diff --git a/compiler/global/global_mapfold.ml b/compiler/global/global_mapfold.ml
index 31c9cde..dd0290d 100644
--- a/compiler/global/global_mapfold.ml
+++ b/compiler/global/global_mapfold.ml
@@ -77,3 +77,11 @@ let global_funs_default = {
   field = field;
   param = param;
 }
+
+(** [it_gather gather f] will create a function to iterate
+    over a type using [f] and then use [gather] to combine
+    the value of the local accumulator with the one
+    given as argument. *)
+let it_gather gather f funs acc e =
+  let e, local_acc = f funs acc e in
+    e, gather acc local_acc
diff --git a/compiler/heptagon/transformations/completion_mapfold.ml b/compiler/heptagon/transformations/completion_mapfold.ml
new file mode 100644
index 0000000..6c70538
--- /dev/null
+++ b/compiler/heptagon/transformations/completion_mapfold.ml
@@ -0,0 +1,59 @@
+(**************************************************************************)
+(*                                                                        *)
+(*  Heptagon                                                              *)
+(*                                                                        *)
+(*  Author : Marc Pouzet                                                  *)
+(*  Organization : Demons, LRI, University of Paris-Sud, Orsay            *)
+(*                                                                        *)
+(**************************************************************************)
+(* complete partial definitions with [x = last(x)] *)
+
+open Misc
+open Heptagon
+open Global_mapfold
+open Hept_mapfold
+open Ident
+
+(* adds an equation [x = last(x)] for every partially defined variable *)
+(* in a control structure *)
+let complete_with_last defined_names local_defined_names eq_list =
+  let last n ty = mk_exp (Elast n) ty in
+  let equation n ty eq_list =
+    (mk_equation (Eeq(Evarpat n, last n ty)))::eq_list
+  in
+  let d = Env.diff defined_names local_defined_names in
+    Env.fold equation d eq_list
+
+let block funs (defnames,collect)  b =
+  if collect then
+    b, (b.b_defnames, collect)
+  else
+    let b, _ = Hept_mapfold.block funs (Env.empty, false) b in
+    let added_eq = complete_with_last defnames b.b_defnames [] in
+      { b with b_equs = b.b_equs @ added_eq; b_defnames = defnames },
+  (Env.empty, false)
+
+let eqdesc funs _ ed =
+  match ed with
+    | Epresent _ | Eautomaton _ | Eswitch _ ->
+        (* collect defined names *)
+        let ed, (defnames, _) = Hept_mapfold.eqdesc funs (Env.empty, true) ed in
+          (* add missing defnames *)
+          Hept_mapfold.eqdesc funs (defnames, false) ed
+
+    | _ -> raise Misc.Fallback
+
+let gather (acc, collect) (local_acc, collect) =
+  Env.union local_acc acc, collect
+
+let program p =
+  let funs = Hept_mapfold.hept_funs_default in
+  let funs = { funs with
+                 eqdesc = eqdesc; block = block;
+                 switch_handler = it_gather gather funs.switch_handler;
+                 present_handler = it_gather gather funs.present_handler;
+                 state_handler = it_gather gather funs.state_handler;
+             } in
+  let p, _ = program_it funs (Env.empty, false) p in
+    p
+
diff --git a/compiler/heptagon/transformations/every_mapfold.ml b/compiler/heptagon/transformations/every_mapfold.ml
index 224f04a..67d4e17 100644
--- a/compiler/heptagon/transformations/every_mapfold.ml
+++ b/compiler/heptagon/transformations/every_mapfold.ml
@@ -10,7 +10,7 @@ let is_var = function
 
 let block funs acc b =
   let b, (v, acc_eq_list) = Hept_mapfold.block funs ([], []) b in
-    { b with b_local = v @ b.b_local; b_equs = acc_eq_list }, acc
+    { b with b_local = v @ b.b_local; b_equs = acc_eq_list@b.b_equs }, acc
 
 let edesc funs (v,acc_eq_list) ed =
   let ed, (v, acc_eq_list) = Hept_mapfold.edesc funs (v,acc_eq_list) ed in
diff --git a/test/good/array_iterators.ept b/test/good/array_iterators.ept
index 56d5c1d..b80548f 100644
--- a/test/good/array_iterators.ept
+++ b/test/good/array_iterators.ept
@@ -3,33 +3,33 @@ const n:int = 42
 node plusone(a:int) returns (o:int)
 let
   o = a+1;
-tel	
+tel
 
 node g(a:int^n) returns (o:int^n)
 let
-  o = map plusone <<n>>(a); 
+  o = map plusone <<n>>(a);
 tel
 
 node sum_acc (a, acc_in:int) returns (acc_out:int)
 let
-  acc_out = acc_in + a; 	
+  acc_out = acc_in + a;
 tel
 
 node h(a:int^n) returns (m:int)
 let
-  m = fold sum_acc <<n>>(a, 0); 
+  m = fold sum_acc <<n>>(a, 0);
 tel
 
 node sum_dup (a, acc_in:int) returns (o:int; acc_out:int)
 let
-  acc_out = acc_in + a; 
-  o = acc_out;	
+  acc_out = acc_in + a;
+  o = acc_out;
 tel
 
 node p(a:int^n) returns (o:int^n)
 var acc:int;
 let
-  (o, acc) = mapfold sum_dup <<n>>(a, 0); 
+  (o, acc) = mapfold sum_dup <<n>>(a, 0);
 tel
 
 node k(a,b:int^n) returns (o:int^n)
@@ -41,5 +41,5 @@ node iter_reset(a:int^n; r:bool) returns (o:int^n)
 let
   reset
    o = map plusone <<n>>(a);
-  every r
+  every (r & r)
 tel
\ No newline at end of file