ACP: Avoid the common mistake of `for x in 0u8..`

Proposal

Problem statement

When a type has finite possible values and total ordering, it is tempting to write this code:
for x in SOME_VAL.. {}
However this is plain incorrect... It panics with overflow in debug mode and loops infinitely in release mode, for integers.

Linting against this pattern is helpful, but it's more meaningful to have a correct fix for the expected behavior.

Motivating examples or use cases

Integers and char types(see rust-lang #111514) and many other types might benefit from this.

Solution sketch

Maybe add a to_inclusive() api to open-ended ranges types, such that:
(0u8..).to_inclusive() => (0u8..=255u8)

Alternatives

TO BE ADDED.

Links and related work

• https://github.com/rust-lang/rust/issues/111514

What happens now?

This issue contains an API change proposal (or ACP) and is part of the libs-api team feature lifecycle. Once this issue is filed, the libs-api team will review open proposals as capability becomes available. Current response times do not have a clear estimate, but may be up to several months.

Possible responses

The libs team may respond in various different ways. First, the team will consider the problem (this doesn't require any concrete solution or alternatives to have been proposed):

• We think this problem seems worth solving, and the standard library might be the right place to solve it.
• We think that this probably doesn't belong in the standard library.

Second, if there's a concrete solution:

• We think this specific solution looks roughly right, approved, you or someone else should implement this. (Further review will still happen on the subsequent implementation PR.)
• We're not sure this is the right solution, and the alternatives or other materials don't give us enough information to be sure about that. Here are some questions we have that aren't answered, or rough ideas about alternatives we'd want to see discussed.

Start with the problem statement and the related Rust issue #111514, then review the standard library feature lifecycle linked in the issue. The proposal still leaves alternatives to be added and does not name implementation files or tests. Done means the libs-api team has resolved whether the problem belongs in the standard library and whether a concrete API should proceed.