more progress on bounded polymorphism

Author: capfredf

typed-racket-lib/typed-racket/infer/infer-unit.rkt

@@ -623,6 +623,10 @@
          (let ([s (resolve-once s)])
            (and s (cg s t obj)))]
 
+        [((F: var (? Type? bound)) t)
+         (let ([s (resolve-once bound)])
+           (and s (cg s t obj)))]
+
         ;; constrain b1 to be below T, but don't mention the new vars
         [((Poly: v1 b1) T) (cgen (context-add context #:bounds v1) b1 T)]
 

typed-racket-lib/typed-racket/rep/type-rep.rkt

@@ -1691,7 +1691,12 @@
        (int-err "Wrong number of names: expected ~a got ~a" n (length names)))
      (instantiate-type body
                        (map (lambda (n)
-                              (make-F n (hash-ref new-bounds n #f)))
+                              (define v (match (hash-ref new-bounds n #f)
+                                          [(App: rator (list (F: vb _)))
+                                           #:when (hash-has-key? new-bounds vb)
+                                           (make-App rator (list (hash-ref new-bounds vb)))]
+                                          [_else _else]))
+                              (make-F n v))
                         names))]))
 
 ;; PolyDots 'smart' constructor

typed-racket-test/succeed/bounded-poly.rkt

@@ -17,3 +17,10 @@
   (number->string a))
 
 (c-func 10 (foo 10))
+
+(: d-func (All ([X <: Integer] [Y <: (Foo X)])
+               (-> X Y String)))
+(define (d-func a b)
+  (number->string (foo-a b)))
+
+(d-func 42 (foo 10))