diff --git a/src/ast_simplified/ast_simplified.ml b/src/ast_simplified/ast_simplified.ml
index 566e95155..f2eca5152 100644
--- a/src/ast_simplified/ast_simplified.ml
+++ b/src/ast_simplified/ast_simplified.ml
@@ -1,5 +1,5 @@
 include Types
-include Misc
+(* include Misc *)
 include Combinators
 
 module Types = Types
diff --git a/src/ast_simplified/combinators.ml b/src/ast_simplified/combinators.ml
index 5702dafc7..e1d81b7e0 100644
--- a/src/ast_simplified/combinators.ml
+++ b/src/ast_simplified/combinators.ml
@@ -4,6 +4,17 @@ 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
+end
+open Errors
+
 let t_bool      : type_expression = T_constant ("bool", [])
 let t_string    : type_expression = T_constant ("string", [])
 let t_bytes     : type_expression = T_constant ("bytes", [])
@@ -145,3 +156,13 @@ let get_e_failwith = fun e ->
   | _ -> simple_fail "not a failwith"
 
 let is_e_failwith e = to_bool @@ get_e_failwith e
+
+let extract_pair : expression -> (expression * expression) result = fun e ->
+  match Location.unwrap e with
+  | E_tuple [ a ; b ] -> ok (a , b)
+  | _ -> fail @@ bad_kind "pair" e.location
+
+let extract_list : expression -> (expression list) result = fun e ->
+  match Location.unwrap e with
+  | E_list lst -> ok lst
+  | _ -> fail @@ bad_kind "list" e.location
diff --git a/src/contracts/vote.mligo b/src/contracts/vote.mligo
index 3b4a4a857..cf180b66f 100644
--- a/src/contracts/vote.mligo
+++ b/src/contracts/vote.mligo
@@ -6,14 +6,17 @@ type storage = {
   finish_time : timestamp ;
 }
 
-type init_action = (string * timestamp * timestamp)
+type init_action = {
+  title : string ;
+  beginning_time : timestamp ;
+  finish_time : timestamp ;
+}
 
 type action =
   | Vote of string
-  | Init of (string * timestamp * timestamp)
+  | Init of init_action
 
 let init (init_params : init_action) (_ : storage) =
-  let (title , s , t) = init_params in
   let candidates = Map [
       ("Yes" , 0) ;
       ("No" , 0)
@@ -21,21 +24,19 @@ let init (init_params : init_action) (_ : storage) =
   (
     ([] : operation list),
     {
-      title = title ;
+      title = init_params.title ;
       candidates = candidates ;
       voters = (Set [] : address set) ;
-      beginning_time = s ;
-      finish_time = t ;
+      beginning_time = init_params.beginning_time ;
+      finish_time = init_params.finish_time ;
     }
   )
 
 let vote (parameter : string) (storage : storage) =
-  let now = Current.time () in
-  assert (now >= storage.beginning_time && storage.finish_time < now) ;
-
-  let addr = Current.source () in
-  assert (not Set.mem addr storage.voters) ;
-
+  let now = Current.time in
+  let _ = assert (now >= storage.beginning_time && storage.finish_time < now) in
+  let addr = Current.source in
+  let _ = assert (not Set.mem addr storage.voters) in
   let x = Map.find parameter storage.candidates in
   (
     ([] : operation list),
@@ -47,7 +48,7 @@ let vote (parameter : string) (storage : storage) =
       finish_time = storage.finish_time ;
     }
   )
-						             )
+
 let main (action : action) (storage : storage) =
   match action with
   | Vote p -> vote p storage
diff --git a/src/operators/helpers.ml b/src/operators/helpers.ml
index 7cdc617f4..7982ddde0 100644
--- a/src/operators/helpers.ml
+++ b/src/operators/helpers.ml
@@ -88,6 +88,7 @@ module Typer = struct
         t_string () ;
         t_bytes () ;
         t_address () ;
+        t_timestamp () ;
       ] in
     ok @@ t_bool ()
 
diff --git a/src/operators/operators.ml b/src/operators/operators.ml
index 1ccb179d2..2bf65b4fd 100644
--- a/src/operators/operators.ml
+++ b/src/operators/operators.ml
@@ -90,6 +90,8 @@ module Simplify = struct
 
   module Ligodity = struct
     let constants = [
+      ("assert" , "ASSERT") ;
+      
       ("Current.balance", "BALANCE") ;
       ("balance", "BALANCE") ;
       ("Current.time", "NOW") ;
@@ -100,6 +102,8 @@ module Simplify = struct
       ("gas", "STEPS_TO_QUOTA") ;
       ("Current.sender" , "SENDER") ;
       ("sender", "SENDER") ;
+      ("Current.source" , "SOURCE") ;
+      ("source", "SOURCE") ;
       ("Current.failwith", "FAILWITH") ;
       ("failwith" , "FAILWITH") ;
 
@@ -209,7 +213,7 @@ module Typer = struct
     let%bind () = assert_type_value_eq (dst, v) in
     ok m
 
