Define built-in macros through libcore
This PR defines built-in macros through libcore using a scheme similar to lang items (attribute `#[rustc_builtin_macro]`).
All the macro properties (stability, visibility, etc.) are taken from the source code in libcore, with exception of the expander function transforming input tokens/AST into output tokens/AST, which is still provided by the compiler.
The macros are made available to user code through the standard library prelude (`{core,std}::prelude::v1`), so they are still always in scope.
As a result **built-in macros now have stable absolute addresses in the library**, like `core::prelude::v1::line!()`, this is an insta-stable change.
Right now `prelude::v1` is the only publicly available absolute address for these macros, but eventually they can be moved into more appropriate locations with library team approval (e.g. `Clone` derive -> `core::clone::Clone`).
Now when built-in macros have canonical definitions they can be imported or reexported without issues (https://github.com/rust-lang/rust/issues/61687).
Other changes:
- You can now define a derive macro with a name matching one of the built-in derives (https://github.com/rust-lang/rust/issues/52269). This was an artificial restriction that could be worked around with import renaming anyway.
Known regressions:
- Empty library crate with a crate-level `#![test]` attribute no longer compiles without `--test`. Previously it didn't compile *with* `--test` or with the bin crate type.
Fixes https://github.com/rust-lang/rust/issues/61687
Fixes https://github.com/rust-lang/rust/issues/61804
r? @eddyb
Rollup of 22 pull requests
Successful merges:
- #62084 (allow clippy::unreadable_literal in unicode tables)
- #62120 (Add missing type links in documentation)
- #62310 (Add missing doc links in boxed module)
- #62421 (Introduce `as_deref` to Option)
- #62583 (Implement Unpin for all raw pointers)
- #62692 (rustc: precompute the largest Niche and store it in LayoutDetails.)
- #62801 (Remove support for -Zlower-128bit-ops)
- #62828 (Remove vector fadd/fmul reduction workarounds)
- #62862 (code cleanup)
- #62904 (Disable d32 on armv6 hf targets)
- #62907 (Initialize the MSP430 AsmParser)
- #62956 (Implement slow-path for FirstSets::first)
- #62963 (Allow lexer to recover from some homoglyphs)
- #62964 (clarify and unify some type test names)
- #62970 (ci: gate toolstate repo pushes on the TOOLSTATE_PUBLISH envvar)
- #62980 (std: Add more accessors for `Metadata` on Windows)
- #62983 (Remove needless indirection through Rc)
- #62985 (librustc_errors: Support ui-testing flag in annotate-snippet emitter)
- #63002 (error_index_generator should output stdout/stderr when it panics.)
- #63004 (Add test for issue-54062)
- #63007 (ci: debug network failures while downloading awscli from PyPI)
- #63009 (Remove redundant `mut` from variable declaration.)
Failed merges:
r? @ghost
ci: debug network failures while downloading awscli from PyPI
This adds some random debug code to our CI script while downloading awscli, to *hopefully* pinpoint what's causing the network failures.
r? @Mark-Simulacrum
cc #62967
error_index_generator should output stdout/stderr when it panics.
**bootstrap change**
Call error_index_generator tool using run_quiet which will additionally print std out and std err of the command when it returns an error.
(was `run` uses `run_silent` under the covers.)
Why: PR #62871 is hitting a build error but the panic isn't getting shown so its unclear what the problem is.
std: Add more accessors for `Metadata` on Windows
This commit adds accessors for more fields in `fs::Metadata` on Windows
which weren't previously exposed. There's two sources of `fs::Metadata`
on Windows currently, one from `DirEntry` and one from a file itself.
These two sources of information don't actually have the same set of
fields exposed in their stat information, however. To handle this the
platform-specific accessors of Windows-specific information all return
`Option` to return `None` in the case a metadata comes from a
`DirEntry`, but they're guaranteed to return `Some` if it comes from a
file itself.
This is motivated by some changes in CraneStation/wasi-common#42, and
I'm curious how others feel about this platform-specific functionality!
ci: gate toolstate repo pushes on the TOOLSTATE_PUBLISH envvar
This PR fixes toolstate failing to push on the LinuxTools PR builder by gating the pushes on the new `TOOLSTATE_PUBLISH` environment variable, which is set on prod credentials but not on the PR ones. The old code checked whether the access token was set, but that doesn't work due to an Azure quirk.
