There was confusion around what to do with SERVER_PORT if HTTP_HOST is
sent. Now it's clear these two variables are only used if HTTP_HOST is
not present.
* PEP 646: Simplify based on typing-sig discussions
Feature removals:
* Remove `Map` (to be added in a separate PEP)
* Remove support for all forms of concatenation other than simply prefixing of a single `TypeVarTuple` (fancier forms of concatenation to also be added in a separate PEP)
Semantic changes:
* Try switching `Ts` back to mean the 'unpacked' version (such that `Ts = int, str; Tuple[Ts] = Tuple[int, str]`) to see whether everything still works. (Might revert this, pending future discussion in typing-sig.)
* PEP 646: Clarify that prefixing is not allowed in Callable
* Update PEP 646 based on discussions in typing-sig
Semantic changes:
* Switch back to `Ts` meaning types packed in a `Tuple`
* Disallow unpacked usages of `Ts`
* Unparameterised `Tensor` behaves like `Tensor[Any, ...]`
Clarifications:
* `TypeVarTuple`s are invariant
* `TypeVarTuple`s can not be bound to unknown-length types (e.g. `Tuple[int, ...]`
* `TypeVarTuple`s can not be bound to unions of types
* Empty `*args` behaves like `Tuple[()]`
* `TypeVarTuple`s can not appear in slices
Readability changes:
* Reorder some sections for better flow
* Update PEP 646 with Eric's suggestions and other tweaks
Semantic changes:
* Revert to `*args: *Ts` for new behaviour, and `*args: Tuple[*Ts]` for old behaviour
Fixes:
* Unpacking in Aliases/Ideal Array Type sections
* Various typo/grammar fixes
Other:
* State explicitly that TypeVarTuples can be used in callback protocols
Changes detected by Topy (https://github.com/intgr/topy), all changes
verified by hand, false positives have been omitted.
These range from straight-out misspellings to debatable hyphen placement.
The hyphen changes are supported by grammar manuals of style.
The initial version of the PEP entrenched the tracing mode distinction,
and was worded accordingly.
Now that tracing mode is only relevant as a historical artifact that is
being eliminated, the wording should make that clear.
Also removes a stale mention of Python 3.9.