.

original commit: 4cb555c73d84cfb4a761ea2180960459ed789691

collects/mzlib/etc.ss

@@ -2,7 +2,8 @@
 (module etc mzscheme
   (require "spidey.ss")
   (require-for-syntax (lib "kerncase.ss" "syntax")
-		      (lib "stx.ss" "syntax"))
+		      (lib "stx.ss" "syntax")
+		      "private/stxset.ss")
 
   (provide true false
 	   boolean=? symbol=?
@@ -434,6 +435,10 @@
 	    (syntax (or (current-load-relative-directory)
 			(current-directory)))))]))
 
+ ;; This is a macro-generating macro that wants to expand
+ ;; expressions used in the generated macro. So it's weird,
+ ;; and we put much of the work in a helper macro,
+ ;; `finish-syntax-set'.
  (define-syntax (define-syntax-set stx)
    (syntax-case stx ()
      [(_ (id ...) defn ...)
@@ -454,21 +459,11 @@
 	     "duplicate identifier"
 	     stx
 	     dup)))
-	 (let ([internal-ids (map (lambda (id)
-				    (datum->syntax-object
-				     id
-				     (string->symbol (format "~a/proc" (syntax-e id)))
-				     id))
-				  ids)])
-	   
 
 	;; We'd like to check the `defns', but that requires
-	   ;; and expansion in a different phase. So we punt for now.
+	;; and expansion in a different phase. So we move
-	   
+	;; into that phase using `finish-syntax-set':
-	   ;; Produce result ------------------------------
+	(with-syntax ([orig-stx stx])
-	   (with-syntax ([(int-id ...) internal-ids])
 	  (syntax/loc stx
 	    (define-syntaxes (id ...)
-		 (let ()
+	      (finish-syntax-set orig-stx)))))])))
-		   defn ...
-		   (values int-id ...)))))))])))