Fix an unfortunate bug in Union construction.

original commit: beefe73f7e7b6fbb547f327e206f447e4f6815b0
2013-11-25 12:59:50 -05:00 · 2013-11-25 12:59:50 -05:00 · f7cdf5f1ae
commit f7cdf5f1ae
parent 4c43cfb76c
1 changed files with 1 additions and 1 deletions
--- a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/union.rkt
+++ b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/union.rkt
@ -34,7 +34,7 @@
     (cons a b)]
    [((? (λ _ (subtype a b*))) _) b]
    [((? (λ _ (subtype b* a))) _) (list a)]
-    [(_ _) (cons a b)]))
+    [(_ _) (cons a (filter-not (λ (b-elem) (subtype b-elem a)) b))]))

 ;; Type -> List[Type]
 (define (flat t)