diff --git a/collects/mzlib/class.ss b/collects/mzlib/class.ss
index 6ad0afb..852a0a0 100644
--- a/collects/mzlib/class.ss
+++ b/collects/mzlib/class.ss
@@ -752,12 +752,13 @@
 				 [body-exprs (if (null? body-exprs)
 						 (syntax ((void)))
 						 body-exprs)]
-				 [init (datum->syntax 
+				 [init (datum->syntax-object
+					#f
 					(if name
 					    (string->symbol (format "~a-init" name))
 					    'init)
-					#f #f)]
-				 [name (datum->syntax name #f #f)])
+					#f)]
+				 [name (datum->syntax-object #f name #f)])
 		     (with-syntax ([go 
 				    ;; Create a sequence of case-lambda
 				    ;; clauses, to implement init variable defaults:
@@ -801,7 +802,8 @@
 						(syntax ([(var ... wd-var ...) (init var ... wd-var ... needs-init)]
 							 . rest)))
 					      (syntax rest)))]))]
-				   [go-arity (datum->syntax
+				   [go-arity (datum->syntax-object
+					      #f
 					      (let ([req (let loop ([l init-defs][c 0])
 							   (if (or (null? l) (car l))
 							       c
@@ -816,7 +818,7 @@
 							(list req)
 							(cons req (loop (add1 req)))))]
 						 [else req]))
-					      #f #f)])
+					      #f)])
 		       ;; Assemble the result as a `compose-class-info' call,
 		       ;; which does all the run-time checks, and knows how
 		       ;; to allocate objects and pass boxes to the init
@@ -919,8 +921,8 @@
 	    (interface-expr ...)
 	    init-vars
 	    clauses ...)
-	 (with-syntax ([this (datum->syntax 'this stx (stx-car stx))]
-		       [super-init (datum->syntax 'super-init stx (stx-car stx))])
+	 (with-syntax ([this (datum->syntax-object (stx-car stx) 'this stx)]
+		       [super-init (datum->syntax-object (stx-car stx) 'super-init stx)])
 	   (syntax/loc
 	    stx
 	    (class*/names (this super-init)
@@ -935,7 +937,7 @@
 	[(_ super-expr
 	    init-vars
 	    clauses ...)
-	 (with-syntax ([class* (datum->syntax 'class* stx (stx-car stx))])
+	 (with-syntax ([class* (datum->syntax-object (stx-car stx) 'class* stx)])
 	   (syntax/loc stx (class* super-expr () init-vars clauses ...)))])))
 
   (define-syntax class*-asi
@@ -972,7 +974,7 @@
 				   "duplicate name"
 				   stx
 				   dup)))
-	   (with-syntax ([name (datum->syntax name #f #f)])
+	   (with-syntax ([name (datum->syntax-object #f name #f)])
 	     (syntax/loc
 	      stx
 	      (compose-interface
diff --git a/collects/mzlib/cmdline.ss b/collects/mzlib/cmdline.ss
index 63bb3db..8532075 100644
--- a/collects/mzlib/cmdline.ss
+++ b/collects/mzlib/cmdline.ss
@@ -27,11 +27,13 @@
 		  (lambda (l)
 		    (map
 		     (lambda (a)
-		       (datum->syntax (let ([s (symbol->string (syntax-e a))])
-					(if (char=? #\* (string-ref s (sub1 (string-length s))))
-					    (substring s 0 (sub1 (string-length s)))
-					    s))
-				      #f (quote-syntax here)))
+		       (datum->syntax-object
+			(quote-syntax here)
+			(let ([s (symbol->string (syntax-e a))])
+			  (if (char=? #\* (string-ref s (sub1 (string-length s))))
+			      (substring s 0 (sub1 (string-length s)))
+			      s))
+			#f))
 		     l))])
 	     (let ([clauses
 		    (let loop ([csrcs (syntax->list (syntax (clause ...)))][clauses null])
diff --git a/collects/mzlib/compat.ss b/collects/mzlib/compat.ss
index 38519a3..fe159fc 100644
--- a/collects/mzlib/compat.ss
+++ b/collects/mzlib/compat.ss
@@ -94,8 +94,10 @@
 				 (map syntax-e 
 				      (syntax->list (syntax (init-field ...)))))]
