Compiler & its UI tests: Rename remaining occurrences of "object safe" to "dyn compatible"
Follow-up to #130826.
Part of #130852.
1. 1st commit: Fix stupid oversights. Should've been part of #130826.
2. 2nd commit: Rename the unstable feature `object_safe_for_dispatch` to `dyn_compatible_for_dispatch`. Might not be worth the churn, you decide.
3. 3rd commit: Apply the renaming to all UI tests (contents and paths).
Make opaque types regular HIR nodes
Having opaque types as HIR owner introduces all sorts of complications. This PR proposes to make them regular HIR nodes instead.
I haven't gone through all the test changes yet, so there may be a few surprises.
Many thanks to `@camelid` for the first draft.
Fixes https://github.com/rust-lang/rust/issues/129023Fixes#129099Fixes#125843Fixes#119716Fixes#121422
Account for `impl Trait {` when `impl Trait for Type {` was intended
On editions where bare traits are never allowed, detect if the user has written `impl Trait` with no type, silence any dyn-compatibility errors, and provide a structured suggestion for the potentially missing type:
```
error[E0782]: trait objects must include the `dyn` keyword
--> $DIR/missing-for-type-in-impl.rs:8:6
|
LL | impl Foo<i64> {
| ^^^^^^^^
|
help: add `dyn` keyword before this trait
|
LL | impl dyn Foo<i64> {
| +++
help: you might have intended to implement this trait for a given type
|
LL | impl Foo<i64> for /* Type */ {
| ++++++++++++++
```
CC #131051.
Check elaborated projections from dyn don't mention unconstrained late bound lifetimes
Check that the projections that are *not* explicitly written but which we deduce from elaborating the principal of a `dyn` *also* do not reference unconstrained late-bound lifetimes, just like the ones that the user writes by hand.
That is to say, given:
```
trait Foo<T>: Bar<Assoc = T> {}
trait Bar {
type Assoc;
}
```
The type `dyn for<'a> Foo<&'a T>` (basically) elaborates to `dyn for<'a> Foo<&'a T> + for<'a> Bar<Assoc = &'a T>`[^1]. However, the `Bar` projection predicate is not well-formed, since `'a` must show up in the trait's arguments to be referenced in the term of a projection. We must error in this situation[^well], or else `dyn for<'a> Foo<&'a T>` is unsound.
We already detect this for user-written projections during HIR->rustc_middle conversion, so this largely replicates that logic using the helper functions that were already conveniently defined.
---
I'm cratering this first to see the fallout; if it's minimal or zero, then let's land it as-is. If not, the way that this is implemented is very conducive to an FCW.
---
Fixes#130347
[^1]: We don't actually elaborate it like that in rustc; we only keep the principal trait ref `Foo<&'a T>` and the projection part of `Bar<Assoc = ...>`, but it's useful to be a bit verbose here for the purpose of explaining the issue.
[^well]: Well, we could also make `dyn for<'a> Foo<&'a T>` *not* implement `for<'a> Bar<Assoc = &'a T>`, but this is inconsistent with the case where the user writes `Assoc = ...` in the type itself, and it overly complicates the implementation of trait objects' built-in impls.
On editions where bare traits are never allowed, detect if the user has
written `impl Trait` with no type, silence any dyn-compatibility errors,
and provide a structured suggestion for the potentially missing type:
```
error[E0782]: trait objects must include the `dyn` keyword
--> $DIR/missing-for-type-in-impl.rs:8:6
|
LL | impl Foo<i64> {
| ^^^^^^^^
|
help: add `dyn` keyword before this trait
|
LL | impl dyn Foo<i64> {
| +++
help: you might have intended to implement this trait for a given type
|
LL | impl Foo<i64> for /* Type */ {
| ++++++++++++++
```
Stabilize the `map`/`value` methods on `ControlFlow`
And fix the stability attribute on the `pub use` in `core::ops`.
libs-api in https://github.com/rust-lang/rust/issues/75744#issuecomment-2231214910 seemed reasonably happy with naming for these, so let's try for an FCP.
Summary:
```rust
impl<B, C> ControlFlow<B, C> {
pub fn break_value(self) -> Option<B>;
pub fn map_break<T>(self, f: impl FnOnce(B) -> T) -> ControlFlow<T, C>;
pub fn continue_value(self) -> Option<C>;
pub fn map_continue<T>(self, f: impl FnOnce(C) -> T) -> ControlFlow<B, T>;
}
```
Resolves#75744
``@rustbot`` label +needs-fcp +t-libs-api -t-libs
---
Aside, in case it keeps someone else from going down the same dead end: I looked at the `{break,continue}_value` methods and tried to make them `const` as part of this, but that's disallowed because of not having `const Drop`, so put it back to not even unstably-const.
