From: Andrew Reynolds <andrew.j.reynolds@gmail.com>
Date: Fri, 13 Mar 2020 16:52:13 +0000 (-0500)
Subject: Fix case of non-constant value for sygus sampling (#4051)
X-Git-Tag: cvc5-1.0.0~3495
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=3e96419d27621be3c0c0d4f3af4b14afb0ce24a8;p=cvc5.git

Fix case of non-constant value for sygus sampling (#4051)

Fixes #4050.
---

diff --git a/src/theory/quantifiers/sygus_sampler.cpp b/src/theory/quantifiers/sygus_sampler.cpp
index 10af0d703..d2c2a2380 100644
--- a/src/theory/quantifiers/sygus_sampler.cpp
+++ b/src/theory/quantifiers/sygus_sampler.cpp
@@ -713,8 +713,12 @@ Node SygusSampler::getSygusRandomValue(TypeNode tn,
       Trace("sygus-sample-grammar") << "...returned " << ret << std::endl;
       ret = Rewriter::rewrite(ret);
       Trace("sygus-sample-grammar") << "...after rewrite " << ret << std::endl;
-      Assert(ret.isConst());
-      return ret;
+      // A rare case where we generate a non-constant value from constant
+      // leaves is (/ n 0).
+      if(ret.isConst())
+      {
+        return ret;
+      }
     }
   }
   Trace("sygus-sample-grammar") << "...resort to random value" << std::endl;