diff --git a/libasn1fix/asn1fix_constraint_compat.c b/libasn1fix/asn1fix_constraint_compat.c
index 954d5f5..82abf17 100644
--- a/libasn1fix/asn1fix_constraint_compat.c
+++ b/libasn1fix/asn1fix_constraint_compat.c
@@ -95,6 +95,10 @@
 		default:
 			return 0;
 		}
+	case ACT_CT_PATTERN:
+		if(expr_type & ASN_STRING_MASK)
+			return 1;
+		return 0;
 	case ACT_CA_SET:
 	case ACT_CA_CRC:
 	case ACT_CA_CSV: