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Install projection from RPITIT to default trait method opaque correctly

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This commit is contained in:
Michael Goulet 2023-03-15 22:55:00 +00:00
parent c5c4340760
commit 0949da8f4e
8 changed files with 64 additions and 19 deletions
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17
compiler/rustc_ty_utils/src/ty.rs
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@ -268,8 +268,6 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for ImplTraitInTraitFinder<'_, 'tcx> {
fn visit_ty(&mut self, ty: Ty<'tcx>) -> std::ops::ControlFlow<Self::BreakTy> {
if let ty::Alias(ty::Projection, alias_ty) = *ty.kind()
// FIXME(-Zlower-impl-trait-in-trait-to-assoc-ty) need to project to the opaque, could
// get it via type_of + subst.
&& self.tcx.is_impl_trait_in_trait(alias_ty.def_id)
&& self.tcx.impl_trait_in_trait_parent_fn(alias_ty.def_id) == self.fn_def_id
&& self.seen.insert(alias_ty.def_id)
@ -284,11 +282,24 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for ImplTraitInTraitFinder<'_, 'tcx> {
re
}
});
// If we're lowering to associated item, install the opaque type which is just
// the `type_of` of the trait's associated item. If we're using the old lowering
// strategy, then just reinterpret the associated type like an opaque :^)
let default_ty = if self.tcx.lower_impl_trait_in_trait_to_assoc_ty() {
self
.tcx
.type_of(alias_ty.def_id)
.subst(self.tcx, alias_ty.substs)
} else {
self.tcx.mk_alias(ty::Opaque, alias_ty)
};
self.predicates.push(
ty::Binder::bind_with_vars(
ty::ProjectionPredicate {
projection_ty: alias_ty,
term: self.tcx.mk_alias(ty::Opaque, alias_ty).into(),
term: default_ty.into(),
},
self.bound_vars,
)