 	       [+ (lambda args
-		    (datum->syntax (string->symbol (apply string-append args)) 
-				   (syntax sname) (syntax sname)))])
+		    (datum->syntax-object
+		     (syntax sname)
+		     (string->symbol (apply string-append args)) 
+		     (syntax sname)))])
 	   (with-syntax ([struct: (+ "struct:" name)]
 			 [make- (+ "make-" name)]
 			 [? (+ name "?")]
diff --git a/collects/mzlib/include.ss b/collects/mzlib/include.ss
index 5729dbc..c368887 100644
--- a/collects/mzlib/include.ss
+++ b/collects/mzlib/include.ss
@@ -18,7 +18,7 @@
 		       (module-identifier=? e (quote-syntax up))
 		       (module-identifier=? e (quote-syntax same))))
 		 (syntax->list (syntax (elem1 elem ...))))
-		(apply build-path (syntax->datum (syntax (elem1 elem ...))))])])
+		(apply build-path (syntax-object->datum (syntax (elem1 elem ...))))])])
 	;; Complete the file name
 	(let ([c-file
 	       (if (complete-path? file)
@@ -83,22 +83,22 @@
 			[(null? content) null]
 			[else
 			 (let ([v (syntax-e content)])
-			   (datum->syntax
+			   (datum->syntax-object
+			    stx
 			    (cond
 			     [(pair? v) 
 			      (loop v)]
-			    [(vector? v)
-			     (list->vector (loop (vector->list v)))]
-			    [(box? v)
-			     (box (loop (unbox v)))]
-			    [else
-			     v])
-			    content
-			    stx))]))])
-		(datum->syntax 
+			     [(vector? v)
+			      (list->vector (loop (vector->list v)))]
+			     [(box? v)
+			      (box (loop (unbox v)))]
+			     [else
+			      v])
+			    content))]))])
+		(datum->syntax-object
+		 (quote-syntax here)
 		 `(begin ,@lexed-content)
-		 stx
-		 (quote-syntax here)))))))))
+		 stx))))))))
 
   (provide include))
 
diff --git a/collects/mzlib/match.ss b/collects/mzlib/match.ss
index 0ac91be..d2eb04a 100644
--- a/collects/mzlib/match.ss
+++ b/collects/mzlib/match.ss
@@ -134,7 +134,7 @@
        (define (i v) (match:syntax-err p (format "illegal use of ~a" v)))
        (syntax-case p (_ quote $ ? and or not set! get! quasiquote ... ___)
 	 [_ '_]
-	 [(quote x) `(quote ,(syntax->datum (syntax x)))]
+	 [(quote x) `(quote ,(syntax-object->datum (syntax x)))]
 	 [(quote . _) (i "quote")]
 	 [($ struct p ...)
 	  `($ struct ,@(r (syntax (p ...))))]
@@ -199,7 +199,7 @@
 	  `(,(parse-quasipattern (syntax p)) ,(syntax-e (syntax ..k)))]
 	 [(i . rest)
 	  (identifier? (syntax i))
-	  `(,(syntax->datum (syntax i)) ,@(parse-quasipattern (syntax rest)))]
+	  `(,(syntax-object->datum (syntax i)) ,@(parse-quasipattern (syntax rest)))]
          [(qp . rest)
 	  `(,(parse-quasipattern (syntax qp)) ,@(parse-quasipattern (syntax rest)))]
 	 [_else
@@ -218,7 +218,8 @@
      (syntax-case stx ()
        [(_ exp clause ...)
 	(with-syntax ([body
-		       (datum->syntax
+		       (datum->syntax-object
+			(quote-syntax here)
 			(genmatch
 			 (quote-syntax mv)
 			 (map
@@ -237,7 +238,7 @@
 				"bad match clause")]))
 			  (syntax->list (syntax (clause ...))))
 			 stx)
-			stx (quote-syntax here))])
+			stx)])
 	  (syntax
 	   (let ([mv exp])
 	     body)))])))
@@ -274,20 +275,22 @@
    (lambda (stx)
      (syntax-case stx ()
        [(_ ([pat exp] ...) body1 body ...)
