From: Chris Hanson <org/chris-hanson/cph>
Date: Mon, 16 Apr 2018 02:16:38 +0000 (-0700)
Subject: Change guarantee to show context of error.
X-Git-Tag: mit-scheme-pucked-x11-0.3.1~7^2~126
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=dabc5b302ebbc07ea9d116095550634eb515c74b;p=mit-scheme.git

Change guarantee to show context of error.
---

diff --git a/src/runtime/boot.scm b/src/runtime/boot.scm
index 0a36e5200..7ac9cd8fd 100644
--- a/src/runtime/boot.scm
+++ b/src/runtime/boot.scm
@@ -403,9 +403,9 @@ USA.
       (set-predicate<=! p1 p2))))
 
 (define (guarantee predicate object #!optional caller)
-  (if (predicate object)
-      object
-      (error:not-a predicate object caller)))
+  (if (not (predicate object))
+      (error:not-a predicate object caller))
+  object)
 
 (define (error:not-a predicate object #!optional caller)
   (error:wrong-type-argument object (predicate-description predicate) caller))