From 1401d03d62a927b7714c12cd1a1b39339610f584 Mon Sep 17 00:00:00 2001
From: Lesenechal Remi <lesenechal.remi@gmail.com>
Date: Mon, 7 Oct 2019 11:53:07 +0200
Subject: [PATCH 1/7] Parser patch from Christian

---
 src/passes/1-parser/pascaligo/Parser.mly | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/passes/1-parser/pascaligo/Parser.mly b/src/passes/1-parser/pascaligo/Parser.mly
index a1902bade..f4d25bbe5 100644
--- a/src/passes/1-parser/pascaligo/Parser.mly
+++ b/src/passes/1-parser/pascaligo/Parser.mly
@@ -591,7 +591,11 @@ assignment:
     in {region; value}}
 
 rhs:
-  expr  { Expr $1 }
+  expr {
+    match $1 with
+      EConstr (NoneExpr e) -> (NoneExpr e : rhs)
+    | e -> Expr e
+  }
 
 lhs:
   path       {    Path $1 }

From 08a3e08f5718a543c02b555a7d5e420cda0e49b7 Mon Sep 17 00:00:00 2001
From: Lesenechal Remi <lesenechal.remi@gmail.com>
Date: Mon, 7 Oct 2019 11:54:27 +0200
Subject: [PATCH 2/7] add a new T_constant in ast_simplified and ast_typed

