From e5204e55d323598ef14e189f8dcee24bbcc90087 Mon Sep 17 00:00:00 2001
From: notoria <notoria@users.noreply.github.com>
Date: Sun, 31 Jan 2021 11:03:17 +0100
Subject: [PATCH] Handled the empty case (#770)

---
 src/forms.rs | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/forms.rs b/src/forms.rs
index be572bc4..b99897a1 100644
--- a/src/forms.rs
+++ b/src/forms.rs
@@ -341,7 +341,13 @@ impl PredicateClause {
                     _ => None,
                 }
             },
-            PredicateClause::Rule(ref rule, ..) => Some(&rule.head.1),
+            PredicateClause::Rule(ref rule, ..) => {
+                if rule.head.1.is_empty() {
+                    None
+                } else {
+                    Some(&rule.head.1)
+                }
+            }
         }
     }
 
-- 
2.54.0