I finally realized where the warning about calling the undefined function T was coming from:

diff --git a/contrib/abcl-asdf/abcl-asdf.lisp b/contrib/abcl-asdf/abcl-asdf.lisp
index b96457e..2ded8b5 100644
--- a/contrib/abcl-asdf/abcl-asdf.lisp
+++ b/contrib/abcl-asdf/abcl-asdf.lisp
@@ -130,8 +130,7 @@ (defmethod resolve ((mvn-component asdf::mvn))
         (resolve-dependencies group-id artifact-id version)
         (if alternate-uri
             (values (namestring alternate-uri) alternate-uri)
-            (t 
-             (error "Failed to resolve MVN component name ~A." name))))))
+            (error "Failed to resolve MVN component name ~A." name)))))

 

 (defmethod resolve ((uri pathname))
   (warn "Unimplemented."))

Looks like this was copy/pasted from a cond form elsewhere.

Cyrus