-	(datum->syntax
+	(datum->syntax-object
+	 (quote-syntax here)
 	 (genletrec 
 	  (map (lambda (p) (:ucall parse-pattern p)) (syntax->list (syntax (pat ...))))
 	  (syntax->list (syntax (exp ...)))
 	  (syntax->list (syntax (body1 body ...)))
 	  stx)
-	 stx (quote-syntax here))])))
+	 stx)])))
 
  (define-syntax match-define
    (lambda (stx)
      (syntax-case stx ()
        [(_ pat exp)
-	(datum->syntax
+	(datum->syntax-object
+	 (quote-syntax here)
 	 (gendefine (map (lambda (p) (:ucall parse-pattern p)) (syntax pat))
 		    (syntax exp)
 		    stx)
-	 stx (quote-syntax here))]))))
+	 stx)]))))
diff --git a/collects/mzlib/private/sigutil.ss b/collects/mzlib/private/sigutil.ss
index fac6689..510b7e1 100644
--- a/collects/mzlib/private/sigutil.ss
+++ b/collects/mzlib/private/sigutil.ss
@@ -93,7 +93,7 @@
 		  (map (lambda (n)
 			 (if (syntax? n)
 			     n
-			     (datum->syntax n #f #f)))
+			     (datum->syntax-object #f n #f)))
 		       names))])
 	(when dup
 	  (error-k dup)))))
@@ -104,7 +104,7 @@
 	    [fields (map symbol->string (map syntax-e fields))]
 	    [+ string-append])
 	(map (lambda (s)
-	       (datum->syntax (string->symbol s) #f name-stx))
+	       (datum->syntax-object name-stx (string->symbol s) #f))
 	     (append
 	      (list 
 	       (+ "make-" name)
@@ -430,7 +430,7 @@
 			(if (and (stx-pair? body)
 				 (stx-pair? (car body))
 				 (eq? 'rename (syntax-e (stx-car (car body)))))
-			    (values (map syntax->datum (cdr (stx->list (car body)))) (cdr body))
+			    (values (map syntax-object->datum (cdr (stx->list (car body)))) (cdr body))
 			    (values null body))])
 	    (unless renames
 	      (syntax-error 'unit/sig expr "illegal use of `.'" (car body)))
diff --git a/collects/mzlib/private/unitidmap.ss b/collects/mzlib/private/unitidmap.ss
index b7d0501..cbb04ea 100644
--- a/collects/mzlib/private/unitidmap.ss
+++ b/collects/mzlib/private/unitidmap.ss
@@ -2,7 +2,7 @@
 (module unitidmap mzscheme
 
   (define (make-id-mapper unbox-stx)
-    (let ([set!-stx (datum->syntax 'set! #f unbox-stx)])
+    (let ([set!-stx (datum->syntax-object unbox-stx 'set! #f)])
       (make-set!-transformer
        (lambda (sstx)
 	 (cond
@@ -13,10 +13,10 @@
 	    "cannot set! imported or exported variables"
 	    sstx)]
 	  [else
-	   (datum->syntax
+	   (datum->syntax-object
+	    set!-stx
 	    (cons unbox-stx (cdr (syntax-e sstx)))
-	    sstx
-	    set!-stx)])))))
+	    sstx)])))))
 
   (provide make-id-mapper))
 
diff --git a/collects/mzlib/shared.ss b/collects/mzlib/shared.ss
index f5d79c6..52496a1 100644
--- a/collects/mzlib/shared.ss
+++ b/collects/mzlib/shared.ss
@@ -64,7 +64,7 @@
 					 (let loop ([l l][n 0])
 					   (if (null? l)
 					       null
-					       (cons (datum->syntax n #f (quote-syntax here))
+					       (cons (datum->syntax-object (quote-syntax here) n #f)
 						     (loop (cdr l) (add1 n))))))])
 			    (map (lambda (name expr)
 				   (with-syntax ([name name])
diff --git a/collects/mzlib/trace.ss b/collects/mzlib/trace.ss
index bec614e..c2319f8 100644
--- a/collects/mzlib/trace.ss
+++ b/collects/mzlib/trace.ss
@@ -164,11 +164,12 @@
 		     ids)
 	   (with-syntax ([(traced-name ...)
