From 91a0cf94be3cdfaff29d65122c9ea031a1a4976b Mon Sep 17 00:00:00 2001
From: qunyanm <unknown>
Date: Fri, 12 Feb 2016 15:59:08 -0800
Subject: Fix issue 132. The formal argument can't be assume to be allocated
 when a function is invoked inside an "Old" expression.

---
 Source/Dafny/Translator.cs    |  7 +++++--
 Test/dafny4/Bug132.dfy        | 45 +++++++++++++++++++++++++++++++++++++++++++
 Test/dafny4/Bug132.dfy.expect | 18 +++++++++++++++++
 3 files changed, 68 insertions(+), 2 deletions(-)
 create mode 100644 Test/dafny4/Bug132.dfy
 create mode 100644 Test/dafny4/Bug132.dfy.expect

diff --git a/Source/Dafny/Translator.cs b/Source/Dafny/Translator.cs
index 0314344d..52f52abf 100644
--- a/Source/Dafny/Translator.cs
+++ b/Source/Dafny/Translator.cs
@@ -5045,8 +5045,11 @@ namespace Microsoft.Dafny {
           CheckSubrange(ee.tok, etran.TrExpr(ee), et, builder);
           Bpl.Cmd cmd = Bpl.Cmd.SimpleAssign(p.tok, lhs, CondApplyBox(p.tok, etran.TrExpr(ee), cce.NonNull(ee.Type), et));
           builder.Add(cmd);
-          builder.Add(new Bpl.CommentCmd("assume allocatedness for argument to function"));
-          builder.Add(new Bpl.AssumeCmd(e.Args[i].tok, MkIsAlloc(lhs, et, etran.HeapExpr)));
+          if (!etran.UsesOldHeap) {
+            // the argument can't be assumed to be allocated for the old heap
+            builder.Add(new Bpl.CommentCmd("assume allocatedness for argument to function"));
+            builder.Add(new Bpl.AssumeCmd(e.Args[i].tok, MkIsAlloc(lhs, et, etran.HeapExpr)));
+          }
         }
         // Check that every parameter is available in the state in which the function is invoked; this means checking that it has
         // the right type and is allocated.  These checks usually hold trivially, on account of that the Dafny language only gives
diff --git a/Test/dafny4/Bug132.dfy b/Test/dafny4/Bug132.dfy
new file mode 100644
index 00000000..b2a26876
--- /dev/null
+++ b/Test/dafny4/Bug132.dfy
@@ -0,0 +1,45 @@
+// RUN: %dafny /compile:0 "%s" > "%t"
+// RUN: %diff "%s.expect" "%t"
+
+class Cell {
+  var data: int
+
+  predicate P()
+    reads this
+  { data < 0 }
+
+  predicate Q(e: Cell)
+    reads this, e
+  { e != null ==> e.data == data }
+
+  method Test() {
+    ghost var b;
+    var c := new Cell;
+    if {
+      // In the current state, everything is allowed:
+      case true =>  b := this.P();
+      case true =>  b := c.P();
+      case true =>  b := this.Q(this);
+      case true =>  b := this.Q(c);
+      case true =>  b := c.Q(this);
+      case true =>  b := c.Q(c);
+
+      // 'this' was allocated already in the 'old' state, so all of these are fine:
+      case true =>  b := old(this.P());
+      case true =>  b := old(P());  // same as previous line, of course
+      case true =>  b := old(this.Q(this));
+
+      // 'c' is freshly allocaed in this method, so it cannot be used inside 'old'
+      case true =>  b := old(c.P());  // error: receiver argument must be allocated in the state in which the function is invoked
+      case true =>  b := old(c.Q(this));  // error: receiver argument must be allocated in the state in which the function is invoked
+
+      // The same rule should apply if 'c' is a non-receiver argument
+      case true =>  b := old(this.Q(c));  // BOGUS: this should also generate an error
+
+      // In the following, 'c' is used as both of the two arguments. It's not allowed as either argument.  However, since the error
+      // about the receiver masks the error about the other parameter, only one error (about the receiver) should be reported.
+      case true =>  b := old(c.Q(c));  // BOGUS: this should generate an error about the receiver
+    }
+  }
+}
+
diff --git a/Test/dafny4/Bug132.dfy.expect b/Test/dafny4/Bug132.dfy.expect
new file mode 100644
index 00000000..0452f42d
--- /dev/null
+++ b/Test/dafny4/Bug132.dfy.expect
@@ -0,0 +1,18 @@
+Bug132.dfy(33,29): Error: receiver argument must be allocated in the state in which the function is invoked
+Execution trace:
+    (0,0): anon0
+    (0,0): anon24_Then
+Bug132.dfy(34,29): Error: receiver argument must be allocated in the state in which the function is invoked
+Execution trace:
+    (0,0): anon0
+    (0,0): anon25_Then
+Bug132.dfy(37,36): Error: argument must be allocated in the state in which the function is invoked
+Execution trace:
+    (0,0): anon0
+    (0,0): anon26_Then
+Bug132.dfy(41,29): Error: receiver argument must be allocated in the state in which the function is invoked
+Execution trace:
+    (0,0): anon0
+    (0,0): anon27_Then
+
+Dafny program verifier finished with 3 verified, 4 errors
-- 
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