Account for mutable borrow in argument suggestion
```
error: value assigned to `object` is never read
--> $DIR/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.rs:21:5
|
LL | object = &mut object2;
| ^^^^^^
|
help: you might have meant to mutate the pointed at value being passed in, instead of changing the reference in the local binding
|
LL ~ fn change_object3(object: &mut Object) {
LL |
LL | let object2 = Object;
LL ~ *object = object2;
|
```
instead of
```
error: value assigned to `object` is never read
--> $DIR/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.rs:21:5
|
LL | object = &mut object2;
| ^^^^^^
|
help: you might have meant to mutate the pointed at value being passed in, instead of changing the reference in the local binding
|
LL ~ fn change_object3(object: &mut mut Object) {
LL |
LL | let object2 = Object;
LL ~ *object = object2;
|
```
Fix#136028.
```
error: value assigned to `object` is never read
--> $DIR/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.rs:21:5
|
LL | object = &mut object2;
| ^^^^^^
|
help: you might have meant to mutate the pointed at value being passed in, instead of changing the reference in the local binding
|
LL ~ fn change_object3(object: &mut Object) {
LL |
LL | let object2 = Object;
LL ~ *object = object2;
|
```
instead of
```
error: value assigned to `object` is never read
--> $DIR/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.rs:21:5
|
LL | object = &mut object2;
| ^^^^^^
|
help: you might have meant to mutate the pointed at value being passed in, instead of changing the reference in the local binding
|
LL ~ fn change_object3(object: &mut mut Object) {
LL |
LL | let object2 = Object;
LL ~ *object = object2;
|
```
Fix#136028.
remove support for the (unstable) #[start] attribute
As explained by `@Noratrieb:`
`#[start]` should be deleted. It's nothing but an accidentally leaked implementation detail that's a not very useful mix between "portable" entrypoint logic and bad abstraction.
I think the way the stable user-facing entrypoint should work (and works today on stable) is pretty simple:
- `std`-using cross-platform programs should use `fn main()`. the compiler, together with `std`, will then ensure that code ends up at `main` (by having a platform-specific entrypoint that gets directed through `lang_start` in `std` to `main` - but that's just an implementation detail)
- `no_std` platform-specific programs should use `#![no_main]` and define their own platform-specific entrypoint symbol with `#[no_mangle]`, like `main`, `_start`, `WinMain` or `my_embedded_platform_wants_to_start_here`. most of them only support a single platform anyways, and need cfg for the different platform's ways of passing arguments or other things *anyways*
`#[start]` is in a super weird position of being neither of those two. It tries to pretend that it's cross-platform, but its signature is a total lie. Those arguments are just stubbed out to zero on ~~Windows~~ wasm, for example. It also only handles the platform-specific entrypoints for a few platforms that are supported by `std`, like Windows or Unix-likes. `my_embedded_platform_wants_to_start_here` can't use it, and neither could a libc-less Linux program.
So we have an attribute that only works in some cases anyways, that has a signature that's a total lie (and a signature that, as I might want to add, has changed recently, and that I definitely would not be comfortable giving *any* stability guarantees on), and where there's a pretty easy way to get things working without it in the first place.
Note that this feature has **not** been RFCed in the first place.
*This comment was posted [in May](https://github.com/rust-lang/rust/issues/29633#issuecomment-2088596042) and so far nobody spoke up in that issue with a usecase that would require keeping the attribute.*
Closes https://github.com/rust-lang/rust/issues/29633
try-job: x86_64-gnu-nopt
try-job: x86_64-msvc-1
try-job: x86_64-msvc-2
try-job: test-various
deprecate `std::intrinsics::transmute` etc, use `std::mem::*` instead
The `rustc_allowed_through_unstable_modules` attribute lets users call `std::mem::transmute` as `std::intrinsics::transmute`. The former is a reexport of the latter, and for a long time we didn't properly check stability for reexports, so making this a hard error now would be a breaking change for little gain. But at the same time, `std::intrinsics::transmute` is not the intended path for this function, so I think it is a good idea to show a deprecation warning when that path is used. This PR implements that, for all the functions in `std::intrinsics` that carry the attribute.
I assume this will need ``@rust-lang/libs-api`` FCP.
Exclude dependencies of `std` for diagnostics
Currently crates in the sysroot can show up in diagnostic suggestions, such as in https://github.com/rust-lang/rust/issues/135232. To prevent this, duplicate `all_traits` into `visible_traits` which only shows traits in non-private crates.
Setting `#![feature(rustc_private)]` overrides this and makes items in private crates visible as well, since `rustc_private` enables use of `std`'s private dependencies.
This may be reviewed per-commit.
Fixes: https://github.com/rust-lang/rust/issues/135232
Add an alternative to `tcx.all_traits()` that only shows traits that the
user might be able to use, for diagnostic purposes. With this available,
make use of it for diagnostics including associated type errors, which
is part of the problem with [1].
Includes a few comment updates for related API.
[1]: https://github.com/rust-lang/rust/issues/135232
```
error: value assigned to `object` is never read
--> $DIR/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.rs:11:5
|
LL | object = &object2;
| ^^^^^^
|
note: the lint level is defined here
--> $DIR/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.rs:1:9
|
LL | #![deny(unused_assignments, unused_variables)]
| ^^^^^^^^^^^^^^^^^^
help: you might have meant to mutate the pointed at value being passed in, instead of changing the reference in the local binding
|
LL ~ fn change_object2(object: &mut Object) {
LL | let object2 = Object;
LL ~ *object = object2;
|
```
This might be the first thing someone tries to write to mutate the value *behind* an argument, trying to avoid an E0308.
