From 4c4647bbd61883edee6f55d5dc37c9649d23af2e Mon Sep 17 00:00:00 2001
From: qunyanm <unknown>
Date: Thu, 7 Jan 2016 16:43:53 -0800
Subject: Fix issue 118. When iteratively computing bounds, treat
 RefBoundedPool typed bound as undetermined so that iteration will continue.

---
 Source/Dafny/Resolver.cs      |  5 ++++-
 Test/dafny4/Bug118.dfy        | 12 ++++++++++++
 Test/dafny4/Bug118.dfy.expect |  2 ++
 3 files changed, 18 insertions(+), 1 deletion(-)
 create mode 100644 Test/dafny4/Bug118.dfy
 create mode 100644 Test/dafny4/Bug118.dfy.expect

diff --git a/Source/Dafny/Resolver.cs b/Source/Dafny/Resolver.cs
index 9dc0f829..79f1e7e1 100644
--- a/Source/Dafny/Resolver.cs
+++ b/Source/Dafny/Resolver.cs
@@ -9771,11 +9771,14 @@ namespace Microsoft.Dafny
         bests = all.ConvertAll(tup => ComprehensionExpr.BoundedPool.GetBest(tup.Item2, onlyFiniteBounds));
         // check to see if we found new bounds in this iteration
         int count = 0;
+        // figure out how many bounds are not determined yet.
         for (int i = 0; i < bests.Count; i++) {
-          if (bests[i] == null) {
+          if (bests[i] == null || (bests[i] is ComprehensionExpr.RefBoundedPool)) {
             count++;
           }
         }
+        // if there are bounds that are not determined yet and the number of undetermined bounds
+        // changed, we will need to do another iteration.
         if (count >0 && count != orgCount) {
           changed = true;
           knownBounds = bests;
diff --git a/Test/dafny4/Bug118.dfy b/Test/dafny4/Bug118.dfy
new file mode 100644
index 00000000..1e2dddeb
--- /dev/null
+++ b/Test/dafny4/Bug118.dfy
@@ -0,0 +1,12 @@
+// RUN: %dafny /compile:0 "%s" > "%t"
+// RUN: %diff "%s.expect" "%t"
+
+class Foo {
+  ghost var Repr: set<object>
+}
+
+function SeqRepr(s:seq<Foo>) : set<object>
+  reads set b | b in s 
+{
+  set o,b | b in s && b != null && o in b.Repr :: o     // Works if you say "set b,o | ..."
+}
\ No newline at end of file
diff --git a/Test/dafny4/Bug118.dfy.expect b/Test/dafny4/Bug118.dfy.expect
new file mode 100644
index 00000000..c0c48e2b
--- /dev/null
+++ b/Test/dafny4/Bug118.dfy.expect
@@ -0,0 +1,2 @@
+
+Dafny program verifier finished with 1 verified, 0 errors
-- 
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