Feature gate clean
This PR does a bit of cleaning in the feature-gate-handling code of libsyntax. It also fixes two bugs (#32782 and #32648). Changes include:
* Change the way the existing features are declared in `feature_gate.rs`. The array of features and the `Features` struct are now defined together by a single macro. `featureck.py` has been updated accordingly. Note: there are now three different arrays for active, removed and accepted features instead of a single one with a `Status` item to tell wether a feature is active, removed, or accepted. This is mainly due to the way I implemented my macro in the first time and I can switch back to a single array if needed. But an advantage of the way it is now is that when an active feature is used, the parser only searches through the list of active features. It goes through the other arrays only if the feature is not found. I like to think that error checking (in this case, checking that an used feature is active) does not slow down compilation of valid code. :) But this is not very important...
* Feature-gate checking pass now use the `Features` structure instead of looking through a string vector. This should speed them up a bit. The construction of the `Features` struct should be faster too since it is build directly when parsing features instead of calling `has_feature` dozens of times.
* The MacroVisitor pass has been removed, it was mostly useless since the `#[cfg]-stripping` phase happens before (fixes#32648). The features that must actually be checked before expansion are now checked at the time they are used. This also allows us to check attributes that are generated by macro expansion and not visible to MacroVisitor, but are also removed by macro expansion and thus not visible to PostExpansionVisitor either. This fixes#32782. Note that in order for `#[derive_*]` to be feature-gated but still accepted when generated by `#[derive(Trait)]`, I had to do a little bit of trickery with spans that I'm not totally confident into. Please review that part carefully. (It's in `libsyntax_ext/deriving/mod.rs`.)::
Note: this is a [breaking change], since programs with feature-gated attributes on macro-generated macro invocations were not rejected before. For example:
```rust
macro_rules! bar (
() => ()
);
macro_rules! foo (
() => (
#[allow_internal_unstable] //~ ERROR allow_internal_unstable side-steps
bar!();
);
);
```
foo!();
Make some fatal lexer errors recoverable
I've kept the changes to a minimum since I'm not really sure if this approach is a acceptable.
fixes#12834
cc @nrc
report `const_err` on all expressions that can fail
also a drive-by fix for reporting an "overflow in shift *left*" when shifting an `i64` *right*
This increases the warning noise for shifting by more than the bitwidth and for `-T::MIN`. I can silence the bitwidth warnings explicitly and fix the const evaluator to make sure `--$expr` is treated exactly like `$expr` (which is kinda wrong, but mathematically right).
r? @eddyb
special-case #[derive(Copy, Clone)] with a shallow clone
If a type is Copy then its Clone implementation can be a no-op. Currently `#[derive(Clone)]` generates a deep clone anyway. This can lead to lots of code bloat.
This PR detects the case where Copy and Clone are both being derived (the general case of "is this type Copy" can't be determined by a syntax extension) and generates the shallow Clone impl. Right now this can only be done if there are no type parameters (see https://github.com/rust-lang/rust/issues/31085#issuecomment-178988663), but this restriction can be removed after specialization.
Fixes#31085.
rustdoc: Handle concurrent mkdir requests
It's likely that `rustdoc` as a tool is run concurrently in the same output
(e.g. documenting multiple crates as Cargo does), in which case it needs to
handle concurrent calls to `fs::create_dir`.
Changes #[derive(Copy, Clone)] to use a faster impl of Clone when
both derives are present, and there are no generics in the type.
The faster impl is simply returning *self (which works because the
type is also Copy). See the comments in libsyntax_ext/deriving/clone.rs
for more details.
There are a few types which are Copy but not Clone, in violation
of the definition of Copy. These include large arrays and tuples. The
very existence of these types is arguably a bug, but in order for this
optimization not to change the applicability of #[derive(Copy, Clone)],
the faster Clone impl also injects calls to a new function,
core::clone::assert_receiver_is_clone, to verify that all members are
actually Clone.
This is not a breaking change, because pursuant to RFC 1521, any type
that implements Copy should not do any observable work in its Clone
impl.
Normalize types before using them in debuginfo.
Small oversight, fixes#33096 - odd thing is that the old code doesn't look like it should've ever worked, although it wasn't using all of the type parameters, so maybe that's what changed.
mk: Fix use of deprecated configure var
The `--android-cross-path` has been deprecated for some time now, we should use
`CFG_ARM_LINUX_ANDROIDEABI_NDK` instead.
