diff --git a/collects/tests/typed-racket/unit-tests/typecheck-tests.rkt b/collects/tests/typed-racket/unit-tests/typecheck-tests.rkt
index 2baacdd1..bbd8ba62 100644
--- a/collects/tests/typed-racket/unit-tests/typecheck-tests.rkt
+++ b/collects/tests/typed-racket/unit-tests/typecheck-tests.rkt
@@ -171,6 +171,8 @@
         (tc-e (- 1) -NegFixnum)
         (tc-e (- 1073741823) -NegFixnum)
         (tc-e (- -4) -PosFixnum)
+        (tc-e/t 1152921504606846975 -PosInt)
+        (tc-e/t -1152921504606846975 -NegInt)
         (tc-e (- 3253463567262345623) -NegInt)
         (tc-e (- -23524623547234734568) -PosInt)
         (tc-e (- 241.3) -NegFlonum)
diff --git a/collects/typed-racket/types/numeric-tower.rkt b/collects/typed-racket/types/numeric-tower.rkt
index 31234fc5..1a8404b6 100644
--- a/collects/typed-racket/types/numeric-tower.rkt
+++ b/collects/typed-racket/types/numeric-tower.rkt
@@ -103,6 +103,9 @@
              #'-NegFixnum))
 (define -NonPosFixnum (*Un -NegFixnum -Zero))
 (define -Fixnum       (*Un -NegFixnum -Zero -PosFixnum))
+;; This type, and others like it, should *not* be exported, or used for
+;; anything but building unions. Especially, no literals should be given
+;; these types.
 (define -PosIntNotFixnum
   (make-Base 'Positive-Integer-Not-Fixnum
              #'(and/c exact-integer? positive? (not/c fixnum?))