travis: Don't set `RUST_LOG` globally
I have a suspicion that this caused a large regression in cycle times by forcing
the compiler to perform more checks on every `debug!` statement, so let's test
this out by removing the `RUST_LOG` env var globally.
This regression in cycle time was witnessed between [two] [builds] where the
[PR] in question didn't do much suspicious. Judging by how the stage0 times
*also* regressed though then this is my best guess.
[two]: https://travis-ci.org/rust-lang/rust/builds/210149932
[builds]: https://travis-ci.org/rust-lang/rust/builds/210179995
[PR]: https://github.com/rust-lang/rust/pull/40446
fix innacuracy in mir TerminatorKind::SwitchInt docs
Each index of `values` corresponds to an index of `targets`, and `targets` additionally has a "default case" element at its end, so `targets.len() == values.len() + 1`, not the other way around. For example, [here](0aeb9c1297/src/librustc/mir/mod.rs (L549-L550)) is a concrete instance of `SwitchInt` being constructed with `targets.len() == 2` and `values.len() == 1`.
Extract book into a submodule
Part of https://github.com/rust-lang/rust/issues/39588
We probably don't want to land this till after the beta branches on friday, but would still ❤️ a review from @alexcrichton , since I am a rustbuild noob.
This pr:
1. removes the book
2. adds it back in as a submodule
3. the submodule includes both the old book and the new book
4. it also includes an index page explaining the difference in editions
5. it also includes redirect pages for the old book URLs.
6. so we build all that stuff too.
r? @alexcrichton
Rename TryFrom's associated type and implement str::parse using TryFrom.
Per discussion on the tracking issue, naming `TryFrom`'s associated type `Error` is generally more consistent with similar traits in the Rust ecosystem, and what people seem to assume it should be called. It also helps disambiguate from `Result::Err`, the most common "Err".
See https://github.com/rust-lang/rust/issues/33417#issuecomment-269108968.
`TryFrom<&str>` and `FromStr` are equivalent, so have the latter provide the former to ensure that. Using `TryFrom` in the implementation of `str::parse` means types that implement either trait can use it. When we're ready to stabilize `TryFrom`, we should update `FromStr` to
suggest implementing `TryFrom<&str>` instead for new code.
See https://github.com/rust-lang/rust/issues/33417#issuecomment-277175994
and https://github.com/rust-lang/rust/issues/33417#issuecomment-277253827.
Refs #33417.