Ideally this would use the right triple, but we're only testing ARM for now.
The `--android-cross-path` has been deprecated for some time now, we should use
`CFG_ARM_LINUX_ANDROIDEABI_NDK` instead.
Ideally this would use the right triple, but we're only testing ARM for now.
clarify documentation of TcpStream::connect() for multiple valid addresses
I am not sure how the UDP part of the stdlib behaves when passing multiple valid addresses, but it should be mentioned as there are legit use cases for [`impl<'a> ToSocketAddrs for &'a [SocketAddr]`](http://doc.rust-lang.org/nightly/std/net/trait.ToSocketAddrs.html), a TCP fallback only being one.
Just a little example program for anyone willing to enhance the documentation further:
```rust
use std::net::SocketAddr;
use std::net::ToSocketAddrs;
use std::net::TcpStream;
fn main()
{
let v: Vec<SocketAddr> = vec!
[
"127.0.0.1:1338".to_socket_addrs().unwrap().next().unwrap(),
"127.0.0.1:1337".to_socket_addrs().unwrap().next().unwrap(),
"127.0.0.1:1339".to_socket_addrs().unwrap().next().unwrap(),
];
let stream = TcpStream::connect(&v[..]).unwrap();
}
```
rustdoc: inline all the impls
This used to be done to avoid inlining impls referencing private items, but is now unnecessary since we actually check that impls do not reference non-doc-reachable items.
fixes#32881fixes#33025fixes#33113
r? @alexcrichton
Enable vfp3-d16 for ARMv7 Android target
Android's [armeabi-v7a ABI][1] guarantees at least VFPv3-d16 hardware FPU support, so Rust should include this in the default features for the `arm-linux-androideabi` target.
[1]: https://developer.android.com/ndk/guides/abis.html
Suppress fallback and ambiguity errors
If the infcx has observed other errors, then suppress both default type
parameter fallback (which can be unreliable, as the full constraint set
is not available) and errors related to unresovled
variables (annoyingly, integer type variables cannot currently be
unified with error, so that has to be a separate mechanism). Also add a
flag to `infcx` to allow us to independently indicate when we have
observed an error and hence should trigger this suppression mode.
Fixes#31997
cc @alexcrichton
r? @arielb1
It's likely that `rustdoc` as a tool is run concurrently in the same output
(e.g. documenting multiple crates as Cargo does), in which case it needs to
handle concurrent calls to `fs::create_dir`.
Make the `Iterator::enumerate` doc example more clear
The example uses integers for the value being iterated over, but the indices
added by `enumerate` are also integers, so I always end up double taking and
thinking harder than I should when parsing the documentation. I also always
forget which order the index and value are in the tuple so I frequently hit this
stumbling block. This commit changes the documentation to iterate over
characters so that it is immediately obvious which part of the tuple is the
index and which is the value.
Paths are mostly parsed without taking whitespaces into account, e.g. `std :: vec :: Vec :: new ()` parses successfully, however, there are some special cases involving keywords `super`, `self` and `Self`. For example, `self::` is considered a path start only if there are no spaces between `self` and `::`. These restrictions probably made sense when `self` and friends weren't keywords, but now they are unnecessary.
The first two commits remove this special treatment of whitespaces by removing `token::IdentStyle` entirely and therefore fix https://github.com/rust-lang/rust/issues/14109.
This change also affects naked `self` and `super` (which are not tightly followed by `::`, obviously) they can now be parsed as paths, however they are still not resolved correctly in imports (cc @jseyfried, see `compile-fail/use-keyword.rs`), so https://github.com/rust-lang/rust/issues/29036 is not completely fixed.
The third commit also makes `super`, `self`, `Self` and `static` keywords nominally (before this they acted as keywords for all purposes) and removes most of remaining \"special idents\".
The last commit (before tests) contains some small improvements - some qualified paths with type parameters are parsed correctly, `parse_path` is not used for parsing single identifiers, imports are sanity checked for absence of type parameters - such type parameters can be generated by syntax extensions or by macros when https://github.com/rust-lang/rust/issues/10415 is fixed (~~soon!~~already!).
This patch changes some pretty basic things in `libsyntax`, like `token::Token` and the keyword list, so it's a plugin-[breaking-change].
r? @eddyb
