Document the `proc_macro` feature in the Unstable Book
Discusses the `proc_macro` feature flag and the features it enables:
* Implicit enable of `extern_use_macros` feature and how to import proc macros
* Error handling in proc macros (using panic messages)
* Function-like proc macros using `#[proc_macro]` and a usage example for creating and invoking
* Attribute-like proc macros using `#[proc_macro_attribute]` and a usage example for creating and invoking
[Rendered](https://github.com/abonander/rust/blob/book_proc_macro/src/doc/unstable-book/src/language-features/proc-macro.md)
Update cargo submodule
This pulls in a fix for #41797 to the master branch, I'll send a separate PR for
the beta branch. Note that the Cargo PR in question to pull in is https://github.com/rust-lang/cargo/pull/4046
avoid cycles in mir-dump, take 2
This fixes#41697, for real this time, but I'm not sure how best to add a regression test. I was considering maybe adding some flag so that the MIR dumping doesn't actually get written to files (e.g., overloading the directory flag so you can specify nil or something).
cc @dwrensha @oli-obk
use equality in the coerce-unsized check
This seems both to be a safe, conservative choice, and it sidesteps the cycle in #41849. Note that, before I converted variance into proper queries, we were using a hybrid of subtyping and equality, due to the presence of a flag that forced invariance if variance had not yet been computed. (Also, Coerce Unsized is unstable.)
Fixes#41936.
r? @eddyb
Add lint for unused macros
Addresses parts of #34938, to add a lint for unused macros.
We now output warnings by default when we encounter a macro that we didn't use for expansion.
Issues to be resolved before this PR is ready for merge:
- [x] fix the NodeId issue described above
- [x] remove all unused macros from rustc and the libraries or set `#[allow(unused_macros)]` next to them if they should be kept for some reason. This is needed for successful boostrap and bors to accept the PR. -> #41934
- [x] ~~implement the full extent of #34938, that means the macro match arm checking as well.~~ *let's not do this for now*
This is a resurrection of #40776, combining their Windows setup with an
additional setup on Unix to set the program group's niceness to +10
(low-but-not-lowest priority) when the `low_priority` option is on.
rustdoc: Display `extern "C" fn` instead of `extern fn`
It was decided in rust-lang-nursery/fmt-rfcs#52 to be explicit about the ABI so rustdoc should follow suit.
[Doc] Add links to the `thread::LocalKey` doc.
Part of #29378 .
I do not know exactly what should be done for the `cleanup` part, if you have any idea I'll gladly do it.
r? @rust-lang/docs
[Doc] Implrove `thread::Builder`'s doc.
Part of #29378 .
- Explains *why* we would use the builder instead ofthe free function.
- Changes the parent-child explanation for a spawned-caller in `thread::Builder::spawn`
- Adds a link to `io::Result` in `thread::Builder`
- Corrects the return type doc in `thread::Builder::spawn`
r? @rust-lang/docs
Make unsatisfied trait bounds note multiline
Make diagnostic note for existing method with unsatisfied trait bounds
multiline for cleaner output.
```
= note: the method `count` exists but the following trait bounds were not satisfied:
`[closure@../../src/test/compile-fail/issue-36053-2.rs:17:39: 17:53] : std::ops::FnMut<(&_,)>`
`std::iter::Filter<std::iter::Fuse<std::iter::Once<&str>> [closure@../../src/test/compile-fail/issue-36053-2.rs:17:39: 17:53]> : std::iter::Iterator`
```
Before:
```
= note: the method `count` exists but the following trait bounds were not satisfied: `[closure@../../src/test/compile-fail/issue-36053-2.rs:17:39: 17:53] : std::ops::FnMut<(&_,)>`, `std::iter::Filter<std::iter::Fuse<std::iter::Once<&str>>, [closure@../../src/test/compile-fail/issue-36053-2.rs:17:39: 17:53]> : std::iter::Iterator`
```
Make only rustc_trans depend on rustc_llvm
With these changes, only rustc_trans depends directly on rustc_llvm (and no crate gained a new dependency on trans). This means changing LLVM doesn't rebuild librustc or rustc_metadata, only rustc_trans, rustc_driver and the rustc executable
Also, rustc_driver technically doesn't know about LLVM any more (of course, it still handles a ton of options that conceptually refer to LLVM, but it delegates their implementation to trans).
What I *didn't* implement was merging most or all of rustc_llvm into rustc_trans. I ran into a nasty bug, which was probably just a silly typo somewhere but I probably won't have the time to figure it out in the next week or two. I opened #41699 for that step.
Fixes#41473
Update to the Rusty rust-installer
This updates the rust-installer submodule to the new version written in Rust (rust-lang/rust-installer#62), now moved to `src/tools/rust-installer` and invoked in `dist.rs` as a cargo-based tool command. All of the former shell-script invocations now invoke the tool, otherwise keeping the same arguments as before.
As a small bonus, `rustc-src` now also uses the same tarball generator, so it gains a smaller `.tar.xz` too.
Fixes#41569. r? @alexcrichton
