From 3aeffe3d9f6a500481defc7f1408e4879e885aee Mon Sep 17 00:00:00 2001
From: Sam Tobin-Hochstadt <samth@racket-lang.org>
Date: Thu, 19 Jun 2008 16:07:12 +0000
Subject: [PATCH] Fix filter type.

svn: r10374

original commit: 1880eb4afbbc5044d9643038cec7338f3051bc24
---
 collects/typed-scheme/private/base-env.ss           | 13 ++++++++++++-
 collects/typed-scheme/private/subtype.ss            |  7 +++++--
 .../typed-scheme/private/type-effect-convenience.ss |  6 +++---
 collects/typed-scheme/private/type-utils.ss         |  5 ++++-
 4 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/collects/typed-scheme/private/base-env.ss b/collects/typed-scheme/private/base-env.ss
index 898796f6..255b01f1 100644
--- a/collects/typed-scheme/private/base-env.ss
+++ b/collects/typed-scheme/private/base-env.ss
@@ -7,10 +7,13 @@
  '#%paramz
  (only-in scheme/match/runtime match:error))
 
+
+
 ;; these are all for constructing the types given to variables
 (require (for-syntax
           scheme/base
           "init-envs.ss"
+          "effect-rep.ss"
           (except-in "type-rep.ss" make-arr)
           "type-effect-convenience.ss"
           (only-in "type-effect-convenience.ss" [make-arr* make-arr])
@@ -137,7 +140,15 @@
              (cl-> [((a b . -> . b) b (make-lst a)) b]
                    [((a b c . -> . c) c (make-lst a) (make-lst b)) c]))]
      [foldr  (-poly (a b c) ((a b . -> . b) b (-lst a) . -> . b))]
-     [filter (-poly (a) ((a . -> . B) (-lst a) . -> . (-lst a)))]
+     [filter (-poly (a b) (cl->*
+                           ((a . -> . B
+                               :
+                               (list (make-Latent-Restrict-Effect b))
+                               (list (make-Latent-Remove-Effect b)))
+                            (-lst a)
+                            . -> .
+                            (-lst b))
+                           ((a . -> . B) (-lst a) . -> . (-lst a))))]
      [take   (-poly (a) ((-lst a) -Integer . -> . (-lst a)))]
      [drop   (-poly (a) ((-lst a) -Integer . -> . (-lst a)))]
      [last   (-poly (a) ((-lst a) . -> . a))]
diff --git a/collects/typed-scheme/private/subtype.ss b/collects/typed-scheme/private/subtype.ss
index 91f0accf..f2114838 100644
--- a/collects/typed-scheme/private/subtype.ss
+++ b/collects/typed-scheme/private/subtype.ss
@@ -107,8 +107,11 @@
            (or (and (null? thn-eff*) (null? els-eff*))
                (and (effects-equal? thn-eff thn-eff*)
                     (effects-equal? els-eff els-eff*))
-               (and (andmap sub-eff thn-eff thn-eff*)
-                    (andmap sub-eff els-eff els-eff*)))
+               (and 
+                (= (length thn-eff) (length thn-eff*))
+                (= (length els-eff) (length els-eff*))
+                (andmap sub-eff thn-eff thn-eff*)
+                (andmap sub-eff els-eff els-eff*)))
          (fail! s t))
        ;; either the effects have to be the same, or the supertype can't have effects
        (let ([A (subtypes*/varargs A0 t1 s1 s3)])
diff --git a/collects/typed-scheme/private/type-effect-convenience.ss b/collects/typed-scheme/private/type-effect-convenience.ss
index bbf60088..e09caee9 100644
--- a/collects/typed-scheme/private/type-effect-convenience.ss
+++ b/collects/typed-scheme/private/type-effect-convenience.ss
@@ -38,10 +38,10 @@
 
 (define-syntax ->
   (syntax-rules (:)
-    [(_ dom ... rng)
-     (->* (list dom ...) rng)]
     [(_ dom ... rng : eff1 eff2)
-     (->* (list dom ...) : eff1 eff2)]))
+     (->* (list dom ...) rng : eff1 eff2)]
+    [(_ dom ... rng)
+     (->* (list dom ...) rng)]))
 (define-syntax ->*
   (syntax-rules (:)
     [(_ dom rng)       
diff --git a/collects/typed-scheme/private/type-utils.ss b/collects/typed-scheme/private/type-utils.ss
index c4e1fa84..2d402e11 100644
--- a/collects/typed-scheme/private/type-utils.ss
+++ b/collects/typed-scheme/private/type-utils.ss
@@ -68,7 +68,10 @@
 ;; equality - good
 
 (define tc-result-equal? equal?)
-(define (effects-equal? fs1 fs2) (andmap eq? fs1 fs2))
+(define (effects-equal? fs1 fs2) 
+  (and 
+   (= (length fs1) (length fs2))
+   (andmap eq? fs1 fs2)))
 
 
 ;; fv : Type -> Listof[Name]