Tracking issue for all other issues #19
Description
In the spirit of #8, I thought it might be a good idea to have an issue that categorizes all of the issues we have so that we can keep track of what needs to be done. Please feel free to edit this post to add, remove, change the classification, or change the status of an issue. Ideally, all issues should be resolved (closed) before this PEP is complete.
Motivating examples
Some of these will end up in the motivation section of the PEP. We desperately need more motivating examples. If you've contributed or reviewed type annotation pull requests, it may be worth scanning over them to see if intersections would have helped. It would also be good to scan the Pyright and MyPy issue trackers.
Required behavior of intersections
These include type checker behaviors as well as runtime behavior (we may want to split them). Some of these will end up in a behavior section of the PEP.
- Handling of
Anywithin an Intersection #1 Once we agree on this, then we can copy into the PEP: arguments from the "support" section of the accepted idea, and arguments from the "against" section of the rejected ideas. - Handle "impossible" intersections #5
- Add isinstance behavior #10
- Intersections with
Callable, in particularAny&Callable#16 - Support variable intersections #21
Adding a negation operator
#17 proposes adding Not as part of this PEP. If it is added, then it should probably get its own section.
Survey
The survey section can be populated from #14.
CPython implementation
A CPython implementation should probably be linked. @tomasr8 is working on one in #9.
Bugs
These are possible errors, oversights, or addenda for the PEP that should be resolved: