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commit e2b1eaa06b2c2dcc93d19bb809decedef4cc8979
parent 48b625c2f429a5be41fe3a124e7532752eab0de5
Author: Ben Greenman <types@ccs.neu.edu>
Date:   Thu, 15 Oct 2015 14:00:42 -0400

bugfix in stlc+sub: subs assumed length=?

Diffstat:
M
tapl/stlc+sub.rkt
 | 
4
+++-

1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/tapl/stlc+sub.rkt b/tapl/stlc+sub.rkt
@@ -41,7 +41,9 @@
         (Top? τ2)))
   (define current-sub? (make-parameter sub?))
   (current-typecheck-relation sub?)
-  (define (subs? τs1 τs2) (stx-andmap (current-sub?) τs1 τs2))
+  (define (subs? τs1 τs2)
+    (and (stx-length=? τs1 τs2)
+         (stx-andmap (current-sub?) τs1 τs2)))
   
   (define-syntax (define-sub-relation stx)
     (syntax-parse stx #:datum-literals (<: =>)