-  let map_update : typer = typer_3 "MAP_UPDATE_TODO" @@ fun k v m ->
+  let map_update : typer = typer_3 "MAP_UPDATE" @@ fun k v m ->
     let%bind (src, dst) = get_t_map m in
     let%bind () = assert_type_value_eq (src, k) in
     let%bind v' = get_t_option v in
@@ -221,7 +225,12 @@ module Typer = struct
     let%bind () = assert_type_value_eq (src, k) in
     ok @@ t_bool ()
 
-  let map_find : typer = typer_2 "MAP_FIND_TODO" @@ fun k m ->
+  let map_find : typer = typer_2 "MAP_FIND" @@ fun k m ->
+    let%bind (src, dst) = get_t_map m in
+    let%bind () = assert_type_value_eq (src, k) in
+    ok @@ dst
+
+  let map_find_opt : typer = typer_2 "MAP_FIND_OPT" @@ fun k m ->
     let%bind (src, dst) = get_t_map m in
     let%bind () = assert_type_value_eq (src, k) in
     ok @@ t_option dst ()
@@ -341,6 +350,11 @@ module Typer = struct
     let%bind () = assert_t_int t in
     ok @@ t_nat ()
 
+  let assertion = typer_1 "ASSERT" @@ fun a ->
+    if eq_1 a (t_bool ())
+    then ok @@ t_unit ()
+    else simple_fail "Asserting a non-bool"
+  
   let times = typer_2 "TIMES" @@ fun a b ->
     if eq_2 (a , b) (t_nat ())
     then ok @@ t_nat () else
@@ -375,6 +389,29 @@ module Typer = struct
     then ok @@ t_int () else
       simple_fail "Adding with wrong types. Expected nat, int or tez."
 
+  let set_mem = typer_2 "SET_MEM" @@ fun elt set ->
+    let%bind key = get_t_set set in
+    if eq_1 elt key
+    then ok @@ t_bool ()
+    else simple_fail "Set_mem: elt and set don't match"
+
+  let set_add = typer_2 "SET_ADD" @@ fun elt set ->
+    let%bind key = get_t_set set in
+    if eq_1 elt key
+    then ok set
+    else simple_fail "Set_add: elt and set don't match"
+
+  let set_remove = typer_2 "SET_REMOVE" @@ fun elt set ->
+    let%bind key = get_t_set set in
+    if eq_1 elt key
+    then ok set
+    else simple_fail "Set_remove: elt and set don't match"
+
+  let not_ = typer_1 "NOT" @@ fun elt ->
+    if eq_1 elt (t_bool ())
+    then ok @@ t_bool ()
+    else simple_fail "bad parameter to not"
+  
   let constant_typers = Map.String.of_list [
       add ;
       times ;
@@ -391,6 +428,7 @@ module Typer = struct
       comparator "GE" ;
       boolean_operator_2 "OR" ;
       boolean_operator_2 "AND" ;
+      not_ ;
       map_remove ;
       map_add ;
       map_update ;
@@ -400,6 +438,9 @@ module Typer = struct
       map_map ;
       map_fold ;
       map_iter ;
+      set_mem ;
+      set_add ;
+      set_remove ;
       (* map_size ; (* use size *) *)
       int ;
       size ;
@@ -422,6 +463,7 @@ module Typer = struct
       now ;
       slice ;
       address ;
+      assertion ;
     ]
 
 end
diff --git a/src/parser/ligodity/Lexer.mll b/src/parser/ligodity/Lexer.mll
index 85ae4db48..09ebf7d29 100644
--- a/src/parser/ligodity/Lexer.mll
+++ b/src/parser/ligodity/Lexer.mll
@@ -104,7 +104,7 @@ let keywords = Token.[
   "and",         None;
   "as",          None;
   "asr",         None;
-  "assert",      None;
+(*  "assert",      None; *)
   "class",       None;
   "constraint",  None;
   "do",          None;
diff --git a/src/simplify/ligodity.ml b/src/simplify/ligodity.ml
index cd3a4472d..34866fd91 100644
--- a/src/simplify/ligodity.ml
+++ b/src/simplify/ligodity.ml
@@ -147,6 +147,22 @@ module Errors = struct
     ] in
     error ~data title message
 
+  let bad_set_definition =
+    let title () = "bad set definition" in
+    let message () = "a set definition is a list" in
+    info title message
+
+  let bad_list_definition =
+    let title () = "bad list definition" in
+    let message () = "a list definition is a list" in
+    info title message
+
+  let bad_map_definition =
+    let title () = "bad map definition" in
+    let message () = "a map definition is a list of pairs" in
+    info title message
+
+  
   let corner_case ~loc message =
     let title () = "corner case" in
     let content () = "We don't have a good error message for this case. \
@@ -158,6 +174,7 @@ module Errors = struct
       ("message" , fun () -> message) ;
     ] in
     error ~data title content
+
 end
 
 open Errors
@@ -170,6 +187,7 @@ let rec pattern_to_var : Raw.pattern -> _ = fun p ->
   match p with
   | Raw.PPar p -> pattern_to_var p.value.inside
   | Raw.PVar v -> ok v
+  | Raw.PWild r -> ok @@ ({ region = r ; value = "_" } : Raw.variable)
   | _ -> fail @@ wrong_pattern "var" p
 