For a bit of background, secret environment variables are not available by default, but each step needs to explicitly declare which secret vars to load:
```yaml
- bash: echo foo
env:
SECRET_VAR: $(SECRET_VAR)
```
This works fine when the variable is present but when it's missing, instead of setting `SECRET_VAR` to an empty string or just not setting it at all, Azure Pipelines puts the literal `$(SECRET_VAR)` as the content, which completly breaks the old check we had. I tried almost every thing to make this work in a sensible way, and the only conclusion I reached is to set the variable at the top level with the runtime expression evaluation syntax, which sets the variable to an empty string if missing:
```yaml
# At the top:
variables:
- name: MAYBE_SECRET_VAR
value: $[ variables.MAYBE_SECRET_VAR ]
# In the step:
- bash: echo foo
env:
SECRET_VAR: $(MAYBE_SECRET_VAR)
```
While that *could've worked* it was ugly and messy, so I just opted to add yet another non-secret variable.
r? @alexcrichton
fixes#62811
clarify and unify some type test names
* `is_mutable_pointer`: use `ptr` suffix for consistency with `is_region_ptr`, `is_fn_ptr`, `is_unsafe_ptr`.
* `is_pointer_sized`: the name is misleading as this only tests for pointer-sized *integers*, so rename to `is_ptr_sized_integral`.
Implement slow-path for FirstSets::first
When 2 or more sequences share the same span, we can't use the precomputed map
for their first set. So we compute it recursively.
Fixes#62831.
Disable d32 on armv6 hf targets
We already do this on armv7 targets. It seems that this now gets enabled by default if '+vfp2` is specified, so disable it explicitly.
Hopefully fixes#62841.
r? @alexcrichton
rustc: precompute the largest Niche and store it in LayoutDetails.
Since we only ever can use at most one niche, it makes sense to just store that in the layout, for the simplest caching (especially as it's almost trivial to compute).
There might be a speedup from this, but even if it's marginal now, the caching would be a more significant benefit for future optimization attempts.
Introduce `as_deref` to Option
This is re-submission for #59628.
Renames `deref()` to `as_deref()` and adds `deref_mut()` impls and tests.
CC #50264
r? @Kimundi
(I picked you as you're the previous reviewer.)
This commit adds accessors for more fields in `fs::Metadata` on Windows
which weren't previously exposed. There's two sources of `fs::Metadata`
on Windows currently, one from `DirEntry` and one from a file itself.
These two sources of information don't actually have the same set of
fields exposed in their stat information, however. To handle this the
platform-specific accessors of Windows-specific information all return
`Option` to return `None` in the case a metadata comes from a
`DirEntry`, but they're guaranteed to return `Some` if it comes from a
file itself.
This is motivated by some changes in CraneStation/wasi-common#42, and
I'm curious how others feel about this platform-specific functionality!
Add support for UWP targets
Hi,
This pull request aims at adding support for UWP (Universal Windows Apps) platform.
A few notes:
- This requires a very recent mingw-w64 version (containing this commit and the previous related ones: e8c433c871 (diff-eefdfbfe9cec5f4ebab88c9a64d423a9))
- This was tested using LLVM/clang rather than gcc, and so far it assumes that LLVM/clang will be the native compiler. This is mostly due to the fact that the support for exceptions/stack unwinding for UWP got much more attention in libunwind
- The "uwp" part of the target needs support for it in the `cc-rs` & `backtrace-rs` crates. I'll create the MR there right after I submit this one and will link everything together, but I'm not sure what's the correct way of dealing with external dependencies in the context of rust
- Enabling import libraries and copying them across stages requires a change in cargo, for which I'll open a MR right after I submit this one as well
- The i686 stack unwinding is unsupported for now, because LLVM assumes SjLj, while rust seems to assume SEH will be used. I'm unsure how to fix this
Also, this is my first encounter with rust, so please bear with my code, it might not feel so idiomatic or even correct :)
I'm pretty sure there's a way of doing things in a cleaner way when it comes to win/c.rs, maybe having a UWP & desktop specific modules, and import those conditionally? It doesn't feel right to sprinkle `#[cfg(...)]` all over the place
Off course, I'll gladly update anything you see fit (to the extent of my abilities/knowledge :) )!