 			  (map (lambda (id)
-				 (datum->syntax
+				 (datum->syntax-object
+				  id
 				  (string->symbol
 				   (string-append "traced-"
 						  (symbol->string (syntax-e id))))
-				  #f id))
+				  #f))
 			       ids)])
 	     (syntax
 	      (begin
diff --git a/collects/mzlib/unit.ss b/collects/mzlib/unit.ss
index 6f8c752..42173c5 100644
--- a/collects/mzlib/unit.ss
+++ b/collects/mzlib/unit.ss
@@ -238,9 +238,10 @@
 						[var (make-id-mapper (quote-syntax (unbox loc)))])))
 					   (syntax->list 
 					    (syntax ((ivar iloc) ... (expname eloc) ...))))]
-					 [num-imports (datum->syntax 
+					 [num-imports (datum->syntax-object
+						       (quote-syntax here)
 						       (length (syntax->list (syntax (iloc ...))))
-						       #f (quote-syntax here))])
+						       #f)])
 			     (syntax/loc
 			      stx
 			      (make-unit
@@ -522,10 +523,10 @@
 						   [id e])))])
 				      (with-syntax ([ex-poss ex-poss]
 						    [setup setup]
-						    [pos (datum->syntax 
+						    [pos (datum->syntax-object
+							  (quote-syntax here)
 							  pos
-							  #f
-							  (quote-syntax here))])
+							  #f)])
 					(syntax 
 					 (vector-ref (car setup)
 						     (vector-ref ex-poss pos))))))
@@ -543,18 +544,21 @@
 				     [(import-mapping ...) import-mappings]
 				     [(unit-import-count ...) 
 				      (map (lambda (l) 
-					     (datum->syntax (apply
-							     +
-							     (map (lambda (v)
-								    (if (identifier? v)
-									1
-									(length (cdr (syntax->list v)))))
-								  l))
-							    #f
-							    (quote-syntax here)))
+					     (datum->syntax-object
+					      (quote-syntax here)
+					      (apply
+					       +
+					       (map (lambda (v)
+						      (if (identifier? v)
+							  1
+							  (length (cdr (syntax->list v)))))
+						    l))
+					      #f))
 					   linkages)]
-				     [num-imports (datum->syntax (length imports)
-								 #f (quote-syntax here))]
+				     [num-imports (datum->syntax-object
+						   (quote-syntax here)
+						   (length imports)
+						   #f)]
 				     [export-names export-names]
 				     [export-mapping export-mapping])
 			 (syntax/loc
@@ -598,9 +602,10 @@
 	[(_ unit-expr expr ...)
 	 (let ([exprs (syntax (expr ...))])
 	   (with-syntax ([(bx ...) (generate-temporaries (syntax (expr ...)))]
