- Use intra-doc links for `std::io` in `std::fs`
- Use intra-doc links for File::read in unix/ext/fs.rs
- Remove explicit intra-doc links for `true` in `net/addr.rs`
- Use intra-doc links in alloc/src/sync.rs
- Use intra-doc links in src/ascii.rs
- Switch to intra-doc links in alloc/rc.rs
- Use intra-doc links in core/pin.rs
- Use intra-doc links in std/prelude
- Use shorter links in `std/fs.rs`
`io` is already in scope.
flt2dec: properly handle uninitialized memory
The float-to-str code currently uses uninitialized memory incorrectly (see https://github.com/rust-lang/rust/issues/76092). This PR fixes that.
Specifically, that code used `&mut [T]` as "out references", but it would be incorrect for the caller to actually pass uninitialized memory. So the PR changes this to `&mut [MaybeUninit<T>]`, and then functions return a `&[T]` to the part of the buffer that they initialized (some functions already did that, indirectly via `&Formatted`, others were adjusted to return that buffer instead of just the initialized length).
What I particularly like about this is that it moves `unsafe` to the right place: previously, the outermost caller had to use `unsafe` to assert that things are initialized; now it is the functions that do the actual initializing which have the corresponding `unsafe` block when they call `MaybeUninit::slice_get_ref` (renamed in https://github.com/rust-lang/rust/pull/76217 to `slice_assume_init_ref`).
Reviewers please be aware that I have no idea how any of this code actually works. My changes were purely mechanical and type-driven. The test suite passes so I guess I didn't screw up badly...
Cc @sfackler this is somewhat related to your RFC, and possibly some of this code could benefit from (a generalized version of) the API you describe there. But for now I think what I did is "good enough".
Fixes https://github.com/rust-lang/rust/issues/76092.
`try_reserve` and `try_reserve_exact` docs refer to calling `reserve` and `reserve_exact`.
`try_reserve_exact` example uses `try_reserve` method instead of `try_reserve_exact`.
Make all methods of `std::net::Ipv6Addr` const
Make the following methods of `std::net::Ipv6Addr` unstable const under the `const_ipv6` feature:
- `segments`
- `is_unspecified`
- `is_loopback`
- `is_global` (unstable)
- `is_unique_local`
- `is_unicast_link_local_strict`
- `is_documentation`
- `multicast_scope`
- `is_multicast`
- `to_ipv4_mapped`
- `to_ipv4`
This would make all methods of `Ipv6Addr` const.
Changed the implementation of `is_unspecified` and `is_loopback` to use a `match` instead of `==`, all other methods did not require a change.
All these methods are dependent on `segments`, the current implementation of which requires unstable `const_fn_transmute` ([PR#75085](https://github.com/rust-lang/rust/pull/75085)).
Part of #76205
Move to intra-doc links for library/core/src/panic.rs
Helps with #75080.
@rustbot modify labels: T-doc, A-intra-doc-links, T-rustdoc
Known issues:
* Link from `core` to `std` (#74481):
[`set_hook`]
[`String`]
Add more examples to lexicographic cmp on Iterators.
Given two arrays of T1 and T2, the most important rule of lexicographical comparison is that two arrays
of equal length will be compared until the first difference occured.
The examples provided only focuses on the second rule that says that the
shorter array will be filled with some T2 that is less than every T1.
Which is only possible because of the first rule.
Makes the following methods of `std::net::Ipv4Addr` unstable const under the `const_ipv4` feature:
- `is_global`
- `is_reserved`
- `is_broadcast`
- `to_ipv6_compatible`
- `to_ipv6_mapped`
This results in all methods of `Ipv4Addr` being const.
Also adds tests for these methods in a const context.
Make the following methods of `std::net::Ipv6Addr` unstable const under the `const_ipv6` feature:
- `segments`
- `is_unspecified`
- `is_loopback`
- `is_global` (unstable)
- `is_unique_local`
- `is_unicast_link_local_strict`
- `is_documentation`
- `multicast_scope`
- `is_multicast`
- `to_ipv4_mapped`
- `to_ipv4`
Changed the implementation of `is_unspecified` and `is_loopback` to use a `match` instead of `==`.
Part of #76205
Constify the following methods of `core::cmp::Ordering`:
- `reverse`
- `then`
Stabilizes these methods as const under the `const_ordering` feature.
Also adds a test for these methods in a const context.
Possible because of #49146 (Allow `if` and `match` in constants).
rename get_{ref, mut} to assume_init_{ref,mut} in Maybeuninit
References #63568
Rework with comments addressed from #66174
Have replaced most of the occurrences I've found, hopefully didn't miss out anything
r? @RalfJung
(thanks @danielhenrymantilla for the initial work on this)
This reverts commit 7e2548fe69.
