diff --git a/scheme/ikarus.compiler.altcogen.ss b/scheme/ikarus.compiler.altcogen.ss
index 5050d8d..4308469 100644
--- a/scheme/ikarus.compiler.altcogen.ss
+++ b/scheme/ikarus.compiler.altcogen.ss
@@ -282,7 +282,7 @@
       [(conditional e0 e1 e2) (or (NonTail e0) (NonTail e1) (NonTail e2))]
       [(seq e0 e1)            (or (NonTail e0) (NonTail e1))]
       [(forcall op arg*)      (ormap NonTail arg*)]
-      [(known x t v) (NonTail x)]
+      [(known x t) (NonTail x)]
       [else (error who "invalid expr" x)]))
   (define (Tail x) 
     (struct-case x
diff --git a/scheme/last-revision b/scheme/last-revision
index adb88b7..fc93fdd 100644
--- a/scheme/last-revision
+++ b/scheme/last-revision
@@ -1 +1 @@
-1772
+1773
diff --git a/scheme/pass-specify-rep.ss b/scheme/pass-specify-rep.ss
index 8e186ae..2b384b8 100644
--- a/scheme/pass-specify-rep.ss
+++ b/scheme/pass-specify-rep.ss
@@ -418,7 +418,7 @@
       [(funcall) (prm '!= (V x) (V (K #f)))]
       [(jmpcall) (prm '!= (V x) (V (K #f)))]
       [(forcall) (prm '!= (V x) (V (K #f)))]
-      [(known expr type val)
+      [(known expr type)
        ;;; FIXME: suboptimal
        (P expr)]
       [else (error 'cogen-P "invalid pred expr" x)])) 
@@ -446,7 +446,7 @@
        (make-funcall (Function rator) (map V arg*))]
       [(jmpcall label rator arg*)
        (make-jmpcall label (V rator) (map V arg*))]
-      [(known expr type val)
+      [(known expr type)
        ;;; FIXME: suboptimal
        (E expr)]
       [else (error 'cogen-E "invalid effect expr" x)]))
@@ -485,7 +485,7 @@
                     (K (- disp-symbol-record-proc symbol-ptag))))]
             [else (nonproc x check?)])]
          [(primref op) (V x)]
-         [(known x t v)
+         [(known x t)
           (cond
             [(eq? (T:procedure? t) 'yes)
              ;(record-optimization 'procedure x)