types "string vs non-string" a b
+  | Literal_bytes a, Literal_bytes b when a = b -> ok ()
+  | Literal_bytes _, Literal_bytes _ -> fail @@ different_literals "different bytess" a b
+  | Literal_bytes _, _ -> fail @@ different_literals_because_different_types "bytes vs non-bytes" a b
+  | Literal_void, Literal_void -> ok ()
+  | Literal_void, _ -> fail @@ different_literals_because_different_types "void vs non-void" a b
+  | Literal_unit, Literal_unit -> ok ()
+  | Literal_unit, _ -> fail @@ different_literals_because_different_types "unit vs non-unit" a b
+  | Literal_address a, Literal_address b when a = b -> ok ()
+  | Literal_address _, Literal_address _ -> fail @@ different_literals "different addresss" a b
+  | Literal_address _, _ -> fail @@ different_literals_because_different_types "address vs non-address" a b
+  | Literal_operation _, Literal_operation _ -> fail @@ error_uncomparable_literals "can't compare operations" a b
+  | Literal_operation _, _ -> fail @@ different_literals_because_different_types "operation vs non-operation" a b
+  | Literal_signature a, Literal_signature b when a = b -> ok ()
+  | Literal_signature _, Literal_signature _ -> fail @@ different_literals "different signature" a b
+  | Literal_signature _, _ -> fail @@ different_literals_because_different_types "signature vs non-signature" a b
+  | Literal_key a, Literal_key b when a = b -> ok ()
+  | Literal_key _, Literal_key _ -> fail @@ different_literals "different key" a b
+  | Literal_key _, _ -> fail @@ different_literals_because_different_types "key vs non-key" a b
+  | Literal_key_hash a, Literal_key_hash b when a = b -> ok ()
+  | Literal_key_hash _, Literal_key_hash _ -> fail @@ different_literals "different key_hash" a b
+  | Literal_key_hash _, _ -> fail @@ different_literals_because_different_types "key_hash vs non-key_hash" a b
+  | Literal_chain_id a, Literal_chain_id b when a = b -> ok ()
+  | Literal_chain_id _, Literal_chain_id _ -> fail @@ different_literals "different chain_id" a b
+  | Literal_chain_id _, _ -> fail @@ different_literals_because_different_types "chain_id vs non-chain_id" a b
+
+let rec assert_value_eq (a, b: (expression * expression )) : unit result =
+  Format.printf "in assert_value_eq %a %a\n%!" PP.expression a PP.expression b;
+  let error_content () =
+    Format.asprintf "\n@[<v>- %a@;- %a]" PP.expression a PP.expression b
+  in
+  trace (fun () -> error (thunk "not equal") error_content ()) @@
+  match (a.expression_content , b.expression_content) with
+  | E_literal a , E_literal b ->
+      assert_literal_eq (a, b)
+  | E_literal _ , _ ->
+    simple_fail "comparing a literal with not a literal"
+  | E_constant (ca) , E_constant (cb) when ca.cons_name = cb.cons_name -> (
+      let%bind lst =
+        generic_try (simple_error "constants with different number of elements")
+          (fun () -> List.combine ca.arguments cb.arguments) in
+      let%bind _all = bind_list @@ List.map assert_value_eq lst in
+      ok ()
+    )
+  | E_constant _ , E_constant _ ->
+      simple_fail "different constants"
+  | E_constant _ , _ ->
+      let error_content () =
+        Format.asprintf "%a vs %a"
+          PP.expression a
+          PP.expression b
+      in
+      fail @@ (fun () -> error (thunk "comparing constant with other expression") error_content ())
+
+  | E_constructor (ca), E_constructor (cb) when ca.constructor = cb.constructor -> (
+      let%bind _eq = assert_value_eq (ca.element, cb.element) in
+      ok ()
+    )
+  | E_constructor _, E_constructor _ ->
+      simple_fail "different constructors"
+  | E_constructor _, _ ->
+      simple_fail "comparing constructor with other expression"
+
+
+  | E_record sma, E_record smb -> (
+      let aux _ a b =
+        match a, b with
+        | Some a, Some b -> Some (assert_value_eq (a, b))
+        | _ -> Some (simple_fail "different record keys")
+      in
+      let%bind _all = bind_lmap @@ LMap.merge aux sma smb in
+      ok ()
+    )
+  | E_record _, _ ->
+      simple_fail "comparing record with other expression"
+  
+  | E_record_update ura, E_record_update urb ->
+    let _ = 
+      generic_try (simple_error "Updating different record") @@ 
+      fun () -> assert_value_eq (ura.record, urb.record) in
+    let aux (Label a,Label b) =
+      assert (String.equal a b)
+    in
+    let () = aux (ura.path, urb.path) in
+    let%bind () = assert_value_eq (ura.update,urb.update) in
+    ok ()
+  | E_record_update _, _ ->
+     simple_fail "comparing record update with other expression"
+
+  | (E_map lsta, E_map lstb | E_big_map lsta, E_big_map lstb) -> (
+      let%bind lst = generic_try (simple_error "maps of different lengths")
+          (fun () ->
+             let lsta' = List.sort compare lsta in
+             let lstb' = List.sort compare lstb in
+             List.combine lsta' lstb') in
+      let aux = fun ((ka, va), (kb, vb)) ->
+        let%bind _ = assert_value_eq (ka, kb) in
+        let%bind _ = assert_value_eq (va, vb) in
+        ok () in
+      let%bind _all = bind_map_list aux lst in
+      ok ()
+    )
+  | (E_map _ | E_big_map _), _ ->
+      simple_fail "comparing map with other expression"
+
+  | E_list lsta, E_list lstb -> (
+      let%bind lst =
+        generic_try (simple_error "list of different lengths")
+          (fun () -> List.combine lsta lstb) in
+      let%bind _all = bind_map_list assert_value_eq lst in
+      ok ()
+    )
+  | E_list _, _ ->
+      simple_fail "comparing list with other expression"
+
+  | E_set lsta, E_set lstb -> (
+      let lsta' = List.sort (compare) lsta in
+      let lstb' = List.sort (compare) lstb in
+      let%bind lst =
+        generic_try (simple_error "set of different lengths")
+          (fun () -> List.combine lsta' lstb') in
+      let%bind _all = bind_map_list assert_value_eq lst in
+      ok ()
+    )
+  | E_set _, _ ->
+      simple_fail "comparing set with other expression"
+
+  | (E_ascription a ,  _b') -> assert_value_eq (a.anno_expr , b)
+  | (_a' , E_ascription b) -> assert_value_eq (a , b.anno_expr)
+  | (E_variable _, _) | (E_lambda _, _)
+  | (E_application _, _) | (E_let_in _, _)
+  | (E_recursive _,_) | (E_record_accessor _, _)
+  | (E_look_up _, _) | (E_matching _, _)
+  | (E_sequence _, _) | (E_skip, _) -> simple_fail "comparing not a value"
+
+let is_value_eq (a , b) = to_bool @@ assert_value_eq (a , b)
+
+(* module Rename = struct
+ *   open Trace
+ *
+ *   module Type = struct
+ *     (\* Type renaming, not needed. Yet. *\)
+ *   end
+ * 
+ *   module Value = struct
+ *     type renaming = string * (string * access_path) (\* src -> dst *\)
+ *     type renamings = renaming list
+ *     let filter (r:renamings) (s:string) : renamings =
+ *       List.filter (fun (x, _) -> not (x = s)) r
+ *     let filters (r:renamings) (ss:string list) : renamings =
+ *       List.filter (fun (x, _) -> not (List.mem x ss)) r
+ * 
+ *     let rec rename_instruction (r:renamings) (i:instruction) : instruction result =
+ *       match i with
+ *       | I_assignment ({name;annotated_expression = e} as a) -> (
+ *           match List.assoc_opt name r with
+ *           | None ->
+ *               let%bind annotated_expression = rename_annotated_expression (filter r name) e in
+ *               ok (I_assignment {a with annotated_expression})
+ *           | Some (name', lst) -> (
+ *               let%bind annotated_expression = rename_annotated_expression r e in
+ *               match lst with
+ *               | [] -> ok (I_assignment {name = name' ; annotated_expression})
+ *               | lst ->
+ *                   let (hds, tl) =
+ *                     let open List in
+ *                     let r = rev lst in
+ *                     rev @@ tl r, hd r
+ *                   in
+ *                   let%bind tl' = match tl with
+ *                     | Access_record n -> ok n
+ *                     | Access_tuple _ -> simple_fail "no support for renaming into tuples yet" in
+ *                   ok (I_record_patch (name', hds, [tl', annotated_expression]))
+ *             )
+ *         )
+ *       | I_skip -> ok I_skip
+ *       | I_fail e ->
+ *           let%bind e' = rename_annotated_expression r e in
+ *           ok (I_fail e')
+ *       | I_loop (cond, body) ->
+ *           let%bind cond' = rename_annotated_expression r cond in
+ *           let%bind body' = rename_block r body in
+ *           ok (I_loop (cond', body'))
+ *       | I_matching (ae, m) ->
+ *           let%bind ae' = rename_annotated_expression r ae in
+ *           let%bind m' = rename_matching rename_block r m in
+ *           ok (I_matching (ae', m'))
+ *       | I_record_patch (v, path, lst) ->
+ *           let aux (x, y) =
+ *             let%bind y' = rename_annotated_expression (filter r v) y in
+ *             ok (x, y') in
+ *           let%bind lst' = bind_map_list aux lst in
+ *           match List.assoc_opt v r with
+ *           | None -> (
+ *               ok (I_record_patch (v, path, lst'))
+ *             )
+ *           | Some (v', path') -> (
+ *               ok (I_record_patch (v', path' @ path, lst'))
+ *             )
+ *     and rename_block (r:renamings) (bl:block) : block result =
+ *       bind_map_list (rename_instruction r) bl
+ * 
+ *     and rename_matching : type a . (renamings -> a -> a result) -> renamings -> a matching -> a matching result =
+ *       fun f r m ->
+ *       match m with
+ *       | Match_bool { match_true = mt ; match_false = mf } ->
+ *           let%bind match_true = f r mt in
+ *           let%bind match_false = f r mf in
+ *           ok (Match_bool {match_true ; match_false})
+ *       | Match_option { match_none = mn ; match_some = (some, ms) } ->
+ *           let%bind match_none = f r mn in
+ *           let%bind ms' = f (filter r some) ms in
+ *           ok (Match_option {match_none ; match_some = (some, ms')})
+ *       | Match_list { match_nil = mn ; match_cons = (hd, tl, mc) } ->
+ *           let%bind match_nil = f r mn in
+ *           let%bind mc' = f (filters r [hd;tl]) mc in
+ *           ok (Match_list {match_nil ; match_cons = (hd, tl, mc')})
+ *       | Match_tuple (lst, body) ->
+ *           let%bind body' = f (filters r lst) body in
+ *           ok (Match_tuple (lst, body'))
+ * 
+ *     and rename_matching_instruction = fun x -> rename_matching rename_block x
+ * 
+ *     and rename_matching_expr = fun x -> rename_matching rename_expression x
+ * 
+ *     and rename_annotated_expression (r:renamings) (ae:annotated_expression) : annotated_expression result =
+ *       let%bind expression = rename_expression r ae.expression in
+ *       ok {ae with expression}
+ * 
+ *     and rename_expression : renamings -> expression -> expression result = fun r e ->
+ *       match e with
+ *       | E_literal _ as l -> ok l
+ *       | E_constant (name, lst) ->
+ *           let%bind lst' = bind_map_list (rename_annotated_expression r) lst in
+ *           ok (E_constant (name, lst'))
+ *       | E_constructor (name, ae) ->
+ *           let%bind ae' = rename_annotated_expression r ae in
+ *           ok (E_constructor (name, ae'))
+ *       | E_variable v -> (
+ *           match List.assoc_opt v r with
+ *           | None -> ok (E_variable v)
+ *           | Some (name, path) -> ok (E_accessor (ae (E_variable (name)), path))
+ *         )
+ *       | E_lambda ({binder;body;result} as l) ->
+ *           let r' = filter r binder in
+ *           let%bind body = rename_block r' body in
+ *           let%bind result = rename_annotated_expression r' result in
+ *           ok (E_lambda {l with body ; result})
+ *       | E_application (f, arg) ->
+ *           let%bind f' = rename_annotated_expression r f in
+ *           let%bind arg' = rename_annotated_expression r arg in
+ *           ok (E_application (f', arg'))
+ *       | E_tuple lst ->
+ *           let%bind lst' = bind_map_list (rename_annotated_expression r) lst in
+ *           ok (E_tuple lst')
+ *       | E_accessor (ae, p) ->
+ *           let%bind ae' = rename_annotated_expression r ae in
+ *           ok (E_accessor (ae', p))
+ *       | E_record sm ->
+ *           let%bind sm' = bind_smap
+ *             @@ SMap.map (rename_annotated_expression r) sm in
+ *           ok (E_record sm')
+ *       | E_map m ->
+ *           let%bind m' = bind_map_list
+ *             (fun (x, y) -> bind_map_pair (rename_annotated_expression r) (x, y)) m in
+ *           ok (E_map m')
+ *       | E_list lst ->
+ *           let%bind lst' = bind_map_list (rename_annotated_expression r) lst in
+ *           ok (E_list lst')
+ *       | E_look_up m ->
+ *           let%bind m' = bind_map_pair (rename_annotated_expression r) m in
+ *           ok (E_look_up m')
+ *       | E_matching (ae, m) ->
+ *           let%bind ae' = rename_annotated_expression r ae in
+ *           let%bind m' = rename_matching rename_annotated_expression r m in
+ *           ok (E_matching (ae', m'))
+ *   end
+ * end *)
diff --git a/src/stages/2-ast_sugar/misc.mli b/src/stages/2-ast_sugar/misc.mli
new file mode 100644
index 000000000..0784d109c
--- /dev/null
+++ b/src/stages/2-ast_sugar/misc.mli
@@ -0,0 +1,20 @@
+open Trace
+open Types
+
+
+(*
+
+module Errors : sig
+  val different_literals_because_different_types : name -> literal -> literal -> unit -> error
+
+  val different_literals : name -> literal -> literal -> unit -> error
+
+  val error_uncomparable_literals : name -> literal -> literal -> unit -> error
+end
+
+val assert_literal_eq : ( literal * literal ) -> unit result
+*)
+
+val assert_value_eq : ( expression * expression ) -> unit result
+
+val is_value_eq : ( expression * expression ) -> bool
diff --git a/src/stages/2-ast_sugar/types.ml b/src/stages/2-ast_sugar/types.ml
new file mode 100644
index 000000000..81091dea7
--- /dev/null
+++ b/src/stages/2-ast_sugar/types.ml
@@ -0,0 +1,125 @@
+[@@@warning "-30"]
+
+module Location = Simple_utils.Location
+
+module Ast_sugar_parameter = struct
+  type type_meta = unit
+end
+
+include Stage_common.Types
+
+(*include Ast_generic_type(Ast_core_parameter)
+*)
+include Ast_generic_type (Ast_sugar_parameter)
+
+type inline = bool 
+type program = declaration Location.wrap list
+and declaration =
+  | Declaration_type of (type_variable * type_expression)
+
+  (* A Declaration_constant is described by
+   *   a name
+   *   an optional type annotation
+   *   a boolean indicating whether it should be inlined
+   *   an expression *)
+  | Declaration_constant of (expression_variable * type_expression option * inline * expression)
+
+(* | Macro_declaration of macro_declaration *)
+and expression = {expression_content: expression_content; location: Location.t}
+
+and expression_content =
+  (* Base *)
+  | E_literal of literal
+  | E_constant of constant (* For language constants, like (Cons hd tl) or (plus i j) *)
+  | E_variable of expression_variable
+  | E_application of application
+  | E_lambda of lambda
+  | E_recursive of recursive
+  | E_let_in of let_in
+  (* Variant *)
+  | E_constructor of constructor (* For user defined constructors *)
+  | E_matching of matching
+  (* Record *)
+  | E_record of expression label_map
+  | E_record_accessor of accessor
+  | E_record_update of update
+  (* Advanced *)
+  | E_ascription of ascription
+  (* Sugar *)
+  | E_sequence of sequence
+  | E_skip
+  (* Data Structures *)
+  | E_map of (expression * expression) list 
+  | E_big_map of (expression * expression) list
+  | E_list of expression list
+  | E_set of expression list
+  | E_look_up of (expression * expression)
+
+and constant =
+  { cons_name: constant' (* this is at the end because it is huge *)
+  ; arguments: expression list }
+
+and application = {
+  lamb: expression ; 
+  args: expression ;
+  }
+
+and lambda =
+  { binder: expression_variable
+  ; input_type: type_expression option
+  ; output_type: type_expression option
+  ; result: expression }
+
+and recursive = {
+  fun_name :  expression_variable;
+  fun_type : type_expression;
+  lambda : lambda;
+}
+
+and let_in =
+  { let_binder: expression_variable * type_expression option
+  ; rhs: expression
+  ; let_result: expression
+  ; inline: bool }
+
+and constructor = {constructor: constructor'; element: expression}
+
+and accessor = {expr: expression; label: label}
+
+and update = {record: expression; path: label ; update: expression}
+
+and matching_expr = (expr,unit) matching_content
+and matching =
+  { matchee: expression
+  ; cases: matching_expr
+  }
+
+and ascription = {anno_expr: expression; type_annotation: type_expression}
+and sequence = {
+  expr1: expression ;
+  expr2: expression ;
+  }
+
+and environment_element_definition =
+  | ED_binder
+  | ED_declaration of (expression * free_variables)
+
+and free_variables = expression_variable list
+
+and environment_element =
+  { type_value: type_expression
+  ; source_environment: full_environment
+  ; definition: environment_element_definition }
+
+and environment = (expression_variable * environment_element) list
+
+and type_environment = (type_variable * type_expression) list
+
+(* SUBST ??? *)
+and small_environment = environment * type_environment
+
+and full_environment = small_environment List.Ne.t
+
+and expr = expression
+
+and texpr = type_expression
diff --git a/src/stages/3-ast_core/PP.ml b/src/stages/3-ast_core/PP.ml
new file mode 100644
index 000000000..3410a96fb
--- /dev/null
+++ b/src/stages/3-ast_core/PP.ml
@@ -0,0 +1,136 @@
+[@@@coverage exclude_file]
+open Types
+open Format
+open PP_helpers
+
+include Stage_common.PP
+include Ast_PP_type(Ast_core_parameter)
+
+let expression_variable ppf (ev : expression_variable) : unit =
+  fprintf ppf "%a" Var.pp ev
+
+
+let rec expression ppf (e : expression) =
+  expression_content ppf e.expression_content
+and expression_content ppf (ec : expression_content) =
+  match ec with
+  | E_literal l ->
+      literal ppf l
+  | E_variable n ->
+      fprintf ppf "%a" expression_variable n
+  | E_application {lamb;args} ->
+      fprintf ppf "(%a)@(%a)" expression lamb expression args
+  | E_constructor c ->
+      fprintf ppf "%a(%a)" constructor c.constructor expression c.element
+  | E_constant c ->
+      fprintf ppf "%a(%a)" constant c.cons_name (list_sep_d expression)
+        c.arguments
+  | E_record m ->
+      fprintf ppf "%a" (tuple_or_record_sep_expr expression) m
+  | E_record_accessor ra ->
+      fprintf ppf "%a.%a" expression ra.expr label ra.label
+  | E_record_update {record; path; update} ->
+      fprintf ppf "{ %a with { %a = %a } }" expression record label path expression update
+  | E_map m ->
+      fprintf ppf "map[%a]" (list_sep_d assoc_expression) m
+  | E_big_map m ->
+      fprintf ppf "big_map[%a]" (list_sep_d assoc_expression) m
+  | E_list lst ->
+      fprintf ppf "list[%a]" (list_sep_d expression) lst
+  | E_set lst ->
+      fprintf ppf "set[%a]" (list_sep_d expression) lst
+  | E_look_up (ds, ind) ->
+      fprintf ppf "(%a)[%a]" expression ds expression ind
+  | E_lambda {binder; input_type; output_type; result} ->
+      fprintf ppf "lambda (%a:%a) : %a return %a"
+        expression_variable binder
+        (PP_helpers.option type_expression)
+        input_type
+        (PP_helpers.option type_expression)
+        output_type expression result
+  | E_recursive { fun_name; fun_type; lambda} ->
+      fprintf ppf "rec (%a:%a => %a )" 
+        expression_variable fun_name 
+        type_expression fun_type
+        expression_content (E_lambda lambda)
+  | E_matching {matchee; cases; _} ->
+      fprintf ppf "match %a with %a" expression matchee (matching expression)
+        cases
+  | E_let_in { let_binder ;rhs ; let_result; inline } ->    
+    fprintf ppf "let %a = %a%a in %a" option_type_name let_binder expression rhs option_inline inline expression let_result
+  | E_ascription {anno_expr; type_annotation} ->
+      fprintf ppf "%a : %a" expression anno_expr type_expression
+        type_annotation
+
+and option_type_name ppf
+    ((n, ty_opt) : expression_variable * type_expression option) =
+  match ty_opt with
+  | None ->
+      fprintf ppf "%a" expression_variable n
+  | Some ty ->
+      fprintf ppf "%a : %a" expression_variable n type_expression ty
+
+and assoc_expression ppf : expr * expr -> unit =
+ fun (a, b) -> fprintf ppf "%a -> %a" expression a expression b
+
+and single_record_patch ppf ((p, expr) : label * expr) =
+  fprintf ppf "%a <- %a" label p expression expr
+
+and matching_variant_case : type a . (_ -> a -> unit) -> _ -> (constructor' * expression_variable) * a -> unit =
+  fun f ppf ((c,n),a) ->
+  fprintf ppf "| %a %a -> %a" constructor c expression_variable n f a
+
+and matching : type a . (formatter -> a -> unit) -> formatter -> (a,unit) matching_content -> unit =
+  fun f ppf m -> match m with
+    | Match_tuple ((lst, b), _) ->
+        fprintf ppf "let (%a) = %a" (list_sep_d expression_variable) lst f b
+    | Match_variant (lst, _) ->
+        fprintf ppf "%a" (list_sep (matching_variant_case f) (tag "@.")) lst
+    | Match_bool {match_true ; match_false} ->
+        fprintf ppf "| True -> %a @.| False -> %a" f match_true f match_false
+    | Match_list {match_nil ; match_cons = (hd, tl, match_cons, _)} ->
+        fprintf ppf "| Nil -> %a @.| %a :: %a -> %a" f match_nil expression_variable hd expression_variable tl f match_cons
+    | Match_option {match_none ; match_some = (some, match_some, _)} ->
+        fprintf ppf "| None -> %a @.| Some %a -> %a" f match_none expression_variable some f match_some