Now I know why it was redefined: it seems like it's potentially because
of the orphan rule. Here are the error messages:
error[E0119]: conflicting implementations of trait `std::fmt::Debug` for type `!`:
--> src/primitive_docs.rs:236:1
|
6 | impl Debug for ! {
| ^^^^^^^^^^^^^^^^
|
= note: conflicting implementation in crate `core`:
- impl std::fmt::Debug for !;
error[E0117]: only traits defined in the current crate can be implemented for arbitrary types
--> src/primitive_docs.rs:236:1
|
6 | impl Debug for ! {
| ^^^^^^^^^^^^^^^-
| | |
| | `!` is not defined in the current crate
| impl doesn't use only types from inside the current crate
|
= note: define and implement a trait or new type instead
Make `cow_is_borrowed` methods const
Constify the following methods of `alloc::borrow::Cow`:
- `is_borrowed`
- `is_owned`
Analogous to the const methods `is_some` and `is_none` for Option, and `is_ok` and `is_err` for Result.
These methods are still unstable under `cow_is_borrowed`.
Possible because of #49146 (Allow if and match in constants).
Tracking issue: #65143
Move `#[cfg(test)]` modules into separate files to save recompiling the `std` crate
Implements an accepted proposal: https://github.com/rust-lang/compiler-team/issues/344
Some notes for reviewers:
* `mod tests` nested in `mod foo` in `mod bar`, I move `foo` to a new file, `tests` is a new file in foo: For example library/std/src/sys/sgx/abi/tls.rs
* `mod test` (not `mod tests`) also is moved.
* `mod benches` are moved.
* `mod tests` is placed before any `use` statements: The topic is discussed in https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/Code.20Style.20process
* Some files in cloudabi was changed too. But I notice copyright banners in those files, should we ping cloudabi people?
* I formatted files after moving tests around. I think that may make it easier to review :p .
* Some files don't need `ignore-tidy-filelength` anymore.
Get rid of bounds check in slice::chunks_exact() and related function…
…s during construction
LLVM can't figure out in
let rem = self.len() % chunk_size;
let len = self.len() - rem;
let (fst, snd) = self.split_at(len);
and
let rem = self.len() % chunk_size;
let (fst, snd) = self.split_at(rem);
that the index passed to split_at() is smaller than the slice length and
adds a bounds check plus panic for it.
Apart from removing the overhead of the bounds check this also allows
LLVM to optimize code around the ChunksExact iterator better.
Use intra-doc links for `core/src/slice.mod.rs`
partial help in #75080
r? @jyn514
- most are using primitive types links, which cannot be used with intra links at the moment
- also `std` cannot be referenced in any link, `std::ptr::NonNull` and `std::slice` could not be referenced
Add `-Z proc-macro-backtrace` to allow showing proc-macro panics
Fixes#75050
Previously, we would unconditionally suppress the panic hook during
proc-macro execution. This commit adds a new flag
`-Z proc-macro-backtrace`, which allows running the panic hook for
easier debugging.
Constify the following methods of `std::net::Ipv4Addr`:
- `octets`
- `is_loopback`
- `is_private`
- `is_link_local`
- `is_shared`
- `is_ietf_protocol_assignment`
- `is_benchmarking`
- `is_multicast`
- `is_documentation`
Also insta-stabilizes these methods as const.
Possible because of the stabilization of const integer arithmetic and control flow.
Fixes#75050
Previously, we would unconditionally suppress the panic hook during
proc-macro execution. This commit adds a new flag
-Z proc-macro-backtrace, which allows running the panic hook for
easier debugging.
Constify the following methods of `alloc::borrow::Cow`:
- `is_borrowed`
- `is_owned`
These methods are still unstable under `cow_is_borrowed`.
Possible because of #49146 (Allow if and match in constants).
Tracking issue: #65143
Make some Ordering methods const
Constify the following methods of `core::cmp::Ordering`:
- `reverse`
- `then`
Possible because of #49146 (Allow `if` and `match` in constants).
Tracking issue: #76113
LLVM can't figure out in
let rem = self.len() % chunk_size;
let len = self.len() - rem;
let (fst, snd) = self.split_at(len);
and
let rem = self.len() % chunk_size;
let (fst, snd) = self.split_at(rem);
that the index passed to split_at() is smaller than the slice length and
adds a bounds check plus panic for it.
Apart from removing the overhead of the bounds check this also allows
LLVM to optimize code around the ChunksExact iterator better.
These are unsafe variants of the non-unchecked functions and don't do
any bounds checking.
For the time being these are not public and only a preparation for the
following commit. Making it public and stabilization can follow later
and be discussed in https://github.com/rust-lang/rust/issues/76014 .
`alloc::slice` uses `core::slice` functions, documentation are copied
from there and the links as well without resolution. `crate::ptr...`
cannot be resolved in `alloc::slice`, but `ptr` itself is imported in
both `alloc::slice` and `core::slice`, so we used that instead.
vars() rather than vars function
Co-authored-by: Joshua Nelson <joshua@yottadb.com>
Use [xxx()] rather than the [xxx] function
Co-authored-by: Joshua Nelson <joshua@yottadb.com>
Env text representation of function intra-doc link
Suggested by @jyn514
Link join_paths in env doc for parity
Change xxx to env::xxx for lib env doc
Add link requsted by @jyn514
Fix doc build with same link
Co-authored-by: Joshua Nelson <joshua@yottadb.com>
Fix missing intra-doc link
Fix added whitespace in doc
Co-authored-by: Joshua Nelson <joshua@yottadb.com>
Add brackets for `join_paths`
Co-authored-by: Joshua Nelson <joshua@yottadb.com>
Use unused link join_paths
Removed same link for join_paths
Co-authored-by: Joshua Nelson <joshua@yottadb.com>
Remove unsed link join_paths
Move to intra-doc links for library/core/src/sync/atomic.rs
Helps with #75080.
