diff --git a/compiler/typetran.lisp b/compiler/typetran.lisp
index 6080d2997e9ff24ab2b9502502c7af92e42505b0..a8663e05c5b4757013fef3e088b6a4b8748f40fa 100644
--- a/compiler/typetran.lisp
+++ b/compiler/typetran.lisp
@@ -171,6 +171,7 @@
 ;;; type predicates, accepting any type object.
 ;;;
 (define-type-predicate %string-char-p string-char)
+(define-type-predicate base-char-p base-character)
 (define-type-predicate %standard-char-p standard-char)