eq? is a predicate for eof

original commit: f73d63e1afdca9f509ff0a143ae2348875766ce2

collects/tests/typed-scheme/unit-tests/typecheck-tests.rkt

@@ -811,7 +811,14 @@
         [tc-err (do: : Void
                      ([j : Natural (+ i 'a) (+ j i)])
                      ((>= j 10))
-                     #f)])
+                     #f)]
+        [tc-e/t
+         (let ([x eof])
+           (if (procedure? x)
+               x
+               (lambda (z) (eq? x z))))
+         (make-pred-ty (-val eof))]
+        )
   (test-suite
    "check-type tests"
    (test-exn "Fails correctly" exn:fail:syntax? (lambda () (parameterize ([orig-module-stx #'here])

collects/typed-scheme/typecheck/tc-app.rkt

@@ -41,7 +41,7 @@
 ;; typecheck eq? applications
 ;; identifier expr expr -> tc-results
 (define (tc/eq comparator v1 v2)  
-  (define (eq?-able e) (or (boolean? e) (keyword? e) (symbol? e)))
+  (define (eq?-able e) (or (boolean? e) (keyword? e) (symbol? e) (eof-object? e)))
   (define (eqv?-able e) (or (eq?-able e) (number? e)))
   (define (equal?-able e) #t)
   (define (ok? val)