@rustbot modify labels: T-doc, A-intra-doc-links, T-rustdoc
Known issues:
* Link from core to std:
[`Arc`]
[`std:🧵:yield_now`]
[`std:🧵:sleep`]
[`std::sync::Mutex`]
Shorten liballoc doc intra link while readable
r? @jyn514
Do you want to reviews these sort of pull requests in the future? I might send a few of them while reading vec code.
The most important rule of lexicographical comparison is that two arrays
of equal length will be compared until the first difference occured.
The examples provided only focuses on the second rule that says that the
shorter array will be filled with some T2 that is less than every T.
Which is only possible because of the first rule.
Update compiler-builtins
Update the compiler-builtins dependency to include latest changes.
This allows for `aarch64-unknown-linux-musl` to pass all tests.
Fixes#57820 and fixes#46651
Substantial refactor to the design of LineWriter
# Preamble
This is the first in a series of pull requests designed to move forward with https://github.com/rust-lang/rust/issues/60673 (and the related [5 year old FIXME](ea7181b5f7/src/libstd/io/stdio.rs (L459-L461))), which calls for an update to `Stdout` such that it can be block-buffered rather than line-buffered under certain circumstances (such as a `tty`, or a user setting the mode with a function call). This pull request refactors the logic `LineWriter` into a `LineWriterShim`, which operates on a `BufWriter` by mutable reference, such that it is easy to invoke the line-writing logic on an existing `BufWriter` without having to construct a new `LineWriter`.
Additionally, fixes#72721
## A note on flushing
Because the word **flush** tends to be pretty overloaded in this discussion, I'm going to use the word **unbuffered** to refer to a `BufWriter` sending its data to the wrapped writer via `write`, without calling `flush` on it, and I'll be using **flushed** when referring to sending data via flush, which recursively writes the data all the way to the final sink.
For example, given a `T = BufWriter<BufWriter<File>>`, saying that `T` **unbuffers** its data means that it is sent to the inner `BufWriter`, but not necessarily to the `File`, whereas saying that `T` **flushes** its data means that causes it (via `Write::flush`) to be delivered all the way to `File`.
# Goals
Once it became clear (for reasons described below) that the best way to approach this would involve refactoring `LineWriter` to work more directly on `BufWriter`'s internals, I established the following design goals for the refactor:
- Do not duplicate logic with `BufWriter`. It's great at buffering and then unbuffering data, so use the existing logic as much as possible.
- Minimize superfluous copying of data into `BufWriter`'s buffer.
- Eliminate calls to `BufWriter::flush` and instead do the same thing as `BufWriter::write`, which is to only write to the wrapped writer (rather than flushing all the way down to the final data sink).
- Uphold the "at-most 1 write of new data" convention of `Write::write`
- Minimize or eliminate dropping errors (that is, eliminate the parts of the old design that threw away errors because `write` *must* report if any bytes were written)
- As much as possible, attempt to fully flush completed lines, and *not* flush partial lines. One of the advantages of this design is that, so long as we don't encounter lines larger than the `BufWriter`'s capacity, partial lines will never be unbuffered, while completed lines will *always* be unbuffered (with subsequent calls to `LineWriter::write` retrying failed writes before processing new data.
# Design
There are two major & related parts of the design.
First, a new internal stuct, `LineWriterShim`, is added. This struct implements all of the actual logic of line-writing in a `Write` implementation, but it only operates on an `&mut BufWriter`. This means that this shim can be constructed on-the-fly to apply line writing logic to an existing `BufWriter`. This is in fact how `LineWriter` has been updated to operate, and it is also how `Stdout` is being updated in my [development branch](https://github.com/Lucretiel/rust/tree/stdout-block-buffer) to switch which mode it wants to use at runtime.
[An example of how this looks in practice](f24f272df6/src/libstd/io/stdio.rs (L479-L484)
)
The second major part of the design that the line-buffering logic, implemented in `LineWriterShim`, has been updated to work slightly more directly on the internals of `BufWriter`. Mostly it makes us of the public interface—particularly `buffer()` and `get_mut()`—but it also controls the flushing of the buffer with `flush_buf` rather than `flush`, and it writes to the buffer infallibly with a new `write_to_buffer` method. This has several advantages:
- Data no longer has to round trip through the `BufWriter`'s buffer. If the user provides a complete line, that line is written directly to the inner writer (after ensuring the existing buffer is flushed).
- The conventional contract of `write`—that at-most 1 attempt to write new data is made—is much more cleanly upheld, because we don't have to perform fallible flushes and perform semi-complicated logic of trying to pretend errors at different stages didn't happen. Instead, after attempting to write lines directly to the buffer, we can infallibly add trailing data to the buffer without allowing any attempts to continue writing it to the `inner` writer.
