This commit is an implementation of [RFC 1184][rfc] which tweaks the behavior of
the `#![no_std]` attribute and adds a new `#![no_core]` attribute. The
`#![no_std]` attribute now injects `extern crate core` at the top of the crate
as well as the libcore prelude into all modules (in the same manner as the
standard library's prelude). The `#![no_core]` attribute disables both std and
core injection.
[rfc]: https://github.com/rust-lang/rfcs/pull/1184
Fixes#25022
This adapts the deriving mechanism to not repeat bounds for the same type parameter. To give an example: for the following code:
```rust
#[derive(Clone)]
pub struct FlatMap<I, U: IntoIterator, F> {
iter: I,
f: F,
frontiter: Option<U::IntoIter>,
backiter: Option<U::IntoIter>,
}
```
the latest nightly generates the following impl signature:
```rust
impl <I: ::std::clone::Clone,
U: ::std::clone::Clone + IntoIterator,
F: ::std::clone::Clone>
::std::clone::Clone for FlatMap<I, U, F> where
I: ::std::clone::Clone,
F: ::std::clone::Clone,
U::IntoIter: ::std::clone::Clone,
U::IntoIter: ::std::clone::Clone
```
With these changes, the signature changes to this:
```rust
impl <I, U: IntoIterator, F> ::std::clone::Clone for FlatMap<I, U, F> where
I: ::std::clone::Clone,
F: ::std::clone::Clone,
U::IntoIter: ::std::clone::Clone
```
(Nothing in the body of the impl changes)
Note that the second impl is more permissive, as it doesn't have a `Clone` bound on `U` at all. There was a compile-fail test that failed due to this. I don't understand why we would want the old behaviour (and nobody on IRC could tell me either), so please tell me if there is a good reason that I missed.
This removes some of the more casual language.
The only outright goofiness I couldn't bear to remove is "these modules are the bedrock upon which all of Rust is forged, and they have mighty names like `std::slice` and `std::cmp`", which I believe the greatest sentence I have ever created.
Only `make -j4` takes ~50 mins
`make check` bumps it up to ~1hr 30min
Travis seems more than happy to let this happen.
Time limits appear to be meaningless.
Similar to the previous PR, it's easy to tell how much your PR definitely builds by checking the current logs or just considering how long it's been building for.
part of #24407
I'm not sure whether I should be trying to explain the general rule in the E0210 explanation or just point people to the RFC. However, if we go with the latter option I think that the RFC will need to be revised slightly, since it is not quite as gentle as I would like.
Also, the link to RFC 1023 is not the correct one (it should be https://github.com/rust-lang/rfcs/blob/master/text/1023-rebalancing-coherence.md), but the correct one is too long. I'm aware of @michaelsproul's PR https://github.com/rust-lang/rust/pull/26290 from awhile back, but it doesn't seem to be working. Has there not been a new snapshot yet?
#27360 removed a padding field full of uint8_t's, but didn't remove
the use. This didn't get picked up presumably because (a) bors
doesn't have any BSD builders, and/or (b) #[cfg]'d out blocks don't
get linted.
```
rustc: x86_64-unknown-freebsd/stage1/lib/rustlib/x86_64-unknown-freebsd/lib/liblibc
src/liblibc/lib.rs:1099:42: 1099:49 error: unused import, #[deny(unused_imports)] on by default
src/liblibc/lib.rs:1099 use types::common::c99::{uint8_t, uint32_t, int32_t};
^~~~~~~
error: aborting due to previous error
fatal runtime error: Could not unwind stack, error = 159555904
```
this makes the second code block consistent with the first code block -- other than being in reversed order, the first code block claims b is u16 and c is u32, whereas the second code block claims the opposite. seems to be an obvious typo.
This is *mostly* reducing *my* use of *italics* but there's some other misc changes interspersed as I went along.
This updates the italicizing alphabetically from `a` to `ra`.
r? @steveklabnik
#27360 removed a padding field full of uint8_t's, but didn't remove
the use. This didn't get picked up presumably because (a) bors
doesn't have any BSD builders, and/or (b) #[cfg]'d out blocks don't
get linted.
```
rustc: x86_64-unknown-freebsd/stage1/lib/rustlib/x86_64-unknown-freebsd/lib/liblibc
src/liblibc/lib.rs:1099:42: 1099:49 error: unused import, #[deny(unused_imports)] on by default
src/liblibc/lib.rs:1099 use types::common::c99::{uint8_t, uint32_t, int32_t};
^~~~~~~
error: aborting due to previous error
fatal runtime error: Could not unwind stack, error = 159555904
```
There are still problems in both the design and implementation of this, so we don't want it landing in 1.2.
cc @arielb1 @nikomatsakis
cc #27364
r? @alexcrichton