---
 src/passes/2-simplify/pascaligo.ml              | 3 ++-
 src/passes/4-typer/typer.ml                     | 2 ++
 src/passes/6-transpiler/transpiler.ml           | 2 ++
 src/passes/6-transpiler/untranspiler.ml         | 4 +++-
 src/stages/ast_typed/combinators.ml             | 3 ++-
 src/stages/ast_typed/combinators_environment.ml | 2 +-
 src/stages/ast_typed/misc.ml                    | 3 +++
 src/test/contracts/option.ligo                  | 9 +++++++++
 src/test/integration_tests.ml                   | 4 ++++
 9 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/src/passes/2-simplify/pascaligo.ml b/src/passes/2-simplify/pascaligo.ml
index 31e739f36..8fe81f388 100644
--- a/src/passes/2-simplify/pascaligo.ml
+++ b/src/passes/2-simplify/pascaligo.ml
@@ -792,7 +792,8 @@ and simpl_single_instruction : Raw.single_instr -> (_ -> expression result) resu
       let (a , loc) = r_split a in
       let%bind value_expr = match a.rhs with
         | Expr e -> simpl_expression e
-        | NoneExpr reg -> fail @@ unsupported_ass_None reg
+        (* | NoneExpr reg -> fail @@ unsupported_ass_None reg *)
+        | NoneExpr reg -> simpl_expression (Raw.EConstr (Raw.NoneExpr reg)) 
       in
       match a.lhs with
         | Path path -> (
diff --git a/src/passes/4-typer/typer.ml b/src/passes/4-typer/typer.ml
index 391239506..7eba933bf 100644
--- a/src/passes/4-typer/typer.ml
+++ b/src/passes/4-typer/typer.ml
@@ -615,6 +615,8 @@ and type_expression : environment -> ?tv_opt:O.type_value -> I.expression -> O.a
       let output_type = body.type_annotation in
       return (E_lambda {binder = fst binder ; body}) (t_function input_type output_type ())
     )
+  | E_constant ("NONE", []) ->
+    return (E_constant ("NONE", [])) (t_option_none ())
   | E_constant (name, lst) ->
       let%bind lst' = bind_list @@ List.map (type_expression e) lst in
       let tv_lst = List.map get_type_annotation lst' in
diff --git a/src/passes/6-transpiler/transpiler.ml b/src/passes/6-transpiler/transpiler.ml
index 0cef7b26b..acc4bd7e1 100644
--- a/src/passes/6-transpiler/transpiler.ml
+++ b/src/passes/6-transpiler/transpiler.ml
@@ -130,6 +130,8 @@ let rec transpile_type (t:AST.type_value) : type_value result =
   | T_constant ("option", [o]) ->
       let%bind o' = transpile_type o in
       ok (T_option o')
+  | T_constant ("option_none", []) ->
+      ok (T_option (T_base Base_unit))
   | T_constant (name , _lst) -> fail @@ unrecognized_type_constant name
   (* TODO hmm *)
   | T_sum m ->
diff --git a/src/passes/6-transpiler/untranspiler.ml b/src/passes/6-transpiler/untranspiler.ml
index 78c41cca8..08ed0d141 100644
--- a/src/passes/6-transpiler/untranspiler.ml
+++ b/src/passes/6-transpiler/untranspiler.ml
@@ -107,12 +107,14 @@ let rec untranspile (v : value) (t : AST.type_value) : AST.annotated_expression
         get_string v in
       return (E_literal (Literal_address n))
     )
+  | T_constant ("option_none", []) ->
+    ok e_a_empty_none
   | T_constant ("option", [o]) -> (
       let%bind opt =
         trace_strong (wrong_mini_c_value "option" v) @@
         get_option v in
       match opt with
-      | None -> ok (e_a_empty_none o)
+      | None -> ok e_a_empty_none
       | Some s ->
           let%bind s' = untranspile s o in
           ok (e_a_empty_some s')
diff --git a/src/stages/ast_typed/combinators.ml b/src/stages/ast_typed/combinators.ml
index d9dcebb73..5ae376b9d 100644
--- a/src/stages/ast_typed/combinators.ml
+++ b/src/stages/ast_typed/combinators.ml
@@ -25,6 +25,7 @@ let t_tez ?s () : type_value = make_t (T_constant ("tez", [])) s
 let t_timestamp ?s () : type_value = make_t (T_constant ("timestamp", [])) s
 let t_unit ?s () : type_value = make_t (T_constant ("unit", [])) s
 let t_option o ?s () : type_value = make_t (T_constant ("option", [o])) s
+let t_option_none ?s () : type_value = make_t (T_constant ("option_none", [])) s
 let t_tuple lst ?s () : type_value = make_t (T_tuple lst) s
 let t_list t ?s () : type_value = make_t (T_constant ("list", [t])) s
 let t_set t ?s () : type_value = make_t (T_constant ("set", [t])) s
@@ -254,7 +255,7 @@ let e_a_address s = make_a_e (e_address s) (t_address ())
 let e_a_pair a b = make_a_e (e_pair a b) (t_pair a.type_annotation b.type_annotation ())
 let e_a_some s = make_a_e (e_some s) (t_option s.type_annotation ())
 let e_a_lambda l in_ty out_ty = make_a_e (e_lambda l) (t_function in_ty out_ty ())
-let e_a_none t = make_a_e e_none (t_option t ())
+let e_a_none = make_a_e e_none (t_option_none ())
 let e_a_tuple lst = make_a_e (E_tuple lst) (t_tuple (List.map get_type_annotation lst) ())
 let e_a_record r = make_a_e (e_record r) (t_record (SMap.map get_type_annotation r) ())
 let e_a_application a b = make_a_e (e_application a b) (get_type_annotation b)
diff --git a/src/stages/ast_typed/combinators_environment.ml b/src/stages/ast_typed/combinators_environment.ml
index 1446c8780..3cea2fd1d 100644
--- a/src/stages/ast_typed/combinators_environment.ml
+++ b/src/stages/ast_typed/combinators_environment.ml
@@ -12,7 +12,7 @@ let e_a_empty_string s = e_a_string s Environment.full_empty
 let e_a_empty_address s = e_a_address s Environment.full_empty
 let e_a_empty_pair a b = e_a_pair a b Environment.full_empty
 let e_a_empty_some s = e_a_some s Environment.full_empty
-let e_a_empty_none t = e_a_none t Environment.full_empty
+let e_a_empty_none = e_a_none Environment.full_empty
 let e_a_empty_tuple lst = e_a_tuple lst Environment.full_empty
 let e_a_empty_record r = e_a_record r Environment.full_empty
 let e_a_empty_map lst k v = e_a_map lst k v Environment.full_empty
diff --git a/src/stages/ast_typed/misc.ml b/src/stages/ast_typed/misc.ml
index 5ba66b4ea..b7fb63f76 100644
--- a/src/stages/ast_typed/misc.ml
+++ b/src/stages/ast_typed/misc.ml
@@ -296,6 +296,9 @@ let rec assert_type_value_eq (a, b: (type_value * type_value)) : unit result = m
       bind_list_iter assert_type_value_eq (List.combine ta tb)
     )
   | T_tuple _, _ -> fail @@ different_kinds a b
+  | T_constant ("option", _), T_constant ("option_none", []) |
+    T_constant ("option_none", []), T_constant ("option", _) -> 
+    ok ()
   | T_constant (ca, lsta), T_constant (cb, lstb) -> (
       let%bind _ =
         trace_strong (different_size_constants a b)
diff --git a/src/test/contracts/option.ligo b/src/test/contracts/option.ligo
index c2d36439d..9abf2c845 100644
--- a/src/test/contracts/option.ligo
+++ b/src/test/contracts/option.ligo
@@ -4,3 +4,12 @@ type foobar is option(int)
 