- Perhaps most importantly, `LineWriter` *no longer performs a full flush on every line.* This makes its behavior much more consistent with `BufWriter`, which unbuffers data to its inner writer, without trying to flush it all the way to the final device. Previously, `LineWriter` had no choice but to use `flush` to ensure that the lines were unbuffered, but by writing directly to `inner` via `get_mut()` (when appropriate), we can use a more correct behavior.
## New(ish) line buffering logic
The logic for line writing has been cleaned up, as described above. It now follows this algorithm for `write`, with minor adjustments for `write_all` and `write_vectored`:
- Does our input data contain a newline?
- If no:
- simply use the regular `BufWriter::write` to write it; this will append it to the buffer and/or flush it as necessary based on how full the buffer is and how much input data there is.
- additionally, if the current buffer ends with `'\n'`, attempt to immediately flush it with `flush_buf` before calling `BufWriter::write` This reproduces the old `needs_flush` behavior and ensures completed lines are flushed as soon as possible. The reason we only check if the buffer *ends* with `'\n'` is discussed later.
- If yes:
- First, `flush_buf`
- Then use `bufwriter.get_mut().write()` to write the input data directly to the underlying writer, up to the last newline. Make at most one attempt at this.
- If it errors, return the error
- If it succeeds with a full write, add the remaining data (between the last newline and the end of the input) to the buffer. In order to uphold the "at-most 1 attempt to write new data" convention, no attempts are made to write this data to the inner writer (though obviously a subsequent write may immediately flush it, e.g., if it totally filled the buffer's capacity.
- If it only partially succeeds, buffer the data only up to the last newline. We do this to try to avoid writing partial lines to the inner writer where possible (that is, whenever the lines are shorter than the total buffer capacity).
While it was not my intention for this behavior to diverge from this existing `LineWriter` algorithm, this updated design emerged very naturally once `LineWriter` wasn't burdened with having to only operate via `BufWriter::flush`. There essentially two main changes to observable behavior:
- `flush` is no longer used to unbuffer lines. The are only written to the writer wrapped by `LineWriter`; this inner writer might do its own buffering. This change makes `LineWriter` consistent with the behavior of `BufWriter`. This is probably the most obvious user-visible change; it's the one I most expect to provoke issue reports, if any are provoked.
- Unless a line exceeds the capacity of the buffer, partial lines are not unbuffered (without the user manually calling flush). This is a less surprising behavior, and is enabled because `LineWriter` now has more precise control of what data is buffered and when it is unbuffered. I'd be surprised if anyone is relying on `LineWriter` unbuffering or flushing *partial* lines that are shorter than the capacity, so I'm not worried about this one.
None of these changes are inconsistent with any published documentation of `LineWriter`. Nonetheless, like all changes with user-facing behavior changes, this design will obviously have to be very carefully scrutinized.
# Alternative designs and design rationalle
The initial goal of this project was to provide a way for the `LineWriter` logic to be operable directly on a `BufWriter`, so that the updated `Stdout` doesn't need to do something convoluted like `enum { BufWriter, LineWriter }` (which ends up being ~~impossible~~ difficult to transition between states after being constructed). The design went through several iterations before arriving at the current draft.
The major first version simply involved adding methods like `write_line_buffered` to `BufWriter`; these would contain the actual logic of line-buffered writing, and would additionally have the advantages (described above) of operating directly on the internals of `BufWriter`. The idea was that `LineWriter` would simply call these methods, and the updated `Stdout` would use either `BufWriter::write` or `BufWriter::write_line_buffered`, depending on what mode it was in.
The major issue with this design is that it loses the ability to take advantage of the `io::Write` trait, which provides several useful default implementations of the various io methods, such as `write_fmt` and `write_all`, just using the core methods. For this reason, the `write_line_buffered` design was retained, but moved into a separate struct called `LineWriterShim` which operates on an `&mut LineWriter`. As part of this move, the logic was lightly retooled to not touch the innards of `BufWriter` directly, but instead to make use of the unexported helper methods like `flush_buf`.
The other design evolutions were mostly related to answering questions like "how much data should be buffered", "how should partial line writes be handled", etc. As much as possible I tried to answer these by emulating the current `LineWriter` logic (which, for example, retries partial line writes on subsequent calls to `write`) while still meeting the refactor design goals.
# Next steps
~Currently, this design fails a few `LineWriter` tests, mostly because they expect `LineWriter` to *fully* flush its content. There are also some changes to the way that `LineWriter` buffers data *after* writing completed lines, aimed at ensuring that partial lines are not unbuffered prematurely. I want to make sure I fully understand the intent behind these tests before I either update the test or update this design so that they pass.~
However, in the meantime I wanted to get this published so that feedback could start to accumulate on it. There's a lot of errata around how I arrived at this design that didn't really fit in this overlong document, so please ask questions about anything that confusing or unclear and hopefully I can explain more of the rationale that led to it.
# Test updates
This design required some tests to be updated; I've research the intent behind these tests (mostly via `git blame`) and updated them appropriately. Those changes are cataloged here.
- `test_line_buffer_fail_flush`: This test was added as a regression test for #32085, and is intended to assure that an errors from `flush` aren't propagated when preceded by a successful `write`. Because type of issue is no longer possible, because `write` calls `buffer.get_mut().write()` instead of `buffer.write(); buffer.flush();`, I'm simply removing this test entirely. Other, similar error invariants related to errors during write-retrying are handled in other test cases.
