diff --git a/src/contracts/coase.ligo b/src/contracts/coase.ligo
index 8d5ad912f..ea7f9d057 100644
--- a/src/contracts/coase.ligo
+++ b/src/contracts/coase.ligo
@@ -92,7 +92,7 @@ function buy_single(const action : action_buy_single ; const s : storage_type) :
 function main(const action : action ; const s : storage_type) : (list(operation) * storage_type) is
   block {skip} with
   case action of
-  | Buy_single bs -> buy_single (bs , s)
-  | Sell_single as -> sell_single (as , s)
-  | Transfer_single at -> transfer_single (at , s)
+  | Buy_single (bs) -> buy_single (bs , s)
+  | Sell_single (as) -> sell_single (as , s)
+  | Transfer_single (at) -> transfer_single (at , s)
   end
diff --git a/src/contracts/dispatch-counter.ligo b/src/contracts/dispatch-counter.ligo
index c8c59250a..79a71b837 100644
--- a/src/contracts/dispatch-counter.ligo
+++ b/src/contracts/dispatch-counter.ligo
@@ -11,6 +11,6 @@ function decrement(const i : int ; const n : int) : int is
 function main (const p : action ; const s : int) : (list(operation) * int) is
   block {skip} with ((nil : list(operation)),
     case p of
-    | Increment n -> increment(s , n)
-    | Decrement n -> decrement(s , n)
+    | Increment (n) -> increment (s, n)
+    | Decrement (n) -> decrement (s, n)
     end)
diff --git a/src/contracts/match.ligo b/src/contracts/match.ligo
index 57a74d7dd..ff5e3a0a4 100644
--- a/src/contracts/match.ligo
+++ b/src/contracts/match.ligo
@@ -12,7 +12,7 @@ function match_option (const o : option(int)) : int is
   begin
   case o of
   | None -> skip
-  | Some(s) -> result := s
+  | Some (s) -> result := s
   end
   end with result
 
@@ -27,5 +27,5 @@ function match_expr_option (const o : option(int)) : int is
   begin skip end with
   case o of
   | None -> 42
-  | Some(s) -> s
+  | Some (s) -> s
   end
diff --git a/src/contracts/super-counter.ligo b/src/contracts/super-counter.ligo
index 45ce7462a..fcfa8422e 100644
--- a/src/contracts/super-counter.ligo
+++ b/src/contracts/super-counter.ligo
@@ -5,6 +5,6 @@ type action is
 function main (const p : action ; const s : int) : (list(operation) * int) is
   block {skip} with ((nil : list(operation)),
     case p of
-    | Increment n -> s + n
-    | Decrement n -> s - n
+    | Increment (n) -> s + n
+    | Decrement (n) -> s - n
     end)
diff --git a/src/contracts/website2.ligo b/src/contracts/website2.ligo
index 25b36a880..c58561aa9 100644
--- a/src/contracts/website2.ligo
+++ b/src/contracts/website2.ligo
@@ -13,6 +13,6 @@ function subtract (const a : int ; const b : int) : int is
 function main (const p : action ; const s : int) : (list(operation) * int) is
   block {skip} with ((nil : list(operation)),
     case p of
-    | Increment n -> add(s, n)
-    | Decrement n -> subtract(s, n)
+    | Increment (n) -> add (s, n)
+    | Decrement (n) -> subtract (s, n)
     end)
diff --git a/src/parser/pascaligo/AST.ml b/src/parser/pascaligo/AST.ml
index 8c4de5fd3..a94f3f869 100644
--- a/src/parser/pascaligo/AST.ml
+++ b/src/parser/pascaligo/AST.ml
@@ -632,7 +632,7 @@ and arguments = tuple_injection
 
