Changed treelist-flatten to Any -> TreeListof Any, removed incorrect ToDos regarding Mutable/Immutable TreeLists, added shallow annotations

Author: Ryan Ficklin

typed-racket-lib/typed-racket/base-env/base-env.rkt

@@ -1311,7 +1311,7 @@
 [treelist-cons (-poly (a) (-> (-treelist a) a (-treelist a)))]
 [treelist-delete (-poly (a) (-> (-treelist a) -Index (-treelist a)))]
 [make-treelist (-poly (a) (-> -Nat a (-treelist a)))]
-[treelist-ref (-poly (a) (-> (-treelist a) -Index a))]
+[treelist-ref (-poly (a) (-> (-treelist a) -Index a :T+ #f))]
 [treelist-insert (-poly (a) (-> (-treelist a) -Index a (-treelist a)))]
 [treelist-set (-poly (a) (-> (-treelist a) -Index a (-treelist a)))]
 [treelist-take (-poly (a) (-> (-treelist a) -Index (-treelist a)))]
@@ -1330,13 +1330,13 @@
 [treelist-map (-poly (a b) (-> (-treelist a) (-> a b) (-treelist b)))]
 [treelist-for-each (-poly (a b) (-> (-treelist a) (-> a b) -Void))]
 [treelist-filter (-poly (a) (-> (-> a Univ) (-treelist a) (-treelist a)))]
-[treelist-find (-poly (a) (-> (-treelist a) (-> a Univ) a))]
+[treelist-find (-poly (a) (-> (-treelist a) (-> a Univ) a :T+ #f))]
 [treelist-index-of
  (-poly (a)
         (cl->* ((-treelist a) a . -> . -Index)
                ((-treelist a) a (-> a a Univ) . -> . -Index)))]
-[treelist-flatten (-poly (a) (-> a (-treelist a)))] ;; This type isn't any more or less pratical than Univ, but Univ might not be sound
-[treelist-append* (-poly (a) (-> (-treelist (-treelist a)) (-treelist a)))] ;; Same type specificty issue as above
+[treelist-flatten (Univ . -> . (-treelist Univ))]
+[treelist-append* (-poly (a) (-> (-treelist (-treelist a)) (-treelist a)))]
 [treelist-sort
 (-poly
   (a b)

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

@@ -354,10 +354,9 @@
   [#:mask mask:set])
 
 ;;------
-;; Treelist
+;; Treelist (Immutable)
 ;;------
 
-;; TODO separate mutable/immutable treelist types
 (def-structural TreeList ([elem #:covariant])
   [#:mask mask:treelist])
 

typed-racket-lib/typed-racket/static-contracts/combinators/derived.rkt

@@ -31,7 +31,6 @@
 (define set?/sc (flat/sc #'(lambda (x) (or (set? x) (set-mutable? x) (set-weak? x)))))
 (define empty-set/sc (and/sc set?/sc (flat/sc #'set-empty?)))
 
-;; TODO: Split TreeList into Mutable and Immutable
 (define treelist?/sc (flat/sc #'treelist?))
 (define empty-treelist/sc (and/sc treelist?/sc (flat/sc #'treelist-empty?)))
 

typed-racket-test/unit-tests/typecheck-tests.rkt

@@ -1951,9 +1951,8 @@
         (tc-e (treelist-for-each (treelist "a" "b") (λ (x) x)) -Void)
         (tc-e (treelist-find (treelist "a" "b") (λ (x) (if (equal? x "a") #t #f))) -String)
         (tc-e (treelist-filter even? (treelist 1 2 3 4 5)) (-treelist -PosByte))
-        (tc-e (treelist-flatten (treelist (treelist (treelist (treelist "a")))))
-              (-treelist (-treelist (-treelist (-treelist (-treelist -String)))))) ;;FIXME: this type is unpleasant
-        (tc-e (treelist-flatten "a") (-treelist -String))
+        (tc-e (treelist-flatten (treelist (treelist (treelist (treelist "a"))))) (-treelist Univ))
+        (tc-e (treelist-flatten "a") (-treelist Univ))
         (tc-e (treelist-append* (treelist (treelist "a" "b") (treelist "c" (treelist "d") "e") (treelist))) (-treelist Univ))
         (tc-e (treelist-index-of (treelist "a" "b" "c") "b") -Index)
         (tc-e (treelist-index-of (treelist "a" "b" "c") "b" equal?) -Index)