 const s : foobar = Some(42)
 const n : foobar = None
+
+function assign (var m : int) : foobar is
+  var coco : foobar := None;
+  block
+{ 
+      coco := Some(m);
+      coco := None;
+}
+with coco
diff --git a/src/test/integration_tests.ml b/src/test/integration_tests.ml
index 16a4c7d69..b558d08dd 100644
--- a/src/test/integration_tests.ml
+++ b/src/test/integration_tests.ml
@@ -368,6 +368,10 @@ let option () : unit result =
     let expected = e_typed_none t_int in
     expect_eq_evaluate program "n" expected
   in
+  let%bind () =
+    let expected = e_typed_none t_int in
+    expect_eq program "assign" (e_int 12) expected
+  in
   ok ()
 
 let moption () : unit result =

From 3a3cfa341ab4405c31666f5047f36a13d31c0762 Mon Sep 17 00:00:00 2001
From: Lesenechal Remi <lesenechal.remi@gmail.com>
Date: Mon, 7 Oct 2019 12:03:19 +0200
Subject: [PATCH 3/7] cleaning

---
 src/passes/2-simplify/pascaligo.ml | 13 +------------
 1 file changed, 1 insertion(+), 12 deletions(-)

diff --git a/src/passes/2-simplify/pascaligo.ml b/src/passes/2-simplify/pascaligo.ml
index 8fe81f388..2e0eee337 100644
--- a/src/passes/2-simplify/pascaligo.ml
+++ b/src/passes/2-simplify/pascaligo.ml
@@ -26,16 +26,6 @@ module Errors = struct
     ] in
     error ~data title message
 
-  let unsupported_ass_None region =
-    let title () = "assignment of None" in
-    let message () =
-      Format.asprintf "assignments of None are not supported yet" in
-    let data = [
-      ("none_expr",
-       fun () -> Format.asprintf "%a" Location.pp_lift @@ region)
-    ] in
-    error ~data title message
-
   let bad_bytes loc str =
     let title () = "bad bytes string" in
     let message () =
@@ -792,8 +782,7 @@ and simpl_single_instruction : Raw.single_instr -> (_ -> expression result) resu
       let (a , loc) = r_split a in
       let%bind value_expr = match a.rhs with
         | Expr e -> simpl_expression e
-        (* | NoneExpr reg -> fail @@ unsupported_ass_None reg *)
-        | NoneExpr reg -> simpl_expression (Raw.EConstr (Raw.NoneExpr reg)) 
+        | NoneExpr reg -> simpl_expression (EConstr (NoneExpr reg)) 
       in
       match a.lhs with
         | Path path -> (

From 3a14ef26ef3092e70356f70a9386e4bda897ff40 Mon Sep 17 00:00:00 2001
From: Tom Jack <tom@tomjack.co>
Date: Mon, 7 Oct 2019 08:11:46 -0500
Subject: [PATCH 4/7] Simplify?

---
 src/passes/1-parser/pascaligo/Parser.mly        | 6 +-----
 src/passes/2-simplify/pascaligo.ml              | 2 +-
 src/passes/4-typer/typer.ml                     | 8 ++++++--
 src/passes/6-transpiler/transpiler.ml           | 2 --
 src/passes/6-transpiler/untranspiler.ml         | 4 +---
 src/stages/ast_typed/combinators.ml             | 3 +--
 src/stages/ast_typed/combinators_environment.ml | 2 +-
 src/stages/ast_typed/misc.ml                    | 3 ---
 src/test/contracts/option.ligo                  | 2 +-
 9 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/passes/1-parser/pascaligo/Parser.mly b/src/passes/1-parser/pascaligo/Parser.mly
index f4d25bbe5..a1902bade 100644
--- a/src/passes/1-parser/pascaligo/Parser.mly
+++ b/src/passes/1-parser/pascaligo/Parser.mly
@@ -591,11 +591,7 @@ assignment:
     in {region; value}}
 