Thanks,
Rollup of 15 pull requests
Successful merges:
- #60066 (Stabilize the type_name intrinsic in core::any)
- #60938 (rustdoc: make #[doc(include)] relative to the containing file)
- #61884 (Stablize Euclidean Modulo (feature euclidean_division))
- #61890 (Fix some sanity checks)
- #62528 (Add joining slices of slices with a slice separator, not just a single item)
- #62707 (Add tests for overlapping explicitly dropped locals in generators)
- #62735 (Turn `#[global_allocator]` into a regular attribute macro)
- #62822 (Improve some pointer-related documentation)
- #62887 (Make the parser TokenStream more resilient after mismatched delimiter recovery)
- #62921 (Add method disambiguation help for trait implementation)
- #62930 (Add test for #51559)
- #62942 (Use match ergonomics in Condvar documentation)
- #62977 (Fix inconsistent highlight blocks.)
- #62978 (Remove `cfg(bootstrap)` code for array implementations)
- #62981 (Add note suggesting to borrow a String argument to find)
Failed merges:
- #62964 (clarify and unify some type test names)
r? @ghost
Remove `cfg(bootstrap)` code for array implementations
In https://github.com/rust-lang/rust/pull/62435 ("Use const generics for array impls [part 1]") the old macro-based implementations were not removed but still used with `cfg(bootstrap)` since the bootstrap compiler had some problems with const generics at the time. This does not seem to be the case anymore, so there is no reason to keep the old code.
Unfortunately, the diff is pretty ugly because much of the code was indented by one level before. The change is pretty trivial, though.
PS: I did not run the full test suite locally. There are 40°C outside and 31°C inside my room. I don't want my notebook to melt. I hope that CI is green.
r? @scottmcm
Use match ergonomics in Condvar documentation
Documentation was written before match ergonomics was merged. See #62857.
In short, replaces
```rust
let &(ref lock, ref cvar) = &*pair;
```
with
```rust
let (lock, cvar) = &*pair
```
in the docs of `std::sync::Condvar`.
Add joining slices of slices with a slice separator, not just a single item
https://github.com/rust-lang/rust/issues/27747#issuecomment-294525391
> It's kinda annoying to be able to join strings with a str (which can have multiple chars), but joining a slice of slices, you can only join with a single element.
This turns out to be fixable, with some possible inference regressions.
# TL;DR
Related trait(s) are unstable and tracked at https://github.com/rust-lang/rust/issues/27747, but the `[T]::join` method that is being extended here is already stable.
Example use of the new insta-stable functionality:
```rust
let nested: Vec<Vec<Foo>> = /* … */;
let separator: &[Foo] = /* … */; // Previously: could only be a single &Foo
nested.join(separator)
```
Complete API affected by this PR, after changes:
```rust
impl<T> [T] {
pub fn concat<Item: ?Sized>(&self) -> <Self as Concat<Item>>::Output
where Self: Concat<Item>
{
Concat::concat(self)
}
pub fn join<Separator>(&self, sep: Separator) -> <Self as Join<Separator>>::Output
where Self: Join<Separator>
{
Join::join(self, sep)
}
}
// The `Item` parameter is only useful for the the slice-of-slices impl.
pub trait Concat<Item: ?Sized> {
type Output;
fn concat(slice: &Self) -> Self::Output;
}
pub trait Join<Separator> {
type Output;
fn join(slice: &Self, sep: Separator) -> Self::Output;
}
impl<T: Clone, V: Borrow<[T]>> Concat<T> for [V] {
type Output = Vec<T>;
}
impl<T: Clone, V: Borrow<[T]>> Join<&'_ T> for [V] {
type Output = Vec<T>;
}
// New functionality here!
impl<T: Clone, V: Borrow<[T]>> Join<&'_ [T]> for [V] {
type Output = Vec<T>;
}
impl<S: Borrow<str>> Concat<str> for [S] {
type Output = String;
}
impl<S: Borrow<str>> Join<&'_ str> for [S] {
type Output = String;
}
```
# Details
After https://github.com/rust-lang/rust/pull/62403 but before this PR, the API is:
```rust
impl<T> [T] {
pub fn concat<Separator: ?Sized>(&self) -> T::Output
where T: SliceConcat<Separator>
{
SliceConcat::concat(self)
}
pub fn join<Separator: ?Sized>(&self, sep: &Separator) -> T::Output
where T: SliceConcat<Separator>
{
SliceConcat::join(self, sep)
}
}
pub trait SliceConcat<Separator: ?Sized>: Sized {
type Output;
fn concat(slice: &[Self]) -> Self::Output;
fn join(slice: &[Self], sep: &Separator) -> Self::Output;
}
impl<T: Clone, V: Borrow<[T]>> SliceConcat<T> for V {
type Output = Vec<T>;
}
impl<S: Borrow<str>> SliceConcat<str> for S {
type Output = String;
}
```
By adding a trait impl we should be able to accept a slice of `T` as the separator, as an alternative to a single `T` value.
