diff --git a/typed-racket-lib/typed-racket/env/init-envs.rkt b/typed-racket-lib/typed-racket/env/init-envs.rkt
index a9fbb5ee..b7321e55 100644
--- a/typed-racket-lib/typed-racket/env/init-envs.rkt
+++ b/typed-racket-lib/typed-racket/env/init-envs.rkt
@@ -78,7 +78,7 @@
      `(->acc (list ,@(map sub dom)) ,(sub t) ,(sub pth))]
     [(Result: t (FilterSet: (Top:) (Top:)) (Empty:)) `(-result ,(sub t))]
     [(Union: elems) (split-union elems)]
-    [(Base: n cnt pred _) (int-err "Base type not in predefined-type-table" n)]
+    [(Base: n cnt pred _) (int-err "Base type ~a not in predefined-type-table" n)]
     [(Name: stx args struct?)
      `(make-Name (quote-syntax ,stx)
                  ,(and args