Add empty set patches, add test for empty set patches

src/passes/2-simplify/pascaligo.ml

@@ -828,7 +828,7 @@ and simpl_single_instruction : Raw.single_instr -> (_ -> expression result) resu
   | MapPatch patch ->
       fail @@ unsupported_map_patches patch
   | SetPatch patch -> (
-      let setp = patch.value in
+      let (setp, loc) = r_split patch in
       let (name , access_path) = simpl_path setp.path in
       let%bind inj = bind_list
           @@ List.map (fun (x:Raw.expr) ->
@@ -840,7 +840,7 @@ and simpl_single_instruction : Raw.single_instr -> (_ -> expression result) resu
           e_assign name access_path (e_constant "SET_ADD" [v ; e_variable name]) in
         let assigns = List.map aux inj in
         match assigns with
-        | [] -> fail @@ unsupported_empty_record_patch setp.set_inj
+        | [] -> ok @@ e_skip ~loc ()
         | hd :: tl -> (
             let aux acc cur = e_sequence acc cur in
             ok @@ List.fold_left aux hd tl

src/test/contracts/set_arithmetic.ligo

@@ -20,6 +20,9 @@ function remove_syntax (var s : set(string)) : set(string) is
 function patch_op (var s: set(string)) : set(string) is
   begin patch s with set ["foobar"]; end with s
 
+function patch_op_empty (var s: set(string)) : set(string) is
+  begin patch s with set []; end with s
+
 function mem_op (const s : set(string)) : bool is
   begin skip end with set_mem("foobar" , s)
 

src/test/integration_tests.ml

@@ -249,6 +249,10 @@ let set_arithmetic () : unit result =
     expect_eq program "patch_op"
       (e_set [e_string "foo" ; e_string "bar"])
       (e_set [e_string "foo" ; e_string "bar"; e_string "foobar"]) in
+  let%bind () =
+    expect_eq program "patch_op_empty"
+      (e_set [e_string "foo" ; e_string "bar"])
+      (e_set [e_string "foo" ; e_string "bar"]) in
   let%bind () =
     expect_eq program "mem_op"
       (e_set [e_string "foo" ; e_string "bar" ; e_string "foobar"])