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Rollup merge of #115519 - compiler-errors:next-solver-assoc-ice, r=lcnr

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Don't ICE on associated type projection without feature gate in new solver

Self-explanatory, we should avoid ICEs when the feature gate is not enabled. Continue to ICE when the feature gate *is* enabled, though.

Fixes #115500
This commit is contained in:
Matthias Krüger 2023-09-05 07:15:16 +02:00 committed by GitHub
commit f5e6aa3c4a
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3 changed files with 55 additions and 1 deletions
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16
compiler/rustc_trait_selection/src/solve/project_goals.rs
View File

@ -244,7 +244,21 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> {
// Finally we construct the actual value of the associated type.
let term = match assoc_def.item.kind {
ty::AssocKind::Type => tcx.type_of(assoc_def.item.def_id).map_bound(|ty| ty.into()),
ty::AssocKind::Const => bug!("associated const projection is not supported yet"),
ty::AssocKind::Const => {
if tcx.features().associated_const_equality {
bug!("associated const projection is not supported yet")
} else {
ty::EarlyBinder::bind(
ty::Const::new_error_with_message(
tcx,
tcx.type_of(assoc_def.item.def_id).instantiate_identity(),
DUMMY_SP,
"associated const projection is not supported yet",
)
.into(),
)
}
}
ty::AssocKind::Fn => unreachable!("we should never project to a fn"),
};

19
tests/ui/traits/new-solver/dont-ice-on-assoc-projection.rs Normal file
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@ -0,0 +1,19 @@
// compile-flags: -Ztrait-solver=next-coherence
// Makes sure we don't ICE on associated const projection when the feature gate
// is not enabled, since we should avoid encountering ICEs on stable if possible.
trait Bar {
const ASSOC: usize;
}
impl Bar for () {
const ASSOC: usize = 1;
}
trait Foo {}
impl Foo for () {}
impl<T> Foo for T where T: Bar<ASSOC = 0> {}
//~^ ERROR associated const equality is incomplete
//~| ERROR conflicting implementations of trait `Foo` for type `()`
fn main() {}

21
tests/ui/traits/new-solver/dont-ice-on-assoc-projection.stderr Normal file
View File

@ -0,0 +1,21 @@
error[E0658]: associated const equality is incomplete
--> $DIR/dont-ice-on-assoc-projection.rs:15:32
|
LL | impl<T> Foo for T where T: Bar<ASSOC = 0> {}
| ^^^^^^^^^
|
= note: see issue #92827 <https://github.com/rust-lang/rust/issues/92827> for more information
= help: add `#![feature(associated_const_equality)]` to the crate attributes to enable
error[E0119]: conflicting implementations of trait `Foo` for type `()`
--> $DIR/dont-ice-on-assoc-projection.rs:15:1
|
LL | impl Foo for () {}
| --------------- first implementation here
LL | impl<T> Foo for T where T: Bar<ASSOC = 0> {}
| ^^^^^^^^^^^^^^^^^ conflicting implementation for `()`
error: aborting due to 2 previous errors
Some errors have detailed explanations: E0119, E0658.
For more information about an error, try `rustc --explain E0119`.