From 041dc039d4a32e0e7fa6c3154f3458a7bfb8aa8a Mon Sep 17 00:00:00 2001
From: Mark Thom <markjordanthom@gmail.com>
Date: Mon, 18 May 2020 12:27:26 -0600
Subject: [PATCH] add Addr::Lis as case in PartialStringTail (#530)

---
 src/prolog/iterators.rs            | 4 ++++
 src/prolog/machine/system_calls.rs | 3 +++
 2 files changed, 7 insertions(+)

diff --git a/src/prolog/iterators.rs b/src/prolog/iterators.rs
index 28da88e4..55087f54 100644
--- a/src/prolog/iterators.rs
+++ b/src/prolog/iterators.rs
@@ -92,6 +92,10 @@ fn is_partial_string<'a>(
         Term::Constant(_, Constant::EmptyList) => {
             return Some((string, None));
         }
+        Term::Constant(_, Constant::String(tail)) => {
+            string += &tail;
+            return Some((string, None));
+        }
         _ => {
             return None;
         }
diff --git a/src/prolog/machine/system_calls.rs b/src/prolog/machine/system_calls.rs
index 9554badb..47b36012 100644
--- a/src/prolog/machine/system_calls.rs
+++ b/src/prolog/machine/system_calls.rs
@@ -1164,6 +1164,9 @@ impl MachineState {
                             return Ok(());
                         }
                     }
+                    Addr::Lis(h) => {
+                        self.unify(Addr::HeapCell(h + 1), self[temp_v!(2)]);
+                    }
                     Addr::EmptyList => {
                         self.fail = true;
                         return Ok(());
-- 
2.54.0