diff --git a/collects/typed-racket/base-env/for-clauses.rkt b/collects/typed-racket/base-env/for-clauses.rkt
index 3e36b812..75c2d604 100644
--- a/collects/typed-racket/base-env/for-clauses.rkt
+++ b/collects/typed-racket/base-env/for-clauses.rkt
@@ -8,6 +8,7 @@
 
 ;; intersperses "#:when #t" clauses to emulate the for* variants' semantics
 (define-splicing-syntax-class for-clause
+  #:description "for clause"
   ;; single-valued seq-expr
   (pattern (~and c (var:optionally-annotated-name seq-expr:expr))
            #:with (expand ...) #`(#,(syntax/loc #'c
@@ -25,3 +26,18 @@
   (pattern (~seq (~and kw (~or #:when #:unless #:break #:final)) guard:expr)
            #:with (expand ...) (list #'kw #'guard)
            #:with (expand* ...) #'(expand ...)))
+
+(define-syntax-class for-clauses
+  #:description "for clauses"
+  #:attributes ((expand 2) (expand* 2))
+  (pattern (:for-clause ...)))
+
+(define-syntax-class accumulator-binding
+  #:description "accumumulator binding"
+  #:attributes (ann-name init ty)
+  (pattern (:annotated-name init:expr)))
+
+(define-syntax-class accumulator-bindings
+  #:description "accumumulator bindings"
+  #:attributes ((ann-name 1) (init 1) (ty 1))
+  (pattern (:accumulator-binding ...)))
diff --git a/collects/typed-racket/base-env/prims.rkt b/collects/typed-racket/base-env/prims.rkt
index 44816fd7..b606f4ef 100644
--- a/collects/typed-racket/base-env/prims.rkt
+++ b/collects/typed-racket/base-env/prims.rkt
@@ -791,7 +791,7 @@ This file defines two sorts of primitives. All of them are provided into any mod
   (lambda (stx)
     (syntax-parse stx #:literals (:)
       [(_ a:optional-standalone-annotation
-          (clause:for-clause ...)
+          clause:for-clauses
           c ...) ; c is not always an expression, can be a break-clause
        (maybe-annotate-body
         (quasisyntax/loc stx
@@ -823,7 +823,7 @@ This file defines two sorts of primitives. All of them are provided into any mod
   (syntax-parse stx #:literals (:)
     [(_ : ty
         ((var:optionally-annotated-name) ...)
-        (clause:for-clause ...)
+        clause:for-clauses
         c ...) ; c is not always an expression, can be a break-clause
      (syntax-property
       (quasisyntax/loc stx
@@ -833,7 +833,7 @@ This file defines two sorts of primitives. All of them are provided into any mod
       'type-ascription
       #'ty)]
     [(_ ((var:annotated-name) ...)
-        (clause:for-clause ...)
+        clause:for-clauses
         c ...)
      (syntax-property
       (quasisyntax/loc stx
@@ -846,7 +846,7 @@ This file defines two sorts of primitives. All of them are provided into any mod
   (syntax-parse stx #:literals (:)
     [(_ : ty
         ((var:optionally-annotated-name init:expr) ...)
-        (clause:for-clause ...)
+        clause:for-clauses
         c ...) ; c is not always an expression, can be a break-clause
      (syntax-property
       (quasisyntax/loc stx
@@ -855,22 +855,22 @@ This file defines two sorts of primitives. All of them are provided into any mod
           c ...))
       'type-ascription
       #'ty)]
-    [(_ ((var:annotated-name init:expr) ...)
-        (clause:for-clause ...)
+    [(_ accum:accumulator-bindings
+        clause:for-clauses
         c ...)
      (syntax-property
       (quasisyntax/loc stx
-        (for/fold ((var.ann-name init) ...)
+        (for/fold ((accum.ann-name accum.init) ...)
           (clause.expand ... ...)
           c ...))
       'type-ascription
-      #'(values var.ty ...))]))
+      #'(values accum.ty ...))]))
 
 
 (define-syntax (for*: stx)
   (syntax-parse stx #:literals (:)
     [(_ (~seq : Void) ...
-        (clause:for-clause ...)
+        clause:for-clauses
         c ...) ; c is not always an expression, can be a break-clause
      (quasisyntax/loc stx
        (for: (clause.expand* ... ...)
@@ -881,7 +881,7 @@ This file defines two sorts of primitives. All of them are provided into any mod
   (lambda (stx)
     (syntax-parse stx #:literals (:)
       [(_ a:optional-standalone-annotation
-          (clause:for-clause ...)
+          clause:for-clauses
           c ...) ; c is not always an expression, can be a break-clause
        (maybe-annotate-body
         (quasisyntax/loc stx
@@ -907,7 +907,7 @@ This file defines two sorts of primitives. All of them are provided into any mod
   (syntax-parse stx #:literals (:)
     [(_ : ty
         ((var:optionally-annotated-name) ...)
-        (clause:for-clause ...)
+        clause:for-clauses
         c ...) ; c is not always an expression, can be a break-clause
      (syntax-property
       (quasisyntax/loc stx
@@ -917,7 +917,7 @@ This file defines two sorts of primitives. All of them are provided into any mod
       'type-ascription
       #'ty)]
     [(_ ((var:annotated-name) ...)
-        (clause:for-clause ...)
+        clause:for-clauses
         c ...)
      (syntax-property
       (quasisyntax/loc stx
@@ -930,7 +930,7 @@ This file defines two sorts of primitives. All of them are provided into any mod
   (syntax-parse stx #:literals (:)
     [(_ : ty
         ((var:optionally-annotated-name init:expr) ...)
-        (clause:for-clause ...)
+        clause:for-clauses
         c ...) ; c is not always an expression, can be a break-clause
      (syntax-property
       (quasisyntax/loc stx
@@ -940,7 +940,7 @@ This file defines two sorts of primitives. All of them are provided into any mod
       'type-ascription
       #'ty)]
     [(_ ((var:annotated-name init:expr) ...)
-        (clause:for-clause ...)
+        clause:for-clauses
         c ...)
      (syntax-property
       (quasisyntax/loc stx
@@ -954,7 +954,7 @@ This file defines two sorts of primitives. All of them are provided into any mod
   (lambda (stx)
     (syntax-parse stx #:literals (:)
       [(_ a:optional-standalone-annotation
-          (clause:for-clause ...)
+          clause:for-clauses
           c ...) ; c is not always an expression, can be a break-clause
        (cond
         [(syntax-e #'a.ty)