Add section on common message styles for Result::expect
Based on a question from https://github.com/rust-lang/project-error-handling/issues/50#issuecomment-1092339937
~~One thing I haven't decided on yet, should I duplicate this section on `Option::expect`, link to this section, or move it somewhere else and link to that location from both docs?~~: I ended up moving the section to `std::error` and referencing it from both `Result::expect` and `Option::expect`'s docs.
I think this section, when combined with the similar update I made on [`std::panic!`](https://doc.rust-lang.org/nightly/std/macro.panic.html#when-to-use-panic-vs-result) implies that we should possibly more aggressively encourage and support the "expect as precondition" style described in this section. The consensus among the libs team seems to be that panic should be used for bugs, not expected potential failure modes. The "expect as error message" style seems to align better with the panic for unrecoverable errors style where they're seen as normal errors where the only difference is a desire to kill the current execution unit (aka erlang style error handling). I'm wondering if we should be providing a panic hook similar to `human-panic` or more strongly recommending the "expect as precondition" style of expect message.
Using an obviously-placeholder syntax. An RFC would still be needed before this could have any chance at stabilization, and it might be removed at any point.
But I'd really like to have it in nightly at least to ensure it works well with try_trait_v2, especially as we refactor the traits.
Rename is_{some,ok,err}_with to is_{some,ok,err}_and.
This renames `is_{some,ok,err}_with` to `is_{some,ok,err}_and`. This was discussed on the [tracking issue](https://github.com/rust-lang/rust/issues/93050).
This updates the standard library's documentation to use the new syntax. The
documentation is worthwhile to update as it should be more idiomatic
(particularly for features like this, which are nice for users to get acquainted
with). The general codebase is likely more hassle than benefit to update: it'll
hurt git blame, and generally updates can be done by folks updating the code if
(and when) that makes things more readable with the new format.
A few places in the compiler and library code are updated (mostly just due to
already having been done when this commit was first authored).
Add Result::{ok, err, and, or, unwrap_or} as const
Already opened tracking issue #92384.
I don't think that this should actually cause any issues as long as the constness is unstable, but we may want to double-check that this doesn't get interpreted as a weird `Drop` bound even for non-const usages.
Just a refactor (and rename) for now, so it's not `Result`-specific.
This could be used for a future `Iterator::try_collect`, or similar, but anything like that is left for a future PR.