-			 [num (datum->syntax (length (syntax->list exprs)) 
-					     #f 
-					     (quote-syntax here))])
+			 [num (datum->syntax-object
+			       (quote-syntax here)
+			       (length (syntax->list exprs)) 
+			       #f)])
 	     (syntax/loc
 	      stx
 	      (let ([u unit-expr])
@@ -639,12 +644,13 @@
 					      (syntax-e (syntax prefix)))
 					     ":")])
 				(map (lambda (s)
-				       (datum->syntax
+				       (datum->syntax-object
+					s
 					(string->symbol
 					 (string-append
 					  prefix
 					  (symbol->string (syntax-e s))))
-					s s))
+					s))
 				     (syntax->list (syntax exports))))
 			      (syntax exports))]
 			 [extract-unit (syntax (unit
diff --git a/collects/mzlib/unitsig.ss b/collects/mzlib/unitsig.ss
index b770198..4fbc739 100644
--- a/collects/mzlib/unitsig.ss
+++ b/collects/mzlib/unitsig.ss
@@ -42,16 +42,18 @@
 				    (quote-syntax define-values)
 				    (quote-syntax begin))])
 	    (check-signature-unit-body sig a-unit (parse-unit-renames a-unit) 'unit/sig expr)
-	    (with-syntax ([imports (datum->syntax
+	    (with-syntax ([imports (datum->syntax-object
+				    expr
 				    (flatten-signatures (parse-unit-imports a-unit))
-				    expr expr)]
-			  [exports (datum->syntax
+				    expr)]
+			  [exports (datum->syntax-object
+				    expr
 				    (map
 				     (lambda (name)
 				       (list (do-rename name (parse-unit-renames a-unit))
 					     name))
 				     (signature-vars sig))
-				    expr expr)]
+				    expr)]
 			  [body (reverse! (parse-unit-body a-unit))]
 			  [import-sigs (explode-named-sigs (parse-unit-imports a-unit))]
 			  [export-sig (explode-sig sig)])
@@ -78,7 +80,7 @@
 			exploded-imports
 			exploded-exports)
 		       (parse-compound-unit expr (syntax body))]
-		      [(t) (lambda (l) (datum->syntax l expr expr))])
+		      [(t) (lambda (l) (datum->syntax-object expr l expr))])
 	   (with-syntax ([(tag ...) (t tags)]
 			 [(uexpr ...) (t exprs)]
 			 [(tagx ...) (t (map (lambda (t) (string->symbol (format "u:~a" t))) tags))]
@@ -114,10 +116,14 @@
       (syntax-case expr ()
 	[(_ u sig ...)
 	 (let ([sigs (parse-invoke-vars 'invoke-unit/sig (syntax (sig ...)) expr)])
-	   (with-syntax ([exploded-sigs (datum->syntax (explode-named-sigs sigs) 
-						       expr expr)]
-			 [flat-sigs (datum->syntax (flatten-signatures sigs) 
-						   expr expr)])
+	   (with-syntax ([exploded-sigs (datum->syntax-object
+					 expr
+					 (explode-named-sigs sigs) 
+					 expr)]
+			 [flat-sigs (datum->syntax-object
+				     expr
+				     (flatten-signatures sigs) 
+				     expr)])
 	     (syntax/loc
 	      expr
 	      (let ([unt u])
@@ -138,10 +144,14 @@
 			       (get-sig 'unit->unit/sig expr #f sig))
 			     (syntax->list (syntax (im-sig ...))))]
 	       [ex-sig (get-sig 'unit->unit/sig expr #f (syntax ex-sig))])
-	   (with-syntax ([exploded-imports (datum->syntax (explode-named-sigs im-sigs)
-							  expr expr)]
-			 [exploded-exports (datum->syntax (explode-sig ex-sig)
-							  expr expr)])
+	   (with-syntax ([exploded-imports (datum->syntax-object
+					    expr
+					    (explode-named-sigs im-sigs)
+					    expr)]
+			 [exploded-exports (datum->syntax-object
+					    expr
+					    (explode-sig ex-sig)
+					    expr)])
 	     (syntax
 	      (make-unit/sig
 	       e
@@ -243,7 +253,7 @@
 		       (syntax->list (syntax imports)))])
 		 (let ([im-explodeds (explode-named-sigs im-sigs)]
 		       [im-flattened (apply append (map (lambda (x) (flatten-signature #f x)) im-sigs))]
-		       [d->s (lambda (x) (datum->syntax x (syntax orig) (syntax orig)))])
+		       [d->s (lambda (x) (datum->syntax-object (syntax orig) x (syntax orig)))])
 		   (with-syntax ([dv/iu (if (syntax-e (syntax global?))
 					    (quote-syntax global-define-values/invoke-unit)
 					    (quote-syntax define-values/invoke-unit))]
@@ -291,7 +301,7 @@
 	  [(_ signame)
 	   (let ([sig (get-sig 'provide-signature-elements stx #f (syntax signame))])
 	     (let ([flattened (flatten-signature #f sig)])
-	       (with-syntax ([flattened (map (lambda (x) (datum->syntax x #f (syntax signame)))
+	       (with-syntax ([flattened (map (lambda (x) (datum->syntax-object (syntax signame) x #f))
 					     flattened)])
 		 (syntax
 		  (provide . flattened)))))]))))