From aeee35bccb54a5bf1ce1abe1c57305c3cdbf37d6 Mon Sep 17 00:00:00 2001
From: Asumu Takikawa <asumu@ccs.neu.edu>
Date: Thu, 24 Oct 2013 23:58:45 -0400
Subject: [PATCH] Allow re-definition at TR top-level

original commit: e513cdc1c445f7d2ca15ef7033caada29ccf63ff
---
 .../typed-racket-lib/typed-racket/env/global-env.rkt     | 4 ++--
 .../typed-racket/typecheck/tc-toplevel.rkt               | 3 ++-
 .../tests/typed-racket/succeed/toplevel-redefinition.rkt | 9 +++++++++
 3 files changed, 13 insertions(+), 3 deletions(-)
 create mode 100644 pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/succeed/toplevel-redefinition.rkt

diff --git a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/env/global-env.rkt b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/env/global-env.rkt
index be37369e..4fe82b6e 100644
--- a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/env/global-env.rkt
+++ b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/env/global-env.rkt
@@ -73,8 +73,8 @@
 (define (unregister-type id)
   (free-id-table-remove! the-mapping id))
 
-(define (finish-register-type id)
-  (unless (maybe-finish-register-type id)
+(define (finish-register-type id [top-level? #f])
+  (unless (or top-level? (maybe-finish-register-type id))
     (tc-error/expr #:stx id "Duplicate definition for ~a" (syntax-e id)))
   (void))
 
diff --git a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/typecheck/tc-toplevel.rkt b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/typecheck/tc-toplevel.rkt
index 8635473b..db884bfb 100644
--- a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/typecheck/tc-toplevel.rkt
+++ b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/typecheck/tc-toplevel.rkt
@@ -167,7 +167,8 @@
               (map make-def-binding vars ts))]
            ;; if this already had an annotation, we just construct the binding reps
            [(andmap (lambda (s) (lookup-type s (lambda () #f))) vars)
-            (for-each finish-register-type vars)
+            (define top-level? (eq? (syntax-local-context) 'top-level))
+            (for ([var (in-list vars)]) (finish-register-type var top-level?))
             (map (lambda (s) (make-def-binding s (lookup-type s))) vars)]
            ;; special case to infer types for top level defines
            [else
diff --git a/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/succeed/toplevel-redefinition.rkt b/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/succeed/toplevel-redefinition.rkt
new file mode 100644
index 00000000..f3133c3c
--- /dev/null
+++ b/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/succeed/toplevel-redefinition.rkt
@@ -0,0 +1,9 @@
+#lang racket/load
+
+;; Test that variable redefinition works at the top-level
+
+(require typed/racket)
+(: x Integer)
+(define x 3)
+(define x 5)
+