Adds `#[rustc_force_inline]` which is similar to always inlining but
reports an error if the inlining was not possible, and which always
attempts to inline annotated items, regardless of optimisation levels.
It can only be applied to free functions to guarantee that the MIR
inliner will be able to resolve calls.
Add support for wasm exception handling to Emscripten target
This is a draft because we need some additional setting for the Emscripten target to select between the old exception handling and the new exception handling. I don't know how to add a setting like that, would appreciate advice from Rust folks. We could maybe choose to use the new exception handling if `Ctarget-feature=+exception-handling` is passed? I tried this but I get errors from llvm so I'm not doing it right.
Restrict `#[non_exaustive]` on structs with default field values
Do not allow users to apply `#[non_exaustive]` to a struct when they have also used default field values.
This commit splits the `#[rustc_deny_explicit_impl(implement_via_object = ...)]` attribute
into two attributes `#[rustc_deny_explicit_impl]` and `#[rustc_do_not_implement_via_object]`.
This allows us to have special traits that can have user-defined impls but do not have the
automatic trait impl for trait objects (`impl Trait for dyn Trait`).
`rustc_span::symbol` defines some things that are re-exported from
`rustc_span`, such as `Symbol` and `sym`. But it doesn't re-export some
closely related things such as `Ident` and `kw`. So you can do `use
rustc_span::{Symbol, sym}` but you have to do `use
rustc_span::symbol::{Ident, kw}`, which is inconsistent for no good
reason.
This commit re-exports `Ident`, `kw`, and `MacroRulesNormalizedIdent`,
and changes many `rustc_span::symbol::` qualifiers in `compiler/` to
`rustc_span::`. This is a 200+ net line of code reduction, mostly
because many files with two `use rustc_span` items can be reduced to
one.
Split up attribute parsing code and move data types to `rustc_attr_data_structures`
This change renames `rustc_attr` to `rustc_attr_parsing`, and splits up the parsing code. At the same time, all the data types used move to `rustc_attr_data_structures`. This is in preparation of also having a third crate: `rustc_attr_validation`
I initially envisioned this as two separate PRs, but I think doing it in one go reduces the number of ways others would have to rebase their changes on this. However, I can still split them.
r? `@oli-obk` (we already discussed how this is a first step in a larger plan)
For a more detailed plan on how attributes are going to change, see https://github.com/rust-lang/rust/issues/131229
Edit: this looks like a giant PR, but the changes are actually rather trivial. Each commit is reviewable on its own, and mostly moves code around. No new logic is added.
In #129533 the main hash function changed and the order of `-Z
input-stats` output changed, which showed that it is dependent on the
hash function, even though it is sorted. That's because entries with the
same cumulative size are ordered in a way that depends on the hash
function.
This commit fixes that by using the entry label as the secondary
ordering key.
`CheckAttrVisitor::check_doc_keyword` checks `#[doc(keyword = "..")]`
attributes to ensure they are on an empty module, and that the value is
a non-empty identifier.
The `rustc::existing_doc_keyword` lint checks these attributes to ensure
that the value is the name of a keyword.
It's silly to have two different checking mechanisms for these
attributes. This commit does the following.
- Changes `check_doc_keyword` to check that the value is the name of a
keyword (avoiding the need for the identifier check, which removes a
dependency on `rustc_lexer`).
- Removes the lint.
- Updates tests accordingly.
There is one hack: the `SelfTy` FIXME case used to used to be handled by
disabling the lint, but now is handled with a special case in
`is_doc_keyword`. That hack will go away if/when the FIXME is fixed.
Co-Authored-By: Guillaume Gomez <guillaume1.gomez@gmail.com>
Add some convenience helper methods on `hir::Safety`
Makes a lot of call sites simpler and should make any refactorings needed for https://github.com/rust-lang/rust/pull/134090#issuecomment-2541332415 simpler, as fewer sites have to be touched in case we end up storing some information in the variants of `hir::Safety`
Initial implementation of `#[feature(default_field_values]`, proposed in https://github.com/rust-lang/rfcs/pull/3681.
Support default fields in enum struct variant
Allow default values in an enum struct variant definition:
```rust
pub enum Bar {
Foo {
bar: S = S,
baz: i32 = 42 + 3,
}
}
```
Allow using `..` without a base on an enum struct variant
```rust
Bar::Foo { .. }
```
`#[derive(Default)]` doesn't account for these as it is still gating `#[default]` only being allowed on unit variants.
Support `#[derive(Default)]` on enum struct variants with all defaulted fields
```rust
pub enum Bar {
#[default]
Foo {
bar: S = S,
baz: i32 = 42 + 3,
}
}
```
Check for missing fields in typeck instead of mir_build.
Expand test with `const` param case (needs `generic_const_exprs` enabled).
Properly instantiate MIR const
The following works:
```rust
struct S<A> {
a: Vec<A> = Vec::new(),
}
S::<i32> { .. }
```
Add lint for default fields that will always fail const-eval
We *allow* this to happen for API writers that might want to rely on users'
getting a compile error when using the default field, different to the error
that they would get when the field isn't default. We could change this to
*always* error instead of being a lint, if we wanted.
This will *not* catch errors for partially evaluated consts, like when the
expression relies on a const parameter.
Suggestions when encountering `Foo { .. }` without `#[feature(default_field_values)]`:
- Suggest adding a base expression if there are missing fields.
- Suggest enabling the feature if all the missing fields have optional values.
- Suggest removing `..` if there are no missing fields.
