From 3e5209d32d0d8dcafa173ce23f124d08b5138539 Mon Sep 17 00:00:00 2001
From: Chris Hanson <org/chris-hanson/cph>
Date: Wed, 5 Sep 2018 18:09:56 -0700
Subject: [PATCH] Fix problem with printing of SOS instances.

---
 src/sos/instance.scm | 1 +
 src/sos/tvector.scm  | 1 +
 2 files changed, 2 insertions(+)

diff --git a/src/sos/instance.scm b/src/sos/instance.scm
index fba341f24..29fded5c7 100644
--- a/src/sos/instance.scm
+++ b/src/sos/instance.scm
@@ -331,6 +331,7 @@ USA.
 (define (instance? object)
   (and (tagged-vector? object)
        (class-tag? (tagged-vector-tag object))))
+(register-predicate! instance? 'instance '<= tagged-vector?)
 
 (define (instance-class instance)
   (dispatch-tag->class (tagged-vector-tag instance)))
diff --git a/src/sos/tvector.scm b/src/sos/tvector.scm
index b77f2e8dd..46a034b66 100644
--- a/src/sos/tvector.scm
+++ b/src/sos/tvector.scm
@@ -44,6 +44,7 @@ USA.
 (define (tagged-vector? object)
   (and (%record? object)
        (dispatch-tag? (%record-ref object 0))))
+(register-predicate! tagged-vector? 'tagged-vector '<= %record?)
 
 (define (tagged-vector-tag vector)
   (guarantee-tagged-vector vector 'TAGGED-VECTOR-TAG)
-- 
2.25.1