Customize `<FlatMap as Iterator>::fold`
`FlatMap` can use internal iteration for its `fold`, which shows a
performance advantage in the new benchmarks:
test iter::bench_flat_map_chain_ref_sum ... bench: 4,354,111 ns/iter (+/- 108,871)
test iter::bench_flat_map_chain_sum ... bench: 468,167 ns/iter (+/- 2,274)
test iter::bench_flat_map_ref_sum ... bench: 449,616 ns/iter (+/- 6,257)
test iter::bench_flat_map_sum ... bench: 348,010 ns/iter (+/- 1,227)
... where the "ref" benches are using `by_ref()` that isn't optimized.
So this change shows a decent advantage on its own, but much more when
combined with a `chain` iterator that also optimizes `fold`.
travis: Move sccache to the us-west-1 region
Most of the other rust-lang buckets are in us-west-1 and I think the original
bucket was just accidentally created in the us-east-1 region. Let's consolidate
by moving it to the same location as the rest of our buckets.
bring TyCtxt into scope
got comments both from @eddyb and @nikomatsakis (via https://github.com/rust-lang/rust/pull/44505) that we should always put `TyCtxt` in scope
should I just go and import it at other places in the codebase or we just keep doing small improvements?
rustc: Spawn `cmd /c emcc.bat` explicitly
In #42436 the behavior for spawning processes on Windows was tweaked slightly to
fix various bugs, but this caused #42791 as a regression, namely that to spawn
batch scripts they need to be manually spawned with `cmd /c` instead now. This
updates the compiler to handle this case explicitly for Emscripten.
Closes#42791
bump gcc for bootstrap
On Windows, the gcc crate would send /Wall to msvc, which would cause
builds to get flooded with warnings, exploding compile times from one
hour to more than 72! The gcc crate version 0.3.54 changes this behavior
to send /W4 instead, which greatly cuts down on cl.exe flooding the
command prompt window with warnings.
Ipv4Addr and Ipv6Addr convenience constructors.
Introduce convenience constructors for common types.
This introduces the following constructors:
* Ipv6Addr::localhost()
* Ipv6Addr::unspecified()
* Ipv4Addr::localhost()
* Ipv4Addr::unspecified()
The recently added `From` implementations were nice for avoiding the fallibility of conversions from strings like `"127.0.0.1".parse().unwrap()`, and `"::1".parse().unwrap()`, but while the Ipv4 version is roughly comparable in verbosity, the Ipv6 version lacks zero-segment elision, which makes it significantly more awkward: `[0, 0, 0, 0, 0, 0, 0, 0].into()`. While there isn't a clear way to introduce zero elision to type that can infallibly be converted into Ipv6 addresses, this PR resolves the problem for the two most commonly used addresses, which, incidentally, are the ones that suffer the most from the lack of zero-segment elision.
This change is dead simple, and introduces no backwards incompatibility.
See also, [this topic on the inernals board](https://internals.rust-lang.org/t/pre-rfc-convenience-ip-address-constructors/5878)
Implement <Rc<Any>>::downcast
* Implement `<Rc<Any>>::downcast::<T>`
* New unstable method. Works just like Box\<Any\>, but for Rc.
* Any has two cases for its methods: Any and Any + Send; Rc is never Send, so that case is skipped for Rc.
* Motivation for being a method with self is to match Box and there is no user-supplied type; the inner type is Any and downcast does not conflict with any method of Any.
* Arc was skipped because Any itself has no downcast for the case that makes most sense: Any + Send + Sync
Remove Borrow bound from SliceExt::binary_search
#37761 added a Borrow bound to `binary_search` and `binary_search_by_key` in `core::SliceExt`, but did not add it to the methods in `std::slice`. #41590 attempted to add this bound to `std::slice` but was not merged due to breakage. This PR removes the bound in `core::SliceExt`, so that these methods will have the same signature in `core` and `std`.
Fixes#41561
implement unsafe pointer methods
I also cleaned up some existing documentation a bit here or there since I was doing so much auditing of it. Most notably I significantly rewrote the `offset` docs to clarify safety (`*const` and `*mut`'s offset docs had actually diverged).
