Merge commit 'df5c5f5'

1 files changed, 9 insertions, 0 deletions

diff --git a/Test/dafny2/COST-verif-comp-2011-2-MaxTree-class.dfy b/Test/dafny2/COST-verif-comp-2011-2-MaxTree-class.dfy
index c752bd38..f691384c 100644
--- a/Test/dafny2/COST-verif-comp-2011-2-MaxTree-class.dfy
+++ b/Test/dafny2/COST-verif-comp-2011-2-MaxTree-class.dfy
@@ -117,6 +117,11 @@ class Tree {
     Repr := lft.Repr + {this} + rgt.Repr;

   }

 

+  lemma exists_intro<T>(P: T -> bool, x: T)

+    requires P.requires(x)

+    requires P(x)

+    ensures exists y :: P.requires(y) && P(y) { }

+

   method ComputeMax() returns (mx: int)

     requires Valid() && !IsEmpty();

     ensures forall x :: x in Contents ==> x <= mx;

@@ -124,13 +129,17 @@ class Tree {
     decreases Repr;

   {

     mx := value;

+

     if (!left.IsEmpty()) {

       var m := left.ComputeMax();

       mx := if mx < m  then m else mx;

     }

+

     if (!right.IsEmpty()) {

       var m := right.ComputeMax();

       mx := if mx < m then m else mx;

     }

+

+    exists_intro(x reads this => x in Contents && x == mx, mx);

   }

 }