- `erroneous_flush_retried`: This test was added as a regression test for #37807, and was intended to ensure that flush-retrying (via `needs_flush`) and error-ignoring were being handled correctly (ironically, this issue was caused by the flush-error-ignoring, above). Half of that issue is not possible by design with this refactor, because we no longer make fallible i/o calls that might produce errors we have to ignore after unbuffering lines. The `should_flush` behavior is captured by checking for a trailing newline in the `LineWriter` buffer; this test now checks that behavior.
- `line_vectored`: changes here were pretty minor, mostly related to when partial lines are or aren't written. The old implementation of `write_vectored` used very complicated logic to precisely determine the location of the last newline and precisely write up to that point; this required doing several consecutive fallible writes, with all the complex error handling or ignoring issues that come with it. The updated design does at-most one write of a subset of total buffers (that is, it doesn't split in the middle of a buffer), even if that means writing partial lines. One of the major advantages of the new design is that the underlying vectored write operation on the device can be taken advantage of, even with small writes, so long as they include a newline; previously these were unconditionally buffered then written.
- `line_vectored_partial_and_errors`: Pretty similiar to `line_vectored`, above; this test is for basic error recovery in `write_vectored` for vectored writes. As previously discussed, the mocked behavior being tested for (errors ignored under certain circumstances) no occurs, so I've simplified the test while doing my best to retain its spirit.
Add InstrProfilingPlatformFuchsia.c to profiler_builtins
All other Platform files included in `llvm-project/compiler-rt` were
present, except Fuchsia.
Now that there is a functional end-to-end version of
`-Zinstrument-coverage`, I need to start building and testing
coverage-enabled Rust programs on Fuchsia, and this file is required.
r? @tmandry
FYI, @wesleywiser
Fix potential UB in align_offset doc examples
Currently it takes a pointer only to the first element in the array, this changes the code to take a pointer to the whole array.
miri can't catch this right now because it later calls `x.len()` which re-tags the pointer for the whole array.
https://github.com/rust-lang/miri/issues/1526#issuecomment-680897144
Abort when foreign exceptions are caught by catch_unwind
Prior to this PR, foreign exceptions were not caught by catch_unwind, and instead passed through invisibly. This represented a painful soundness hole in some libraries ([take_mut](https://github.com/Sgeo/take_mut/blob/master/src/lib.rs#L37)), which relied on `catch_unwind` to handle all possible exit paths from a closure.
With this PR, foreign exceptions are now caught by `catch_unwind` and will trigger an abort since catching foreign exceptions is currently UB according to the latest proposals by the FFI unwind project group.
cc @rust-lang/wg-ffi-unwind
All other Platform files included in `llvm-project/compiler-rt` were
present, except Fuchsia.
Now that there is a functional end-to-end version of
`-Zinstrument-coverage`, I need to start building and testing
coverage-enabled Rust programs on Fuchsia, and this file is required.
[AVR] Replace broken 'avr-unknown-unknown' target with 'avr-unknown-gnu-atmega328' target
The `avr-unknown-unknown` target has never worked correctly, always trying to invoke
the host linker and failing. It aimed to be a mirror of AVR-GCC's
default handling of the `avr-unknown-unknown' triple (assume bare
minimum chip features, silently skip linking runtime libraries, etc).
This behaviour is broken-by-default as it will cause a miscompiled executable
when flashed.
This patch improves the AVR builtin target specifications to instead
expose only a 'avr-unknown-gnu-atmega328' target. This target system is
`gnu`, as it uses the AVR-GCC frontend along with avr-binutils. The
target triple ABI is 'atmega328'.
In the future, it should be possible to replace the dependency on
AVR-GCC and binutils by using the in-progress AVR LLD and compiler-rt support.
Perhaps at that point it would make sense to add an
'avr-unknown-unknown-atmega328' target as a better default when
implemented.
There is no current intention to add in-tree AVR target specifications for other
AVR microcontrollers - this one can serve as a reference implementation
for other devices via `rustc --print target-spec-json
avr-unknown-gnu-atmega328p`.
There should be no users of the existing 'avr-unknown-unknown' Rust
target as a custom target specification JSON has always been
recommended, and the avr-unknown-unknown target could never pass the
linking step anyway.
Update docs for SystemTime Windows implementation
Windows now uses `GetSystemTimePreciseAsFileTime` (since #69858) on versions of Windows that support it.
Unconfuse Unpin docs a bit
* Don't say that Unpin is used to prevent moves, because it is used
to *allow* moves
* Be more precise about kindedness of things, it is
`Pin<Pointer<Data>>`, rather than just `Pin<Pointer>`.
Call into fastfail on abort in libpanic_abort on Windows x86(_64)
This partially resolves#73215 though this is only for x86 targets. This code is directly lifted from [libstd](13290e83a6/library/std/src/sys/windows/mod.rs (L315)). `__fastfail` is the preferred way to abort a process on Windows as it will hook into debugger toolchains.
