From 52ce83228dc5ffa9bc5fa33b06b568d16eece770 Mon Sep 17 00:00:00 2001
From: Olof-Joachim Frahm <olof@macrolet.net>
Date: Fri, 26 Apr 2013 01:36:50 +0200
Subject: [PATCH] Print type of value when reporting a TYPE-ERROR.

---
 src/code/condition.lisp |   10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/code/condition.lisp b/src/code/condition.lisp
index a1d40d5..29797bc 100644
--- a/src/code/condition.lisp
+++ b/src/code/condition.lisp
@@ -620,10 +620,12 @@
    (expected-type :reader type-error-expected-type :initarg :expected-type))
   (:report
    (lambda (condition stream)
-     (format stream
-             "~@<The value ~2I~:_~S ~I~_is not of type ~2I~_~S.~:>"
-             (type-error-datum condition)
-             (type-error-expected-type condition)))))
+     (let ((datum (type-error-datum condition)))
+       (format stream
+               "~@<The value ~2I~:_~S ~I~_is not of type ~2I~_~S ~I~_but ~2I~_~S.~:>"
+               datum
+               (type-error-expected-type condition)
+               (type-of datum))))))
 
 (def!method print-object ((condition type-error) stream)
   (if (and *print-escape*
-- 
1.7.10.4