…nstead.

uninitialized -> uninit
into_initialized -> assume_init
read_initialized -> read
set -> write

syntax: Remove warning for unnecessary path disambiguators

`rustfmt` is now stable and it removes unnecessary turbofishes, so removing the warning as discussed in rust-lang#43540 (where it was introduced).
One hardcoded warning less.

Closes rust-lang#58055

r? @nikomatsakis

…rochenkov

librustc_driver => 2018

Transitions `librustc_driver` to Rust 2018; cc rust-lang#58099

r? @Centril

Add FromStr impl for NonZero types

This is a WIP implementation because I do have some questions regarding the solution.

Somebody should ping the lang team on this I guess.
Please see the annotations on the code for more details.

Closes rust-lang#58604

…petrochenkov

librustc_interface => 2018

r? @oli-obk

This will likely produce an ICE for some reason... so super-WIP.

…avus

Add suggestion to use `&*var` when `&str: From<String>` is expected

Fix rust-lang#53879.

…=joshtriplett

Make ASCII case conversions more than 4× faster

Reformatted output of `./x.py bench src/libcore --test-args ascii` below. The `libcore` benchmark calls `[u8]::make_ascii_lowercase`. `lookup` has code (effectively) identical to that before this PR, and ~~`branchless`~~ `mask_shifted_bool_match_range` after this PR.

~~See [code comments](rust-lang@ce933f7#diff-01076f91a26400b2db49663d787c2576R3796) in `u8::to_ascii_uppercase` in `src/libcore/num/mod.rs` for an explanation of the branchless algorithm.~~

**Update:** the algorithm was simplified while keeping the performance. See `branchless` v.s. `mask_shifted_bool_match_range` benchmarks.

Credits to @raphlinus for the idea in https://twitter.com/raphlinus/status/1107654782544736261, which extends this algorithm to “fake SIMD” on `u32` to convert four bytes at a time. The `fake_simd_u32` benchmarks implements this with [`let (before, aligned, after) = bytes.align_to_mut::<u32>()`](https://doc.rust-lang.org/std/primitive.slice.html#method.align_to_mut). Note however that this is buggy when addition carries/overflows into the next byte (which does not happen if the input is known to be ASCII).

This could be fixed (to optimize `[u8]::make_ascii_lowercase` and `[u8]::make_ascii_uppercase` in `src/libcore/slice/mod.rs`) either with some more bitwise trickery that I didn’t quite figure out, or by using “real” SIMD intrinsics for byte-wise addition. I did not pursue this however because the current (incorrect) fake SIMD algorithm is only marginally faster than the one-byte-at-a-time branchless algorithm. This is because LLVM auto-vectorizes the latter, as can be seen on https://rust.godbolt.org/z/anKtbR.