 rhs:
-  expr {
-    match $1 with
-      EConstr (NoneExpr e) -> (NoneExpr e : rhs)
-    | e -> Expr e
-  }
+  expr  { Expr $1 }
 
 lhs:
   path       {    Path $1 }
diff --git a/src/passes/2-simplify/pascaligo.ml b/src/passes/2-simplify/pascaligo.ml
index 2e0eee337..ddb3d7bd8 100644
--- a/src/passes/2-simplify/pascaligo.ml
+++ b/src/passes/2-simplify/pascaligo.ml
@@ -782,7 +782,7 @@ and simpl_single_instruction : Raw.single_instr -> (_ -> expression result) resu
       let (a , loc) = r_split a in
       let%bind value_expr = match a.rhs with
         | Expr e -> simpl_expression e
-        | NoneExpr reg -> simpl_expression (EConstr (NoneExpr reg)) 
+        | NoneExpr reg -> simpl_expression (EConstr (NoneExpr reg))
       in
       match a.lhs with
         | Path path -> (
diff --git a/src/passes/4-typer/typer.ml b/src/passes/4-typer/typer.ml
index 7eba933bf..7acbf5138 100644
--- a/src/passes/4-typer/typer.ml
+++ b/src/passes/4-typer/typer.ml
@@ -616,7 +616,11 @@ and type_expression : environment -> ?tv_opt:O.type_value -> I.expression -> O.a
       return (E_lambda {binder = fst binder ; body}) (t_function input_type output_type ())
     )
   | E_constant ("NONE", []) ->
-    return (E_constant ("NONE", [])) (t_option_none ())
+    let%bind tv_opt = bind_map_option get_t_option tv_opt in
+    begin match tv_opt with
+    | None -> fail @@ simple_info "None without a type annotation"
+    | Some tv -> return (E_constant ("NONE", [])) (t_option tv ())
+    end
   | E_constant (name, lst) ->
       let%bind lst' = bind_list @@ List.map (type_expression e) lst in
       let tv_lst = List.map get_type_annotation lst' in
@@ -728,7 +732,7 @@ and type_expression : environment -> ?tv_opt:O.type_value -> I.expression -> O.a
           fail @@ not_supported_yet "assign expressions with maps are not supported yet" ae
       in
       bind_fold_list aux (typed_name.type_value , []) path in
-    let%bind expr' = type_expression e expr in
+    let%bind expr' = type_expression e ~tv_opt:assign_tv expr in
     let t_expr' = get_type_annotation expr' in
     let%bind () =
       trace_strong (type_error
diff --git a/src/passes/6-transpiler/transpiler.ml b/src/passes/6-transpiler/transpiler.ml
index acc4bd7e1..0cef7b26b 100644
--- a/src/passes/6-transpiler/transpiler.ml
+++ b/src/passes/6-transpiler/transpiler.ml
@@ -130,8 +130,6 @@ let rec transpile_type (t:AST.type_value) : type_value result =
   | T_constant ("option", [o]) ->
       let%bind o' = transpile_type o in
       ok (T_option o')
-  | T_constant ("option_none", []) ->
-      ok (T_option (T_base Base_unit))
   | T_constant (name , _lst) -> fail @@ unrecognized_type_constant name
   (* TODO hmm *)
   | T_sum m ->
diff --git a/src/passes/6-transpiler/untranspiler.ml b/src/passes/6-transpiler/untranspiler.ml
index 08ed0d141..78c41cca8 100644
--- a/src/passes/6-transpiler/untranspiler.ml
+++ b/src/passes/6-transpiler/untranspiler.ml
@@ -107,14 +107,12 @@ let rec untranspile (v : value) (t : AST.type_value) : AST.annotated_expression
         get_string v in
       return (E_literal (Literal_address n))
     )
-  | T_constant ("option_none", []) ->
-    ok e_a_empty_none
   | T_constant ("option", [o]) -> (
       let%bind opt =
         trace_strong (wrong_mini_c_value "option" v) @@
         get_option v in
       match opt with
-      | None -> ok e_a_empty_none
+      | None -> ok (e_a_empty_none o)