 and pattern =
   PCons   of (pattern, cons) nsepseq reg
-| PConstr of (constr * pattern reg) reg
+| PConstr of (constr * tuple_pattern option) reg
 | PVar    of Lexer.lexeme reg
 | PWild   of wild
 | PInt    of (Lexer.lexeme * Z.t) reg
@@ -644,7 +644,9 @@ and pattern =
 | PNone   of c_None
 | PSome   of (c_Some * pattern par reg) reg
 | PList   of list_pattern
-| PTuple  of (pattern, comma) nsepseq par reg
+| PTuple  of tuple_pattern
+
+and tuple_pattern = (pattern, comma) nsepseq par reg
 
 and list_pattern =
   Sugar of pattern injection reg
diff --git a/src/parser/pascaligo/AST.mli b/src/parser/pascaligo/AST.mli
index eaa3d67b7..b9c7693cb 100644
--- a/src/parser/pascaligo/AST.mli
+++ b/src/parser/pascaligo/AST.mli
@@ -616,7 +616,7 @@ and arguments = tuple_injection
 
 and pattern =
   PCons   of (pattern, cons) nsepseq reg
-| PConstr of (constr * pattern reg) reg
+| PConstr of (constr * tuple_pattern option) reg
 | PVar    of Lexer.lexeme reg
 | PWild   of wild
 | PInt    of (Lexer.lexeme * Z.t) reg
@@ -628,7 +628,9 @@ and pattern =
 | PNone   of c_None
 | PSome   of (c_Some * pattern par reg) reg
 | PList   of list_pattern
-| PTuple  of (pattern, comma) nsepseq par reg
+| PTuple  of tuple_pattern
+
+and tuple_pattern = (pattern, comma) nsepseq par reg
 
 and list_pattern =
   Sugar of pattern injection reg
diff --git a/src/parser/pascaligo/Parser.mly b/src/parser/pascaligo/Parser.mly
index 6ec70672f..45f58dcd8 100644
--- a/src/parser/pascaligo/Parser.mly
+++ b/src/parser/pascaligo/Parser.mly
@@ -1052,22 +1052,22 @@ pattern:
     in PCons {region; value=$1}}
 
 core_pattern:
-  var        {    PVar $1 }
-| WILD       {   PWild $1 }
-| Int        {    PInt $1 }
-| String     { PString $1 }
-| C_Unit     {   PUnit $1 }
-| C_False    {  PFalse $1 }
-| C_True     {   PTrue $1 }
-| C_None     {   PNone $1 }
-| list_patt  {   PList $1 }
-| tuple_patt {  PTuple $1 }
-| constr_patt { PConstr $1 }
+  var                      {    PVar $1 }
+| WILD                     {   PWild $1 }
+| Int                      {    PInt $1 }
+| String                   { PString $1 }
+| C_Unit                   {   PUnit $1 }
+| C_False                  {  PFalse $1 }
+| C_True                   {   PTrue $1 }
+| C_None                   {   PNone $1 }
+| list_pattern             {   PList $1 }
+| tuple_pattern            {  PTuple $1 }
+| constr_pattern           { PConstr $1 }
 | C_Some par(core_pattern) {
     let region = cover $1 $2.region
     in PSome {region; value = $1,$2}}
 
-list_patt:
+list_pattern:
   injection(List,core_pattern) { Sugar $1 }
 | Nil                          {  PNil $1 }
 | par(cons_pattern)            {   Raw $1 }
@@ -1075,15 +1075,14 @@ list_patt:
 cons_pattern:
   core_pattern CONS pattern { $1,$2,$3 }
 
