Add support for empty constructors.

src/passes/2-simplify/cameligo.ml

@@ -89,7 +89,7 @@ module Errors = struct
        fun () -> Format.asprintf "%a" Location.pp_lift @@ pattern_loc)
     ] in
     error ~data title message
-
+  
   let unsupported_non_var_pattern p =
     let title () = "pattern is not a variable" in
     let message () =
@@ -238,7 +238,7 @@ let rec simpl_type_expression : Raw.type_expr -> type_expression result = fun te
 
 and simpl_list_type_expression (lst:Raw.type_expr list) : type_expression result =
   match lst with
-  | [] -> assert false
+  | [] -> ok @@ t_unit
   | [hd] -> simpl_type_expression hd
   | lst ->
       let%bind lst = bind_map_list simpl_type_expression lst in
@@ -779,7 +779,11 @@ and simpl_cases : type a . (Raw.pattern * a) list -> (a, unit) matching result =
     | PConstr v ->
        let const, pat_opt =
          match v with
-           PConstrApp {value; _} -> value
+           PConstrApp {value; _} -> 
+           (match value with
+           | constr, None ->              
+              constr, Some (PVar {value = "unit"; region = Region.ghost})
+           | _ -> value)
          | PSomeApp {value=region,pat; _} ->
             {value="Some"; region}, Some pat
          | PNone region ->

src/passes/2-simplify/pascaligo.ml

@@ -952,6 +952,11 @@ and simpl_cases : type a . (Raw.pattern * a) list -> (a, unit) matching result =
   let get_constr (t: Raw.pattern) =
     match t with
     | PConstr (PConstrApp v) -> (
+      let value = v.value in
+      match value with
+       | constr, None ->        
+        ok (constr.value, "unit")        
+      | _ -> 
        let const, pat_opt = v.value in
         let%bind pat =
           trace_option (unsupported_cst_constr t) @@

src/test/contracts/empty_case.ligo

@@ -0,0 +1,9 @@
+type foo is
+  | Bar of int
+  | Baz
+
+function main (const f: foo) : int is 
+  (case f of 
+  | Bar (n) -> n
+  | Baz -> -1
+  end)

src/test/contracts/empty_case.mligo

@@ -0,0 +1,8 @@
+type foo =
+  | Bar of int
+  | Baz
+
+let main (f: foo): int = 
+  match f with 
+  | Bar i -> i
+  | Baz -> -1

src/test/contracts/empty_case.religo

@@ -0,0 +1,9 @@
+type foo =
+  | Bar(int)
+  | Baz;
+
+let main = (f: foo): int =>
+  switch (f) {
+  | Bar(i) => i
+  | Baz => (-1)
+  };

src/test/integration_tests.ml

@@ -1830,6 +1830,48 @@ let bytes_unpack () : unit result =
   let%bind () = expect_eq program "id_address" (e_address addr) (e_some (e_address addr)) in
   ok ()
 
+let empty_case () : unit result = 
+  let%bind program = type_file "./contracts/empty_case.ligo" in
+  let%bind () =
+    let input _ = e_constructor "Bar" (e_int 1) in
+    let expected _ = e_int 1 in 
+    expect_eq_n program "main" input expected
+  in 
+  let%bind () =
+    let input _ = e_constructor "Baz" (e_unit ()) in
+    let expected _ = e_int (-1) in 
+    expect_eq_n program "main" input expected
+  in 
+  ok ()
+
+let empty_case_mligo () : unit result = 
+  let%bind program = mtype_file "./contracts/empty_case.mligo" in
+  let%bind () =
+    let input _ = e_constructor "Bar" (e_int 1) in
+    let expected _ = e_int 1 in 
+    expect_eq_n program "main" input expected
+  in 
+  let%bind () =
+    let input _ = e_constructor "Baz" (e_unit ()) in
+    let expected _ = e_int (-1) in 
+    expect_eq_n program "main" input expected
+  in 
+  ok ()
+
+let empty_case_religo () : unit result = 
+  let%bind program = retype_file "./contracts/empty_case.religo" in
+  let%bind () =
+    let input _ = e_constructor "Bar" (e_int 1) in
+    let expected _ = e_int 1 in 
+    expect_eq_n program "main" input expected
+  in 
+  let%bind () =
+    let input _ = e_constructor "Baz" (e_unit ()) in
+    let expected _ = e_int (-1) in 
+    expect_eq_n program "main" input expected
+  in 
+  ok ()
+
 let main = test_suite "Integration (End to End)" [
     test "bytes unpack" bytes_unpack ;
     test "key hash" key_hash ;
@@ -1973,4 +2015,7 @@ let main = test_suite "Integration (End to End)" [
     test "type tuple destruct (mligo)" type_tuple_destruct ;
     test "let in multi-bind (mligo)" let_in_multi_bind ;
     test "tuple param destruct (mligo)" tuple_param_destruct ;
+    test "empty case" empty_case ;
+    test "empty case (mligo)" empty_case_mligo ;
+    test "empty case (religo)" empty_case_religo ;
   ]