RFC 2008: Future-proofing enums/structs with #[non_exhaustive] attribute
This work-in-progress pull request contains my changes to implement [RFC 2008](https://github.com/rust-lang/rfcs/pull/2008). The related tracking issue is #44109.
As of writing, enum-related functionality is not included and there are some issues related to tuple/unit structs. Enum related tests are currently ignored.
WIP PR requested by @nikomatsakis [in Gitter](https://gitter.im/rust-impl-period/WG-compiler-middle?at=59e90e6297cedeb0482ade3e).
The Dist Step is not ran in that case so we would end up trying to
install something that we didn't dist.
Signed-off-by: Marc-Antoine Perennou <Marc-Antoine@Perennou.com>
Add derive and doc comment capabilities to newtype_index macro
This moves `RustcDecodable` and `RustcEncodable` out of the macro definition and into the macro uses. They were conflicting with `CrateNum`'s impls of `serialize::UseSpecializedEncodable` and `serialize::UseSpecializedDecodable`, and now it's not :). `CrateNum` is now defined with the `newtype_index` macro. I also added support for doc comments on constant definitions and allowed a type to remove the pub specification on the tuple param (otherwise a LOT of code would refuse to compile for `CrateNum`). I was getting dozens of errors like this if `CrateNum` was defined as `pub struct CrateNum(pub u32)`:
```
error[E0530]: match bindings cannot shadow tuple structs
--> src/librustc/dep_graph/dep_node.rs:624:25
|
63 | use hir::def_id::{CrateNum, DefId, DefIndex, CRATE_DEF_INDEX};
| -------- a tuple struct `CrateNum` is imported here
...
624 | [] MissingLangItems(CrateNum),
| ^^^^^^^^ cannot be named the same as a tuple struct
```
I also cleaned up the formatting of the macro bodies as they were getting impossibly long. Should I go back and fix the matching rules to this style too?
I also want to see what the test results look like because `CrateNum` used to just derive `Debug`, but the `newtype_index` macro has a custom implementation. This might require further pushes.
Feel free to bikeshed on the macro language, I have no preference here.
Fix libstd compile error for windows-gnu targets without `backtrace`
This is basically an addition to #44979. Compiling `libstd` still fails when targeting `windows-gnu` with `panic = "abort"` because the items in the `...c::gnu` module are not used. They are only referenced from `backtrace_gnu.rs`, which is indirectly feature gated behind `backtrace` [here](9f3b09116b/src/libstd/sys/windows/mod.rs (L23)).
Add a nicer error message for missing in for loop, fixes#40782.
As suggested by @estebank in issue #40782, this works in the same way as #42578: if the in keyword is missing, we continue parsing the expression and if this works correctly an adapted error message is produced. Otherwise we return the old error.
A specific test case has also been added.
This is my first PR on rust-lang/rust so any feedback is very welcome.
When encountering a let binding type error, attempt to parse as
initializer instead. If successful, it is likely just a typo:
```rust
fn main() {
let x: Vec::with_capacity(10);
}
```
```
error: expected type, found `10`
--> file.rs:3:31
|
3 | let x: Vec::with_capacity(10, 20);
| -- ^^
| ||
| |help: did you mean assign here?: `=`
| while parsing the type for `x`
```
add TerminatorKind::FalseEdges and use it in matches
impl #45184 and fixes#45043 right way.
False edges unexpectedly affects uninitialized variables analysis in MIR borrowck.
We don't want to stabilize them now already. The goal of this set of
commits is just to add inherent methods to the four types. Stabilizing
all of those methods can be done later.
Many AsciiExt imports have become useless thanks to the inherent ascii
methods added in the last commits. These were removed. In some places, I
fully specified the ascii method being called to enforce usage of the
AsciiExt trait. Note that some imports are not removed but tagged with
a `#[cfg(stage0)]` attribute. This is necessary, because certain ascii
methods are not yet available in stage0. All those imports will be
removed later.
Additionally, failing tests were fixed. The test suite should exit
successfully now.
This is done in order to deprecate AsciiExt eventually. Note that
this commit contains a bunch of `cfg(stage0)` statements. This is
due to a new compiler feature this commit depends on: the
`slice_u8` lang item. Once this lang item is available in the
stage0 compiler, all those cfg flags (and more) can be removed.
This is done in order to deprecate AsciiExt eventually. Note that
this commit contains a bunch of `cfg(stage0)` statements. This is
due to a new compiler feature I am using: the `slice_u8` lang item.
Once this lang item is available in the stage0 compiler, all those
cfg flags (and more) can be removed.
The doc comments were incorrect before: since the inherent ascii methods
shadow the `AsciiExt` methods, the examples didn't use the `AsciiExt` at
all. Since the trait will be deprecated soon anyway, the easiest solution
was to remove the examples and already mention that the methods will be
deprecated in the near future.
Since the methods on u8 directly will shadow the AsciiExt methods,
we cannot change the signature without breaking everything. It
would have been nice to take `u8` as argument instead of `&u8`, but
we cannot break stuff! So this commit reverts it to the original
`&u8` version.
Those methods will shadow the methods of `AsciiExt`, so if we don't
make them insta-stable, everyone will hitting stability errors. It
is fine adding those as stable, because they are just being moved
around [according to sfackler][1].
OPEN QUESTION: this commit also stabilizes the `AsciiExt` methods
that were previously feature gated by the `ascii_ctype` feature.
Maybe we don't want to stablilize those yet.
[1]: https://github.com/rust-lang/rust/pull/44042#issuecomment-329939279
This is the first step in order to deprecate AsciiExt. Since
this is a WIP commit, there is still some code duplication (notably
the static arrays) that will be removed later.
[Syntax] Implement auto trait syntax
Implements `auto trait Send {}` as a substitute for `trait Send {} impl Send for .. {}`.
See the [internals thread](https://internals.rust-lang.org/t/pre-rfc-renaming-oibits-and-changing-their-declaration-syntax/3086) for motivation. Part of #13231.
The first commit is just a rename moving from "default trait" to "auto trait". The rest is parser->AST->HIR work and making it the same as the current syntax for everything below HIR. It's under the `optin_builtin_traits` feature gate.
When can we remove the old syntax? Do we need to wait for a new `stage0`? We also need to formally decide for the new form (even if the keyword is not settled yet).
Observations:
- If you `auto trait Auto {}` and then `impl Auto for .. {}` that's accepted even if it's redundant.
- The new syntax is simpler internally which will allow for a net removal of code, for example well-formedness checks are effectively moved to the parser.
- Rustfmt and clippy are broken, need to fix those.
- Rustdoc just ignores it for now.
ping @petrochenkov @nikomatsakis