+
+(* Shows the type expected for the matched value *)
+and matching_type ppf m = match m with
+  | Match_tuple _ ->
+      fprintf ppf "tuple"
+  | Match_variant (lst, _) ->
+      fprintf ppf "variant %a" (list_sep matching_variant_case_type (tag "@.")) lst
+  | Match_bool _ ->
+      fprintf ppf "boolean"
+  | Match_list _ ->
+      fprintf ppf "list"
+  | Match_option _ ->
+      fprintf ppf "option"
+
+and matching_variant_case_type ppf ((c,n),_a) =
+  fprintf ppf "| %a %a" constructor c expression_variable n
+
+and option_mut ppf mut = 
+  if mut then 
+    fprintf ppf "[@mut]"
+  else
+    fprintf ppf ""
+
+and option_inline ppf inline = 
+  if inline then 
+    fprintf ppf "[@inline]"
+  else
+    fprintf ppf ""
+
+let declaration ppf (d : declaration) =
+  match d with
+  | Declaration_type (type_name, te) ->
+      fprintf ppf "type %a = %a" type_variable type_name type_expression te
+  | Declaration_constant (name, ty_opt, i, expr) ->
+      fprintf ppf "const %a = %a%a" option_type_name (name, ty_opt) expression
+        expr
+        option_inline i
+
+let program ppf (p : program) =
+  fprintf ppf "@[<v>%a@]"
+    (list_sep declaration (tag "@;"))
+    (List.map Location.unwrap p)
diff --git a/src/stages/3-ast_core/ast_core.ml b/src/stages/3-ast_core/ast_core.ml
new file mode 100644
index 000000000..e9614490a
--- /dev/null
+++ b/src/stages/3-ast_core/ast_core.ml
@@ -0,0 +1,8 @@
+include Types
+
+(* include Misc *)
+include Combinators
+module Types = Types
+module Misc = Misc
+module PP=PP
+module Combinators = Combinators
diff --git a/src/stages/3-ast_core/combinators.ml b/src/stages/3-ast_core/combinators.ml
new file mode 100644
index 000000000..db2417902
--- /dev/null
+++ b/src/stages/3-ast_core/combinators.ml
@@ -0,0 +1,266 @@
+open Types
+open Simple_utils.Trace
+module Option = Simple_utils.Option
+
+module SMap = Map.String
+
+module Errors = struct
+  let bad_kind expected location =
+    let title () = Format.asprintf "a %s was expected" expected in
+    let message () = "" in
+    let data = [
+      ("location" , fun () -> Format.asprintf "%a" Location.pp location) ;
+    ] in
+    error ~data title message
+  let bad_type_operator type_op =
+    let title () = Format.asprintf "bad type operator %a" (PP.type_operator PP.type_expression) type_op in
+    let message () = "" in
+    error title message
+end
+open Errors
+
+let make_t type_content = {type_content; type_meta = ()}
+
+  
+let tuple_to_record lst =
+  let aux (i,acc) el = (i+1,(string_of_int i, el)::acc) in
+  let (_, lst ) = List.fold_left aux (0,[]) lst in
+  lst
+
+let t_bool         : type_expression = make_t @@ T_constant (TC_bool)
+let t_string       : type_expression = make_t @@ T_constant (TC_string)
+let t_bytes        : type_expression = make_t @@ T_constant (TC_bytes)
+let t_int          : type_expression = make_t @@ T_constant (TC_int)
+let t_operation    : type_expression = make_t @@ T_constant (TC_operation)
+let t_nat          : type_expression = make_t @@ T_constant (TC_nat)
+let t_tez          : type_expression = make_t @@ T_constant (TC_mutez)
+let t_unit         : type_expression = make_t @@ T_constant (TC_unit)
+let t_address      : type_expression = make_t @@ T_constant (TC_address)
+let t_signature    : type_expression = make_t @@ T_constant (TC_signature)
+let t_key          : type_expression = make_t @@ T_constant (TC_key)
+let t_key_hash     : type_expression = make_t @@ T_constant (TC_key_hash)
+let t_timestamp    : type_expression = make_t @@ T_constant (TC_timestamp)
+let t_option  o    : type_expression = make_t @@ T_operator (TC_option o)
+let t_list  t      : type_expression = make_t @@ T_operator (TC_list t)
+let t_variable n   : type_expression = make_t @@ T_variable (Var.of_name n)
+let t_record_ez lst =
+  let lst = List.map (fun (k, v) -> (Label k, v)) lst in
+  let m = LMap.of_list lst in
+  make_t @@ T_record m
+let t_record m  : type_expression =
+  let lst = Map.String.to_kv_list m in
+  t_record_ez lst
+
+let t_pair (a , b) : type_expression = t_record_ez [("0",a) ; ("1",b)]
+let t_tuple lst    : type_expression = t_record_ez (tuple_to_record lst)
+
+let ez_t_sum (lst:(string * type_expression) list) : type_expression =
+  let aux prev (k, v) = CMap.add (Constructor k) v prev in
+  let map = List.fold_left aux CMap.empty lst in
+  make_t @@ T_sum map
+let t_sum m : type_expression =
+  let lst = Map.String.to_kv_list m in
+  ez_t_sum lst
+
+let t_function type1 type2  : type_expression = make_t @@ T_arrow {type1; type2}
+let t_map key value         : type_expression = make_t @@ T_operator (TC_map (key, value))
+let t_big_map key value     : type_expression = make_t @@ T_operator (TC_big_map (key , value))
+let t_set key               : type_expression = make_t @@ T_operator (TC_set key)
+let t_contract contract     : type_expression = make_t @@ T_operator (TC_contract contract)
+
+(* TODO find a better way than using list*)
+let t_operator op lst: type_expression result =
+  match op,lst with 
+  | TC_set _         , [t] -> ok @@ t_set t
+  | TC_list _        , [t] -> ok @@ t_list t
+  | TC_option _      , [t] -> ok @@ t_option t
+  | TC_map (_,_)     , [kt;vt] -> ok @@ t_map kt vt
+  | TC_big_map (_,_) , [kt;vt] -> ok @@ t_big_map kt vt
+  | TC_contract _    , [t] -> ok @@ t_contract t
+  | _ , _ -> fail @@ bad_type_operator op
+
+let make_expr ?(loc = Location.generated) expression_content =
+  let location = loc in
+  { expression_content; location }
+
+let e_var ?loc (n: string) : expression = make_expr ?loc @@ E_variable (Var.of_name n)
+let e_literal ?loc l : expression = make_expr ?loc @@ E_literal l
+let e_unit ?loc () : expression = make_expr ?loc @@ E_literal (Literal_unit)
+let e_int ?loc n : expression = make_expr ?loc @@ E_literal (Literal_int n)
+let e_nat ?loc n : expression = make_expr ?loc @@ E_literal (Literal_nat n)
+let e_timestamp ?loc n : expression = make_expr ?loc @@ E_literal (Literal_timestamp n)
+let e_bool ?loc   b : expression = make_expr ?loc @@ E_literal (Literal_bool b)
+let e_string ?loc s : expression = make_expr ?loc @@ E_literal (Literal_string s)
+let e_address ?loc s : expression = make_expr ?loc @@ E_literal (Literal_address s)
+let e_mutez ?loc s : expression = make_expr ?loc @@ E_literal (Literal_mutez s)
+let e_signature ?loc s : expression = make_expr ?loc @@ E_literal (Literal_signature s)
+let e_key ?loc s : expression = make_expr ?loc @@ E_literal (Literal_key s)
+let e_key_hash ?loc s : expression = make_expr ?loc @@ E_literal (Literal_key_hash s)
+let e_chain_id ?loc s : expression = make_expr ?loc @@ E_literal (Literal_chain_id s)
+let e'_bytes b : expression_content result =
+  let%bind bytes = generic_try (simple_error "bad hex to bytes") (fun () -> Hex.to_bytes (`Hex b)) in
+  ok @@ E_literal (Literal_bytes bytes)
+let e_bytes_hex ?loc b : expression result =
+  let%bind e' = e'_bytes b in
+  ok @@ make_expr ?loc e'
+let e_bytes_raw ?loc (b: bytes) : expression =
+  make_expr ?loc @@ E_literal (Literal_bytes b)
+let e_bytes_string ?loc (s: string) : expression =
+  make_expr ?loc @@ E_literal (Literal_bytes (Hex.to_bytes (Hex.of_string s)))
+let e_big_map ?loc lst : expression = make_expr ?loc @@ E_big_map lst
+let e_some ?loc s  : expression = make_expr ?loc @@ E_constant {cons_name = C_SOME; arguments = [s]}
+let e_none ?loc () : expression = make_expr ?loc @@ E_constant {cons_name = C_NONE; arguments = []}
+let e_string_cat ?loc sl sr : expression = make_expr ?loc @@ E_constant {cons_name = C_CONCAT; arguments = [sl ; sr ]}
+let e_map_add ?loc k v old  : expression = make_expr ?loc @@ E_constant {cons_name = C_MAP_ADD; arguments = [k ; v ; old]}
+let e_map ?loc lst : expression = make_expr ?loc @@ E_map lst
+let e_set ?loc lst : expression = make_expr ?loc @@ E_set lst
+let e_list ?loc lst : expression = make_expr ?loc @@ E_list lst
+let e_constructor ?loc s a : expression = make_expr ?loc @@ E_constructor { constructor = Constructor s; element = a}
+let e_matching ?loc a b : expression = make_expr ?loc @@ E_matching {matchee=a;cases=b}
+let e_matching_bool ?loc a b c : expression = e_matching ?loc a (Match_bool {match_true = b ; match_false = c})
+let e_accessor ?loc a b = make_expr ?loc @@ E_record_accessor {expr = a; label= Label b}
+let e_accessor_list ?loc a b  = List.fold_left (fun a b -> e_accessor ?loc a b) a b
+let e_variable ?loc v = make_expr ?loc @@ E_variable v
+let e_let_in ?loc (binder, ascr) inline rhs let_result = 
+  make_expr ?loc @@ E_let_in { let_binder = (binder,ascr) ; rhs ; let_result; inline }
+let e_annotation ?loc anno_expr ty = make_expr ?loc @@ E_ascription {anno_expr; type_annotation = ty}
+let e_application ?loc a b = make_expr ?loc @@ E_application {lamb=a ; args=b}
+let e_binop ?loc name a b  = make_expr ?loc @@ E_constant {cons_name = name ; arguments = [a ; b]}
+let e_constant ?loc name lst = make_expr ?loc @@ E_constant {cons_name=name ; arguments = lst}
+let e_look_up ?loc x y = make_expr ?loc @@ E_look_up (x , y)
+let e_cond ?loc expr match_true match_false = e_matching expr ?loc (Match_bool {match_true; match_false})
+(*
+let e_assign ?loc a b c = location_wrap ?loc @@ E_assign (Var.of_name a , b , c) (* TODO handlethat*)
+*)
+let ez_match_variant (lst : ((string * string) * 'a) list) =
+  let lst = List.map (fun ((c,n),a) -> ((Constructor c, Var.of_name n), a) ) lst in
+  Match_variant (lst,())
+let e_matching_variant ?loc a (lst : ((string * string)* 'a) list) =
+  e_matching ?loc a (ez_match_variant lst)
+let e_record_ez ?loc (lst : (string * expr) list) : expression =
+  let map = List.fold_left (fun m (x, y) -> LMap.add (Label x) y m) LMap.empty lst in
+  make_expr ?loc @@ E_record map
+let e_record ?loc map =
+  let lst = Map.String.to_kv_list map in
+  e_record_ez ?loc lst 
+
+let e_update ?loc record path update = 
+  let path = Label path in
+  make_expr ?loc @@ E_record_update {record; path; update}
+
+let e_tuple ?loc lst : expression = e_record_ez ?loc (tuple_to_record lst)
+let e_pair ?loc a b  : expression = e_tuple ?loc [a;b]
+
+let make_option_typed ?loc e t_opt =
+  match t_opt with
+  | None -> e
+  | Some t -> e_annotation ?loc e t
+
+
+let e_typed_none ?loc t_opt =
+  let type_annotation = t_option t_opt in
+  e_annotation ?loc (e_none ?loc ()) type_annotation
+
+let e_typed_list ?loc lst t =
+  e_annotation ?loc (e_list lst) (t_list t)
+
+let e_typed_map ?loc lst k v = e_annotation ?loc (e_map lst) (t_map k v)
+let e_typed_big_map ?loc lst k v = e_annotation ?loc (e_big_map lst) (t_big_map k v)
+
+let e_typed_set ?loc lst k = e_annotation ?loc (e_set lst) (t_set k)
+
+
+let e_lambda ?loc (binder : expression_variable)
+    (input_type : type_expression option)
+    (output_type : type_expression option)
+    (result : expression)
+  : expression =
+  make_expr ?loc @@ E_lambda {
+    binder = binder ;
+    input_type = input_type ;
+    output_type = output_type ;
+    result ;
+  }
+let e_recursive ?loc fun_name fun_type lambda = make_expr ?loc @@ E_recursive {fun_name; fun_type; lambda}
+
+
+let e_assign_with_let ?loc var access_path expr = 
+  let var = Var.of_name (var) in
+  match access_path with 
+  | [] -> (var, None), true, expr, false
+
+  | lst -> 
+    let rec aux path record= match path with 
+    | [] -> failwith "acces_path cannot be empty"
+    | [e] -> e_update ?loc record e expr
+    | elem::tail -> 
+      let next_record = e_accessor record elem in
+      e_update ?loc record elem (aux tail next_record )
+    in 
+    (var, None), true, (aux lst (e_variable var)), false
+
+let get_e_accessor = fun t ->
+  match t with
+  | E_record_accessor {expr; label} -> ok (expr , label)
+  | _ -> simple_fail "not an accessor"
+
+let assert_e_accessor = fun t ->
+  let%bind _ = get_e_accessor t in
+  ok ()
+
+let get_e_pair = fun t ->
+  match t with
+  | E_record r -> ( 
+  let lst = LMap.to_kv_list r in
+    match lst with 
+    | [(Label "O",a);(Label "1",b)]
+    | [(Label "1",b);(Label "0",a)] -> 
+        ok (a , b)
+    | _ -> simple_fail "not a pair"
+    )
+  | _ -> simple_fail "not a pair"
+
+let get_e_list = fun t ->
+  match t with
+  | E_list lst -> ok lst
+  | _ -> simple_fail "not a list"
+
+let tuple_of_record (m: _ LMap.t) =
+  let aux i = 
+    let opt = LMap.find_opt (Label (string_of_int i)) m in
+    Option.bind (fun opt -> Some (opt,i+1)) opt
+  in
+  Base.Sequence.to_list @@ Base.Sequence.unfold ~init:0 ~f:aux
+
+let get_e_tuple = fun t ->
+  match t with
+  | E_record r -> ok @@ tuple_of_record r
+  | _ -> simple_fail "ast_core: get_e_tuple: not a tuple"
+
+(* Same as get_e_pair *)
+let extract_pair : expression -> (expression * expression) result = fun e ->
+  match e.expression_content with
+  | E_record r -> ( 
+  let lst = LMap.to_kv_list r in
+    match lst with 
+    | [(Label "O",a);(Label "1",b)]
+    | [(Label "1",b);(Label "0",a)] -> 
+        ok (a , b)
+    | _ -> fail @@ bad_kind "pair" e.location
+    )
+  | _ -> fail @@ bad_kind "pair" e.location
+
+let extract_list : expression -> (expression list) result = fun e ->
+  match e.expression_content with
+  | E_list lst -> ok lst
+  | _ -> fail @@ bad_kind "list" e.location
+
+let extract_record : expression -> (label * expression) list result = fun e ->
+  match e.expression_content with
+  | E_record lst -> ok @@ LMap.to_kv_list lst
+  | _ -> fail @@ bad_kind "record" e.location
+
+let extract_map : expression -> (expression * expression) list result = fun e ->
+  match e.expression_content with
+  | E_map lst -> ok lst
+  | _ -> fail @@ bad_kind "map" e.location
diff --git a/src/stages/3-ast_core/combinators.mli b/src/stages/3-ast_core/combinators.mli
new file mode 100644
index 000000000..ae0aab1bd
--- /dev/null
+++ b/src/stages/3-ast_core/combinators.mli
@@ -0,0 +1,133 @@
+open Types
+open Simple_utils.Trace
+(*
+module Option = Simple_utils.Option
+
+module SMap = Map.String
+
+module Errors : sig
+  val bad_kind : name -> Location.t -> unit -> error
+end
+*)
+val make_t      : type_content -> type_expression
+val t_bool      : type_expression
+val t_string    : type_expression
+val t_bytes     : type_expression
+val t_int       : type_expression
+val t_operation : type_expression
+val t_nat       : type_expression
+val t_tez       : type_expression
+val t_unit      : type_expression
+val t_address   : type_expression
+val t_key       : type_expression
+val t_key_hash  : type_expression
+val t_timestamp : type_expression
+val t_signature : type_expression
+(*
+val t_option    : type_expression -> type_expression
+*)
+val t_list      : type_expression -> type_expression
+val t_variable  : string -> type_expression
+(*
+val t_record    : te_map -> type_expression
+*)
+val t_pair : ( type_expression * type_expression ) -> type_expression
+val t_tuple     : type_expression list -> type_expression
+
+val t_record : type_expression Map.String.t -> type_expression
+val t_record_ez : (string * type_expression) list -> type_expression
+
+val t_sum : type_expression Map.String.t -> type_expression
+val ez_t_sum : ( string * type_expression ) list -> type_expression
+
+val t_function : type_expression -> type_expression -> type_expression
+val t_map : type_expression -> type_expression -> type_expression
+
+val t_operator : type_operator -> type_expression list -> type_expression result
+val t_set : type_expression -> type_expression
+
+val make_expr : ?loc:Location.t -> expression_content -> expression
+val e_var : ?loc:Location.t -> string -> expression
+val e_literal : ?loc:Location.t -> literal -> expression
+val e_unit : ?loc:Location.t -> unit -> expression
+val e_int : ?loc:Location.t -> int -> expression 
+val e_nat : ?loc:Location.t -> int -> expression
+val e_timestamp : ?loc:Location.t -> int -> expression
+val e_bool : ?loc:Location.t -> bool -> expression
+val e_string : ?loc:Location.t -> string -> expression
+val e_address : ?loc:Location.t -> string -> expression 
+val e_signature : ?loc:Location.t -> string -> expression 
+val e_key : ?loc:Location.t -> string -> expression 
+val e_key_hash : ?loc:Location.t -> string -> expression 
+val e_chain_id : ?loc:Location.t -> string -> expression 
+val e_mutez : ?loc:Location.t -> int -> expression
+val e'_bytes : string -> expression_content result
+val e_bytes_hex : ?loc:Location.t -> string -> expression result
+val e_bytes_raw : ?loc:Location.t -> bytes -> expression
+val e_bytes_string : ?loc:Location.t -> string -> expression
+val e_big_map : ?loc:Location.t -> ( expr * expr ) list -> expression
+
+val e_record_ez  : ?loc:Location.t -> ( string * expr ) list -> expression
+val e_tuple : ?loc:Location.t -> expression list -> expression
+val e_some : ?loc:Location.t -> expression -> expression
+val e_none : ?loc:Location.t -> unit -> expression
+val e_string_cat : ?loc:Location.t -> expression -> expression -> expression
+val e_map_add : ?loc:Location.t -> expression -> expression ->  expression -> expression
+val e_map : ?loc:Location.t -> ( expression * expression ) list -> expression
+val e_set : ?loc:Location.t -> expression list -> expression
+val e_list : ?loc:Location.t -> expression list -> expression
+val e_pair : ?loc:Location.t -> expression -> expression -> expression
+val e_constructor : ?loc:Location.t -> string -> expression -> expression
+val e_matching : ?loc:Location.t -> expression -> matching_expr -> expression
+val e_matching_bool : ?loc:Location.t -> expression -> expression -> expression -> expression
+val e_accessor : ?loc:Location.t -> expression -> string -> expression
+val e_accessor_list : ?loc:Location.t -> expression -> string list -> expression
+val e_variable : ?loc:Location.t -> expression_variable -> expression
+val e_cond: ?loc:Location.t -> expression -> expression -> expression -> expression
+val e_let_in : ?loc:Location.t -> ( expression_variable * type_expression option ) -> bool -> expression -> expression -> expression
+val e_annotation : ?loc:Location.t -> expression -> type_expression -> expression
+val e_application : ?loc:Location.t -> expression -> expression -> expression
+val e_binop    : ?loc:Location.t -> constant' -> expression -> expression -> expression
+val e_constant : ?loc:Location.t -> constant' -> expression list -> expression
+val e_look_up : ?loc:Location.t -> expression -> expression -> expression
+val ez_match_variant : ((string * string ) * 'a ) list -> ('a,unit) matching_content
+val e_matching_variant : ?loc:Location.t -> expression -> ((string * string) * expression) list -> expression
+
+val make_option_typed : ?loc:Location.t -> expression -> type_expression option -> expression
+
+val e_typed_none : ?loc:Location.t -> type_expression -> expression
+
+val e_typed_list : ?loc:Location.t -> expression list -> type_expression -> expression
+
+val e_typed_map : ?loc:Location.t -> ( expression * expression ) list  -> type_expression -> type_expression -> expression
+val e_typed_big_map : ?loc:Location.t -> ( expression * expression ) list  -> type_expression -> type_expression -> expression
+
+val e_typed_set : ?loc:Location.t -> expression list -> type_expression -> expression
+
+val e_lambda : ?loc:Location.t -> expression_variable -> type_expression option -> type_expression option -> expression -> expression
+val e_recursive : ?loc:Location.t -> expression_variable -> type_expression -> lambda -> expression
+val e_record : ?loc:Location.t -> expr Map.String.t -> expression
+val e_update : ?loc:Location.t -> expression -> string -> expression -> expression
+val e_assign_with_let : ?loc:Location.t -> string -> string list -> expression -> ((expression_variable*type_expression option)*bool*expression*bool)
+
+(*
+val get_e_accessor : expression' -> ( expression * access_path ) result
+*)
+
+val assert_e_accessor : expression_content -> unit result
+
+val get_e_pair : expression_content -> ( expression * expression ) result
+
+val get_e_list : expression_content -> ( expression list ) result
+val get_e_tuple : expression_content -> ( expression list ) result
+(*
+val get_e_failwith : expression -> expression result 
+val is_e_failwith : expression -> bool
+*)
+val extract_pair : expression -> ( expression * expression ) result 
+
+val extract_list : expression -> (expression list) result
+
+val extract_record : expression -> (label * expression) list result
+
+val extract_map : expression -> (expression * expression) list result
diff --git a/src/stages/3-ast_core/dune b/src/stages/3-ast_core/dune
new file mode 100644
index 000000000..ce45b1899
--- /dev/null
+++ b/src/stages/3-ast_core/dune
@@ -0,0 +1,13 @@
+(library
+  (name ast_core)
+  (public_name ligo.ast_core)
+  (libraries
+    simple-utils
+    tezos-utils
+    stage_common
+  )
+  (preprocess
+    (pps ppx_let bisect_ppx --conditional)
+  )
+  (flags (:standard -open Simple_utils ))
+)
diff --git a/src/stages/ast_simplified/misc.ml b/src/stages/3-ast_core/misc.ml
similarity index 99%
rename from src/stages/ast_simplified/misc.ml
rename to src/stages/3-ast_core/misc.ml
index f2094d3ca..a09efa475 100644
--- a/src/stages/ast_simplified/misc.ml
+++ b/src/stages/3-ast_core/misc.ml
@@ -184,7 +184,7 @@ let rec assert_value_eq (a, b: (expression * expression )) : unit result =
   | (E_application _, _) | (E_let_in _, _)
   | (E_recursive _,_) | (E_record_accessor _, _)
   | (E_look_up _, _) | (E_matching _, _)
-  | (E_skip, _) -> simple_fail "comparing not a value"
+   -> simple_fail "comparing not a value"
 
