From 0026f3fdef150bd54719c2215c0f68bc64877a5b Mon Sep 17 00:00:00 2001
From: Markus Triska <triska@metalevel.at>
Date: Wed, 1 Dec 2021 20:54:06 +0100
Subject: [PATCH 1/2] use anonymous variable

---
 src/lib/builtins.pl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/lib/builtins.pl b/src/lib/builtins.pl
index eace0865..e3bd22a6 100644
--- a/src/lib/builtins.pl
+++ b/src/lib/builtins.pl
@@ -954,7 +954,7 @@ retract_module_clause(Head, Body, Module) :-
     ).
 
 
-first_match_index([Clause | Clauses], Clause, N, N) :-
+first_match_index([Clause | _], Clause, N, N) :-
     !.
 first_match_index([_ | Clauses], Clause, N0, N) :-
     N1 is N0 + 1,

From 48cea6efdfd17b5661cec5c04813889c5bac744f Mon Sep 17 00:00:00 2001
From: Markus Triska <triska@metalevel.at>
Date: Wed, 1 Dec 2021 20:58:38 +0100
Subject: [PATCH 2/2] FIXED: retract/1 issues due to module qualification

This addresses #1125.
---
 src/lib/builtins.pl | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/lib/builtins.pl b/src/lib/builtins.pl
index e3bd22a6..00a26238 100644
--- a/src/lib/builtins.pl
+++ b/src/lib/builtins.pl
@@ -998,14 +998,14 @@ retract_clause(Head, Body) :-
 
 :- meta_predicate retract(0).
 
-retract(Clause) :-
-    (  Clause \= (_ :- _) ->
-       Head = Clause,
-       Body = true,
-       retract_clause(Head, Body)
-    ;  Clause = (Head :- Body) ->
-       retract_clause(Head, Body)
-    ).
+retract(Clause0) :-
+    strip_module(Clause0, Module, Clause),
+    (   Clause = (Head :- Body) ->
+        true
+    ;   Head = Clause,
+        Body = true
+    ),
+    retract_clause(Module:Head, Body).
 
 
 :- meta_predicate retractall(0).