TypeError: argument stack: Expected Adw.ViewStack, but got whatip.main_stack.MainStack

Using the whatip-git AUR package with libadwaita 1.0.0alpha.2:

Traceback (most recent call last):
  File "/usr/lib/python3.9/site-packages/whatip/__main__.py", line 184, in do_command_line
    self.do_activate()
  File "/usr/lib/python3.9/site-packages/whatip/__main__.py", line 73, in do_activate
    self.window = AppWindow()
  File "/usr/lib/python3.9/site-packages/whatip/app_window.py", line 22, in __init__
    self.bottom_bar.set_stack(self.main_stack)
TypeError: argument stack: Expected Adw.ViewStack, but got whatip.main_stack.MainStack