From 268274911a1bb91695464cc4b7f16d41b229bf2e Mon Sep 17 00:00:00 2001
From: Arie Gurfinkel <arie.gurfinkel@uwaterloo.ca>
Date: Sun, 3 Jun 2018 09:13:38 -0700
Subject: [PATCH] Fix to cube-and-clause interface in prop_solver

---
 src/muz/spacer/spacer_prop_solver.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/muz/spacer/spacer_prop_solver.cpp b/src/muz/spacer/spacer_prop_solver.cpp
index 4613cd089..64f1bfc9a 100644
--- a/src/muz/spacer/spacer_prop_solver.cpp
+++ b/src/muz/spacer/spacer_prop_solver.cpp
@@ -376,7 +376,7 @@ lbool prop_solver::check_assumptions(const expr_ref_vector & _hard,
     unsigned soft_sz = soft.size();
     (void) soft_sz;
     vector<expr_ref_vector> clauses;
-    clauses.push_back(clause);
+    if (!clause.empty()) clauses.push_back(clause);
     lbool res = internal_check_assumptions(hard, soft, clauses);
     if (!m_use_push_bg) { m_ctx->pop(1); }