This fully rewords the diagnostic that was previously only emitted for assoc ty bindings.
That's because it incorrectly called trait aliases *type aliases* and didn't really
make it clear what the root cause is.
The added test used to ICE prior to this change.
I've double-checked that the preexisting test I've modified still ICEs in
nightly-2025-03-29.
We used to lower such bad defaulted const args in trait object types to
`{type error}`; now correctly lower them to `{const error}`.
The added tests used to ICE prior to this change.
Removes the attribute from `MetaSized` and `PointeeSized`, with a special case in the trait solvers for `MetaSized`.
`dyn MetaSized` is a perfectly cromulent type, and seems to only have had #[rustc_do_not_implement_via_object] so the builtin object
candidate does not overlap with the builtin MetaSized impl that all `dyn` types get.
Resolves this with a special case by checking `is_sizedness_trait` where the trait solvers previously checked `implement_via_object`.
`dyn PointeeSized` alone is rejected for other reasons (since `dyn PointeeSized` is considered to have no principal trait because `PointeeSized`
is removed at an earlier stage of the compiler), but `(dyn PointeeSized + Send)` is valid and equivalent to `dyn Send`.
Add suggestions from code review
Update compiler/rustc_trait_selection/src/traits/dyn_compatibility.rs and tests
Co-authored-by: lcnr <rust@lcnr.de>
No longer require that we prove that the predicates of aliases hold when
checking the well-formedness of the alias. This permits more uses of GATs
and changes the output of yet more tests.
compiler: report error when trait object type param reference self
Fixes#139082.
Emits an error when `Self` is found in the projection bounds of a trait
object. In type aliases, `Self` has no meaning, so `type A = &'static
dyn B` where `trait B = Fn() -> Self` will expands to `type A = &'static
Fn() -> Self` which is illegal, causing the region solver to bail out
when hitting the uninferred Self.
r? ````@compiler-errors```` ````@fee1-dead````
Fixes#139082.
Emits an error when `Self` is found in the projection bounds of a trait
object. In type aliases, `Self` has no meaning, so `type A = &'static
dyn B` where `trait B = Fn() -> Self` will expands to `type A = &'static
Fn() -> Self` which is illegal, causing the region solver to bail out
when hitting the uninferred Self.
Bug: #139082
Signed-off-by: xtex <xtexchooser@duck.com>
```
error[E0610]: `{integer}` is a primitive type and therefore doesn't have fields
--> $DIR/attempted-access-non-fatal.rs:7:15
|
LL | let _ = 2.l;
| ^
|
help: if intended to be a floating point literal, consider adding a `0` after the period and a `f64` suffix
|
LL - let _ = 2.l;
LL + let _ = 2.0f64;
|
```
This CL makes a number of small changes to dyn compatibility errors:
- "object safety" has been renamed to "dyn-compatibility" throughout
- "Convert to enum" suggestions are no longer generated when there
exists a type-generic impl of the trait or an impl for `dyn OtherTrait`
- Several error messages are reorganized for user readability
Additionally, the dyn compatibility error creation code has been
split out into functions.
cc #132713
cc #133267
León Orell Valerian Liehr