Univ bug with string as arg2, re issue #892

infradig · infradig · commit bdf72d112d2f · 2025-09-19T10:26:52.000+10:00
diff --git a/src/bif_predicates.c b/src/bif_predicates.c
@@ -1626,7 +1626,8 @@ static bool bif_iso_univ_2(query *q)
 	}
 
 	if (is_var(p1)) {
-		cell *p22 = p2 + 1;
+		cell *p22 = p2;
+		if (is_iso_list(p2)) p22++;
 		p22 = deref(q, p22, p2_ctx);
 
 		if (is_var(p22))

Original file line number	Diff line number	Diff line change
`@@ -1626,7 +1626,8 @@ static bool bif_iso_univ_2(query *q)`
`1626`	`1626`	`}`
`1627`	`1627`
`1628`	`1628`	`if (is_var(p1)) {`
`1629`		`- cell *p22 = p2 + 1;`
	`1629`	`+ cell *p22 = p2;`
	`1630`	`+ if (is_iso_list(p2)) p22++;`
`1630`	`1631`	`p22 = deref(q, p22, p2_ctx);`
`1631`	`1632`
`1632`	`1633`	`if (is_var(p22))`