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This commit is contained in:
Michael Goulet
2023-01-25 17:02:16 +00:00
parent c24844048f
commit f7fc0b7121
4 changed files with 16 additions and 20 deletions
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26
compiler/rustc_trait_selection/src/solve/trait_goals.rs
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@@ -262,11 +262,9 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
// `T` -> `dyn Trait` unsizing
(_, &ty::Dynamic(data, region, ty::Dyn)) => {
// Can only unsize to an object-safe type
// FIXME: Can auto traits be *not* object safe?
if data
.auto_traits()
.chain(data.principal_def_id())
.any(|def_id| !tcx.is_object_safe(def_id))
.principal_def_id()
.map_or(false, |def_id| !tcx.check_is_object_safe(def_id))
{
return Err(NoSolution);
}
@@ -365,7 +363,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
})
}
fn consider_builtin_dyn_unsize_candidates(
fn consider_builtin_dyn_upcast_candidates(
ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, Self>,
) -> Vec<CanonicalResponse<'tcx>> {
@@ -387,9 +385,8 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
return vec![];
}
let mut responses = vec![];
let mut unsize_dyn_to_principal = |principal: Option<ty::PolyExistentialTraitRef<'tcx>>| {
let _ = ecx.infcx.probe(|_| -> Result<(), NoSolution> {
ecx.infcx.probe(|_| -> Result<_, NoSolution> {
// Require that all of the trait predicates from A match B, except for
// the auto traits. We do this by constructing a new A type with B's
// auto traits, and equating these types.
@@ -414,16 +411,17 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
goal.with(tcx, ty::Binder::dummy(ty::OutlivesPredicate(a_region, b_region))),
);
responses.push(ecx.evaluate_all_and_make_canonical_response(nested_obligations)?);
Ok(())
});
ecx.evaluate_all_and_make_canonical_response(nested_obligations)
})
};
let mut responses = vec![];
// If the principal def ids match (or are both none), then we're not doing
// trait upcasting. We're just removing auto traits (or shortening the lifetime).
if a_data.principal_def_id() == b_data.principal_def_id() {
unsize_dyn_to_principal(a_data.principal());
if let Ok(response) = unsize_dyn_to_principal(a_data.principal()) {
responses.push(response);
}
} else if let Some(a_principal) = a_data.principal()
&& let Some(b_principal) = b_data.principal()
{
@@ -433,7 +431,9 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
}
let erased_trait_ref = super_trait_ref
.map_bound(|trait_ref| ty::ExistentialTraitRef::erase_self_ty(tcx, trait_ref));
unsize_dyn_to_principal(Some(erased_trait_ref));
if let Ok(response) = unsize_dyn_to_principal(Some(erased_trait_ref)) {
responses.push(response);
}
}
}