Fix for 6.4 and 6.5 where with-disappeared-uses does not allow multiple body statements.

private/define-syntax+simple-api.rkt

@@ -33,6 +33,7 @@
        #:with colon-stxclass (format-id #'cls ":~a" #'cls)
        #:with name-forward (format-id #'name "~a-forward-attributes" #'name)
        (with-disappeared-uses
+        (let ()
           (define c (syntax-local-value/record #'cls syntax/parse:stxclass?))
           (define attrs (syntax/parse:stxclass-attrs c))
           (define/with-syntax (attr-name …) (map syntax/parse:attr-name attrs))
@@ -40,7 +41,8 @@
             (stx-map (λ (a) (datum->syntax #'body (syntax-e a)))
                      #'(attr-name …)))
           (define-temp-ids "~a/arg" (attr-name …))
-        (define/with-syntax (attr-depth …) (map syntax/parse:attr-depth attrs))
+          (define/with-syntax (attr-depth …)
+            (map syntax/parse:attr-depth attrs))
           #'(begin
               (define (name stx2)
                 (syntax-parameterize ([stx (make-rename-transformer #'stx2)])
@@ -64,4 +66,4 @@
                       (attribute #,(format-id stx3 "~a.~a"
                                               #'forward-args-prefix
                                               'attr-name))
-                    …)]))))])))
+                      …)])))))])))