I'm wondering if we should remove typing from the stdlib. Now's the time to think about this, as the feature freeze for 3.7 is about 12 weeks away.

Cons:

• People have to depend on a PyPI package to use typing (but they do anyway for typing_extensions)
• It's a backward incompatibility for users of Python 3.5 and 3.6 (but the typing module was always provisional)

Pros:

• The typing module can evolve much faster outside the stdlib
• We could get rid of typing_extensions (and maybe even mypy_extensions)

If we don't do this I worry that we're entering a period where many new typesystem features end up in typing_extensions and users will be confused about which items are in typing and which in typing_extensions (not to mention mypy_extensions). Anything new to be added to typing (e.g. Const, Final, Literal, or changing ABCs to Protocols) would have to be added to typing_extensions instead, and users would be confused about which features exist in which module. Moving typing out of the stdlib can make things potentially simpler, at the cost of an extra pip install (but they'll need one anyway for mypy).

Thoughts?