In a `some_slice.join(some_separator)` call, trait resolution will pick an impl or the other based on the type of `some_separator`. In `some_slice.concat()` however there is no separator, so this call would become ambiguous. Some regression in type inference or trait resolution may be acceptable on principle, but requiring a turbofish for every single call to `concat` isn’t great.
The solution to that is splitting the `SliceConcat` trait into two `Concat` and `Join` traits, one for each eponymous method. Only `Join` would gain a new impl, so that `some_slice.concat()` would not become ambiguous.
Now, at the trait level the `Concat` trait does not need a `Separator` parameter anymore. However, simply removing it causes one of the impls not to be accepted anymore:
```rust
error[E0207]: the type parameter `T` is not constrained by the impl trait, self type, or predicates
--> src/liballoc/slice.rs:608:6
|
608 | impl<T: Clone, V: Borrow<[T]>> Concat for [V] {
| ^ unconstrained type parameter
```
This makes sense: if `[V]::concat` is a method that is itself not generic, then its return type (which is the `Concat::Output` associated type) needs to be determined based on solely `V`. And although there is no such type in the standard library, there is nothing stopping another crate from defining a `V` type that implements both `Borrow<[Foo]>` and `Borrow<[Bar]>`. It might not be a good idea, but it’s possible. Both would apply here, and there would be no way to determine `T`.
This could be a warning sign that this API is too generic. Perhaps we’d be better off having one less type variable, and only implement `Concat for [&'_ [T]]` and `Concat for [Vec<T>]` etc. However this aspect of `[V]::concat` is already stable, so we’re stuck with it.
The solution is to keep a dummy type parameter on the `Concat` trait. That way, if a type has multiple `Borrow<[_]>` impls, it’ll end up with multiple corresponding `Concat<_>` impls.
In `impl<S: Borrow<str>> Concat<str> for [S]`, the second occurrence of `str` is not meaningful. It could be any type. As long as there is only once such type with an applicable impl, trait resolution will be appeased without demanding turbofishes.
# Joining strings with `char`
For symmetry I also tried adding this impl (because why not):
```rust
impl<S: Borrow<str>> Join<char> for [S] {
type Output = String;
}
```
This immediately caused an inference regression in a dependency of rustc:
```rust
error[E0277]: the trait bound `std::string::String: std::borrow::Borrow<[std::string::String]>` is not satisfied
--> /home/simon/.cargo/registry/src/github.com-1ecc6299db9ec823/getopts-0.2.19/src/lib.rs:595:37
|
595 | row.push_str(&desc_rows.join(&desc_sep));
| ^^^^ the trait `std::borrow::Borrow<[std::string::String]>` is not implemented for `std::string::String`
|
= help: the following implementations were found:
<std::string::String as std::borrow::Borrow<str>>
= note: required because of the requirements on the impl of `std::slice::Join<&std::string::String>` for `[std::string::String]`
```
In the context of this code, two facts are known:
* `desc_rows` is a `Vec<String>`
* `desc_sep` is a `String`
Previously the first fact alone reduces the resolution of `join` to only one solution, where its argument it expected to be `&str`. Then, `&String` is coerced to `&str`.
With the new `Join` impl, the first fact leavs two applicable impls where the separator can be either `&str` or `char`. But `&String` is neither of these things. It appears that possible coercions are not accounted for, in the search for a solution in trait resolution.
I have not included this new impl in this PR. It’s still possible to add later, but the `getopts` breakage does not need to block the rest of the PR. And the functionality easy for end-user to duplicate: `slice_of_strings.join(&*char_separator.encode_utf8(&mut [0_u8, 4]))`
The `&*` part of that last code snippet is another case of the same issue: `encode_utf8` returns `&mut str` which can be coerced to `&str`, but isn’t when trait resolution is ambiguous.
