Split out a separate feature gate for impl trait in associated types
in https://github.com/rust-lang/rust/issues/107645 it was decided that we'll take a new route for type alias impl trait. The exact route isn't clear yet, so while I'm working on implementing some of these proposed changes (e.g. in https://github.com/rust-lang/rust/pull/110010) to be able to experiment with them, I will also work on stabilizing another sugar version first: impl trait in associated types. Similarly I'll look into creating feature gates for impl trait in const/static types.
This PR does nothing but split the feature gate, so that you need to enable a different feature gate for
```rust
impl Trait for Type {
type Assoc = impl SomeTrait;
}
```
than what you need for `type Foo = impl SomeTrait;`
Remove `..` from return type notation
`@nikomatsakis` and I decided that using `..` in the return-type notation syntax is probably overkill.
r? `@eholk` since you reviewed the last one
Since this is piggybacking now totally off of a pre-existing syntax (parenthesized generics), let me know if you need any explanation of the logic here, since it's a bit more complicated now.
Update `error [E0449]: unnecessary visibility qualifier` to be more clear
This updates the error message `error[E0449]: unnecessary visibility qualifier` by clearly indicating that visibility qualifiers already inherit their visibility from a parent item. The error message previously implied that the qualifiers were permitted, which is not the case anymore.
Resolves#109822.
Emit feature error for parenthesized generics in associated type bounds
We don't actually do AST->HIR lowering with some `-Zunpretty` flags, so it's not correct to just delay a bug instead of emitting a feature error.
Some diagnostics regressed because of the new errors, but oh well. 🤷Fixes#109898
Remove `box_syntax`
r? `@Nilstrieb`
This removes the feature `box_syntax`, which allows the use of `box <expr>` to create a Box, and finalises removing use of the feature from the compiler. `box_patterns` (allowing the use of `box <pat>` in a pattern) is unaffected.
It also removes `ast::ExprKind::Box` - the only way to create a 'box' expression now is with the rustc-internal `#[rustc_box]` attribute.
As a temporary measure to help users move away, `box <expr>` now parses the inner expression, and emits a `MachineApplicable` lint to replace it with `Box::new`
Closes#49733
Gate usages of `dyn*` and const closures in macros
We silently accepted `dyn*` and const closures in macros as long as they didn't expand to anything containing these experimental features, unlike other gated features such as `for<'a>` binders on closures, etc. Let's not do that, to make sure nobody begins relying on this.
This makes it easier to open the messages file while developing on features.
The commit was the result of automatted changes:
for p in compiler/rustc_*; do mv $p/locales/en-US.ftl $p/messages.ftl; rmdir $p/locales; done
for p in compiler/rustc_*; do sed -i "s#\.\./locales/en-US.ftl#../messages.ftl#" $p/src/lib.rs; done
Instead of loading the Fluent resources for every crate in
`rustc_error_messages`, each crate generates typed identifiers for its
own diagnostics and creates a static which are pulled together in the
`rustc_driver` crate and provided to the diagnostic emitter.
Signed-off-by: David Wood <david.wood@huawei.com>
Implement partial support for non-lifetime binders
This implements support for non-lifetime binders. It's pretty useless currently, but I wanted to put this up so the implementation can be discussed.
Specifically, this piggybacks off of the late-bound lifetime collection code in `rustc_hir_typeck::collect::lifetimes`. This seems like a necessary step given the fact we don't resolve late-bound regions until this point, and binders are sometimes merged.
Q: I'm not sure if I should go along this route, or try to modify the earlier nameres code to compute the right bound var indices for type and const binders eagerly... If so, I'll need to rename all these queries to something more appropriate (I've done this for `resolve_lifetime::Region` -> `resolve_lifetime::ResolvedArg`)
cc rust-lang/types-team#81
r? `@ghost`
`check_builtin_attribute` calls `parse_meta` to convert an `Attribute`
to a `MetaItem`, which it then checks. However, many callers of
`check_builtin_attribute` start with a `MetaItem`, and then convert it
to an `Attribute` by calling `cx.attribute(meta_item)`. This `MetaItem`
to `Attribute` to `MetaItem` conversion is silly.
This commit adds a new function `check_builtin_meta_item`, which can be
called instead from these call sites. `check_builtin_attribute` also now
calls it. The commit also renames `check_meta` as `check_attr` to better
match its arguments.