       | Some s ->
           let%bind s' = untranspile s o in
           ok (e_a_empty_some s')
diff --git a/src/stages/ast_typed/combinators.ml b/src/stages/ast_typed/combinators.ml
index 5ae376b9d..d9dcebb73 100644
--- a/src/stages/ast_typed/combinators.ml
+++ b/src/stages/ast_typed/combinators.ml
@@ -25,7 +25,6 @@ let t_tez ?s () : type_value = make_t (T_constant ("tez", [])) s
 let t_timestamp ?s () : type_value = make_t (T_constant ("timestamp", [])) s
 let t_unit ?s () : type_value = make_t (T_constant ("unit", [])) s
 let t_option o ?s () : type_value = make_t (T_constant ("option", [o])) s
-let t_option_none ?s () : type_value = make_t (T_constant ("option_none", [])) s
 let t_tuple lst ?s () : type_value = make_t (T_tuple lst) s
 let t_list t ?s () : type_value = make_t (T_constant ("list", [t])) s
 let t_set t ?s () : type_value = make_t (T_constant ("set", [t])) s
@@ -255,7 +254,7 @@ let e_a_address s = make_a_e (e_address s) (t_address ())
 let e_a_pair a b = make_a_e (e_pair a b) (t_pair a.type_annotation b.type_annotation ())
 let e_a_some s = make_a_e (e_some s) (t_option s.type_annotation ())
 let e_a_lambda l in_ty out_ty = make_a_e (e_lambda l) (t_function in_ty out_ty ())
-let e_a_none = make_a_e e_none (t_option_none ())
+let e_a_none t = make_a_e e_none (t_option t ())
 let e_a_tuple lst = make_a_e (E_tuple lst) (t_tuple (List.map get_type_annotation lst) ())
 let e_a_record r = make_a_e (e_record r) (t_record (SMap.map get_type_annotation r) ())
 let e_a_application a b = make_a_e (e_application a b) (get_type_annotation b)
diff --git a/src/stages/ast_typed/combinators_environment.ml b/src/stages/ast_typed/combinators_environment.ml
index 3cea2fd1d..1446c8780 100644
--- a/src/stages/ast_typed/combinators_environment.ml
+++ b/src/stages/ast_typed/combinators_environment.ml
@@ -12,7 +12,7 @@ let e_a_empty_string s = e_a_string s Environment.full_empty
 let e_a_empty_address s = e_a_address s Environment.full_empty
 let e_a_empty_pair a b = e_a_pair a b Environment.full_empty
 let e_a_empty_some s = e_a_some s Environment.full_empty
-let e_a_empty_none = e_a_none Environment.full_empty
+let e_a_empty_none t = e_a_none t Environment.full_empty
 let e_a_empty_tuple lst = e_a_tuple lst Environment.full_empty
 let e_a_empty_record r = e_a_record r Environment.full_empty
 let e_a_empty_map lst k v = e_a_map lst k v Environment.full_empty
diff --git a/src/stages/ast_typed/misc.ml b/src/stages/ast_typed/misc.ml
index b7fb63f76..5ba66b4ea 100644
--- a/src/stages/ast_typed/misc.ml
+++ b/src/stages/ast_typed/misc.ml
@@ -296,9 +296,6 @@ let rec assert_type_value_eq (a, b: (type_value * type_value)) : unit result = m
       bind_list_iter assert_type_value_eq (List.combine ta tb)
     )
   | T_tuple _, _ -> fail @@ different_kinds a b
-  | T_constant ("option", _), T_constant ("option_none", []) |
-    T_constant ("option_none", []), T_constant ("option", _) -> 
-    ok ()
   | T_constant (ca, lsta), T_constant (cb, lstb) -> (
       let%bind _ =
         trace_strong (different_size_constants a b)
diff --git a/src/test/contracts/option.ligo b/src/test/contracts/option.ligo
index 9abf2c845..d3d1ef36c 100644
--- a/src/test/contracts/option.ligo
+++ b/src/test/contracts/option.ligo
@@ -8,7 +8,7 @@ const n : foobar = None
 function assign (var m : int) : foobar is
   var coco : foobar := None;
   block
-{ 
+{
       coco := Some(m);
       coco := None;
 }

