check duplicate identifiers in parametric->/c

closes PR 15017
2015-03-27 07:41:23 -05:00 · 2015-03-27 07:41:23 -05:00 · df9cd3342a
commit df9cd3342a
parent 1a5e3e5953
1 changed files with 6 additions and 0 deletions
--- a/racket/collects/racket/contract/private/parametric.rkt
+++ b/racket/collects/racket/contract/private/parametric.rkt
@ -16,6 +16,12 @@
                               "expected an identifier"
                               stx
                               x)))
+       (define dup (check-duplicate-identifier (syntax->list #'(x ...))))
+       (when dup (raise-syntax-error
+                  'parametric->/c 
+                  "duplicate identifier"
+                  stx
+                  dup))
       #`(make-polymorphic-contract opaque/c
                                    '(x ...)
                                    (lambda (x ...) c)