Other platforms expose a `_rust_abort` symbol which wraps `std::sys::abort_internal`. This would also work on Windows, but is a slightly largely change as we'd need to make sure that the symbol is properly exposed to the linker. I'm inlining the call to the `__fastfail`, but the indirection through `rust_abort` might be a cleaner approach.
A different instruction must be used on ARM architectures. I'd like to verify this works first before tackling ARM.
I would like to propose these two simple methods for stabilization:
- Knowing that a range is exhaused isn't otherwise trivial
- Clippy would like to suggest them, but had to do extra work to disable that path <https://github.com/rust-lang/rust-clippy/issues/3807> because they're unstable
- These work on `PartialOrd`, consistently with now-stable `contains`, and are thus more general than iterator-based approaches that need `Step`
- They've been unchanged for some time, and have picked up uses in the compiler
- Stabilizing them doesn't block any future iterator-based is_empty plans, as the inherent ones are preferred in name resolution
Minor changes to Ipv4Addr
Minor changes to Ipv4Addr
* Impl IntoInner rather than AsInner for Ipv4Addr
* Add some comments
* Add test to show endiannes of Ipv4Addr display
* Don't say that Unpin is used to prevent moves, because it is used
to *allow* moves
* Be more precise about kindedness of things, it is
`Pin<Pointer<Data>>`, rather than just `Pin<Pointer>`.
Report an ambiguity if both modules and primitives are in scope for intra-doc links
Closes https://github.com/rust-lang/rust/issues/75381
- Add a new `prim@` disambiguator, since both modules and primitives are in the same namespace
- Refactor `report_ambiguity` into a closure
Additionally, I noticed that rustdoc would previously allow `[struct@char]` if `char` resolved to a primitive (not if it had a DefId). I fixed that and added a test case.
I also need to update libstd to use `prim@char` instead of `type@char`. If possible I would also like to refactor `ambiguity_error` to use `Disambiguator` instead of its own hand-rolled match - that ran into issues with `prim@` (I updated one and not the other) and it would be better for them to be in sync.
Use allow(unused_imports) instead of cfg(doc) for imports used only for intra-doc links
This prevents links from breaking when items are re-exported in a
different crate and the original isn't being documented.
Spotted in https://github.com/rust-lang/rust/pull/75832#discussion_r475275837 (thanks ollie!)
r? @ollie27
Fix typo in documentation of i32 wrapping_abs()
Hi!
I was reading through the std library docs and noticed that this section flowed a bit oddly; comparing it against https://doc.rust-lang.org/std/primitive.i32.html#method.wrapping_div and https://doc.rust-lang.org/std/primitive.i32.html#method.wrapping_neg , I noticed that those two pieces of documentation used a semicolon here.
This is my first time submitting a PR to this repo. Am I doing this right? Are tiny typo-fix PRs like this worth submitting, or are they not a good use of time?
Thank you!
Switch to intra-doc links in `std::macros`
Part of #75080.
---
* Switch to intra-doc links in `std::macros`
* Fix typo in module docs
* Link to `std::io::stderr` instead of `std::io::Stderr` to match the
link text
* Link to `std::io::stdout`
---
@rustbot modify labels: A-intra-doc-links T-doc T-rustdoc
Document that slice refers to any pointer type to a sequence
I was recently confused about the way slices are represented in memory. The necessary information was not available in the std-docs directly, but was a mix of different material from the reference and book.
This PR should clear up the definition of slices a bit more in the documentation. Especially the fact that the term slice refers to the pointer/reference type, e.g. `&[T]`, and not `[T]`.
It also documents that slice pointers are twice the size of pointers to `Sized` types, as this concept may be unfamiliar to users coming from other languages that do not have the concept of "fat pointers" (especially C/C++).
I've documented why this was important to me and my findings in [this blog post](https://codecrash.me/understanding-rust-slices).
r? @lcnr
stabilize ptr_offset_from
This stabilizes ptr::offset_from, and closes https://github.com/rust-lang/rust/issues/41079. It also removes the deprecated `wrapping_offset_from`. This function was deprecated 19 days ago and was never stable; given an FCP of 10 days and some waiting time until FCP starts, that leaves at least a month between deprecation and removal which I think is fine for a nightly-only API.
Regarding the open questions in https://github.com/rust-lang/rust/issues/41079:
* Should offset_from abort instead of panic on ZSTs? -- As far as I know, there is no precedent for such aborts. We could, however, declare this UB. Given that the size is always known statically and the check thus rather cheap, UB seems excessive.
* Should there be more methods like this with different restrictions (to allow nuw/nsw, perhaps) or that return usize (like how isize-taking offset is more conveniently done with usize-taking add these days)? -- No reason to block stabilization on that, we can always add such methods later.
Also nominating the lang team because this exposes an intrinsic.
The stabilized method is best described [by its doc-comment](56d4b2d69a/src/libcore/ptr/const_ptr.rs (L227)). The documentation forgot to mention the requirement that both pointers must "have the same provenance", aka "be derived from pointers to the same allocation", which I am adding in this PR. This is a precondition that [Miri already implements](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2018&gist=a3b9d0a07a01321f5202cd99e9613480) and that, should LLVM ever obtain a `psub` operation to subtract pointers, will likely be required for that operation (following the semantics in [this paper](https://people.mpi-sws.org/~jung/twinsem/twinsem.pdf)).
