From f77ab7177246b664b80b8d347ff12b817632bda1 Mon Sep 17 00:00:00 2001
From: Jay McCarthy <jay@racket-lang.org>
Date: Fri, 7 Jan 2011 19:49:42 -0700
Subject: [PATCH] Fixing  PR11592

---
 collects/plai/datatype.rkt | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/collects/plai/datatype.rkt b/collects/plai/datatype.rkt
index 960cbedce4..0f8f397204 100644
--- a/collects/plai/datatype.rkt
+++ b/collects/plai/datatype.rkt
@@ -352,7 +352,12 @@
     ;;; far, either the clauses are malformed or the error is completely
     ;;; unintelligible.
     [(_ type-id test-expr clauses ...)
-     (map validate-clause (syntax->list #'(clauses ...)))]
+     (begin
+       (unless (identifier? #'type-id)
+         (plai-syntax-error 'type-case #'type-id type-case:not-a-type))
+       (validate-and-remove-type-symbol #'type-id (syntax-local-value #'type-id (λ () #f)))
+       (andmap validate-clause (syntax->list #'(clauses ...)))
+       (plai-syntax-error 'type-case stx "Unknown error"))]
     [_ (plai-syntax-error 'type-case stx type-case:generic)]))