 let is_value_eq (a , b) = to_bool @@ assert_value_eq (a , b)
 
diff --git a/src/stages/3-ast_core/misc.mli b/src/stages/3-ast_core/misc.mli
new file mode 100644
index 000000000..0784d109c
--- /dev/null
+++ b/src/stages/3-ast_core/misc.mli
@@ -0,0 +1,20 @@
+open Trace
+open Types
+
+
+(*
+
+module Errors : sig
+  val different_literals_because_different_types : name -> literal -> literal -> unit -> error
+
+  val different_literals : name -> literal -> literal -> unit -> error
+
+  val error_uncomparable_literals : name -> literal -> literal -> unit -> error
+end
+
+val assert_literal_eq : ( literal * literal ) -> unit result
+*)
+
+val assert_value_eq : ( expression * expression ) -> unit result
+
+val is_value_eq : ( expression * expression ) -> bool
diff --git a/src/stages/ast_simplified/types.ml b/src/stages/3-ast_core/types.ml
similarity index 92%
rename from src/stages/ast_simplified/types.ml
rename to src/stages/3-ast_core/types.ml
index 696dbd028..2b8f0dbc2 100644
--- a/src/stages/ast_simplified/types.ml
+++ b/src/stages/3-ast_core/types.ml
@@ -2,15 +2,15 @@
 
