diff --git a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/type-table.rkt b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/type-table.rkt
index 2bb45b6f..cec367f7 100644
--- a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/type-table.rkt
+++ b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/type-table.rkt
@@ -19,7 +19,8 @@
  [add-typeof-expr (syntax? tc-results/c . -> . any/c)]
  [type-of (syntax? . -> . tc-results/c)]
  [reset-type-table (-> any/c)]
- [type-table->tooltips (-> (listof (vector/c any/c integer? integer? string?)))]
+ [type-table->tooltips
+  (-> (listof (vector/c any/c integer? integer? (or/c string? (-> string?)))))]
  [test-position-add-true (syntax? . -> . any)]
  [test-position-add-false (syntax? . -> . any)]
  [test-position-takes-true-branch (syntax? . -> . boolean?)]
diff --git a/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/unit-tests/tooltip-tests.rkt b/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/unit-tests/tooltip-tests.rkt
index 42efcb70..99ead430 100644
--- a/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/unit-tests/tooltip-tests.rkt
+++ b/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/unit-tests/tooltip-tests.rkt
@@ -51,7 +51,9 @@
           [else
            (define stxs (vector-ref result 2))
            (define tooltips
-             (syntax-property (car stxs) 'mouse-over-tooltips))
+             (and (list? stxs)
+                  (syntax? (car stxs))
+                  (syntax-property (car stxs) 'mouse-over-tooltips)))
            (if tooltips
                (and (pred tooltips)
                     (unique-locations? tooltips))