Fix up singleton values

collects/typed-scheme/private/infer-unit.ss

@@ -464,7 +464,7 @@
 ;; and T-dotted is the repeated type
 (define (infer/dots X dotted-var S T T-dotted R must-vars [expected #f])
   (with-handlers ([exn:infer? (lambda _ #f)])
-    (let* ([short-S (debug (take S (length T)))]
+    (let* ([short-S (take S (length T))]
            [rest-S (drop S (length T))]
            [cs-short (cgen/list null (cons dotted-var X) short-S T)]
            [new-vars (for/list ([i (in-range (length rest-S))]) (gensym dotted-var))]
@@ -484,4 +484,4 @@
 (define (i s t r)
   (infer/simple (list s) (list t) r))
 
-(trace cgen/arr cgen cgen/list)
+;;(trace cgen/arr cgen cgen/list)

collects/typed-scheme/private/type-utils.ss

@@ -56,6 +56,12 @@
                                  (make-ValuesDots (map sb types) (sb dty) dbound))])
       target))
 
+;; the other definition is not accessible here
+(define (-values args)
+  (if (= (length args) 1)
+      (car args)
+      (make-Values args)))
+
 ;; substitute-dots : Listof[Type] Option[type] Name Type -> Type
 (define (substitute-dots images rimage name target)    
   (define (sb t) (substitute-dots images rimage name t))
@@ -63,7 +69,7 @@
       (type-case sb target
                  [#:ValuesDots types dty dbound
                                (if (eq? name dbound)
-                                   (make-Values
+                                   (-values
                                     (append 
                                      (map sb types)
                                      ;; We need to recur first, just to expand out any dotted usages of this.