New zeroed slice
Add to #63291 the methods
```rust
impl<T> Box<[T]> { pub fn new_zeroed_slice(len: usize) -> Box<[MaybeUninit<T>]> {…} }
impl<T> Rc<[T]> { pub fn new_zeroed_slice(len: usize) -> Rc<[MaybeUninit<T>]> {…} }
impl<T> Arc<[T]> { pub fn new_zeroed_slice(len: usize) -> Arc<[MaybeUninit<T>]> {…} }
```
as suggested in https://github.com/rust-lang/rust/issues/63291#issuecomment-605511675 .
Also optimize `{Rc, Arc}::new_zeroed` to use `alloc_zeroed`, otherwise they are no more efficient than using `new_uninit` and zeroing the memory manually (which was the original implementation).
Move to intra-doc links for library/core/src/alloc/{layout, global, mod}.rs
Helps with #75080. The files already contained intra-doc links, so there are only minor changes.
@rustbot modify labels: T-doc, A-intra-doc-links, T-rustdoc
Known issues:
* [`handle_alloc_error`]: Link from `core` to `alloc` could not be resolved.
* [`slice`]: slice is a primitive type, but could not be resolved; had to use [`crate::slice`] instead.
Move to intra-doc links for /library/core/src/intrinsics.rs
Helps with #75080.
@rustbot modify labels: T-doc, A-intra-doc-links, T-rustdoc
Known issues:
* The following f32 and f64 primitive methods cannot be resolved:
f32/f64::powi
f32/f64::sqrt
f32/f64::sin
f32/f64::cos
f32/f64::powf
f32/f64::exp
f32/f64::exp2
f32/f64::ln
f32/f64::log2
f32/f64::log10
f32/f64::mul_add
f32/f64::abs
f32/f64::copysign
f32/f64::floor
f32/f64::ceil
f32/f64::trunc
f32/f64::round
* Links from core to std:
[`std::pointer::*`]
[`std::process::abort`]
[`from_raw_parts`]
[`Vec::append`]
* Links with anchors?
I provided a separate commit that replaced links with anchors by intra-doc links.
Here the anchor location information gets lost, so its questionable whether to
actually replace those links.
enable align_to tests in Miri
With https://github.com/rust-lang/miri/issues/1074 resolved, we can enable these tests in Miri.
I also tweaked the test sized to get reasonable execution times with decent test coverage.
clarify documentation of remove_dir errors
remove_dir will error if the path doesn't exist or isn't a directory.
It's useful to clarify that this is "remove dir or fail" not "remove dir
if it exists".
I don't think this belongs in the title. "Removes an existing, empty
directory" is strangely worded-- there's no such thing as a non-existing
directory. Better to just say explicitly it will return an error.
Use min_specialization in libcore
Getting `TrustedRandomAccess` to work is the main interesting thing here.
- `get_unchecked` is now an unstable, hidden method on `Iterator`
- The contract for `TrustedRandomAccess` is made clearer in documentation
- Fixed a bug where `Debug` would create aliasing references when using the specialized zip impl
- Added tests for the side effects of `next_back` and `nth`.
closes#68536
Move to intra-doc links for task.rs and vec.rs
Partial fix for #75080
links for [`get`], [`get_mut`] skipped due to #75643
link for [`copy_from_slice`] skipped due to #63351
Remove `#[cfg(miri)]` from OnceCell tests
They were carried over from once_cell crate, but they are not entirely
correct (as miri now supports more things), and we don't run miri
tests for std, so let's just remove them.
Maybe one day we'll run miri in std, but then we can just re-install
these attributes.
Move to intra doc links for std::io
Helps with #75080.
@rustbot modify labels: T-doc, A-intra-doc-links, T-rustdoc
r? @jyn514
I had no problems with those files so I added some small links here and there.
Improve codegen for `align_offset`
In this PR the `align_offset` implementation is changed/improved to produce better code in certain scenarios such as when pointer type is has a stride of 1 or when building for low optimisation levels.
While these changes do not achieve the "ideal" codegen referenced in #75579, it gets significantly closer to it. I’m not actually sure if the codegen can actually be much better with this function returning the offset, rather than the aligned pointer.
See the descriptions for separate commits for further information.
They were carried over from once_cell crate, but they are not entirely
correct (as miri now supports more things), and we don't run miri
tests for std, so let's just remove them.
Maybe one day we'll run miri in std, but then we can just re-install
these attributes.
Switch to intra-doc links in /src/sys/unix/ext/*.rs
Partial fix for #75080
@rustbot modify labels: T-doc, A-intra-doc-links, T-rustdoc
r? @jyn514
These two links are not resolving to either `crate::fs::File...` or `fs::File...`
```
# unix/ext/fs.rs
27: /// [`File::read`]: ../../../../std/fs/struct.File.html#method.read
130: /// [`File::write`]: ../../../../std/fs/struct.File.html#method.write
```
docs(marker/copy): provide example for `&T` being `Copy`
### Edited 2020-08-16 (most recent)
In the current documentation about the `Copy` marker trait, there is a section
with examples of structs that can implement `Copy`. Currently there is no example for
showing that shared references (`&T`) are also `Copy`.
