From da32997f937dc933b638f87ba68dcb6054d3a2ee Mon Sep 17 00:00:00 2001
From: Nikolaj Bjorner <nbjorner@microsoft.com>
Date: Thu, 24 May 2018 10:15:36 -0700
Subject: [PATCH] fix #1638

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
---
 src/cmd_context/cmd_context.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/cmd_context/cmd_context.cpp b/src/cmd_context/cmd_context.cpp
index e42f884d6..b3ad7dc01 100644
--- a/src/cmd_context/cmd_context.cpp
+++ b/src/cmd_context/cmd_context.cpp
@@ -1520,6 +1520,9 @@ void cmd_context::check_sat(unsigned num_assumptions, expr * const * assumptions
         scoped_rlimit _rlimit(m().limit(), rlimit);
         try {
             r = m_solver->check_sat(num_assumptions, assumptions);
+            if (r == l_undef && m().canceled()) {
+                m_solver->set_reason_unknown(eh);
+            }
         }
         catch (z3_error & ex) {
             throw ex;