Benchmark results on Linux x64 with Intel i7-7700K: (updated from rust-lang#59283 (comment))

```rust
6830 bytes string:

alloc_only                          ... bench:    112 ns/iter (+/- 0) = 62410 MB/s
black_box_read_each_byte            ... bench:  1,733 ns/iter (+/- 8) = 4033 MB/s
lookup_table                        ... bench:  1,766 ns/iter (+/- 11) = 3958 MB/s
branch_and_subtract                 ... bench:    417 ns/iter (+/- 1) = 16762 MB/s
branch_and_mask                     ... bench:    401 ns/iter (+/- 1) = 17431 MB/s
branchless                          ... bench:    365 ns/iter (+/- 0) = 19150 MB/s
libcore                             ... bench:    367 ns/iter (+/- 1) = 19046 MB/s
fake_simd_u32                       ... bench:    361 ns/iter (+/- 2) = 19362 MB/s
fake_simd_u64                       ... bench:    361 ns/iter (+/- 1) = 19362 MB/s
mask_mult_bool_branchy_lookup_table ... bench:  6,309 ns/iter (+/- 19) = 1107 MB/s
mask_mult_bool_lookup_table         ... bench:  4,183 ns/iter (+/- 29) = 1671 MB/s
mask_mult_bool_match_range          ... bench:    339 ns/iter (+/- 0) = 20619 MB/s
mask_shifted_bool_match_range       ... bench:    339 ns/iter (+/- 1) = 20619 MB/s

32 bytes string:

alloc_only                          ... bench:     15 ns/iter (+/- 0) = 2133 MB/s
black_box_read_each_byte            ... bench:     29 ns/iter (+/- 0) = 1103 MB/s
lookup_table                        ... bench:     24 ns/iter (+/- 4) = 1333 MB/s
branch_and_subtract                 ... bench:     16 ns/iter (+/- 0) = 2000 MB/s
branch_and_mask                     ... bench:     16 ns/iter (+/- 0) = 2000 MB/s
branchless                          ... bench:     16 ns/iter (+/- 0) = 2000 MB/s
libcore                             ... bench:     15 ns/iter (+/- 0) = 2133 MB/s
fake_simd_u32                       ... bench:     17 ns/iter (+/- 0) = 1882 MB/s
fake_simd_u64                       ... bench:     16 ns/iter (+/- 0) = 2000 MB/s
mask_mult_bool_branchy_lookup_table ... bench:     42 ns/iter (+/- 0) = 761 MB/s
mask_mult_bool_lookup_table         ... bench:     35 ns/iter (+/- 0) = 914 MB/s
mask_mult_bool_match_range          ... bench:     16 ns/iter (+/- 0) = 2000 MB/s
mask_shifted_bool_match_range       ... bench:     16 ns/iter (+/- 0) = 2000 MB/s

7 bytes string:

alloc_only                          ... bench:     14 ns/iter (+/- 0) = 500 MB/s
black_box_read_each_byte            ... bench:     22 ns/iter (+/- 0) = 318 MB/s
lookup_table                        ... bench:     16 ns/iter (+/- 0) = 437 MB/s
branch_and_subtract                 ... bench:     16 ns/iter (+/- 0) = 437 MB/s
branch_and_mask                     ... bench:     16 ns/iter (+/- 0) = 437 MB/s
branchless                          ... bench:     19 ns/iter (+/- 0) = 368 MB/s
libcore                             ... bench:     20 ns/iter (+/- 0) = 350 MB/s
fake_simd_u32                       ... bench:     18 ns/iter (+/- 0) = 388 MB/s
fake_simd_u64                       ... bench:     21 ns/iter (+/- 0) = 333 MB/s
mask_mult_bool_branchy_lookup_table ... bench:     20 ns/iter (+/- 0) = 350 MB/s
mask_mult_bool_lookup_table         ... bench:     19 ns/iter (+/- 0) = 368 MB/s
mask_mult_bool_match_range          ... bench:     19 ns/iter (+/- 0) = 368 MB/s
mask_shifted_bool_match_range       ... bench:     19 ns/iter (+/- 0) = 368 MB/s
```

adjust MaybeUninit API to discussions

uninitialized -> uninit
into_initialized -> assume_init
read_initialized -> read
set -> write

add rustfix-able suggestions to trim_{left,right} deprecations

Fixes rust-lang#53802 (technically already fixed by rust-lang#58002, but that issue is about these methods).

…tests, r=shepmaster

Refactor tuple comparison tests

…ochenkov

Reject integer suffix when tuple indexing

Fix rust-lang#59418.

r? @varkor

…erpretcx, r=oli-obk

Renames `EvalContext` to `InterpretCx`

This PR renames `EvalContext` to `InterpretCx` in `src/librustc_mir`.
This PR is related to rust-lang#54395 .

…iagnostic, r=oli-obk

Generalize diagnostic for `x = y` where `bool` is the expected type

Extracted out of rust-lang#59288.

Currently we special case a diagnostic for `if x = y { ...` since the expected type is `bool` in this case and we instead suggest `if x == y`. This PR generalizes this such that given an expression of form `x = y` (`ExprKind::Assign(..)`) where the expected type is `bool`, we emit a suggestion `x == y`.

r? @oli-obk

Let's do a perf run to make sure this was not the source of regressions in rust-lang#59288.

fix: Make incremental artifact deletion more robust

Should fix the intermittent errors reported in rust-lang#57958

cc rust-lang#48614

Add `Default` to `std::alloc::System`

`System` is a unit struct, thus, it can be constructed without any additional information. Therefore `Default` is a noop. However, in generic code, a `T: Default` may happen as in

```rust
#[derive(Default)]
struct Foo<A> {
    allocator: A
}
```

Does this need a feature gate?
Should I also add `PartialEq/Eq/PartialOrd/Ord/Hash`?

Add some tests

close rust-lang#52977

It seems that there are no tests for this issue, so I opened this PR.
off-topic: I noticed [this test](https://github.com/rust-lang/rust/blob/master/src/test/ui/existential_types/nested_existential_types.rs)'s indents are bad, could I include commit to fix this, or should I separate?

r? @oli-obk

…Amanieu

Include id in Thread's Debug implementation

Since Rust 1.19.0, `id` is a stable method, so there is no reason to not include it in Debug implementation.