 let rec pattern_to_typed_var : Raw.pattern -> _ = fun p ->
@@ -181,6 +199,7 @@ let rec pattern_to_typed_var : Raw.pattern -> _ = fun p ->
       ok (v , Some tp.type_expr)
     )
   | Raw.PVar v -> ok (v , None)
+  | Raw.PWild r -> ok (({ region = r ; value = "_" } : Raw.variable) , None)
   | _ -> fail @@ wrong_pattern "typed variable" p
 
 let rec expr_to_typed_expr : Raw.expr -> _ = fun e ->
@@ -358,10 +377,37 @@ let rec simpl_expression :
       let (c_name , _c_loc) = r_split c_name in
       let args =
         match args with
-          None -> []
+        | None -> []
         | Some arg -> [arg] in
       let%bind arg = simpl_tuple_expression @@ args in
-      return @@ e_constructor ~loc c_name arg
+      match c_name with
+      | "Set" -> (
+          let%bind args' =
+            trace bad_set_definition @@
+            extract_list arg in
+          return @@ e_set ~loc args'
+        )
+      | "List" -> (
+          let%bind args' =
+            trace bad_list_definition @@
+            extract_list arg in
+          return @@ e_list ~loc args'
+        )
+      | "Map" -> (
+          let%bind args' =
+            trace bad_map_definition @@
+            extract_list arg in
+          let%bind pairs =
+            trace bad_map_definition @@
+            bind_map_list extract_pair args' in
+          return @@ e_map ~loc pairs
+        )
+      | "Some" -> (
+          return @@ e_some ~loc arg
+        )
+      | _ -> (
+          return @@ e_constructor ~loc c_name arg
+        )
     )
   | EArith (Add c) ->
       simpl_binop "ADD" c
diff --git a/src/test/coase_tests.ml b/src/test/coase_tests.ml
index 2f16212d4..9d385ebc0 100644
--- a/src/test/coase_tests.ml
+++ b/src/test/coase_tests.ml
@@ -217,7 +217,7 @@ let sell () =
       let expected_storage =
         let cards = List.hds @@ cards_ez first_owner n in
         basic 99 1000 cards (2 * n) in
-      Ast_simplified.assert_value_eq (expected_storage , storage)
+      Ast_simplified.Misc.assert_value_eq (expected_storage , storage)
     in
     let%bind () =
       let amount = Memory_proto_alpha.Alpha_context.Tez.zero in
diff --git a/src/test/test_helpers.ml b/src/test/test_helpers.ml
index 1b3063390..f178adcd2 100644
--- a/src/test/test_helpers.ml
+++ b/src/test/test_helpers.ml
@@ -71,7 +71,7 @@ let expect_eq ?options program entry_point input expected =
           Ast_simplified.PP.expression result in
       error title content in
     trace expect_error @@
-    Ast_simplified.assert_value_eq (expected , result) in
+    Ast_simplified.Misc.assert_value_eq (expected , result) in
   expect ?options program entry_point input expecter
 
 let expect_evaluate program entry_point expecter =
@@ -85,7 +85,7 @@ let expect_evaluate program entry_point expecter =
 
 let expect_eq_evaluate program entry_point expected =
   let expecter = fun result ->
-    Ast_simplified.assert_value_eq (expected , result) in
+    Ast_simplified.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 =
diff --git a/src/test/vote_tests.ml b/src/test/vote_tests.ml
index 3fd337ab0..575d36075 100644
--- a/src/test/vote_tests.ml
+++ b/src/test/vote_tests.ml
@@ -27,5 +27,5 @@ let init_vote () =
   ok ()
 
 let main = test_suite "Vote" [
-    (* test "type" init_vote ; *)
+    test "type" init_vote ;
   ]
diff --git a/src/typer/typer.ml b/src/typer/typer.ml
index fc0d9abef..f351e614c 100644
--- a/src/typer/typer.ml
+++ b/src/typer/typer.ml
@@ -206,11 +206,13 @@ module Errors = struct
     ] in
     error ~data title message ()
 
-  let constant_error loc =
+  let constant_error loc lst tv_opt =
     let title () = "typing constant" in
     let message () = "" in
     let data = [
       ("location" , fun () -> Format.asprintf "%a" Location.pp loc ) ;
+      ("argument_types" , fun () -> Format.asprintf "%a" PP_helpers.(list_sep Ast_typed.PP.type_value (const " , ")) lst) ;
+      ("type_opt" , fun () -> Format.asprintf "%a" PP_helpers.(option Ast_typed.PP.type_value) tv_opt) ;
     ] in
     error ~data title message
 end
@@ -761,7 +763,7 @@ and type_constant (name:string) (lst:O.type_value list) (tv_opt:O.type_value opt
   let%bind typer =
     trace_option (unrecognized_constant name loc) @@
     Map.String.find_opt name ct in
-  trace (constant_error loc) @@
+  trace (constant_error loc lst tv_opt) @@
   typer lst tv_opt
 
 let untype_type_value (t:O.type_value) : (I.type_expression) result =