From 3c2e2546939f04036cb971567ec979f57ed015ca Mon Sep 17 00:00:00 2001
From: Eric Dobson <eric.n.dobson@gmail.com>
Date: Fri, 14 Mar 2014 18:54:50 -0700
Subject: [PATCH] Fix implied-atomic to work on -top and -bot.

original commit: 9e2787c0cf6eb3e45256ad31075978d3955ef34c
---
 .../typed-racket/types/filter-ops.rkt         | 29 ++++++++++---------
 .../typed-racket/unit-tests/filter-tests.rkt  |  6 ++++
 2 files changed, 21 insertions(+), 14 deletions(-)

diff --git a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/filter-ops.rkt b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/filter-ops.rkt
index ed4a9e03..3225fba5 100644
--- a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/filter-ops.rkt
+++ b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/filter-ops.rkt
@@ -36,20 +36,21 @@
 
 ;; is f1 implied by f2?
 (define (implied-atomic? f1 f2)
-  (if (filter-equal? f1 f2)
-      #t
-      (match* (f1 f2)
-              [((OrFilter: fs) f2)
-               (memf (lambda (f) (filter-equal? f f2)) fs)]
-              [((TypeFilter: t1 p1 i1)
-                (TypeFilter: t2 p1 i2))
-               (and (name-ref=? i1 i2)
-                    (subtype t2 t1))]
-              [((NotTypeFilter: t2 p1 i2)
-                (NotTypeFilter: t1 p1 i1))
-               (and (name-ref=? i1 i2)
-                    (subtype t2 t1))]
-              [(_ _) #f])))
+  (match* (f1 f2)
+    [(f f) #t]
+    [((Top:) _) #t]
+    [(_ (Bot:)) #t]
+    [((OrFilter: fs) f2)
+     (memf (lambda (f) (filter-equal? f f2)) fs)]
+    [((TypeFilter: t1 p1 i1)
+      (TypeFilter: t2 p1 i2))
+     (and (name-ref=? i1 i2)
+          (subtype t2 t1))]
+    [((NotTypeFilter: t2 p1 i2)
+      (NotTypeFilter: t1 p1 i1))
+     (and (name-ref=? i1 i2)
+          (subtype t2 t1))]
+    [(_ _) #f]))
 
 (define (hash-name-ref i)
   (if (identifier? i) (hash-id i) i))
diff --git a/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/unit-tests/filter-tests.rkt b/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/unit-tests/filter-tests.rkt
index c2bc0f47..5836ab74 100644
--- a/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/unit-tests/filter-tests.rkt
+++ b/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/unit-tests/filter-tests.rkt
@@ -39,8 +39,14 @@
              -top -top)
       (check implied-atomic?
              -bot -bot)
+      (check implied-atomic?
+             -top -bot)
       (check not-implied-atomic?
              -bot -top)
+      (check implied-atomic?
+             -top (-filter -Symbol 0))
+      (check implied-atomic?
+             (-filter -Symbol 0) -bot)
       (check implied-atomic?
              (-filter (Un -String -Symbol) 0)
              (-filter -Symbol 0))