From daf19869de0e0c512305c389695ba929697cfb5a Mon Sep 17 00:00:00 2001
From: Robby Findler <robby@racket-lang.org>
Date: Sat, 26 Dec 2015 22:05:29 -0600
Subject: [PATCH] chaperone-hash-set fixes

---
 pkgs/racket-doc/scribblings/reference/sets.scrbl | 8 ++++----
 pkgs/racket-test-core/tests/racket/set.rktl      | 5 +++++
 racket/collects/racket/private/set-types.rkt     | 9 +++++++--
 3 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/pkgs/racket-doc/scribblings/reference/sets.scrbl b/pkgs/racket-doc/scribblings/reference/sets.scrbl
index 8f8aefc29c..966eb7238e 100644
--- a/pkgs/racket-doc/scribblings/reference/sets.scrbl
+++ b/pkgs/racket-doc/scribblings/reference/sets.scrbl
@@ -699,11 +699,11 @@ Supported for any @racket[st] that @supp{supports} @racket[set->stream].
                                [ref-proc (-> set? any/c any/c)]
                                [add-proc (-> set? any/c any/c)]
                                [remove-proc (-> set? any/c any/c)]
-                               [clear-proc (or/c #f (-> set? any))]
+                               [clear-proc (or/c #f (-> set? any)) #f]
                                [prop impersonator-property?]
                                [prop-val any/c] ... ...)
          (and/c set? impersonator?)]{
- Impersonates @racket[set], redirecting via the given procedures.
+ Impersonates @racket[st], redirecting via the given procedures.
 
  The @racket[ref-proc] procedure
  is called whenever an element is extracted from @racket[st]. Its first argument
@@ -737,11 +737,11 @@ Supported for any @racket[st] that @supp{supports} @racket[set->stream].
                              [ref-proc (-> set? any/c any/c)]
                              [add-proc (-> set? any/c any/c)]
                              [remove-proc (-> set? any/c any/c)]
-                             [clear-proc (or/c #f (-> set? any))]
+                             [clear-proc (or/c #f (-> set? any)) #f]
                              [prop impersonator-property?]
                              [prop-val any/c] ... ...)
          (and/c set? chaperone?)]{
- Chaperones @racket[set]. Like @racket[impersonate-hash-set] but with
+ Chaperones @racket[st]. Like @racket[impersonate-hash-set] but with
  the constraints that the results of the @racket[ref-proc],
  @racket[add-proc], and @racket[remove-proc] must be
  @racket[chaperone-of?] their second arguments. Also, the input
diff --git a/pkgs/racket-test-core/tests/racket/set.rktl b/pkgs/racket-test-core/tests/racket/set.rktl
index 3322a3d996..c1a3eb5c5c 100644
--- a/pkgs/racket-test-core/tests/racket/set.rktl
+++ b/pkgs/racket-test-core/tests/racket/set.rktl
@@ -631,5 +631,10 @@
                                        (λ (s e) (+ e 1))
                                        (λ (s l) l)
                                        (λ (s l) l))))
+(test #t even?
+      (set-first (impersonate-hash-set (weak-set 1 3 5)
+                                       (λ (s e) (+ e 1))
+                                       (λ (s l) l)
+                                       (λ (s l) l))))
 
 (report-errs)
diff --git a/racket/collects/racket/private/set-types.rkt b/racket/collects/racket/private/set-types.rkt
index 7192549c45..08f52577ee 100644
--- a/racket/collects/racket/private/set-types.rkt
+++ b/racket/collects/racket/private/set-types.rkt
@@ -403,10 +403,15 @@
                              remove-proc
                              clear-proc+props)
   (define who (if impersonate? 'impersonate-hash-set 'chaperone-hash-set))
-  (unless (if impersonate? (set-mutable? s) (or (set? s) (set-mutable? s)))
+  (unless (if impersonate?
+              (or (set-mutable? s) (set-weak? s))
+              (or (set? s) (set-mutable? s) (set-weak? s)))
     (apply raise-argument-error
            who
-           (if impersonate? "set-mutable?" (format "~s" '(or/c set? set-mutable?)))
+           (format "~s"
+                   (if impersonate?
+                       '(or/c set-mutable? set-weak?)
+                       '(or/c set? set-mutable? set-weak?)))
            0 s ref-proc add-proc clear-proc+props))
   (unless (and (procedure? ref-proc)
                (procedure-arity-includes? ref-proc 2))