std: Update compiler-rt for more ABI fixes
This update of compiler-rt includes rust-lang/compiler-rt#26 which provides a
targeted fix to the powisf2 intrinsics to keep #37559 fixed but also address
the new issue of #37630. I've also [written up my thoughts][1] on why it appears
that this is the correct fix for now (hoepfully at least).
Closes#37630
[1]: https://github.com/rust-lang/compiler-rt/pull/26#issuecomment-259751998
This teaches `format_args!` how to interpret format printf- and
shell-style format directives. This is used in cases where there are
unused formatting arguments, and the reason for that *might* be because
the programmer is trying to use the wrong kind of formatting string.
This was prompted by an issue encountered by simulacrum on the #rust IRC
channel. In short: although `println!` told them that they weren't using
all of the conversion arguments, the problem was in using printf-syle
directives rather than ones `println!` would undertand.
Where possible, `format_args!` will tell the programmer what they should
use instead. For example, it will suggest replacing `%05d` with `{:0>5}`,
or `%2$.*3$s` with `{1:.3$}`. Even if it cannot suggest a replacement,
it will explicitly note that Rust does not support that style of directive,
and direct the user to the `std::fmt` documentation.
While the commit message on this one sounds terrible, it's really not so
bad. The issue is that our test runner _expects_ a `fn main() {}` in
code blocks that it'll test, but this code really shouldn't have them.
If it did, then clicking the "play" link in the docs would result in
play.rust-lang.org not treating this code as a test example to be run.
Don't provide hint to add lifetime on impl items that implement a trait.
```rust
use std::str::FromStr;
pub struct Foo<'a> {
field: &'a str,
}
impl<'a> FromStr for Foo<'a> {
type Err = ();
fn from_str(path: &str) -> Result<Self, ()> {
Ok(Foo { field: path })
}
}
```
would give the following hint:
```nocode
help: consider using an explicit lifetime parameter as shown: fn from_str(path: &'a str) -> Result<Self, ()>
--> <anon>:9:5
|
9 | fn from_str(path: &str) -> Result<Self, ()> {
| ^
```
which is never correct, since then there will be a lifetime mismatch
between the impl and the trait.
Remove this hint for impl items that implement a trait.
Discussed in #37546 the libs team reached the conclusion that a default zero
duration seems like a reasonable implementation of the `Default` trait.
Closes#37546
proc_macro_plugin: Wrap nonexistent filename in <>
I'm not sure how big of an issue this can become in practice, but `FileMap`s made from something that's not a file are supposed to wrap the file name in `<>`.
For an example fix, see kevinmehall/rust-peg@332fd4dbae. There, it caused cargo to always recompile a crate using rust-peg, even when nothing was changed, because cargo sees that the dummy file doesn't exist.
Fix regression involving custom derives on items with `$crate`
The regression was introduced in #37213.
I believe we cannot make the improvements from #37213 work with the current custom derive setup (c.f. https://github.com/rust-lang/rust/issues/37637#issuecomment-258959145) -- we'll have to wait for `TokenStream`'s API to improve.
Fixes#37637.
r? @nrc
This update of compiler-rt includes rust-lang/compiler-rt#26 which provides a
targeted fix to the powisf2 intrinsics to keep #37559 fixed but also address
the new issue of #37630. I've also [written up my thoughts][1] on why it appears
that this is the correct fix for now (hoepfully at least).
Closes#37630
[1]: https://github.com/rust-lang/compiler-rt/pull/26#issuecomment-259751998
Without these changes, play.rust-lang.org (as of today) would wrap
our examples in `fn main() {}`. This prevents the user from being able
to easily run the tests.
macros: improve reexports
This PR
- avoids building multiple module graphs for a crate that is referenced by multiple `extern crate` items,
- registers `#[no_link] extern crate`s to avoid loading the same crate metadata twice,
- stability checks `#[no_link] extern crate`s,
- [breaking-chage]: `#[no_link] #[macro_use] extern crate syntax;` is allowed on stable today
- fixes `$crate` in `#[macro_reexport]`ed macros,
- [breaking-change] for `#[feature(macro_reexport)]` (technically)
- allows selective macro importing (i.e. `#[macro_use(foo, bar)]`) from custom derive crates, and
- refactors the crate metadata to support re-exported macros in arbitrary modules (not yet needed).
r? @nrc
This allows the initial build of src/bootstrap itself to use a local
cargo taken from `configure --local-rust-root`. It was already finding
rustc this way, but was always downloading cargo since it didn't know
where to find it.
It now matches the same logic that `config.rs` will use for stage0,
where both rustc and cargo are taken from `CFG_LOCAL_RUST_ROOT`.
Document the question mark operator in reference and the book's syntax index
The question mark operator will be stabilized for the Rust 1.13 release (unfortunately). Even though I don't like the operator, it still should be documented in the syntax index in the book and in the reference.
Maybe there are people who also want to change the book's chapters on error handling, depending on their views of what idiomatic error handling is, now that the operator is stable, but I don't want to and I'd prefer to keep this PR focused on the reference and syntax index only.
Please also apply this PR to the beta branch of rust.