-tuple_patt:
+tuple_pattern:
   par(nsepseq(core_pattern,COMMA)) { $1 }
 
-constr_patt:
-  Constr core_pattern {
-    let second =
-      let region = pattern_to_region $2 in
-      {region; value=$2}
-    in
-    let region = cover $1.region second.region in
-    let value = ($1 , second) in
-    {region; value}}
+constr_pattern:
+  Constr tuple_pattern {
+    let region = cover $1.region $2.region
+    in {region; value = $1, Some $2}
+  }
+| Constr {
+    {region=$1.region; value = $1, None}
+  }
diff --git a/src/parser/pascaligo/ParserLog.ml b/src/parser/pascaligo/ParserLog.ml
index 599543b4e..46341e800 100644
--- a/src/parser/pascaligo/ParserLog.ml
+++ b/src/parser/pascaligo/ParserLog.ml
@@ -681,8 +681,10 @@ and print_pattern = function
 
 and print_constr_pattern {value; _} =
   let (constr, args) = value in
-  print_constr constr ;
-  print_pattern args.value ;
+  print_constr constr;
+  match args with
+    None -> ()
+  | Some tuple -> print_ptuple tuple
 
 and print_psome {value; _} =
   let c_Some, patterns = value in
diff --git a/src/simplify/pascaligo.ml b/src/simplify/pascaligo.ml
index 922790453..01e83b325 100644
--- a/src/simplify/pascaligo.ml
+++ b/src/simplify/pascaligo.ml
@@ -15,6 +15,17 @@ let pseq_to_list = function
 let get_value : 'a Raw.reg -> 'a = fun x -> x.value
 
 module Errors = struct
+  let unsupported_cst_constr p =
+    let title () = "constant constructor" in
+    let message () =
+      Format.asprintf "constant constructors are not supported yet" in
+    let pattern_loc = Raw.pattern_to_region p in
+    let data = [
+      ("pattern_loc",
+       fun () -> Format.asprintf "%a" Location.pp_lift @@ pattern_loc)
+    ] in
+    error ~data title message
+
   let unsupported_ass_None region =
     let title () = "assignment of None" in
     let message () =
@@ -848,33 +859,43 @@ and simpl_cases : type a . (Raw.pattern * a) list -> a matching result = fun t -
   let get_var (t:Raw.pattern) =
     match t with
     | PVar v -> ok v.value
-    | p -> fail @@ unsupported_non_var_pattern p
-  in
-  let get_tuple (t:Raw.pattern) = match t with
+    | p -> fail @@ unsupported_non_var_pattern p in
+  let get_tuple (t: Raw.pattern) =
+    match t with
     | PCons v -> npseq_to_list v.value
     | PTuple v -> npseq_to_list v.value.inside
-    | x -> [ x ]
-  in
-  let get_single (t:Raw.pattern) =
+    | x -> [ x ] in
+  let get_single (t: Raw.pattern) =
     let t' = get_tuple t in
     let%bind () =
       trace_strong (unsupported_tuple_pattern t) @@
       Assert.assert_list_size t' 1 in
     ok (List.hd t') in
-  let get_constr (t:Raw.pattern) = match t with
-    | PConstr v ->
-        let%bind var = get_single (snd v.value).value >>? get_var in
-        ok ((fst v.value).value , var)
-    | _ -> fail @@ only_constructors t
-  in
+  let get_constr (t: Raw.pattern) =
+    match t with
+    | PConstr v -> (
+        let (const , pat_opt) = v.value in
+        let%bind pat =
+          trace_option (unsupported_cst_constr t) @@
+          pat_opt in
+        let%bind single_pat = get_single (PTuple pat) in
+        let%bind var = get_var single_pat in
+        ok (const.value , var)
+      )
+(*
+    | PConstr {value = constr, Some tuple; _} ->
+        let%bind var = get_single (PTuple tuple) >>? get_var in
+        ok (constr.value, var)
+    | PConstr {value = constr, None; _} ->
+              *)
+    | _ -> fail @@ only_constructors t in
   let%bind patterns =
     let aux (x , y) =
       let xs = get_tuple x in
       trace_strong (unsupported_tuple_pattern x) @@
       Assert.assert_list_size xs 1 >>? fun () ->
       ok (List.hd xs , y)
-    in
-    bind_map_list aux t in
+    in bind_map_list aux t in
   match patterns with
   | [(PFalse _ , f) ; (PTrue _ , t)]
   | [(PTrue _ , t) ; (PFalse _ , f)] ->