From 086a1b75255c0cce0a5d9634e27fee319f3d18d9 Mon Sep 17 00:00:00 2001
From: Jay McCarthy <jay@racket-lang.org>
Date: Fri, 9 Aug 2013 09:07:50 -0600
Subject: [PATCH] Update gc2 based on an error found by Robby's student

---
 pkgs/plai/gc2/mutator.rkt                           | 13 ++++++-------
 .../tests/gc2/good-collectors/good-collector.rkt    |  2 +-
 pkgs/plai/tests/gc2/good-mutators/yixi.rkt          |  8 ++++++++
 3 files changed, 15 insertions(+), 8 deletions(-)
 create mode 100644 pkgs/plai/tests/gc2/good-mutators/yixi.rkt

diff --git a/pkgs/plai/gc2/mutator.rkt b/pkgs/plai/gc2/mutator.rkt
index efae8f0c58..0fc235cc5a 100644
--- a/pkgs/plai/gc2/mutator.rkt
+++ b/pkgs/plai/gc2/mutator.rkt
@@ -268,14 +268,13 @@
                leftovers
                (cons (make-root 'closure-root
                                 (λ () this-loc)
-                                (λ (v) 
-                                  (set! this-loc v)
-                                  (this-setter v)
-                                  (for ([root (in-list this-other-roots)])
-                                    (set-root! v))))
+                                (λ (v) (set! this-loc v)
+                                   (this-setter v)
+                                   (for ([root (in-list this-other-roots)])
+                                     (set-root! v))))
                      closure-roots))])))
   (parameterize ([active-roots remaining-roots])
-    (collector:closure closure closure-roots)))
+    (collector:closure closure (reverse closure-roots))))
   
 (define-syntax (mutator-app stx)
   (syntax-case stx ()
@@ -627,7 +626,7 @@
       (apply (closure-code-proc v) 
              (append 
               (for/list ([i (in-range (closure-code-env-count v))])
-                        (collector:closure-env-ref proc/loc i))
+                (collector:closure-env-ref proc/loc i))
               args)))]
    [else
     (error 'procedure-application "expected procedure, given ~e" v)]))
diff --git a/pkgs/plai/tests/gc2/good-collectors/good-collector.rkt b/pkgs/plai/tests/gc2/good-collectors/good-collector.rkt
index 87497439e0..a241a0ba88 100644
--- a/pkgs/plai/tests/gc2/good-collectors/good-collector.rkt
+++ b/pkgs/plai/tests/gc2/good-collectors/good-collector.rkt
@@ -93,7 +93,7 @@ A collector for use in testing the random mutator generator.
 (define (gc:first pr-ptr) 
   (if (equal? (heap-ref pr-ptr) 'pair)
       (heap-ref (+ pr-ptr 1))
-      (error 'first "non pair")))
+      (error 'first "non pair: loc ~e val ~e" pr-ptr (heap-ref pr-ptr))))
 
 (test (with-heap (vector 'free 'flat 3 'pair 0 1)
                  (gc:first 3))
diff --git a/pkgs/plai/tests/gc2/good-mutators/yixi.rkt b/pkgs/plai/tests/gc2/good-mutators/yixi.rkt
new file mode 100644
index 0000000000..66b9510dbb
--- /dev/null
+++ b/pkgs/plai/tests/gc2/good-mutators/yixi.rkt
@@ -0,0 +1,8 @@
+#lang plai/gc2/mutator
+(allocator-setup "../good-collectors/good-collector.rkt" 255)
+
+(define (f b) 17)
+(define (g l f)
+  ((lambda (x) (f (first l)))
+   1))
+(g '(3) f)
\ No newline at end of file