 module Location = Simple_utils.Location
 
-module Ast_simplified_parameter = struct
+module Ast_core_parameter = struct
   type type_meta = unit
 end
 
 include Stage_common.Types
 
-(*include Ast_generic_type(Ast_simplified_parameter)
+(*include Ast_generic_type(Ast_core_parameter)
 *)
-include Ast_generic_type (Ast_simplified_parameter)
+include Ast_generic_type (Ast_core_parameter)
 
 type inline = bool 
 type program = declaration Location.wrap list
@@ -34,9 +34,8 @@ and expression_content =
   | E_variable of expression_variable
   | E_application of application
   | E_lambda of lambda
-  | E_let_in of let_in
   | E_recursive of recursive
-  | E_skip
+  | E_let_in of let_in
   (* Variant *)
   | E_constructor of constructor (* For user defined constructors *)
   | E_matching of matching
@@ -58,27 +57,29 @@ and constant =
   { cons_name: constant' (* this is at the end because it is huge *)
   ; arguments: expression list }
 
-and application = {expr1: expression; expr2: expression}
+and application = {
+  lamb: expression ; 
+  args: expression ;
+  }
 
 and lambda =
-  { binder: expression_variable 
+  { binder: expression_variable
   ; input_type: type_expression option
   ; output_type: type_expression option
   ; result: expression }
 
-and let_in =
-  { let_binder: expression_variable * type_expression option
-  ; mut: bool
-  ; rhs: expression
-  ; let_result: expression
-  ; inline: bool }
-
 and recursive = {
   fun_name :  expression_variable;
   fun_type : type_expression;
   lambda : lambda;
 }
 
+and let_in =
+  { let_binder: expression_variable * type_expression option
+  ; rhs: expression
+  ; let_result: expression
+  ; inline: bool }
+
 and constructor = {constructor: constructor'; element: expression}
 
 and accessor = {expr: expression; label: label}
diff --git a/src/stages/ast_typed/PP.ml b/src/stages/4-ast_typed/PP.ml
similarity index 97%
rename from src/stages/ast_typed/PP.ml
rename to src/stages/4-ast_typed/PP.ml
index aed4648c5..1325d0476 100644
--- a/src/stages/ast_typed/PP.ml
+++ b/src/stages/4-ast_typed/PP.ml
@@ -19,8 +19,8 @@ and expression_content ppf (ec: expression_content) =
       literal ppf l
   | E_variable n ->
       fprintf ppf "%a" expression_variable n
-  | E_application app ->
-      fprintf ppf "(%a)@(%a)" expression app.expr1 expression app.expr2
+  | E_application {lamb;args} ->
+      fprintf ppf "(%a)@(%a)" expression lamb expression args
   | E_constructor c ->
       fprintf ppf "%a(%a)" constructor c.constructor expression c.element
   | E_constant c ->
diff --git a/src/stages/ast_typed/ast_typed.ml b/src/stages/4-ast_typed/ast_typed.ml
similarity index 100%
rename from src/stages/ast_typed/ast_typed.ml
rename to src/stages/4-ast_typed/ast_typed.ml
diff --git a/src/stages/ast_typed/combinators.ml b/src/stages/4-ast_typed/combinators.ml
similarity index 98%
rename from src/stages/ast_typed/combinators.ml
rename to src/stages/4-ast_typed/combinators.ml
index d6f1e8da5..014ab8f2f 100644
--- a/src/stages/ast_typed/combinators.ml
+++ b/src/stages/4-ast_typed/combinators.ml
@@ -23,7 +23,7 @@ module Errors = struct
     error (thunk "No declaration with the given name") message
 end
 
