Document the return keyword
Partial fix of #34601.
This documents the `return` keyword with two short example to explain it is not needed for the last expression in a function and a long example to show its use when interrupting a function execution early.
I did not put a link to the reference since the only link I found was https://doc.rust-lang.org/stable/reference/expressions/return-expr.html#return-expressions.
@rustbot modify labels: T-doc,C-enhancement
Document the mut keyword
Partial fix for #34601.
Documentation for the `mut` keyword. I think it's okay for it to be quite short, this is not the book not the reference, but if you find something is missing, do not hesitate to tell me.
Add a fast path for `std:🧵:panicking`.
This is done by adding a global atomic variable (non-TLS) that counts how many threads are panicking. In order to check if the current thread is panicking, this variable is read and, if it is zero, no thread (including the one where `panicking` is being called) is panicking and `panicking` can return `false` immediately without needing to access TLS. If the global counter is not zero, the local counter is accessed from TLS to check if the current thread is panicking.
`improper_ctypes_definitions` lint
Addresses #19834, #66220, and #66373.
This PR takes another attempt at #65134 (reverted in #66378). Instead of modifying the existing `improper_ctypes` lint to consider `extern "C" fn` definitions in addition to `extern "C" {}` declarations, this PR adds a new lint - `improper_ctypes_definitions` - which only applies to `extern "C" fn` definitions.
In addition, the `improper_ctype_definitions` lint differs from `improper_ctypes` by considering `*T` and `&T` (where `T: Sized`) FFI-safe (addressing #66220).
There wasn't a clear consensus in #66220 (where the issues with #65134 were primarily discussed) on the approach to take, but there has [been some discussion in Zulip](https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/.2366220.20improper_ctypes.20definitions.20vs.20declarations/near/198903086). I fully expect that we'll want to iterate on this before landing.
cc @varkor + @shepmaster (from #19834) @hanna-kruppe (active in discussing #66220), @SimonSapin (#65134 caused problems for Servo, want to make sure that this PR doesn't)
This commit adds a new lint - `improper_ctypes_definitions` - which
functions identically to `improper_ctypes`, but on `extern "C" fn`
definitions (as opposed to `improper_ctypes`'s `extern "C" {}`
declarations).
Signed-off-by: David Wood <david@davidtw.co>
Rollup of 7 pull requests
Successful merges:
- #71756 (add Windows system error codes that should map to io::ErrorKind::TimedOut)
- #73495 (Converted all platform-specific stdin/stdout/stderr implementations to use io:: traits)
- #73575 (Fix typo in error_codes doc)
- #73578 (Make is_freeze and is_copy_modulo_regions take TyCtxtAt)
- #73586 (switch_ty is redundant)
- #73600 (Fix spurious 'value moved here in previous iteration of loop' messages)
- #73610 (Clean up E0699 explanation)
Failed merges:
r? @ghost
Converted all platform-specific stdin/stdout/stderr implementations to use io:: traits
Currently, some of the platform-specific standard streams (`src/libstd/sys/*/stdio.rs`) manually implement parts of the `io::Write` interface directly as methods on the struct, rather than by actually implementing the trait. There doesn't seem to be any reason for this, other than an unused advantage of `fn write(&self, ...)` instead of `fn write(&mut self, ...)`.
Unfortunately, this means that those implementations don't have the default-implemented io methods, like `read_exact` and `write_all`. This caused #72705, which adds forwarding methods to the user-facing standard stream implementations, to fail to compile on those platforms.
This change converts *all* such standard stream structs to use the standard library traits. This change should not cause any breakages, because the changed types are not publicly exported, and in fact are only ever used in `src/libstd/io/stdio.rs`.
impl ToSocketAddrs for (String, u16)
This adds a convenience impl of `ToSocketAddrs for (String, u16)`. When authoring HTTP services it's common to take command line options for `host` and `port` and parse them into `String` and `u16` respectively. Consider the following program:
```rust
#[derive(Debug, StructOpt)]
struct Config {
host: String,
port: u16,
}
async fn main() -> io::Result<()> {
let config = Config::from_args();
let stream = TcpStream::connect((&*config.host, config.port))?; // &* is not ideal
// ...
}
```
Networking is a pretty common starting point for people new to Rust, and seeing `&*` in basic examples can be confusing. Even as someone that has experience with networking in Rust I tend to forget that `String` can't be passed directly there. Instead with this patch we can omit the `&*` conversion and pass `host` directly:
```rust
#[derive(Debug, StructOpt)]
struct Config {
host: String,
port: u16,
}
async fn main() -> io::Result<()> {
let config = Config::from_args();
let stream = TcpStream::connect((config.host, config.port))?; // no more conversions!
