Replace push loops with extend() where possible
Or set the vector capacity where I couldn't do it.
According to my [simple benchmark](https://gist.github.com/ljedrz/568e97621b749849684c1da71c27dceb) `extend`ing a vector can be over **10 times** faster than `push`ing to it in a loop:
10 elements (6.1 times faster):
```
test bench_extension ... bench: 75 ns/iter (+/- 23)
test bench_push_loop ... bench: 458 ns/iter (+/- 142)
```
100 elements (11.12 times faster):
```
test bench_extension ... bench: 87 ns/iter (+/- 26)
test bench_push_loop ... bench: 968 ns/iter (+/- 3,528)
```
1000 elements (11.04 times faster):
```
test bench_extension ... bench: 311 ns/iter (+/- 9)
test bench_push_loop ... bench: 3,436 ns/iter (+/- 233)
```
Seems like a good idea to use `extend` as much as possible.
Rollup of bare_trait_objects PRs
All deny attributes were moved into bootstrap so they can be disabled with a line of config.
Warnings for external tools are allowed and it's up to the tool's maintainer to keep it warnings free.
r? @Mark-Simulacrum
cc @ljedrz @kennytm
Prefer `Option::map`/etc over `match` wherever it improves clarity
This isn't intended to change behavior anywhere. A lot of times statements like `match x { None => None, Some(y) => [...] }` can be rewritten using `Option::map` or `Option::and_then` in a way that preserves or improves clarity, so that's what I've done here.
I think it's particularly valuable to keep things in `libcore` and `libstd` pretty/idiomatic since it's not uncommon to follow the `[src]` links when browsing the rust-lang.org docs for std/core. If there's any concern about pushing style-based changes though, I'll happily back out the non-std/core commits here.
When encountering format string errors in a raw string, or regular
string literal with embedded newlines, account for the positional
change to use correct spans.
:drive by fix: 🚗
- Don't print the newline on its own to avoid the possibility of
printing it out of order due to `stdout` locking.
- Modify wording of `concat!()` with non-literals to not mislead into
believing that only `&str` literals are accepted.
- Add test for `concat!()` with non-literals.
resolve: Functions introducing procedural macros reserve a slot in the macro namespace as well
Similarly to https://github.com/rust-lang/rust/pull/52234, this gives us symmetry between internal and external views of a crate, but in this case it's always an error to call a procedural macro in the same crate in which it's defined.
Closes https://github.com/rust-lang/rust/issues/52225
rustc: Tweak expansion of #[proc_macro] for 2018
The syntactical expansion of `#[proc_macro]` and related attributes currently
contains absolute paths which conflicts with a lint for the 2018 edition,
causing issues like #52214. This commit puts a band-aid on the issue by ensuring
that procedural macros can also migrate to the 2018 edition for now by tweaking
the expansion based on what features are activated. A more long-term solution
would probably tweak the edition hygiene of spans, but this should do the trick
for now.
Closes#52214
The syntactical expansion of `#[proc_macro]` and related attributes currently
contains absolute paths which conflicts with a lint for the 2018 edition,
causing issues like #52214. This commit puts a band-aid on the issue by ensuring
that procedural macros can also migrate to the 2018 edition for now by tweaking
the expansion based on what features are activated. A more long-term solution
would probably tweak the edition hygiene of spans, but this should do the trick
for now.
Closes#52214
rustc: Verify #[proc_macro] is only a word
... and perform the same verification for #[proc_macro_attribute], currently
neither of these attributes take any arguments.
Closes#52273
This is gated on edition 2018 & the `async_await` feature gate.
The parser will accept `async fn` and `async unsafe fn` as fn
items. Along the same lines as `const fn`, only `async unsafe fn`
is permitted, not `unsafe async fn`.The parser will not accept
`async` functions as trait methods.
To do a little code clean up, four fields of the function type
struct have been merged into the new `FnHeader` struct: constness,
asyncness, unsafety, and ABI.
Also, a small bug in HIR printing is fixed: it previously printed
`const unsafe fn` as `unsafe const fn`, which is grammatically
incorrect.