Refactoring to `OpaqueTyOrigin`
Pulled out of a larger PR that uses these changes to do cross-crate encoding of opaque origin, so we can use them for edition 2024 migrations. These changes should be self-explanatory on their own, tho 😄
Fix `adt_const_params` leaking `{type error}` in error msg
Fixes the confusing diagnostic described in #118179. (users would see `{type error}` in some situations, which is pretty weird)
`adt_const_params` tracking issue: #95174
properly elaborate effects implied bounds for super traits
Summary: This PR makes it so that we elaborate `<T as Tr>::Fx: EffectsCompat<somebool>` into `<T as SuperTr>::Fx: EffectsCompat<somebool>` when we know that `trait Tr: ~const SuperTr`.
Some discussion at https://github.com/rust-lang/project-const-traits/issues/2.
r? project-const-traits
`@rust-lang/project-const-traits:` how do we feel about this approach?
Assert that `explicit_super_predicates_of` and `explicit_item_super_predicates` truly only contains bounds for the type itself
We distinguish _implied_ predicates (anything that is implied from elaborating a trait bound) from _super_ predicates, which are are the subset of implied predicates that share the same self type as the trait predicate we're elaborating. This was originally done in #107614, which fixed a large class of ICEs and strange errors where the compiler expected the self type of a trait predicate not to change when elaborating super predicates.
Specifically, super predicates are special for various reasons: they're the valid candidates for trait upcasting, are the only predicates we elaborate when doing closure signature inference, etc. So making sure that we get this list correct and don't accidentally "leak" any other predicates into this list is quite important.
This PR adds some debug assertions that we're in fact not doing so, and it fixes an oversight in the effect desugaring rework.
Implement Return Type Notation (RTN)'s path form in where clauses
Implement return type notation (RTN) in path position for where clauses. We already had RTN in associated type position ([e.g.](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021&gist=627a4fb8e2cb334863fbd08ed3722c09)), but per [the RFC](https://rust-lang.github.io/rfcs/3654-return-type-notation.html#where-rtn-can-be-used-for-now):
> As a standalone type, RTN can only be used as the Self type of a where-clause [...]
Specifically, in order to enable code like:
```rust
trait Foo {
fn bar() -> impl Sized;
}
fn is_send(_: impl Send) {}
fn test<T>()
where
T: Foo,
T::bar(..): Send,
{
is_send(T::bar());
}
```
* In the resolver, when we see a `TyKind::Path` whose final segment is `GenericArgs::ParenthesizedElided` (i.e. `(..)`), resolve that path in the *value* namespace, since we're looking for a method.
* When lowering where clauses in HIR lowering, we first try to intercept an RTN self type via `lower_ty_maybe_return_type_notation`. If we find an RTN type, we lower it manually in a way that respects its higher-ranked-ness (see below) and resolves to the corresponding RPITIT. Anywhere else, we'll emit the same "return type notation not allowed in this position yet" error we do when writing RTN in every other position.
* In `resolve_bound_vars`, we add some special treatment for RTN types in where clauses. Specifically, we need to add new lifetime variables to our binders for the early- and late-bound vars we encounter on the method. This implements the higher-ranked desugaring [laid out in the RFC](https://rust-lang.github.io/rfcs/3654-return-type-notation.html#converting-to-higher-ranked-trait-bounds).
This PR also adds a bunch of tests, mostly negative ones (testing error messages).
In a follow-up PR, I'm going to mark RTN as no longer incomplete, since this PR basically finishes the impl surface that we should initially stabilize, and the RFC was accepted.
cc [RFC 3654](https://github.com/rust-lang/rfcs/pull/3654) and https://github.com/rust-lang/rust/issues/109417
Correct outdated object size limit
The comment here about 48 bit addresses being enough was written in 2016 but was made incorrect in 2019 by 5-level paging, and then persisted for another 5 years before being noticed and corrected.
The bolding of the "exclusive" part is merely to call attention to something I missed when reading it and doublechecking the math.
try-job: i686-msvc
try-job: test-various
When we have two types with the same name, one without type parameters and the other with type parameters and a derive macro, we were before incorrectly suggesting to remove type parameters from the former, which ICEd because we were suggesting to remove nothing. We now gate against this.
The output is still not perfect. E0107 should explicitly detect this case and provide better context, but for now let's avoid the ICE.