-let make_t type_content simplified = { type_content ; type_meta=simplified }
+let make_t type_content core = { type_content ; type_meta=core }
 let make_a_e ?(location = Location.generated) expression_content type_expression environment = {
   expression_content ;
   type_expression ;
@@ -294,7 +294,7 @@ let e_chain_id s : expression_content = E_literal (Literal_chain_id s)
 let e_operation s : expression_content = E_literal (Literal_operation s)
 let e_lambda l : expression_content = E_lambda l
 let e_pair a b : expression_content = ez_e_record [(Label "0",a);(Label "1", b)]
-let e_application expr1 expr2 : expression_content = E_application {expr1;expr2}
+let e_application lamb args : expression_content = E_application {lamb;args}
 let e_variable v : expression_content = E_variable v
 let e_list lst : expression_content = E_list lst
 let e_let_in let_binder inline rhs let_result = E_let_in { let_binder ; rhs ; let_result; inline }
diff --git a/src/stages/ast_typed/combinators.mli b/src/stages/4-ast_typed/combinators.mli
similarity index 100%
rename from src/stages/ast_typed/combinators.mli
rename to src/stages/4-ast_typed/combinators.mli
diff --git a/src/stages/ast_typed/combinators_environment.ml b/src/stages/4-ast_typed/combinators_environment.ml
similarity index 100%
rename from src/stages/ast_typed/combinators_environment.ml
rename to src/stages/4-ast_typed/combinators_environment.ml
diff --git a/src/stages/ast_typed/combinators_environment.mli b/src/stages/4-ast_typed/combinators_environment.mli
similarity index 100%
rename from src/stages/ast_typed/combinators_environment.mli
rename to src/stages/4-ast_typed/combinators_environment.mli
diff --git a/src/stages/ast_typed/dune b/src/stages/4-ast_typed/dune
similarity index 84%
rename from src/stages/ast_typed/dune
rename to src/stages/4-ast_typed/dune
index 7eed79e47..d33c8dac6 100644
--- a/src/stages/ast_typed/dune
+++ b/src/stages/4-ast_typed/dune
@@ -4,7 +4,7 @@
   (libraries
     simple-utils
     tezos-utils
-    ast_simplified ; Is that a good idea?
+    ast_core ; Is that a good idea?
     stage_common
   )
   (preprocess
diff --git a/src/stages/ast_typed/environment.ml b/src/stages/4-ast_typed/environment.ml
similarity index 100%
rename from src/stages/ast_typed/environment.ml
rename to src/stages/4-ast_typed/environment.ml
diff --git a/src/stages/ast_typed/environment.mli b/src/stages/4-ast_typed/environment.mli
similarity index 100%
rename from src/stages/ast_typed/environment.mli
rename to src/stages/4-ast_typed/environment.mli
diff --git a/src/stages/ast_typed/misc.ml b/src/stages/4-ast_typed/misc.ml
similarity index 99%
rename from src/stages/ast_typed/misc.ml
rename to src/stages/4-ast_typed/misc.ml
index 20a778f9c..04efcca5f 100644
--- a/src/stages/ast_typed/misc.ml
+++ b/src/stages/4-ast_typed/misc.ml
@@ -206,7 +206,7 @@ module Free_variables = struct
         | true -> empty
         | false -> singleton name
       )
-    | E_application {expr1;expr2} -> unions @@ List.map self [ expr1 ; expr2 ]
+    | E_application {lamb;args} -> unions @@ List.map self [ lamb ; args ]
     | E_constructor {element;_} -> self element
     | E_record m -> unions @@ List.map self @@ LMap.to_list m
     | E_record_accessor {expr;_} -> self expr
diff --git a/src/stages/ast_typed/misc.mli b/src/stages/4-ast_typed/misc.mli
similarity index 100%
rename from src/stages/ast_typed/misc.mli
rename to src/stages/4-ast_typed/misc.mli
diff --git a/src/stages/ast_typed/misc_smart.ml b/src/stages/4-ast_typed/misc_smart.ml
similarity index 97%
rename from src/stages/ast_typed/misc_smart.ml
rename to src/stages/4-ast_typed/misc_smart.ml
index 414f01670..0040f7d90 100644
--- a/src/stages/ast_typed/misc_smart.ml
+++ b/src/stages/4-ast_typed/misc_smart.ml
@@ -63,8 +63,8 @@ module Captured_variables = struct
         | ED_binder -> ok empty
         | ED_declaration {expr=_ ; free_variables=_} -> simple_fail "todo"
       )
-    | E_application {expr1;expr2} ->
-      let%bind lst' = bind_map_list self [ expr1 ; expr2 ] in
+    | E_application {lamb;args} ->
+      let%bind lst' = bind_map_list self [ lamb ; args ] in
       ok @@ unions lst'
     | E_constructor {element;_} -> self element
     | E_record m ->
diff --git a/src/stages/ast_typed/misc_smart.mli b/src/stages/4-ast_typed/misc_smart.mli
similarity index 100%
rename from src/stages/ast_typed/misc_smart.mli
rename to src/stages/4-ast_typed/misc_smart.mli
diff --git a/src/stages/ast_typed/types.ml b/src/stages/4-ast_typed/types.ml
similarity index 97%
rename from src/stages/ast_typed/types.ml
rename to src/stages/4-ast_typed/types.ml
index af143aa89..fdb24969b 100644
--- a/src/stages/ast_typed/types.ml
+++ b/src/stages/4-ast_typed/types.ml
@@ -1,6 +1,6 @@
 [@@@warning "-30"]
 
-module S = Ast_simplified
+module S = Ast_core
 include Stage_common.Types
 
 module Ast_typed_type_parameter = struct
@@ -40,8 +40,8 @@ and expression_content =
   | E_variable of expression_variable
   | E_application of application
   | E_lambda of lambda
-  | E_let_in of let_in
   | E_recursive of recursive
+  | E_let_in of let_in
   (* Variant *)
   | E_constructor of constructor (* For user defined constructors *)
   | E_matching of matching
@@ -61,7 +61,10 @@ and constant =
   { cons_name: constant'
   ; arguments: expression list }
 
-and application = {expr1: expression; expr2: expression}
+and application = {
+  lamb: expression ; 
+  args: expression ;
+  }
 
 and lambda =  {
     binder: expression_variable ;
diff --git a/src/stages/mini_c/PP.ml b/src/stages/5-mini_c/PP.ml
similarity index 100%
rename from src/stages/mini_c/PP.ml
rename to src/stages/5-mini_c/PP.ml
diff --git a/src/stages/mini_c/PP.mli b/src/stages/5-mini_c/PP.mli
similarity index 100%
rename from src/stages/mini_c/PP.mli
rename to src/stages/5-mini_c/PP.mli
diff --git a/src/stages/mini_c/combinators.ml b/src/stages/5-mini_c/combinators.ml
similarity index 100%
rename from src/stages/mini_c/combinators.ml
rename to src/stages/5-mini_c/combinators.ml
diff --git a/src/stages/mini_c/combinators.mli b/src/stages/5-mini_c/combinators.mli
similarity index 100%
rename from src/stages/mini_c/combinators.mli
rename to src/stages/5-mini_c/combinators.mli
diff --git a/src/stages/mini_c/combinators_smart.ml b/src/stages/5-mini_c/combinators_smart.ml
similarity index 100%
rename from src/stages/mini_c/combinators_smart.ml
rename to src/stages/5-mini_c/combinators_smart.ml
diff --git a/src/stages/mini_c/dune b/src/stages/5-mini_c/dune
similarity index 100%
rename from src/stages/mini_c/dune
rename to src/stages/5-mini_c/dune
diff --git a/src/stages/mini_c/environment.ml b/src/stages/5-mini_c/environment.ml
similarity index 100%
rename from src/stages/mini_c/environment.ml
rename to src/stages/5-mini_c/environment.ml
diff --git a/src/stages/mini_c/environment.mli b/src/stages/5-mini_c/environment.mli
similarity index 100%
rename from src/stages/mini_c/environment.mli
rename to src/stages/5-mini_c/environment.mli
diff --git a/src/stages/mini_c/mini_c.ml b/src/stages/5-mini_c/mini_c.ml
similarity index 100%
rename from src/stages/mini_c/mini_c.ml
rename to src/stages/5-mini_c/mini_c.ml
diff --git a/src/stages/mini_c/misc.ml b/src/stages/5-mini_c/misc.ml
similarity index 100%
rename from src/stages/mini_c/misc.ml
rename to src/stages/5-mini_c/misc.ml
diff --git a/src/stages/mini_c/types.ml b/src/stages/5-mini_c/types.ml
similarity index 100%
rename from src/stages/mini_c/types.ml
rename to src/stages/5-mini_c/types.ml
diff --git a/src/stages/typesystem/misc.ml b/src/stages/typesystem/misc.ml
index 10a59f4bc..4b60cf454 100644
--- a/src/stages/typesystem/misc.ml
+++ b/src/stages/typesystem/misc.ml
@@ -89,28 +89,28 @@ module Substitution = struct
           let _TODO = substs in
           failwith "TODO: T_function"
 
-    and s_simpl_type_content : Ast_simplified.type_content w = fun ~substs -> function
-      | Ast_simplified.T_sum _ -> failwith "TODO: subst: unimplemented case s_type_expression sum"
-      | Ast_simplified.T_record _ -> failwith "TODO: subst: unimplemented case s_type_expression record"
-      | Ast_simplified.T_arrow _ -> failwith "TODO: subst: unimplemented case s_type_expression arrow"
-      | Ast_simplified.T_variable _ -> failwith "TODO: subst: unimplemented case s_type_expression variable"
-      | Ast_simplified.T_operator op ->
+    and s_abstr_type_content : Ast_core.type_content w = fun ~substs -> function
+      | Ast_core.T_sum _ -> failwith "TODO: subst: unimplemented case s_type_expression sum"
+      | Ast_core.T_record _ -> failwith "TODO: subst: unimplemented case s_type_expression record"
+      | Ast_core.T_arrow _ -> failwith "TODO: subst: unimplemented case s_type_expression arrow"
+      | Ast_core.T_variable _ -> failwith "TODO: subst: unimplemented case s_type_expression variable"
+      | Ast_core.T_operator op ->
          let%bind op =
-           Ast_simplified.bind_map_type_operator
-             (s_simpl_type_expression ~substs)
+           Ast_core.bind_map_type_operator
+             (s_abstr_type_expression ~substs)
              op in
          (* TODO: when we have generalized operators, we might need to subst the operator name itself? *)
-         ok @@ Ast_simplified.T_operator op
-      | Ast_simplified.T_constant constant ->
-         ok @@ Ast_simplified.T_constant constant
+         ok @@ Ast_core.T_operator op
+      | Ast_core.T_constant constant ->
+         ok @@ Ast_core.T_constant constant
 
-    and s_simpl_type_expression : Ast_simplified.type_expression w = fun ~substs {type_content;type_meta} ->
-      let%bind type_content = s_simpl_type_content ~substs type_content in
-      ok @@ Ast_simplified.{type_content;type_meta}
+    and s_abstr_type_expression : Ast_core.type_expression w = fun ~substs {type_content;type_meta} ->
+      let%bind type_content = s_abstr_type_content ~substs type_content in
+      ok @@ Ast_core.{type_content;type_meta}
 
     and s_type_expression : T.type_expression w = fun ~substs { type_content; type_meta } ->
       let%bind type_content = s_type_content ~substs type_content in
-      let%bind type_meta = bind_map_option (s_simpl_type_expression ~substs) type_meta in
+      let%bind type_meta = bind_map_option (s_abstr_type_expression ~substs) type_meta in
       ok @@ T.{ type_content; type_meta}
     and s_literal : T.literal w = fun ~substs -> function
       | T.Literal_unit ->
@@ -151,10 +151,10 @@ module Substitution = struct
       | T.E_variable        tv ->
         let%bind tv = s_variable ~substs tv in
         ok @@ T.E_variable tv
-      | T.E_application {expr1;expr2} ->
-        let%bind expr1 = s_expression ~substs expr1 in
-        let%bind expr2 = s_expression ~substs expr2 in
-        ok @@ T.E_application {expr1;expr2}
+      | T.E_application {lamb;args} ->
+        let%bind lamb = s_expression ~substs lamb in
+        let%bind args = s_expression ~substs args in
+        ok @@ T.E_application {lamb;args}
       | T.E_lambda          { binder; result } ->
         let%bind binder = s_variable ~substs binder in
         let%bind result = s_expression ~substs result in
diff --git a/src/test/coase_tests.ml b/src/test/coase_tests.ml
index 5df29091f..dcf82891a 100644
--- a/src/test/coase_tests.ml
+++ b/src/test/coase_tests.ml
@@ -4,8 +4,7 @@ open Trace
 open Test_helpers
 
 let type_file f =
-  let%bind simplified  = Ligo.Compile.Of_source.compile f (Syntax_name "pascaligo") in
-  let%bind typed,state = Ligo.Compile.Of_simplified.compile (Contract "main") simplified in
+  let%bind typed,state = Ligo.Compile.Utils.type_file f "pascaligo" (Contract "main") in
   ok @@ (typed,state)
 
 let get_program =
@@ -20,16 +19,15 @@ let get_program =
       )
 
 let compile_main () = 
-  let%bind simplified      = Ligo.Compile.Of_source.compile "./contracts/coase.ligo" (Syntax_name "pascaligo") in
-  let%bind typed_prg,_     = Ligo.Compile.Of_simplified.compile (Contract "main") simplified in
-  let%bind mini_c_prg      = Ligo.Compile.Of_typed.compile typed_prg in
-  let%bind michelson_prg   = Ligo.Compile.Of_mini_c.aggregate_and_compile_contract mini_c_prg "main" in
+  let%bind typed_prg      = get_program () in
+  let%bind mini_c_prg     = Ligo.Compile.Of_typed.compile typed_prg in
+  let%bind michelson_prg  = Ligo.Compile.Of_mini_c.aggregate_and_compile_contract mini_c_prg "main" in
   let%bind (_contract: Tezos_utils.Michelson.michelson) =
     (* fails if the given entry point is not a valid contract *)
     Ligo.Compile.Of_michelson.build_contract michelson_prg in
   ok ()
 
