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Initial support for auto traits with default bounds

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This commit is contained in:
Bryanskiy
2025-03-06 20:36:44 +03:00
parent 79de6c0bbe
commit 581c5fbc40
24 changed files with 830 additions and 86 deletions
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42
compiler/rustc_next_trait_solver/src/solve/trait_goals.rs
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@@ -1086,6 +1086,25 @@ where
goal: Goal<I, TraitPredicate<I>>,
) -> Option<Result<Candidate<I>, NoSolution>> {
let self_ty = goal.predicate.self_ty();
let check_impls = || {
let mut disqualifying_impl = None;
self.cx().for_each_relevant_impl(
goal.predicate.def_id(),
goal.predicate.self_ty(),
|impl_def_id| {
disqualifying_impl = Some(impl_def_id);
},
);
if let Some(def_id) = disqualifying_impl {
trace!(?def_id, ?goal, "disqualified auto-trait implementation");
// No need to actually consider the candidate here,
// since we do that in `consider_impl_candidate`.
return Some(Err(NoSolution));
} else {
None
}
};
match self_ty.kind() {
// Stall int and float vars until they are resolved to a concrete
// numerical type. That's because the check for impls below treats
@@ -1096,6 +1115,10 @@ where
Some(self.forced_ambiguity(MaybeCause::Ambiguity))
}
// Backward compatibility for default auto traits.
// Test: ui/traits/default_auto_traits/extern-types.rs
ty::Foreign(..) if self.cx().is_default_trait(goal.predicate.def_id()) => check_impls(),
// These types cannot be structurally decomposed into constituent
// types, and therefore have no built-in auto impl.
ty::Dynamic(..)
@@ -1156,24 +1179,7 @@ where
| ty::Never
| ty::Tuple(_)
| ty::Adt(_, _)
| ty::UnsafeBinder(_) => {
let mut disqualifying_impl = None;
self.cx().for_each_relevant_impl(
goal.predicate.def_id(),
goal.predicate.self_ty(),
|impl_def_id| {
disqualifying_impl = Some(impl_def_id);
},
);
if let Some(def_id) = disqualifying_impl {
trace!(?def_id, ?goal, "disqualified auto-trait implementation");
// No need to actually consider the candidate here,
// since we do that in `consider_impl_candidate`.
return Some(Err(NoSolution));
} else {
None
}
}
| ty::UnsafeBinder(_) => check_impls(),
ty::Error(_) => None,
}
}