Fix polymorphic class checking.

pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/typecheck/check-class-unit.rkt

@@ -214,11 +214,10 @@
     [(? Class? class-type)
      (ret (parse-and-check form class-type))]
     [(Poly-names: ns body-type)
-     ;; FIXME: make sure this case is correct, does it
-     ;; introduce the right names in scope?
-     (check-class form (ret body-type))]
-    [#f (ret (parse-and-check form #f))]
-    [_ (check-below (ret (parse-and-check form #f)) expected)]))
+     (match (check-class form (ret body-type))
+       [(tc-result1: t f o)
+        (ret (make-Poly ns t) f o)])]
+    [_ (ret (parse-and-check form #f))]))
 
 ;; Syntax Option<Type> -> Type
 ;; Parse the syntax and extract useful information to pass to the

pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/typecheck/tc-expr-unit.rkt

@@ -236,8 +236,7 @@
       #:literal-sets (kernel-literals tc-expr-literals)
       ;; a TR-annotated class
       [stx:tr:class^
-       (check-class form expected)
-       expected]
+       (check-class form expected)]
       [stx:exn-handlers^
        (register-ignored! form)
        (check-subforms/with-handlers/check form expected)]

pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/unit-tests/class-tests.rkt

@@ -1316,4 +1316,11 @@
                (define/public (m a-foo) (get-field x a-foo))))
            (void))
          -Void]
+   ;; test that filters are correctly handled for polymorphic classes
+   [tc-e (let ()
+           (class object%
+             (super-new)
+             (init x)))
+         #:ret (ret (-poly (A) (-class #:init ([x A #f]))))
+         #:expected (ret (-poly (A) (-class #:init ([x A #f]))) -no-filter -no-obj)]
    ))