-open Ast_simplified
+open Ast_imperative
 
 let card owner =
   e_record_ez [
@@ -222,15 +220,16 @@ let sell () =
       let storage = basic 100 1000 cards (2 * n) in
       e_pair sell_action storage
     in
-    let make_expecter : int -> expression -> unit result = fun n result ->
-      let%bind (ops , storage) = get_e_pair result.expression_content in
+    let make_expecter : int -> Ast_core.expression -> unit result = fun n result ->
+      let%bind (ops , storage) = Ast_core.get_e_pair result.expression_content in
       let%bind () =
-        let%bind lst = get_e_list ops.expression_content in
+        let%bind lst = Ast_core.get_e_list ops.expression_content in
         Assert.assert_list_size lst 1 in
       let expected_storage =
         let cards = List.hds @@ cards_ez first_owner n in
         basic 99 1000 cards (2 * n) in
-      Ast_simplified.Misc.assert_value_eq (expected_storage , storage)
+      let%bind expected_storage = Test_helpers.expression_to_core expected_storage in
+      Ast_core.Misc.assert_value_eq (expected_storage , storage)
     in
     let%bind () =
       let amount = Memory_proto_alpha.Protocol.Alpha_context.Tez.zero in
diff --git a/src/test/hash_lock_tests.ml b/src/test/hash_lock_tests.ml
index 7a6db1ea8..e33364cda 100644
--- a/src/test/hash_lock_tests.ml
+++ b/src/test/hash_lock_tests.ml
@@ -1,10 +1,9 @@
 open Trace
 open Test_helpers
-open Ast_simplified
+open Ast_imperative
 
 let type_file f =
-  let%bind simplified  = Ligo.Compile.Of_source.compile f (Syntax_name "cameligo") in
-  let%bind typed,state = Ligo.Compile.Of_simplified.compile (Contract "main") simplified in
+  let%bind typed,state = Ligo.Compile.Utils.type_file f "cameligo" (Contract "main") in
   ok @@ (typed,state)
 
 let get_program =
@@ -18,10 +17,9 @@ let get_program =
       )
 
 let compile_main () =
-  let%bind simplified      = Ligo.Compile.Of_source.compile "./contracts/hashlock.mligo" (Syntax_name "cameligo") in
-  let%bind typed_prg,_ = Ligo.Compile.Of_simplified.compile (Contract "main") simplified in
-  let%bind mini_c_prg      = Ligo.Compile.Of_typed.compile typed_prg in
-  let%bind michelson_prg   = Ligo.Compile.Of_mini_c.aggregate_and_compile_contract mini_c_prg "main" in
+  let%bind typed_prg,_   = get_program () in
+  let%bind mini_c_prg    = Ligo.Compile.Of_typed.compile typed_prg in
+  let%bind michelson_prg = Ligo.Compile.Of_mini_c.aggregate_and_compile_contract mini_c_prg "main" in
   let%bind (_contract: Tezos_utils.Michelson.michelson) =
     (* fails if the given entry point is not a valid contract *)
     Ligo.Compile.Of_michelson.build_contract michelson_prg in
diff --git a/src/test/id_tests.ml b/src/test/id_tests.ml
index 294cd08ff..4d7a88a6d 100644
--- a/src/test/id_tests.ml
+++ b/src/test/id_tests.ml
@@ -1,11 +1,10 @@
 open Trace
 open Test_helpers
-open Ast_simplified
+open Ast_imperative
 
 
 let mtype_file f =
-  let%bind simplified  = Ligo.Compile.Of_source.compile f (Syntax_name "cameligo") in
-  let%bind typed,state = Ligo.Compile.Of_simplified.compile (Contract "main") simplified in
+  let%bind typed,state = Ligo.Compile.Utils.type_file f "cameligo" (Contract "main") in
   ok (typed,state)
 
 let get_program =
@@ -19,8 +18,7 @@ let get_program =
       )
 
 let compile_main () =
-  let%bind simplified      = Ligo.Compile.Of_source.compile "./contracts/id.mligo" (Syntax_name "cameligo") in
-  let%bind typed_prg,_ = Ligo.Compile.Of_simplified.compile (Contract "main") simplified in
+  let%bind typed_prg,_     = get_program () in
   let%bind mini_c_prg      = Ligo.Compile.Of_typed.compile typed_prg in
   let%bind michelson_prg   = Ligo.Compile.Of_mini_c.aggregate_and_compile_contract mini_c_prg "main" in
   let%bind (_contract: Tezos_utils.Michelson.michelson) =
diff --git a/src/test/integration_tests.ml b/src/test/integration_tests.ml
index 9c17f2479..2b9bc2ed8 100644
--- a/src/test/integration_tests.ml
+++ b/src/test/integration_tests.ml
@@ -1,22 +1,18 @@
 open Trace
 open Test_helpers
 
-open Ast_simplified.Combinators
+open Ast_imperative.Combinators
 
 let retype_file f =
-  let%bind simplified  = Ligo.Compile.Of_source.compile f (Syntax_name "reasonligo") in
-  let%bind typed,state = Ligo.Compile.Of_simplified.compile Env simplified in
-  let () = Typer.Solver.discard_state state in
+  let%bind typed,state = Ligo.Compile.Utils.type_file f "reasonligo" Env in
   let () = Typer.Solver.discard_state state in
   ok typed
 let mtype_file f =
-  let%bind simplified  = Ligo.Compile.Of_source.compile f (Syntax_name "cameligo") in
-  let%bind typed,state = Ligo.Compile.Of_simplified.compile Env simplified in
+  let%bind typed,state = Ligo.Compile.Utils.type_file f "cameligo" Env in
   let () = Typer.Solver.discard_state state in
   ok typed
 let type_file f =
-  let%bind simplified  = Ligo.Compile.Of_source.compile f (Syntax_name "pascaligo") in
-  let%bind typed,state = Ligo.Compile.Of_simplified.compile Env simplified in
+  let%bind typed,state = Ligo.Compile.Utils.type_file f "pascaligo" Env in
   let () = Typer.Solver.discard_state state in
   ok typed
 
@@ -428,52 +424,52 @@ let bytes_arithmetic () : unit result =
   let%bind () = expect_eq program "slice_op" tata at in
   let%bind () = expect_fail program "slice_op" foo in
   let%bind () = expect_fail program "slice_op" ba in
-  let%bind b1 = Test_helpers.run_typed_program_with_simplified_input program "hasherman" foo in
-  let%bind () = expect_eq program "hasherman" foo b1 in
-  let%bind b3 = Test_helpers.run_typed_program_with_simplified_input program "hasherman" foototo in
-  let%bind () = Assert.assert_fail @@ Ast_simplified.Misc.assert_value_eq (b3 , b1) in
+  let%bind b1 = Test_helpers.run_typed_program_with_imperative_input program "hasherman" foo in
+  let%bind () = expect_eq_core program "hasherman" foo b1 in
+  let%bind b3 = Test_helpers.run_typed_program_with_imperative_input program "hasherman" foototo in
+  let%bind () = Assert.assert_fail @@ Ast_core.Misc.assert_value_eq (b3 , b1) in
   ok ()
 
 let crypto () : unit result =
   let%bind program = type_file "./contracts/crypto.ligo" in
   let%bind foo = e_bytes_hex "0f00" in
   let%bind foototo = e_bytes_hex "0f007070" in
-  let%bind b1 = Test_helpers.run_typed_program_with_simplified_input program "hasherman512" foo in
-  let%bind () = expect_eq program "hasherman512" foo b1 in
-  let%bind b2 = Test_helpers.run_typed_program_with_simplified_input program "hasherman512" foototo in
-  let%bind () = Assert.assert_fail @@ Ast_simplified.Misc.assert_value_eq (b2 , b1) in
-  let%bind b4 = Test_helpers.run_typed_program_with_simplified_input program "hasherman_blake" foo in
-  let%bind () = expect_eq program "hasherman_blake" foo b4 in
-  let%bind b5 = Test_helpers.run_typed_program_with_simplified_input program "hasherman_blake" foototo in
-  let%bind () = Assert.assert_fail @@ Ast_simplified.Misc.assert_value_eq (b5 , b4) in
+  let%bind b1 = Test_helpers.run_typed_program_with_imperative_input program "hasherman512" foo in
+  let%bind () = expect_eq_core program "hasherman512" foo b1 in
+  let%bind b2 = Test_helpers.run_typed_program_with_imperative_input program "hasherman512" foototo in
+  let%bind () = Assert.assert_fail @@ Ast_core.Misc.assert_value_eq (b2 , b1) in
+  let%bind b4 = Test_helpers.run_typed_program_with_imperative_input program "hasherman_blake" foo in
+  let%bind () = expect_eq_core program "hasherman_blake" foo b4 in
+  let%bind b5 = Test_helpers.run_typed_program_with_imperative_input program "hasherman_blake" foototo in
+  let%bind () = Assert.assert_fail @@ Ast_core.Misc.assert_value_eq (b5 , b4) in
   ok ()
 
 let crypto_mligo () : unit result =
   let%bind program = mtype_file "./contracts/crypto.mligo" in
   let%bind foo = e_bytes_hex "0f00" in
   let%bind foototo = e_bytes_hex "0f007070" in
-  let%bind b1 = Test_helpers.run_typed_program_with_simplified_input program "hasherman512" foo in
-  let%bind () = expect_eq program "hasherman512" foo b1 in
-  let%bind b2 = Test_helpers.run_typed_program_with_simplified_input program "hasherman512" foototo in
-  let%bind () = Assert.assert_fail @@ Ast_simplified.Misc.assert_value_eq (b2 , b1) in
-  let%bind b4 = Test_helpers.run_typed_program_with_simplified_input program "hasherman_blake" foo in
-  let%bind () = expect_eq program "hasherman_blake" foo b4 in
-  let%bind b5 = Test_helpers.run_typed_program_with_simplified_input program "hasherman_blake" foototo in
-  let%bind () = Assert.assert_fail @@ Ast_simplified.Misc.assert_value_eq (b5 , b4) in
+  let%bind b1 = Test_helpers.run_typed_program_with_imperative_input program "hasherman512" foo in
+  let%bind () = expect_eq_core program "hasherman512" foo b1 in
+  let%bind b2 = Test_helpers.run_typed_program_with_imperative_input program "hasherman512" foototo in
+  let%bind () = Assert.assert_fail @@ Ast_core.Misc.assert_value_eq (b2 , b1) in
+  let%bind b4 = Test_helpers.run_typed_program_with_imperative_input program "hasherman_blake" foo in
+  let%bind () = expect_eq_core program "hasherman_blake" foo b4 in
+  let%bind b5 = Test_helpers.run_typed_program_with_imperative_input program "hasherman_blake" foototo in
+  let%bind () = Assert.assert_fail @@ Ast_core.Misc.assert_value_eq (b5 , b4) in
   ok ()
 
 let crypto_religo () : unit result =
   let%bind program = retype_file "./contracts/crypto.religo" in
   let%bind foo = e_bytes_hex "0f00" in
   let%bind foototo = e_bytes_hex "0f007070" in
-  let%bind b1 = Test_helpers.run_typed_program_with_simplified_input program "hasherman512" foo in
-  let%bind () = expect_eq program "hasherman512" foo b1 in
-  let%bind b2 = Test_helpers.run_typed_program_with_simplified_input program "hasherman512" foototo in
-  let%bind () = Assert.assert_fail @@ Ast_simplified.Misc.assert_value_eq (b2 , b1) in
-  let%bind b4 = Test_helpers.run_typed_program_with_simplified_input program "hasherman_blake" foo in
-  let%bind () = expect_eq program "hasherman_blake" foo b4 in
-  let%bind b5 = Test_helpers.run_typed_program_with_simplified_input program "hasherman_blake" foototo in
-  let%bind () = Assert.assert_fail @@ Ast_simplified.Misc.assert_value_eq (b5 , b4) in
+  let%bind b1 = Test_helpers.run_typed_program_with_imperative_input program "hasherman512" foo in
+  let%bind () = expect_eq_core program "hasherman512" foo b1 in
+  let%bind b2 = Test_helpers.run_typed_program_with_imperative_input program "hasherman512" foototo in
+  let%bind () = Assert.assert_fail @@ Ast_core.Misc.assert_value_eq (b2 , b1) in
+  let%bind b4 = Test_helpers.run_typed_program_with_imperative_input program "hasherman_blake" foo in
+  let%bind () = expect_eq_core program "hasherman_blake" foo b4 in
+  let%bind b5 = Test_helpers.run_typed_program_with_imperative_input program "hasherman_blake" foototo in
+  let%bind () = Assert.assert_fail @@ Ast_core.Misc.assert_value_eq (b5 , b4) in
   ok ()
 
 let bytes_arithmetic_mligo () : unit result =
@@ -490,10 +486,10 @@ let bytes_arithmetic_mligo () : unit result =
   let%bind () = expect_eq program "slice_op" tata at in
   let%bind () = expect_fail program "slice_op" foo in
   let%bind () = expect_fail program "slice_op" ba in
-  let%bind b1 = Test_helpers.run_typed_program_with_simplified_input program "hasherman" foo in
-  let%bind () = expect_eq program "hasherman" foo b1 in
-  let%bind b3 = Test_helpers.run_typed_program_with_simplified_input program "hasherman" foototo in
-  let%bind () = Assert.assert_fail @@ Ast_simplified.Misc.assert_value_eq (b3 , b1) in
+  let%bind b1 = Test_helpers.run_typed_program_with_imperative_input program "hasherman" foo in
+  let%bind () = expect_eq_core program "hasherman" foo b1 in
+  let%bind b3 = Test_helpers.run_typed_program_with_imperative_input program "hasherman" foototo in
+  let%bind () = Assert.assert_fail @@ Ast_core.Misc.assert_value_eq (b3 , b1) in
   ok ()
 