// ...
}
```
I think should be an easy and small ergonomics improvement for networking. Thanks!
Add a lint to catch clashing `extern` fn declarations.
Closes#69390.
Adds lint `clashing_extern_decl` to detect when, within a single crate, an extern function of the same name is declared with different types. Because two symbols of the same name cannot be resolved to two different functions at link time, and one function cannot possibly have two types, a clashing extern declaration is almost certainly a mistake.
This lint does not run between crates because a project may have dependencies which both rely on the same extern function, but declare it in a different (but valid) way. For example, they may both declare an opaque type for one or more of the arguments (which would end up distinct types), or use types that are valid conversions in the language the extern fn is defined in. In these cases, we can't say that the clashing declaration is incorrect.
r? @eddyb
Prevent attacker from manipulating FPU tag word used in SGX enclave
Insufficient sanitization of the x87 FPU tag word in the trusted enclave runtime allowed unprivileged adversaries in the containing host application to induce incoherent or unexpected results for ABI-compliant compiled enclave application code that uses the x87 FPU.
Vulnerability was disclosed to us by Fritz Alder, Jo Van Bulck, David Oswald and Frank Piessens
cc: @jethrogb
RISC-V Emulated Testing
Adds a disabled docker image on which to run RISC-V tests. Based on the armhf image.
Test using
```
./src/ci/docker/run.sh riscv64gc-linux
```
cc: @msizanoen1
Update the doc for std::prelude to the correct behavior
Fixes#64686.
One line change to ensure the docs are correct about the behavior of the compiler when inserting`std::prelude::v1`.
I don't think examples are necessary but I can add some (especially those from the original issue) if needed.
Ensure std benchmarks get tested.
This ensures that the std benchmarks don't break in the future. Currently they aren't compiled or tested on CI, so they can easily bitrot. Testing a benchmark runs it with one iteration. Adding these should only add a few seconds to CI.
Closes#54176Closes#61913
Complete the std::time documentation to warn about the inconsistencies between OS
Fixes#48980.
I put the new documentation in `src/libstd/time.rs` at the module-level because it affects all types, even the one that are not directly system dependents if they are used with affected types, but there may be a better place for it.
add raw_ref macros
In https://github.com/rust-lang/rust/issues/64490, various people were in favor of exposing `&raw` as a macro first before making the actual syntax stable. So this PR (unstably) introduces those macros.
I'll create the tracking issue if we're okay moving forward with this.
Insufficient sanitization of the x87 FPU tag word in the trusted enclave runtime allowed unprivileged adversaries in the containing host application to induce incoherent or unexpected results for ABI-compliant compiled enclave application code that uses the x87 FPU.
Vulnerability was disclosed to us by Fritz Alder, Jo Van Bulck, David Oswald and Frank Piessens
Revert heterogeneous SocketAddr PartialEq impls
Originally added in #72239.
These lead to inference regressions (mostly in tests) in code that looks like:
```rust
let socket = SocketAddrV4::new(Ipv4Addr::new(127, 0, 0, 1), 8080);
assert_eq!(socket, "127.0.0.1:8080".parse().unwrap());
```
That compiles as of stable 1.44.0 but fails in beta with:
```console
error[E0284]: type annotations needed
--> src/main.rs:3:41
|
3 | assert_eq!(socket, "127.0.0.1:8080".parse().unwrap());
| ^^^^^ cannot infer type for type parameter `F` declared on the associated function `parse`
|
= note: cannot satisfy `<_ as std::str::FromStr>::Err == _`
help: consider specifying the type argument in the method call
|
3 | assert_eq!(socket, "127.0.0.1:8080".parse::<F>().unwrap());
|
```
Closes#73242.
Add methods to go from a nul-terminated Vec<u8> to a CString
Fixes#73100.
Doc tests have been written and the documentation on the error type
updated too.
I used `#[stable(feature = "cstring_from_vec_with_nul", since = "1.46.0")]` but I don't know if the version is correct.
Example about explicit mutex dropping
Fixes#67457.
Following the remarks made in #73074, I added an example on the main `Mutex` type, with a situation where there is mutable data and a computation result.
In my testing it is effectively needed to explicitly drop the lock, else it deadlocks.
r? @dtolnay because you were the one to review the previous PR.
