Fix descr edge cases (#15338)

Author: gldubc

lib/elixir/lib/module/types/descr.ex

@@ -3242,15 +3242,15 @@ defmodule Module.Types.Descr do
   end
 
   defp map_literal_intersection_closed([{k1, v1} | t1], [{k2, _} | _] = l2) when k1 < k2 do
-    if v1 == @not_set do
+    if is_optional_static(v1) do
       map_literal_intersection_closed(t1, l2)
     else
       throw(:empty)
     end
   end
 
   defp map_literal_intersection_closed([{k1, _} | _] = l1, [{k2, v2} | t2]) when k1 > k2 do
-    if v2 == @not_set do
+    if is_optional_static(v2) do
       map_literal_intersection_closed(l1, t2)
     else
       throw(:empty)
@@ -3262,8 +3262,8 @@ defmodule Module.Types.Descr do
   end
 
   defp map_literal_intersection_closed(t1, t2) do
-    if Enum.any?(t1, fn {_, v} -> v != @not_set end) or
-         Enum.any?(t2, fn {_, v} -> v != @not_set end) do
+    if Enum.any?(t1, fn {_, v} -> not is_optional_static(v) end) or
+         Enum.any?(t2, fn {_, v} -> not is_optional_static(v) end) do
       throw(:empty)
     end
 
@@ -5565,6 +5565,7 @@ defmodule Module.Types.Descr do
   @doc """
   Returns all of the values that are part of a tuple.
   """
+  def tuple_values(:term), do: :badtuple
   def tuple_values(descr) when descr == %{}, do: :badtuple
 
   def tuple_values(descr) do
@@ -5578,7 +5579,13 @@ defmodule Module.Types.Descr do
 
       {dynamic, static} ->
         if tuple_only?(static) and descr_key?(dynamic, :tuple) do
-          dynamic(process_tuples_values(Map.get(dynamic, :tuple, :bdd_bot)))
+          dynamic_value =
+            case dynamic do
+              :term -> term()
+              %{tuple: bdd} -> process_tuples_values(bdd)
+            end
+
+          dynamic(dynamic_value)
           |> union(process_tuples_values(Map.get(static, :tuple, :bdd_bot)))
         else
           :badtuple

lib/elixir/test/elixir/module/types/descr_test.exs

@@ -358,6 +358,10 @@ defmodule Module.Types.DescrTest do
                closed_map(a: integer(), c: not_set())
              ) ==
                closed_map(a: integer())
+
+      assert intersection(empty_map(), closed_map(a: if_set(integer()))) == empty_map()
+      assert intersection(closed_map(a: if_set(integer())), empty_map()) == empty_map()
+      refute disjoint?(empty_map(), closed_map(a: if_set(integer())))
     end
 
     test "map with domain keys" do
@@ -1776,6 +1780,8 @@ defmodule Module.Types.DescrTest do
     end
 
     test "tuple_values" do
+      assert tuple_values(term()) == :badtuple
+      assert tuple_values(dynamic()) == dynamic()
       assert tuple_values(integer()) == :badtuple
       assert tuple_values(tuple([none()])) == :badtuple
       assert tuple_values(tuple([])) == none()