 let bytes_arithmetic_religo () : unit result =
@@ -510,10 +506,10 @@ let bytes_arithmetic_religo () : unit result =
   let%bind () = expect_eq program "slice_op" tata at in
   let%bind () = expect_fail program "slice_op" foo in
   let%bind () = expect_fail program "slice_op" ba in
-  let%bind b1 = Test_helpers.run_typed_program_with_simplified_input program"hasherman" foo in
-  let%bind () = expect_eq program "hasherman" foo b1 in
-  let%bind b3 = Test_helpers.run_typed_program_with_simplified_input program "hasherman" foototo in
-  let%bind () = Assert.assert_fail @@ Ast_simplified.Misc.assert_value_eq (b3 , b1) in
+  let%bind b1 = Test_helpers.run_typed_program_with_imperative_input program"hasherman" foo in
+  let%bind () = expect_eq_core program "hasherman" foo b1 in
+  let%bind b3 = Test_helpers.run_typed_program_with_imperative_input program "hasherman" foototo in
+  let%bind () = Assert.assert_fail @@ Ast_core.Misc.assert_value_eq (b3 , b1) in
   ok ()
 
 let set_arithmetic () : unit result =
@@ -978,7 +974,6 @@ let reoption () : unit result =
 let map_ type_f path : unit result =
   let%bind program = type_f path in
   let ez lst =
-    let open Ast_simplified.Combinators in
     let lst' = List.map (fun (x, y) -> e_int x, e_int y) lst in
     e_typed_map lst' t_int t_int
   in
@@ -1067,7 +1062,6 @@ let map_ type_f path : unit result =
 let big_map_ type_f path : unit result =
   let%bind program = type_f path in
   let ez lst =
-    let open Ast_simplified.Combinators in
     let lst' = List.map (fun (x, y) -> e_int x, e_int y) lst in
     (e_typed_big_map lst' t_int t_int)
   in
@@ -1280,7 +1274,6 @@ let loop () : unit result =
     expect_eq program "inner_capture_in_conditional_block"  input expected in
   let%bind () =
     let ez lst =
-      let open Ast_simplified.Combinators in
       let lst' = List.map (fun (x, y) -> e_string x, e_int y) lst in
         e_typed_map lst' t_string t_int
     in
@@ -2035,13 +2028,13 @@ let get_contract_ligo () : unit result =
   let%bind program = type_file "./contracts/get_contract.ligo" in
   let%bind () =
     let make_input = fun _n -> e_unit () in
-    let make_expected : int -> Ast_simplified.expression -> unit result = fun _n result ->
-      let%bind (ops , storage) = get_e_pair result.expression_content in
+    let make_expected : int -> Ast_core.expression -> unit result = fun _n result ->
+      let%bind (ops , storage) = Ast_core.get_e_pair result.expression_content in
       let%bind () =
-        let%bind lst = get_e_list ops.expression_content in
+        let%bind lst = Ast_core.get_e_list ops.expression_content in
         Assert.assert_list_size lst 1 in
-      let expected_storage = e_unit () in
-      Ast_simplified.Misc.assert_value_eq (expected_storage , storage)
+      let expected_storage = Ast_core.e_unit () in
+      Ast_core.Misc.assert_value_eq (expected_storage , storage)
       in
     let%bind () =
       let amount = Memory_proto_alpha.Protocol.Alpha_context.Tez.zero in
diff --git a/src/test/md_file_tests.ml b/src/test/md_file_tests.ml
index 14748f9c8..6114e9126 100644
--- a/src/test/md_file_tests.ml
+++ b/src/test/md_file_tests.ml
@@ -68,8 +68,10 @@ let compile_groups _filename grp_list =
     (fun ((s,grp),contents) ->
       trace (failed_to_compile_md_file _filename (s,grp,contents)) @@
       let%bind v_syntax   = Compile.Helpers.syntax_to_variant (Syntax_name s) None in
-      let%bind simplified = Compile.Of_source.compile_string contents v_syntax in
-      let%bind typed,_    = Compile.Of_simplified.compile Env simplified in
+      let%bind imperative = Compile.Of_source.compile_string contents v_syntax in
+      let%bind sugar      = Ligo.Compile.Of_imperative.compile imperative in
+      let%bind core       = Ligo.Compile.Of_sugar.compile sugar in
+      let%bind typed,_    = Compile.Of_core.compile Env core in
       let%bind mini_c     = Compile.Of_typed.compile typed in
       bind_map_list
         (fun ((_, _, exp),_) -> Compile.Of_mini_c.aggregate_and_compile_expression mini_c exp)
diff --git a/src/test/multisig_tests.ml b/src/test/multisig_tests.ml
index 704171e01..948704894 100644
--- a/src/test/multisig_tests.ml
+++ b/src/test/multisig_tests.ml
@@ -6,8 +6,7 @@ let mfile = "./contracts/multisig.mligo"
 let refile = "./contracts/multisig.religo"
 
 let type_file f s =
-  let%bind simplified  = Ligo.Compile.Of_source.compile f (Syntax_name s) in
-  let%bind typed,state = Ligo.Compile.Of_simplified.compile (Contract "main") simplified in
+  let%bind typed,state = Ligo.Compile.Utils.type_file f s (Contract "main") in
   ok @@ (typed,state)
 
 let get_program f st =
@@ -29,7 +28,7 @@ let compile_main f s () =
     Ligo.Compile.Of_michelson.build_contract michelson_prg in
   ok ()
 
-open Ast_simplified
+open Ast_imperative
 
 let init_storage threshold counter pkeys =
   let keys = List.map
@@ -175,12 +174,12 @@ let main = test_suite "Multisig" [
     test "valid_2_of_3 (mligo)"          (valid_2_of_3       mfile "cameligo");
     test "invalid_3_of_3 (mligo)"        (invalid_3_of_3     mfile "cameligo");
     test "not_enough_2_of_3 (mligo)"     (not_enough_2_of_3  mfile "cameligo");
-    test "compile (religo)"              (compile_main refile "reasonligo");
+    test "compile (religo)"              (compile_main       refile "reasonligo");
     test "unmatching_counter (religo)"   (unmatching_counter refile "reasonligo");
-    test "valid_1_of_1 (religo)"         (valid_1_of_1 refile "reasonligo");
-    test "invalid_1_of_1 (religo)"       (invalid_1_of_1 refile "reasonligo");
-    test "not_enough_signature (religo)" (not_enough_1_of_2 refile "reasonligo");
-    test "valid_2_of_3 (religo)"         (valid_2_of_3 refile "reasonligo");
-    test "invalid_3_of_3 (religo)"       (invalid_3_of_3 refile "reasonligo");
-    test "not_enough_2_of_3 (religo)"    (not_enough_2_of_3 refile "reasonligo");
+    test "valid_1_of_1 (religo)"         (valid_1_of_1       refile "reasonligo");
+    test "invalid_1_of_1 (religo)"       (invalid_1_of_1     refile "reasonligo");
+    test "not_enough_signature (religo)" (not_enough_1_of_2  refile "reasonligo");
+    test "valid_2_of_3 (religo)"         (valid_2_of_3       refile "reasonligo");
+    test "invalid_3_of_3 (religo)"       (invalid_3_of_3     refile "reasonligo");
+    test "not_enough_2_of_3 (religo)"    (not_enough_2_of_3  refile "reasonligo");
   ]
diff --git a/src/test/multisig_v2_tests.ml b/src/test/multisig_v2_tests.ml
index 391be83d2..8b2b8972b 100644
--- a/src/test/multisig_v2_tests.ml
+++ b/src/test/multisig_v2_tests.ml
@@ -2,8 +2,7 @@ open Trace
 open Test_helpers
 
 let type_file f = 
-  let%bind simplified  = Ligo.Compile.Of_source.compile f (Syntax_name "pascaligo") in
-  let%bind typed,state = Ligo.Compile.Of_simplified.compile (Contract "main") simplified in
+  let%bind typed,state = Ligo.Compile.Utils.type_file f "pascaligo" (Contract "main") in
   ok @@ (typed,state)
 
 let get_program =
@@ -17,16 +16,15 @@ let get_program =
       )
 
 let compile_main () = 
-  let%bind simplified      = Ligo.Compile.Of_source.compile "./contracts/multisig-v2.ligo" (Syntax_name "pascaligo") in
-  let%bind typed_prg,_ = Ligo.Compile.Of_simplified.compile (Contract "main") simplified in
-  let%bind mini_c_prg      = Ligo.Compile.Of_typed.compile typed_prg in
-  let%bind michelson_prg   = Ligo.Compile.Of_mini_c.aggregate_and_compile_contract mini_c_prg "main" in
+  let%bind typed_prg,_   = get_program () in 
+  let%bind mini_c_prg    = Ligo.Compile.Of_typed.compile typed_prg in
+  let%bind michelson_prg = Ligo.Compile.Of_mini_c.aggregate_and_compile_contract mini_c_prg "main" in
   let%bind (_contract: Tezos_utils.Michelson.michelson) =
     (* fails if the given entry point is not a valid contract *)
     Ligo.Compile.Of_michelson.build_contract michelson_prg in
   ok ()
 
-open Ast_simplified
+open Ast_imperative
 
 let empty_op_list = 
   (e_typed_list [] t_operation)
diff --git a/src/test/pledge_tests.ml b/src/test/pledge_tests.ml
index d6af4f369..4f6df8a01 100644
--- a/src/test/pledge_tests.ml
+++ b/src/test/pledge_tests.ml
@@ -1,11 +1,9 @@
 open Trace
 open Test_helpers
-open Ast_simplified
-
+open Ast_imperative
 
 let retype_file f =
-  let%bind simplified  = Ligo.Compile.Of_source.compile f (Syntax_name "reasonligo") in
-  let%bind typed,state = Ligo.Compile.Of_simplified.compile Env simplified in
+  let%bind typed,state = Ligo.Compile.Utils.type_file f "reasonligo" Env in
   ok (typed,state)
 
 let get_program =
@@ -19,10 +17,9 @@ let get_program =
       )
 
 let compile_main () =
-  let%bind simplified      = Ligo.Compile.Of_source.compile "./contracts/pledge.religo" (Syntax_name "reasonligo") in
-  let%bind typed_prg,_ = Ligo.Compile.Of_simplified.compile Env simplified in
-  let%bind mini_c_prg      = Ligo.Compile.Of_typed.compile typed_prg in
-  let%bind michelson_prg   = Ligo.Compile.Of_mini_c.aggregate_and_compile_contract mini_c_prg "main" in
+  let%bind typed_prg,_    = get_program () in
+  let%bind mini_c_prg     = Ligo.Compile.Of_typed.compile typed_prg in
+  let%bind michelson_prg  = Ligo.Compile.Of_mini_c.aggregate_and_compile_contract mini_c_prg "main" in
   let%bind (_contract: Tezos_utils.Michelson.michelson) =
     (* fails if the given entry point is not a valid contract *)
     Ligo.Compile.Of_michelson.build_contract michelson_prg in
diff --git a/src/test/replaceable_id_tests.ml b/src/test/replaceable_id_tests.ml
index 60bcb203e..1c634c611 100644
--- a/src/test/replaceable_id_tests.ml
+++ b/src/test/replaceable_id_tests.ml
@@ -2,8 +2,7 @@ open Trace
 open Test_helpers
 
 let type_file f = 
-  let%bind simplified  = Ligo.Compile.Of_source.compile f (Syntax_name "pascaligo") in
-  let%bind typed,state = Ligo.Compile.Of_simplified.compile (Contract "main") simplified in
+  let%bind typed,state = Ligo.Compile.Utils.type_file f "pascaligo" (Contract "main") in
   ok @@ (typed,state)
 
 let get_program =
@@ -17,15 +16,15 @@ let get_program =
       )
 
 let compile_main () = 
-  let%bind simplified      = Ligo.Compile.Of_source.compile "./contracts/replaceable_id.ligo" (Syntax_name "pascaligo") in
-  let%bind typed_prg,_ = Ligo.Compile.Of_simplified.compile (Contract "main") simplified in
+  let%bind typed_prg,_     = get_program () in 
   let%bind mini_c_prg      = Ligo.Compile.Of_typed.compile typed_prg in
   let%bind michelson_prg   = Ligo.Compile.Of_mini_c.aggregate_and_compile_contract mini_c_prg "main" in
   let%bind (_contract: Tezos_utils.Michelson.michelson) =
     (* fails if the given entry point is not a valid contract *)
     Ligo.Compile.Of_michelson.build_contract michelson_prg in
   ok ()
-open Ast_simplified
+
+open Ast_imperative
 
 let empty_op_list = 
   (e_typed_list [] t_operation)
diff --git a/src/test/test_helpers.ml b/src/test/test_helpers.ml
index f7ca0f320..ded88c33b 100644
--- a/src/test/test_helpers.ml
+++ b/src/test/test_helpers.ml
@@ -29,15 +29,21 @@ let test name f =
 
 let test_suite name lst = Test_suite (name , lst)
 
+let expression_to_core expression =
+  let%bind sugar = Compile.Of_imperative.compile_expression expression in
+  let%bind core  = Compile.Of_sugar.compile_expression sugar in
+  ok @@ core
 
