From 507b50ed1ccc51bbd24f3cea6f3c287b97b3d299 Mon Sep 17 00:00:00 2001
From: Rustan Leino <leino@microsoft.com>
Date: Wed, 29 Jun 2011 16:49:45 -0700
Subject: Dafny: Fixed axioms for Seq#Contains vs. the sequence building
 functions

---
 Binaries/DafnyPrelude.bpl | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

(limited to 'Binaries')

diff --git a/Binaries/DafnyPrelude.bpl b/Binaries/DafnyPrelude.bpl
index 30992d46..94a8833a 100644
--- a/Binaries/DafnyPrelude.bpl
+++ b/Binaries/DafnyPrelude.bpl
@@ -137,11 +137,16 @@ axiom (forall<T> s0: Seq T, s1: Seq T, x: T ::
   { Seq#Contains(Seq#Append(s0, s1), x) }
   Seq#Contains(Seq#Append(s0, s1), x) <==>
     Seq#Contains(s0, x) || Seq#Contains(s1, x));
-axiom (forall<T> s: Seq T, i: int, v: T, len: int, x: T ::
-  { Seq#Contains(Seq#Build(s, i, v, len), x) }
-  Seq#Contains(Seq#Build(s, i, v, len), x) <==>
-    (0 <= i && i < len && x == v)  ||  
-    (exists j: int :: { Seq#Index(s,j) } 0 <= j && j < Seq#Length(s) && j < len && j!=i && Seq#Index(s,j) == x));
+axiom (forall<T> i: int, v: T, len: int, x: T ::
+  { Seq#Contains(Seq#Build(Seq#Empty(), i, v, len), x) }
+  0 <= i && i < len ==>
+  (Seq#Contains(Seq#Build(Seq#Empty(), i, v, len), x) <==> x == v));
+axiom (forall<T> s: Seq T, i0: int, v0: T, len0: int, i1: int, v1: T, len1: int, x: T ::
+  { Seq#Contains(Seq#Build(Seq#Build(s, i0, v0, len0), i1, v1, len1), x) }
+  0 <= i0 && i0 < len0 && len0 <= i1 && i1 < len1 ==>
+  (Seq#Contains(Seq#Build(Seq#Build(s, i0, v0, len0), i1, v1, len1), x) <==>
+     v1 == x ||
+     Seq#Contains(Seq#Build(s, i0, v0, len0), x)));
 axiom (forall<T> s: Seq T, n: int, x: T ::
   { Seq#Contains(Seq#Take(s, n), x) }
   Seq#Contains(Seq#Take(s, n), x) <==>
-- 
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