From 1c2c6cbc43985ce3dd4aa3345f277f618ec6a9f9 Mon Sep 17 00:00:00 2001
From: Tom Jack <tom@tomjack.co>
Date: Mon, 7 Oct 2019 08:47:51 -0500
Subject: [PATCH 5/7] Delete unused NoneExpr

---
 src/passes/1-parser/pascaligo/AST.ml       | 2 --
 src/passes/1-parser/pascaligo/AST.mli      | 1 -
 src/passes/1-parser/pascaligo/ParserLog.ml | 1 -
 src/passes/2-simplify/pascaligo.ml         | 1 -
 4 files changed, 5 deletions(-)

diff --git a/src/passes/1-parser/pascaligo/AST.ml b/src/passes/1-parser/pascaligo/AST.ml
index 214daaafe..8a95555eb 100644
--- a/src/passes/1-parser/pascaligo/AST.ml
+++ b/src/passes/1-parser/pascaligo/AST.ml
@@ -408,7 +408,6 @@ and lhs =
 
 and rhs =
       Expr of expr
-| NoneExpr of c_None
 
 and loop =
   While of while_loop reg
@@ -760,7 +759,6 @@ let lhs_to_region : lhs -> Region.t = function
 
 let rhs_to_region = function
       Expr e -> expr_to_region e
-| NoneExpr r -> r
 
 let selection_to_region = function
   FieldName {region; _}
diff --git a/src/passes/1-parser/pascaligo/AST.mli b/src/passes/1-parser/pascaligo/AST.mli
index 15e7e9883..f3a22e743 100644
--- a/src/passes/1-parser/pascaligo/AST.mli
+++ b/src/passes/1-parser/pascaligo/AST.mli
@@ -392,7 +392,6 @@ and lhs =
 
 and rhs =
       Expr of expr
-| NoneExpr of c_None
 
 and loop =
   While of while_loop reg
diff --git a/src/passes/1-parser/pascaligo/ParserLog.ml b/src/passes/1-parser/pascaligo/ParserLog.ml
index 4c8223aab..b6e9d651f 100644
--- a/src/passes/1-parser/pascaligo/ParserLog.ml
+++ b/src/passes/1-parser/pascaligo/ParserLog.ml
@@ -311,7 +311,6 @@ and print_assignment {value; _} =
 
 and print_rhs = function
       Expr e -> print_expr e
-| NoneExpr r -> print_token r "None"
 
 and print_lhs = function
   Path path -> print_path path
diff --git a/src/passes/2-simplify/pascaligo.ml b/src/passes/2-simplify/pascaligo.ml
index ddb3d7bd8..f536a409a 100644
--- a/src/passes/2-simplify/pascaligo.ml
+++ b/src/passes/2-simplify/pascaligo.ml
@@ -782,7 +782,6 @@ and simpl_single_instruction : Raw.single_instr -> (_ -> expression result) resu
       let (a , loc) = r_split a in
       let%bind value_expr = match a.rhs with
         | Expr e -> simpl_expression e
-        | NoneExpr reg -> simpl_expression (EConstr (NoneExpr reg))
       in
       match a.lhs with
         | Path path -> (

From e2c831a23157276caac74611d6d9e4b3433431b5 Mon Sep 17 00:00:00 2001
From: Tom Jack <tom@tomjack.co>
Date: Mon, 7 Oct 2019 09:12:10 -0500
Subject: [PATCH 6/7] Simplify more

---
 src/passes/4-typer/typer.ml | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/src/passes/4-typer/typer.ml b/src/passes/4-typer/typer.ml
index 7acbf5138..28258b9fb 100644
--- a/src/passes/4-typer/typer.ml
+++ b/src/passes/4-typer/typer.ml
@@ -615,12 +615,6 @@ and type_expression : environment -> ?tv_opt:O.type_value -> I.expression -> O.a
       let output_type = body.type_annotation in
       return (E_lambda {binder = fst binder ; body}) (t_function input_type output_type ())
     )
-  | E_constant ("NONE", []) ->
-    let%bind tv_opt = bind_map_option get_t_option tv_opt in
-    begin match tv_opt with
-    | None -> fail @@ simple_info "None without a type annotation"
-    | Some tv -> return (E_constant ("NONE", [])) (t_option tv ())
-    end
   | E_constant (name, lst) ->
       let%bind lst' = bind_list @@ List.map (type_expression e) lst in
       let tv_lst = List.map get_type_annotation lst' in

