This sounds like an issue to report to Spack itself: Issues · spack/spack · GitHub
With a quick search I could not find any other reports of the same, so this is either very new, or depending on your system setup. What Python version are you using? It should run with any major Python version out there: Getting Started — Spack 0.16.0 documentation
If you don’t find anything, you could try installing
typing (and any other missing packages) e.g. with
pip3 install --user typing. But maybe try reporting this to Spack already, the
setup-env.sh should work out of the box.