Individualize feature gates for const fn invocation
This PR changes the meaning of `#![feature(const_fn)]` so it is only required to declare a const fn but not to call one. Based on discussion at #24111. I was hoping we could have an FCP here in order to move that conversation forward.
This sets the stage for future stabilization of the constness of several functions in the standard library (listed below), so could someone please tag the lang team for review.
- `std::cell`
- `Cell::new`
- `RefCell::new`
- `UnsafeCell::new`
- `std::mem`
- `size_of`
- `align_of`
- `std::ptr`
- `null`
- `null_mut`
- `std::sync`
- `atomic`
- `Atomic{Bool,Ptr,Isize,Usize}::new`
- `once`
- `Once::new`
- primitives
- `{integer}::min_value`
- `{integer}::max_value`
Some other functions are const but they are also unstable or hidden, e.g. `Unique::new` so they don't have to be considered at this time.
After this stabilization, the following `*_INIT` constants in the standard library can be deprecated. I wasn't sure whether to include those deprecations in the current PR.
- `std::sync`
- `atomic`
- `ATOMIC_{BOOL,ISIZE,USIZE}_INIT`
- `once`
- `ONCE_INIT`
Moving buckets from us-east-1 to us-west-1 because us-west-1 is where
rust-central-station itself runs and in general is where we have all our other
buckets.
rustbuild: Compile the error-index in stage 2
Right now we comiple rustdoc in stage 2 and the error index in stage 0, which
ends up compiling rustdoc twice! To avoid compiling rustdoc twice (which takes
awhile) let's just compile it once in stage 2.
This boolean field on the error `Handler` is toggled to silence
warnings when `-A warnings` is passed. (This is actually a separate
mechanism from the global lint level—whether there's some redundancy
to be factored away here is an important question, but not one we
concern ourselves with in this commit.) But the same rationale
applies for `--cap-lints allow`. In particular, this makes the "soft"
feature-gate warning introduced in 8492ad24 (which is not a lint, but
just calls `struct_span_warn`) not pollute the builds of dependent
crates.
Thanks to @kennytm for pointing out the potential of
`can_emit_warnings` for this purpose.
Resolves#44213.
LLVM 5.0.0's lld-link frontend errors out if passed /natvis.
LLVM 6 (maybe earlier?) should at least ignore the flag.
Hopefully LLVM will eventually support the flag, at which point
this workaround can perhaps be simply removed, if 6? is old enough.
travis: Disable LLVM assertions on OSX
Our OSX builders are routinely and significantly over hour 2 hour "soft limit"
for testing PRs. I *think* that a big portion of this time comes from the fact
that LLVM and debug assertions are enabled. In an effort to speed up these
builders and reduce cycle time this commit disables LLVM assertions on OSX for
all builders.
My thinking is that we'll let this bake for a bit after merged to see what the
effect is on timing on Travis. If it doesn't actually help much we can turn them
back on, and if it doesn't help enough we can disable Rust debug assertions as
well.
Most users would expect set_permissions(Metadata.permissions()) to be
non-destructive. While we can't guarantee this, we can at least pass
the needed info to chmod.
Also update the PermissionsExt documentation to disambiguate what it
contains, and to refer to the underlying value as `st_mode` rather than
its type `mode_t`.
Closes#44147
Previously it would use the librustc output directory which would cause rustdoc
to get entirely recompiled, whereas the intention is that it uses the
already-compiled artifacts from building rustdoc itself, using the tool output
directory
Our OSX builders are routinely and significantly over hour 2 hour "soft limit"
for testing PRs. I *think* that a big portion of this time comes from the fact
that LLVM and debug assertions are enabled. In an effort to speed up these
builders and reduce cycle time this commit disables LLVM assertions on OSX for
all builders.
My thinking is that we'll let this bake for a bit after merged to see what the
effect is on timing on Travis. If it doesn't actually help much we can turn them
back on, and if it doesn't help enough we can disable Rust debug assertions as
well.
Right now we comiple rustdoc in stage 2 and the error index in stage 0, which
ends up compiling rustdoc twice! To avoid compiling rustdoc twice (which takes
awhile) let's just compile it once in stage 2.
Compile fail stable
Since #30726, we never made the `compile_fail` flag nor the error code check stable. I think it's time to change this fact.
r? @alexcrichton
