added sample of guarded by in which coq is stronger

diff --git a/helm/software/matita/tests/fix_che_non_passa_ma_dovrebbe.ma b/helm/software/matita/tests/fix_che_non_passa_ma_dovrebbe.ma
new file mode 100644 (file)
index 0000000..54c4426
--- /dev/null
+++ b/helm/software/matita/tests/fix_che_non_passa_ma_dovrebbe.ma
@@ -0,0 +1,25 @@
+(**************************************************************************)
+(*       ___                                                              *)
+(*      ||M||                                                             *)
+(*      ||A||       A project by Andrea Asperti                           *)
+(*      ||T||                                                             *)
+(*      ||I||       Developers:                                           *)
+(*      ||T||         The HELM team.                                      *)
+(*      ||A||         http://helm.cs.unibo.it                             *)
+(*      \   /                                                             *)
+(*       \ /        This file is distributed under the terms of the       *)
+(*        v         GNU General Public License Version 2                  *)
+(*                                                                        *)
+(**************************************************************************)
+
+include "nat/nat.ma".
+include "list/list.ma".
+
+let rec cazzo (l:list nat) (f:list nat -> nat -> nat) (x:nat) on l :=
+  match l with [ nil => x
+  | cons hd tl => cazzo tl f (f tl x)].
+  
+let rec f (l:list nat) (x:nat) on l  :=
+  match l with 
+  [ nil => x
+  | cons hd tl => cazzo tl f x].
\ No newline at end of file