From 36ec771adfd2eec9f64e1ca3abb99d23d3bd737c Mon Sep 17 00:00:00 2001
From: Tom Jack <tom@tomjack.co>
Date: Mon, 7 Oct 2019 09:24:56 -0500
Subject: [PATCH 7/7] Remove singleton inductive type

---
 src/passes/1-parser/pascaligo/AST.ml       | 6 ++----
 src/passes/1-parser/pascaligo/AST.mli      | 3 +--
 src/passes/1-parser/pascaligo/Parser.mly   | 2 +-
 src/passes/1-parser/pascaligo/ParserLog.ml | 3 +--
 src/passes/2-simplify/pascaligo.ml         | 4 +---
 5 files changed, 6 insertions(+), 12 deletions(-)

diff --git a/src/passes/1-parser/pascaligo/AST.ml b/src/passes/1-parser/pascaligo/AST.ml
index 8a95555eb..44c6c0734 100644
--- a/src/passes/1-parser/pascaligo/AST.ml
+++ b/src/passes/1-parser/pascaligo/AST.ml
@@ -406,8 +406,7 @@ and lhs =
   Path    of path
 | MapPath of map_lookup reg
 
-and rhs =
-      Expr of expr
+and rhs = expr
 
 and loop =
   While of while_loop reg
@@ -757,8 +756,7 @@ let lhs_to_region : lhs -> Region.t = function
   Path path -> path_to_region path
 | MapPath {region; _} -> region
 
-let rhs_to_region = function
-      Expr e -> expr_to_region e
+let rhs_to_region = expr_to_region
 
 let selection_to_region = function
   FieldName {region; _}
diff --git a/src/passes/1-parser/pascaligo/AST.mli b/src/passes/1-parser/pascaligo/AST.mli
index f3a22e743..4984830e0 100644
--- a/src/passes/1-parser/pascaligo/AST.mli
+++ b/src/passes/1-parser/pascaligo/AST.mli
@@ -390,8 +390,7 @@ and lhs =
   Path    of path
 | MapPath of map_lookup reg
 
-and rhs =
-      Expr of expr
+and rhs = expr
 
 and loop =
   While of while_loop reg
diff --git a/src/passes/1-parser/pascaligo/Parser.mly b/src/passes/1-parser/pascaligo/Parser.mly
index a1902bade..bc99f9176 100644
--- a/src/passes/1-parser/pascaligo/Parser.mly
+++ b/src/passes/1-parser/pascaligo/Parser.mly
@@ -591,7 +591,7 @@ assignment:
     in {region; value}}
 
 rhs:
-  expr  { Expr $1 }
+  expr  { $1 }
 
 lhs:
   path       {    Path $1 }
diff --git a/src/passes/1-parser/pascaligo/ParserLog.ml b/src/passes/1-parser/pascaligo/ParserLog.ml
index b6e9d651f..3be60d699 100644
--- a/src/passes/1-parser/pascaligo/ParserLog.ml
+++ b/src/passes/1-parser/pascaligo/ParserLog.ml
@@ -309,8 +309,7 @@ and print_assignment {value; _} =
   print_token assign ":=";
   print_rhs rhs
 
-and print_rhs = function
-      Expr e -> print_expr e
+and print_rhs e = print_expr e
 
 and print_lhs = function
   Path path -> print_path path
diff --git a/src/passes/2-simplify/pascaligo.ml b/src/passes/2-simplify/pascaligo.ml
index f536a409a..5627c49f6 100644
--- a/src/passes/2-simplify/pascaligo.ml
+++ b/src/passes/2-simplify/pascaligo.ml
@@ -780,9 +780,7 @@ and simpl_single_instruction : Raw.single_instr -> (_ -> expression result) resu
     )
   | Assign a -> (
       let (a , loc) = r_split a in
-      let%bind value_expr = match a.rhs with
-        | Expr e -> simpl_expression e
-      in
+      let%bind value_expr = simpl_expression a.rhs in
       match a.lhs with
         | Path path -> (
             let (name , path') = simpl_path path in