It is worth to have a dedicated example for `&T` being `Copy`, because shared
references are an integral part of the language and it being `Copy` is not as
intuitive as other types that share this behaviour like `i32` or `bool`.
The example picks up on the previous non-`Copy` struct and shows that
structs can be `Copy`, even when they hold a shared reference to a non-`Copy` type.
-----------------------------------------
### Edited 2020-08-02, 3:28 p.m.
I've just realized that it says "in addition to the **implementors listed below**", which makes this PR kind of "wrong", because `&T` is indeed in the "implementors listed below".
Maybe we can instead show an example with `&T` in the [When can my type be Copy](https://doc.rust-lang.org/std/marker/trait.Copy.html#when-can-my-type-be-copy) section.
What I really want to achieve is that it becomes more obvious that `&T` is also `Copy`, because, I think, it is very valuable to know and it wasn't obvious for me, until I read something about it in a forum post.
What do you think? I would create another PR for that.
**Please feel free to close this PR.**
-----------------------------------
### Original post
In the current documentation about the `Copy` marker trait, there is a section
about "additional implementors", which list additional implementors of the `Copy` trait.
The fact that shared references are also `Copy` is mixed with another point,
which makes it hard to recognize and make it seem not as important.
This clarifies the fact that shared references are also `Copy`, by mentioning it as a
separate item in the list of "additional implementors".
See also X-Link mem::{swap, take, replace}
Since it's easy to end up at one of these functions when you really wanted the other one, cross link them with descriptions of why you'd want to use them.
Don't panic in Vec::shrink_to_fit
We can help the compiler see that `Vec::shrink_to_fit` will never reach the panic case in `RawVec::shrink_to_fit`, just by guarding the call only for cases where the capacity is strictly greater. A capacity less than the length is only possible through an unsafe call to `set_len`, which would break the `Vec` invariants, so `shrink_to_fit` can just ignore that.
This removes the panicking code from the examples in both #71861 and #75636.
Move to intra doc links for ascii.rs and panic.rs
Helps with #75080.
@rustbot modify labels: T-doc, A-intra-doc-links, T-rustdoc
I also updated the doc to fix the wording in `AsciiExt` since it is now deprecated.
The two file are small changes so I bundled them together.
Some links could not be changed to make them work, I believe those are known issues with primitive types.
Add `as_uninit`-like methods to pointer types and unify documentation of `as_ref` methods
This adds a convenient method to retrieve a `&(mut) [MaybeUninit<T>]` from slice pointers (`*const [T]`, `*mut [T]`, `NonNull<[T]>`). See also https://github.com/rust-lang/wg-allocators/issues/66#issuecomment-671789105.
~I'll add a tracking issue as soon as it's reviewed and CI passed.~
Tracking Issue: #75402
r? @RalfJung
Reference lang items during AST lowering
Fixes#60607 and fixes#61019.
This PR introduces `QPath::LangItem` to the HIR and uses it in AST lowering instead of constructing a `hir::Path` from a slice of symbols:
- Credit for much of this work goes to @matthewjasper, I basically just [rebased their earlier work](a227c706b7 (diff-c0f791ead38d2d02916faaad0f56f41d)).
- ~~Changes to Clippy might not be correct, they compile but attempting to run tests through `./x.py` produced failures which appeared spurious, so I didn't run any clippy tests.~~
- Changes to save analysis might not be correct - tests pass but I don't have a lot of confidence in those changes being correct.
- I've used `GenericBounds::LangItemTrait` rather than changing `PolyTraitRef`, as suggested by @matthewjasper [in this comment](a227c706b7 (r40107992)) but I'd prefer that be left for a follow-up.
- I've split things into smaller commits fairly arbitrarily to make the diff easier to review, each commit should compile but might not pass tests until the final commit.
r? @oli-obk
cc @matthewjasper
Fix example in `NonNull::as_uninit_slice`
Rename feature gate to "ptr_as_uninit"
Make methods more consistent with already stable methods
Make `pointer::as_uninit_slice` return an `Option`
Fix placement for `// SAFETY` section
Add `as_uninit_ref` and `as_uninit_mut` to pointers
Fix doctest
Update tracking issue
Fix doc links
Apply suggestions from review
Make wording about counterparts consistent
Fix doc links
Improve documentation
Fix doc-tests
Fix doc links ... again
Apply suggestions from review
Apply suggestions from Review
Apply suggestion from review to all affected files
Add missing words in safety sections in `as_uninit_slice_mut`
Fix safety-comment in `NonNull::as_uninit_slice_mut`
Move to intra-doc links for /library/core/src/any.rs
Helps with #75080.
@rustbot modify labels: T-doc, A-intra-doc-links, T-rustdoc
Known issues:
* Links from `core` to `std` (#74481):
* `[Box]: ../../std/boxed/struct.Box.html`
pin docs: add some forward references
@nagisa had some questions about pinning that were answered in the docs, which they did not realize because that discussion is below the examples. I still think it makes sense to introduce the examples before that discussion, since it give the discussion something concrete to refer to, but this PR adds some forward references so people don't think the examples conclude the docs.
@nagisa do you think this would have helped?
