From a35cb2643a8e094bf64b4e9fb4a2d44805131e69 Mon Sep 17 00:00:00 2001
From: Jip Spel <jip.spel@cs.rwth-aachen.de>
Date: Tue, 9 Apr 2019 15:07:16 +0200
Subject: [PATCH] Extend error message

---
 src/storm/generator/PrismNextStateGenerator.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/storm/generator/PrismNextStateGenerator.cpp b/src/storm/generator/PrismNextStateGenerator.cpp
index 8a7030b17..c368a976d 100644
--- a/src/storm/generator/PrismNextStateGenerator.cpp
+++ b/src/storm/generator/PrismNextStateGenerator.cpp
@@ -107,7 +107,8 @@ namespace storm {
 
 #ifdef STORM_HAVE_CARL
             else if (std::is_same<ValueType, storm::RationalFunction>::value && !program.undefinedConstantsAreGraphPreserving()) {
-                STORM_LOG_THROW(false, storm::exceptions::InvalidArgumentException, "The program contains undefined constants that appear in some places other than update probabilities and reward value expressions, which is not admitted.");
+                auto undef = program.getUndefinedConstantsAsString();
+                STORM_LOG_THROW(false, storm::exceptions::InvalidArgumentException, "The program contains undefined constants that appear in some places other than update probabilities and reward value expressions, which is not admitted. Undefined constants are: " << undef);
             }
 #endif
         }