This commit adds support for user type annotations in variables declared
using `ref` bindings. When a variable declared using a `ref` binding,
then the `LocalDecl` has the type `&T` where the `&` was introduced by
the `ref` binding but the canonicalized type annotation has only a
`T` since the reference is implicit with the `ref` binding.
Therefore, to support type annotations, the canonicalized type
annotation either needs wrapped in a reference, or the `LocalDecl` type
must have a wrapped reference removed for comparison. It is easier to
remove the outer reference from the `LocalDecl` for the purpose of
comparison, so that is the approach this commit takes.
This commit uses the map introduced by the previous commit to ensure
that types are always checked for well-formedness by the NLL type check.
Previously, without the map introduced by the previous commit, types
would not be checked for well-formedness if the `AscribeUserType`
statement that would trigger that check was removed as unreachable code.
This commit refactors the `UserTypeAnnotation` type to be referred to by
an index within `UserTypeProjection`. `UserTypeAnnotation` is instead
kept in an `IndexVec` within the `Mir` struct.
Further, instead of `UserTypeAnnotation` containing canonicalized types,
it now contains normal types and the entire `UserTypeAnnotation` is
canonicalized. To support this, the type was moved from the `rustc::mir`
module to `rustc::ty` module.
Mention ToString in std::fmt docs
I believe this should be added because `x.to_string()` is preferred over `format!("{}", x)` as the recommended way to convert a value to a string. `std::fmt` and the `format` macro is where people look for documentation about this, and thus we should include references to this preferred functions there.
Resolves#55065
resolve: Fix one more ICE in import validation
So if you have an unresolved import
```rust
mod m {
use foo::bar;
}
```
error recovery will insert a special item with `Def::Err` definition into module `m`, so other things depending on `bar` won't produce extra errors.
The issue was that erroneous `bar` was overwriting legitimate `bar`s coming from globs, e.g.
```rust
mod m {
use baz::*; // imports real existing `bar`
use foo::bar;
}
```
causing some unwanted diagnostics talking about "unresolved items", and producing inconsistent resolutions like https://github.com/rust-lang/rust/issues/57015.
This PR stops overwriting real successful resolutions with `Def::Err`s.
Fixes https://github.com/rust-lang/rust/issues/57015
Implement RFC 2338, "Type alias enum variants"
This PR implements [RFC 2338](https://github.com/rust-lang/rfcs/pull/2338), allowing one to write code like the following.
```rust
#![feature(type_alias_enum_variants)]
enum Foo {
Bar(i32),
Baz { i: i32 },
}
type Alias = Foo;
fn main() {
let t = Alias::Bar(0);
let t = Alias::Baz { i: 0 };
match t {
Alias::Bar(_i) => {}
Alias::Baz { i: _i } => {}
}
}
```
Since `Self` can be considered a type alias in this context, it also enables using `Self::Variant` as both a constructor and pattern.
Fixes issues #56199 and #56611.
N.B., after discussing the syntax for type arguments on enum variants with @petrochenkov and @eddyb (there are also a few comments on the [tracking issue](https://github.com/rust-lang/rust/issues/49683)), the consensus seems to be treat the syntax as follows, which ought to be backwards-compatible.
```rust
Option::<u8>::None; // OK
Option::None::<u8>; // OK, but lint in near future (hard error next edition?)
Alias::<u8>::None; // OK
Alias::None::<u8>; // Error
```
I do not know if this will need an FCP, but let's start one if so.
resolve: Fix another ICE in import validation
Imports are allowed to have ambiguous resolutions as long as all of them have same `Def`.
As it turned out, it's possible for different `Module`s to have same `Def` when `extern crate` items are involved.
Fixes https://github.com/rust-lang/rust/issues/56596
submodules: update clippy from fc24fce7 to 721f688e
Fixes clippy toolstate.
Changes:
````
rustup https://github.com/rust-lang/rust/pull/57069
Rustfmt.
fix breakage from rust-lang/rust#57088
fix a couple of ftrivial typos (NFC).
update CARGO_CLIPPY_HELP string to suggest tool lints.
rustc_tools_util: add readme
rustc_tool_utils: expand Cargo.toml with a few keywords in preparation for crates.io release
Fix macro detection in `empty_loop`.
Changed `macro_backtrace()` to `in_macro()`.
Fix lint detection on macro expansion.
````
r? @oli-obk
Fixes clippy toolstate
Changes:
````
Match on ast/hir::ExprKind::Err
Update *.stderr files
Use -Zui-testing flag
Mention S-inactive-closed PRs in the CONTRIBUTING.md
tests: fix formatting and update test output
base tests: make sure to fail CI if tests need formatting
base tests: switch to nightly toolchain before checking formatting of tests with rustfmt
rustup https://github.com/rust-lang/rust/pull/57069
Rustfmt.
fix breakage from rust-lang/rust#57088
fix a couple of ftrivial typos (NFC).
update CARGO_CLIPPY_HELP string to suggest tool lints.
rustc_tools_util: add readme
rustc_tool_utils: expand Cargo.toml with a few keywords in preparation for crates.io release
Fix macro detection in `empty_loop`.
Changed `macro_backtrace()` to `in_macro()`.
Fix lint detection on macro expansion.
````
