Test Broken by move to 1.14, I can't find the specific change that causes this

And in ExUnit test this works correctly too

$ mix test
Compiling 1 file (.ex)
Generated xxx app
.

Finished in 0.03 seconds (0.00s async, 0.03s sync)
1 test, 0 failures

Randomized with seed 488666
$ cat test/xxx_test.exs
defmodule ThrowawayTest do
  use ExUnit.Case

  {:module, _name, bytecode, _exports} =
    defmodule TestModule do
      @type my_type() :: :a | :b | :c | :d
      def hello, do: 1
    end

  @bytecode bytecode

  test "generates the expected types" do
    assert {:ok, [type: {:my_type, _, []}]} = Code.Typespec.fetch_types(@bytecode)
  end
end