Enable doctests on Descr, fix stale examples

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

@@ -1384,10 +1384,10 @@ defmodule Module.Types.Descr do
       {:ok, atom()}
 
       iex> fun_apply(fun([integer()], atom()), [float()])
-      :badarg
+      {:badarg, [integer()], false}
 
-      iex> fun_apply(fun([dynamic()], atom()), [dynamic()])
-      {:ok, atom()}
+      iex> fun_apply(dynamic(fun([integer()], atom())), [integer()])
+      {:ok, dynamic(atom())}
   """
   def fun_apply(:term, _arguments), do: :badfun
 
@@ -4946,12 +4946,12 @@ defmodule Module.Types.Descr do
       iex> tuple_fetch(tuple([integer(), atom()]), 0)
       {false, integer()}
 
-      iex> tuple_fetch(bare_union(tuple([integer()]), tuple([integer(), atom()])), 1)
-      {true, atom()}
-
       iex> tuple_fetch(dynamic(), 0)
       {true, dynamic()}
 
+      iex> tuple_fetch(bare_union(tuple([integer()]), tuple([integer(), atom()])), 1)
+      :badindex
+
       iex> tuple_fetch(integer(), 0)
       :badtuple
 

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

@@ -15,6 +15,7 @@ defmodule Module.Types.DescrTest do
   use ExUnit.Case, async: true
 
   import Module.Types.Descr
+  doctest Module.Types.Descr, import: true
   defmacro domain_key(arg) when is_atom(arg), do: [arg]
 
   defp number(), do: opt_union(integer(), float())