This is a direct port of my prior work on the float formatting. The detailed description is available [here](https://github.com/lifthrasiir/rust-strconv#flt2dec). In brief,
* This adds a new hidden module `core::num::flt2dec` for testing from `libcoretest`. Why is it in `core::num` instead of `core::fmt`? Because I envision that the table used by `flt2dec` is directly applicable to `dec2flt` (cf. #24557) as well, which exceeds the realm of "formatting".
* This contains both Dragon4 algorithm (exact, complete but slow) and Grisu3 algorithm (exact, fast but incomplete).
* The code is accompanied with a large amount of self-tests and some exhaustive tests. In particular, `libcoretest` gets a new dependency on `librand`. For the external interface it relies on the existing test suite.
* It is known that, in the best case, the entire formatting code has about 30 KBs of binary overhead (judged from strconv experiments). Not too bad but there might be a potential room for improvements.
This is rather large code. I did my best to comment and annotate the code, but you have been warned.
For the maximal availability the original code was licensed in CC0, but I've also dual-licensed it in MIT/Apache as well so there should be no licensing concern.
This is [breaking-change] as it changes the float output slightly (and it also affects the casing of `inf` and `nan`). I hope this is not a big deal though :)
Fixes#7030, #18038 and #24556. Also related to #6220 and #20870.
## Known Issues
- [x] I've yet to finish `make check-stage1`. It does pass main test suites including `run-pass` but there might be some unknown edges on the doctests.
- [ ] Figure out how this PR affects rustc.
- [ ] Determine which internal routine is mapped to the formatting specifier. Depending on the decision, some internal routine can be safely removed (for instance, currently `to_shortest_str` is unused).
I've found that there are still huge amounts of occurrences of `task`s in the documentation. This PR tries to eliminate all of them in favor of `thread`.
dropck: must assume `Box<Trait + 'a>` has a destructor of interest.
Fix#25199.
This detail was documented in [RFC 769]; the implementation was just missing.
[breaking-change]
The breakage here falls into both obvious and non-obvious cases.
The obvious case: if you were relying on the unsoundness this exposes (namely being able to reference dead storage from a destructor, by doing it via a boxed trait object bounded by the lifetime of the dead storage), then this change disallows that.
The non-obvious cases: The way dropck works, it causes lifetimes to be extended to longer extents than they covered before. I.e. lifetimes that are attached as trait-bounds may become longer than they were previously.
* This includes lifetimes that are only *implicitly* attached as trait-bounds (due to [RFC 599]). So you may have code that was e.g. taking a parameter of type `&'a Box<Trait>` (which expands to `&'a Box<Trait+'a>`), that now may need to be assigned type `&'a Box<Trait+'static>` to ensure that `'a` is not inadvertantly inferred to a region that is actually too long. (See commit ee06263 for an example of this.)
[RFC 769]: https://github.com/rust-lang/rfcs/blob/master/text/0769-sound-generic-drop.md#the-drop-check-rule
[RFC 599]: https://github.com/rust-lang/rfcs/blob/master/text/0599-default-object-bound.md
This syntax was removed in b24a3b8 but references remained in the
grammar, the reference, rustdoc generation, and some auxiliary test
files that don't seem to have been used since 812637e.
Thanks!! 💟
This was causing function calls to be emitted for bitwise complements, even with optimizations on.
Steps to reproduce:
```
$ cat wrapping.rs
fn main() {
let a = std::num::Wrapping(std::env::args().len() as u32);
let b = !a;
println!("{}", b.0);
}
$ rustc -O wrapping.rs --emit=asm,link
$ grep Not wrapping.s
callq _ZN3num8wrapping23Wrapping$LT$u32$GT$.Not3not20hba4b266232e02b1dHkbE
```
This syntax was removed in b24a3b8 but references remained in the
grammar, the reference, rustdoc generation, and some auxiliary test
files that don't seem to have been used since 812637e.
Tiny tiny nitpick that I just noticed after getting a new laptop ( 🍺 + 💻 = 👼 ) and thus needing to ./configure anew on Yosemite.
It's weird to see a message that says you're on 10.9 if you're on 10.10, in a oh-i-wonder-what-else-is-wrong sort of sense-- easy fix with a `>=` since `gcc --version` on 10.10 with the newest xcode still says it's clang.
❤️
Building with `--target=mipsel-unknown-linux-gnu` currently results in the following errors, fixed by this PR:
```
rustc: x86_64-unknown-linux-gnu/stage2/lib/rustlib/mipsel-unknown-linux-gnu/lib/libstd
/vol/rust/src/libstd/os/linux/raw.rs:76:21: 76:28 error: use of undeclared type name `c_ulong`
/vol/rust/src/libstd/os/linux/raw.rs:76 pub st_dev: c_ulong,
^~~~~~~
/vol/rust/src/libstd/os/linux/raw.rs:83:22: 83:29 error: use of undeclared type name `c_ulong`
/vol/rust/src/libstd/os/linux/raw.rs:83 pub st_rdev: c_ulong,
^~~~~~~
/vol/rust/src/libstd/sys/common/net2.rs:210:52: 210:70 error: unresolved name `libc::TCP_KEEPIDLE`
/vol/rust/src/libstd/sys/common/net2.rs:210 setsockopt(&self.inner, libc::IPPROTO_TCP, libc::TCP_KEEPIDLE,
```
If you have 0 references (`&T`) to a resource, presumably, you could have a mutable reference (`&mut T`). So this only start to make sense at having 1 reference to a resource.
An automated script was run against the `.rs` and `.md` files,
subsituting every occurrence of `task` with `thread`. In the `.rs`
files, only the texts in the comment blocks were affected.
This change is worrisome to me, both because:
1. I thought the rules in RFC 599 imply that the `Box<Trait>` without `'static`
in the first case would expand to the second case, but their behaviors
here differ. And,
2. The explicit handling of `'static` should mean `dropck` has no application
here and thus we should have seen no change to the expected error messages.
Nonetheless, the error messages changed.
