tuple of class

Summary:
Without this change, we don't match the old-refinement behavior w.r.t. supportdyn (https://fburl.com/code/dcmt01jv) (The ~is_class flag determines whether or not we wrap the type in supportdyn)

I noticed this when updating the `as` keyword to behave using the new refinement logic

Differential Revision: D89591115

fbshipit-source-id: 1116fc8d23a6fbf9075229c598c2637ab632ed30

Author: viratyosin

hphp/hack/src/typing/typing.ml

@@ -7993,6 +7993,13 @@ end = struct
         in
         refine_local ty env
       in
+      let rec is_class_or_tuple_of_class predicate =
+        match snd predicate with
+        | IsTag (ClassTag _) -> true
+        | IsTupleOf { tp_required } ->
+          List.exists ~f:is_class_or_tuple_of_class tp_required
+        | _ -> false
+      in
       ( env,
         refine_local
           ty_true
@@ -8002,10 +8009,7 @@ end = struct
                   Typing_logic.valid)
             in
             (env, predicate_ty))
-          ~ty_refine_is_class:
-            (match predicate with
-            | (_, IsTag (ClassTag _)) -> true
-            | _ -> false),
+          ~ty_refine_is_class:(is_class_or_tuple_of_class predicate),
         refine_local
           ty_false
           (fun env -> (env, MakeType.neg reason predicate))
@@ -8059,10 +8063,16 @@ end = struct
                  (T223013561)
               *)
               let (env, inter) = Inter.intersect_list env reason tyl in
+              let rec is_class_or_tuple_of_class ty =
+                match get_node ty with
+                | Ttuple { t_required; _ } ->
+                  List.exists t_required ~f:is_class_or_tuple_of_class
+                | _ -> Typing_utils.is_class ty
+              in
               Typing_helpers.refine_and_simplify_intersection
                 ~hint_first:false
                 env
-                ~is_class:(Typing_utils.is_class refine)
+                ~is_class:(is_class_or_tuple_of_class refine)
                 reason
                 inter
                 refine)

hphp/hack/test/typecheck/type_switch/is_tuple_of_class.php

@@ -0,0 +1,15 @@
+<?hh
+
+abstract class MyAbstract {
+  abstract const type TOutput;
+
+  abstract public function getOutput(): this::TOutput;
+}
+
+function my_fun2(MyAbstract $x): (int, dict<arraykey, mixed>) {
+  $output = tuple(0, $x->getOutput());
+  if ($output is (int, dict<_, _>)) {
+    return $output;
+  }
+  throw new Exception();
+}

hphp/hack/test/typecheck/type_switch/is_tuple_of_class.php.exp

@@ -0,0 +1 @@
+No errors