-open Ast_simplified
+open Ast_imperative
 
 let pack_payload (program:Ast_typed.program) (payload:expression) : bytes result =
   let%bind code =
     let env = Ast_typed.program_environment program in
 
-    let%bind (typed,_) = Compile.Of_simplified.compile_expression
-        ~env ~state:(Typer.Solver.initial_state) payload in
+    let%bind sugar     = Compile.Of_imperative.compile_expression payload in
+    let%bind core      = Compile.Of_sugar.compile_expression sugar in
+    let%bind (typed,_) = Compile.Of_core.compile_expression
+        ~env ~state:(Typer.Solver.initial_state) core in
     let%bind mini_c = Compile.Of_typed.compile_expression typed in
     Compile.Of_mini_c.compile_expression mini_c in
   let (Ex_ty payload_ty) = code.expr_ty in
@@ -77,27 +83,29 @@ let sha_256_hash pl =
   let open Proto_alpha_utils.Memory_proto_alpha.Alpha_environment in
   Raw_hashes.sha256 pl
 
-open Ast_simplified.Combinators
+open Ast_imperative.Combinators
 
-let typed_program_with_simplified_input_to_michelson
+let typed_program_with_imperative_input_to_michelson
     (program: Ast_typed.program) (entry_point: string)
-    (input: Ast_simplified.expression) : Compiler.compiled_expression result =
+    (input: Ast_imperative.expression) : Compiler.compiled_expression result =
   Printexc.record_backtrace true;
   let env = Ast_typed.program_environment program in
   let state = Typer.Solver.initial_state in
-  let%bind app              = Compile.Of_simplified.apply entry_point input in
-  let%bind (typed_app,_)    = Compile.Of_simplified.compile_expression ~env ~state app in
+  let%bind sugar            = Compile.Of_imperative.compile_expression input in
+  let%bind core             = Compile.Of_sugar.compile_expression sugar in
+  let%bind app              = Compile.Of_core.apply entry_point core in
+  let%bind (typed_app,_)    = Compile.Of_core.compile_expression ~env ~state app in
   let%bind compiled_applied = Compile.Of_typed.compile_expression typed_app in
   let%bind mini_c_prg       = Compile.Of_typed.compile program in
   Compile.Of_mini_c.aggregate_and_compile_expression mini_c_prg compiled_applied
 
-let run_typed_program_with_simplified_input ?options
+let run_typed_program_with_imperative_input ?options
     (program: Ast_typed.program) (entry_point: string)
-    (input: Ast_simplified.expression) : Ast_simplified.expression result =
-  let%bind michelson_program = typed_program_with_simplified_input_to_michelson program entry_point input in
+    (input: Ast_imperative.expression) : Ast_core.expression result =
+  let%bind michelson_program = typed_program_with_imperative_input_to_michelson program entry_point input in
   let%bind michelson_output  = Ligo.Run.Of_michelson.run_no_failwith ?options michelson_program.expr michelson_program.expr_ty in
   Uncompile.uncompile_typed_program_entry_function_result program entry_point michelson_output
-
+ 
 let expect ?options program entry_point input expecter =
   let%bind result =
     let run_error =
@@ -106,7 +114,7 @@ let expect ?options program entry_point input expecter =
       error title content
     in
     trace run_error @@
-    run_typed_program_with_simplified_input ?options program entry_point input in
+    run_typed_program_with_imperative_input ?options program entry_point input in
   expecter result
 
 let expect_fail ?options program entry_point input =
@@ -117,10 +125,10 @@ let expect_fail ?options program entry_point input =
   in
   trace run_error @@
   Assert.assert_fail @@
-  run_typed_program_with_simplified_input ?options program entry_point input
+  run_typed_program_with_imperative_input ?options program entry_point input
 
 let expect_string_failwith ?options program entry_point input expected_failwith =
-  let%bind michelson_program = typed_program_with_simplified_input_to_michelson program entry_point input in
+  let%bind michelson_program = typed_program_with_imperative_input_to_michelson program entry_point input in
   let%bind err = Ligo.Run.Of_michelson.run_failwith
     ?options michelson_program.expr michelson_program.expr_ty in
   match err with
@@ -128,15 +136,28 @@ let expect_string_failwith ?options program entry_point input expected_failwith
     | _ -> simple_fail "Expected to fail with a string"
 
 let expect_eq ?options program entry_point input expected =
+  let%bind expected = expression_to_core expected in
   let expecter = fun result ->
     let expect_error =
       let title () = "expect result" in
       let content () = Format.asprintf "Expected %a, got %a"
-          Ast_simplified.PP.expression expected
-          Ast_simplified.PP.expression result in
+          Ast_core.PP.expression expected
+          Ast_core.PP.expression result in
       error title content in
     trace expect_error @@
-    Ast_simplified.Misc.assert_value_eq (expected , result) in
+    Ast_core.Misc.assert_value_eq (expected,result) in
+  expect ?options program entry_point input expecter
+
+let expect_eq_core ?options program entry_point input expected =
+  let expecter = fun result ->
+    let expect_error =
+      let title () = "expect result" in
+      let content () = Format.asprintf "Expected %a, got %a"
+          Ast_core.PP.expression expected
+          Ast_core.PP.expression result in
+      error title content in
+    trace expect_error @@
+    Ast_core.Misc.assert_value_eq (expected,result) in
   expect ?options program entry_point input expecter
 
 let expect_evaluate program entry_point expecter =
@@ -153,8 +174,9 @@ let expect_evaluate program entry_point expecter =
   expecter res_simpl
 
 let expect_eq_evaluate program entry_point expected =
+  let%bind expected  = expression_to_core expected in
   let expecter = fun result ->
-    Ast_simplified.Misc.assert_value_eq (expected , result) in
+    Ast_core.Misc.assert_value_eq (expected , result) in
   expect_evaluate program entry_point expecter
 
 let expect_n_aux ?options lst program entry_point make_input make_expecter =
@@ -183,7 +205,7 @@ let expect_eq_exp_trace_aux ?options explst program entry_point make_input make_
   let aux exp =
     let%bind input = make_input exp in
     let%bind expected = make_expected exp in
-    let pps = Format.asprintf "%a" Ast_simplified.PP.expression exp in
+    let pps = Format.asprintf "%a" Ast_core.PP.expression exp in
     trace (simple_error ("expect_eq_exp " ^ pps )) @@
     let result = expect_eq ?options program entry_point input expected in
     result
@@ -195,7 +217,7 @@ let expect_failwith_exp_trace_aux ?options explst program entry_point make_input
   let aux exp =
     let%bind input = make_input exp in
     let%bind expected = make_expected_failwith exp in
-    let pps = Format.asprintf "%a" Ast_simplified.PP.expression exp in
+    let pps = Format.asprintf "%a" Ast_core.PP.expression exp in
     trace (simple_error ("expect_eq_exp " ^ pps )) @@
     let result = expect_string_failwith ?options program entry_point input expected in
     result
@@ -237,7 +259,6 @@ let expect_eq_n_int a b c =
   expect_eq_n a b e_int (fun n -> e_int (c n))
 
 let expect_eq_b_bool a b c =
-  let open Ast_simplified.Combinators in
   expect_eq_b a b (fun bool -> e_bool (c bool))
 
 
diff --git a/src/test/time_lock_repeat_tests.ml b/src/test/time_lock_repeat_tests.ml
index b5a3f7427..2720cfb64 100644
--- a/src/test/time_lock_repeat_tests.ml
+++ b/src/test/time_lock_repeat_tests.ml
@@ -1,10 +1,9 @@
 open Trace
 open Test_helpers
-open Ast_simplified
+open Ast_imperative
 
 let type_file f =
-  let%bind simplified  = Ligo.Compile.Of_source.compile f (Syntax_name "cameligo") in
-  let%bind typed,state = Ligo.Compile.Of_simplified.compile (Contract "main") simplified in
+  let%bind typed,state = Ligo.Compile.Utils.type_file f "cameligo" (Contract "main") in
   ok @@ (typed,state)
 
 let get_program =
@@ -18,8 +17,7 @@ let get_program =
       )
 
 let compile_main () =
-  let%bind simplified      = Ligo.Compile.Of_source.compile "./contracts/timelock_repeat.mligo" (Syntax_name "cameligo") in
-  let%bind typed_prg,_ = Ligo.Compile.Of_simplified.compile (Contract "main") simplified in
+  let%bind typed_prg,_     = type_file "./contracts/timelock_repeat.mligo" in
   let%bind mini_c_prg      = Ligo.Compile.Of_typed.compile typed_prg in
   let%bind michelson_prg   = Ligo.Compile.Of_mini_c.aggregate_and_compile_contract mini_c_prg "main" in
   let%bind (_contract: Tezos_utils.Michelson.michelson) =
diff --git a/src/test/time_lock_tests.ml b/src/test/time_lock_tests.ml
index eb3001f49..e22cb1792 100644
--- a/src/test/time_lock_tests.ml
+++ b/src/test/time_lock_tests.ml
@@ -2,8 +2,7 @@ open Trace
 open Test_helpers
 
 let type_file f = 
-  let%bind simplified  = Ligo.Compile.Of_source.compile f (Syntax_name "pascaligo") in
-  let%bind typed,state = Ligo.Compile.Of_simplified.compile (Contract "main") simplified in
+  let%bind typed,state = Ligo.Compile.Utils.type_file f "pascaligo" (Contract "main") in
   ok @@ (typed,state)
 
 let get_program =
@@ -17,8 +16,7 @@ let get_program =
       )
 
 let compile_main () = 
-  let%bind simplified      = Ligo.Compile.Of_source.compile "./contracts/time-lock.ligo" (Syntax_name "pascaligo") in
-  let%bind typed_prg,_ = Ligo.Compile.Of_simplified.compile (Contract "main") simplified in
+  let%bind typed_prg,_     =  type_file "./contracts/time-lock.ligo" in
   let%bind mini_c_prg      = Ligo.Compile.Of_typed.compile typed_prg in
   let%bind michelson_prg   = Ligo.Compile.Of_mini_c.aggregate_and_compile_contract mini_c_prg "main" in
   let%bind (_contract: Tezos_utils.Michelson.michelson) =
@@ -26,7 +24,8 @@ let compile_main () =
     Ligo.Compile.Of_michelson.build_contract michelson_prg in
   ok ()
 
-open Ast_simplified
+open Ast_imperative
+
 let empty_op_list =
   (e_typed_list [] t_operation)
 let empty_message = e_lambda (Var.of_name "arguments")
diff --git a/src/test/typer_tests.ml b/src/test/typer_tests.ml
index df0817ba8..57b06a7b7 100644
--- a/src/test/typer_tests.ml
+++ b/src/test/typer_tests.ml
@@ -1,10 +1,10 @@
 open Trace
-open Ast_simplified
+open Ast_core
 open Test_helpers
 
 module Typed = Ast_typed
 module Typer = Typer
-module Simplified = Ast_simplified
+module Simplified = Ast_core
 
 let int () : unit result =
   let open Combinators in
@@ -72,7 +72,7 @@ end
 (* TODO: deep types (e.g. record of record)
    TODO: negative tests (expected type error) *)
 
-let main = test_suite "Typer (from simplified AST)" [
+let main = test_suite "Typer (from core AST)" [
     test "int" int ;
     test "unit"        TestExpressions.unit ;
     test "int2"        TestExpressions.int ;
diff --git a/src/test/vote_tests.ml b/src/test/vote_tests.ml
index ddc3d620d..9122eff9e 100644
--- a/src/test/vote_tests.ml
+++ b/src/test/vote_tests.ml
@@ -2,8 +2,7 @@ open Trace
 open Test_helpers
 
 let type_file f =
-  let%bind simplified  = Ligo.Compile.Of_source.compile f (Syntax_name "cameligo") in
-  let%bind typed,state = Ligo.Compile.Of_simplified.compile (Contract "main") simplified in
+  let%bind typed,state = Ligo.Compile.Utils.type_file f "cameligo" (Contract "main") in
   ok @@ (typed,state)
 
 let get_program =
@@ -16,7 +15,7 @@ let get_program =
         ok (program , state)
       )
 
-open Ast_simplified
+open Ast_imperative
 
 let init_storage name = e_record_ez [
     ("title" , e_string name) ;
@@ -39,14 +38,14 @@ let yea = e_constructor "Vote" (e_constructor "Yea" (e_unit ()))
 let init_vote () =
   let%bind (program , _) = get_program () in
   let%bind result =
-    Test_helpers.run_typed_program_with_simplified_input
+    Test_helpers.run_typed_program_with_imperative_input
       program "main" (e_pair yea (init_storage "basic")) in
-  let%bind (_, storage) = extract_pair result in
-  let%bind storage' = extract_record storage in
+  let%bind (_, storage) = Ast_core.extract_pair result in
+  let%bind storage' = Ast_core.extract_record storage in
 (*  let votes = List.assoc (Label "voters") storage' in
   let%bind votes' = extract_map votes in *)
   let yea = List.assoc (Label "yea") storage' in
-  let%bind () = Ast_simplified.Misc.assert_value_eq (yea, e_nat 1) in
+  let%bind () = Ast_core.Misc.assert_value_eq (yea, Ast_core.e_nat 1) in
   ok ()
 
 let main = test_suite "Vote" [