Correct comment to match behavior
Corrects the header comment on `saturating_duration_since` to match the behavior of returning 0 if the other timestamp is _later_ than the invocant, not earlier,
This is purely a documentation change, so hopefully it doesn't require an issue; if it does, I'll open one and resubmit.
Add primitive module to libcore
This re-exports the primitive types from libcore at `core::primitive` to allow
macro authors to have a reliable location to use them from.
Fixes#44865
Split non macro portion of unused_doc_comment from macro part into two passes/lints
## Motivation
This change is motivated by the needs of the [spandoc library](https://github.com/yaahc/spandoc). The specific use case is that my macro is removing doc comments when an attribute is applied to a fn with doc comments, but I would like the lint to still appear when I forget to add the `#[spandoc]` attribute to a fn, so I don't want to have to silence the lint globally.
## Approach
This change splits the `unused _doc_comment` lint into two lints, `unused_macro_doc_comment` and `unused_doc_comment`. The non macro portion is moved into an `early_lint_pass` rather than a pre_expansion_pass. This allows proc macros to silence `unused_doc_comment` warnings by either adding an attribute to silence it or by removing the doc comment before the early_pass runs.
The `unused_macro_doc_comment` lint however will still be impossible for proc-macros to silence, but the only alternative that I can see is to remove this lint entirely, which I don't think is acceptable / is a decision I'm not comfortable making personally, so instead I opted to split the macro portion of the check into a separate lint so that it can be silenced globally with an attribute if necessary without needing to globally silence the `unused_doc_comment` lint as well, which is still desireable.
fixes https://github.com/rust-lang/rust/issues/67838
Stabilize Once::is_completed
Closes#54890
This function has been around for some time. I haven't seen anyone raise any objections to it. I've personally found it useful myself. It would be nice to finally stabilize it and
Fix std::fs::copy on WASI target
Previously `std::fs::copy` on wasm32-wasi would reuse code from the `sys_common` module and would successfully copy contents of the file just to fail right before closing it.
This was happening because `sys_common::copy` tries to copy permissions of the file, but permissions are not a thing in WASI (at least yet) and `set_permissions` is implemented as an unconditional runtime error.
This change instead adds a custom working implementation of `std::fs::copy` (like Rust already has on some other targets) that doesn't try to call `set_permissions` and is essentially a thin wrapper around `std::io::copy`.
Fixes#68560.
Added From<Vec<NonZeroU8>> for CString
Added a `From<Vec<NonZeroU8>>` `impl` for `CString`
# Rationale
- `CString::from_vec_unchecked` is a subtle function, that makes `unsafe` code harder to audit when the generated `Vec`'s creation is non-trivial. This `impl` allows to write safer `unsafe` code thanks to the very explicit semantics of the `Vec<NonZeroU8>` type.
- One such situation is when trying to `.read()` a `CString`, see issue #59229.
- this lead to a PR: #59314, that was closed for being too specific / narrow (it only targetted being able to `.read()` a `CString`, when this pattern could have been generalized).
- the issue suggested another route, based on `From<Vec<NonZeroU8>>`, which is indeed a less general and more concise code pattern.
- quoting @shnatsel:
- > For me the main thing about making this safe is simplifying auditing - people have spent like an hour looking at just this one unsafe block in libflate because it's not clear what exactly is unchecked, so you have to look it up when auditing anyway. This has distracted us from much more serious memory safety issues the library had.
Having this trivial impl in stdlib would turn this into safe code with compiler more or less guaranteeing that it's fine, and save anyone auditing the code a whole lot of time.
Previously `std::fs::copy` on wasm32-wasi would reuse code from the `sys_common` module and would successfully copy contents of the file just to fail right before closing it.
This was happening because `sys_common::copy` tries to copy permissions of the file, but permissions are not a thing in WASI (at least yet) and `set_permissions` is implemented as an unconditional runtime error.
This change instead adds a custom working implementation of `std::fs::copy` (like Rust already has on some other targets) that doesn't try to call `set_permissions` and is essentially a thin wrapper around `std::io::copy`.
Fixes#68560.
