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rework pointee handling for the new rigid alias approach

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lcnr 2025-02-11 13:09:15 +01:00 • committed by Michael Goulet
parent de273e459e
commit 05bd5ced2d
1 changed files with 85 additions and 73 deletions
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24
compiler/rustc_next_trait_solver/src/solve/normalizes_to/mod.rs
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@ -538,7 +538,6 @@ where
let cx = ecx.cx();
let metadata_def_id = cx.require_lang_item(TraitSolverLangItem::Metadata);
assert_eq!(metadata_def_id, goal.predicate.def_id());
ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc).enter(|ecx| {
let metadata_ty = match goal.predicate.self_ty().kind() {
ty::Bool
| ty::Char
@ -575,14 +574,28 @@ where
// and opaque types: If the `self_ty` is `Sized`, then the metadata is `()`.
// FIXME(ptr_metadata): This impl overlaps with the other impls and shouldn't
// exist. Instead, `Pointee<Metadata = ()>` should be a supertrait of `Sized`.
let alias_bound_result =
ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc).enter(|ecx| {
let sized_predicate = ty::TraitRef::new(
cx,
cx.require_lang_item(TraitSolverLangItem::Sized),
[I::GenericArg::from(goal.predicate.self_ty())],
);
// FIXME(-Znext-solver=coinductive): Should this be `GoalSource::ImplWhereBound`?
ecx.add_goal(GoalSource::Misc, goal.with(cx, sized_predicate));
Ty::new_unit(cx)
ecx.instantiate_normalizes_to_term(goal, Ty::new_unit(cx).into());
ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
});
// In case the dummy alias-bound candidate does not apply, we instead treat this projection
// as rigid.
return alias_bound_result.or_else(|NoSolution| {
ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc).enter(|this| {
this.structurally_instantiate_normalizes_to_term(
goal,
goal.predicate.alias,
);
this.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
})
});
}
ty::Adt(def, args) if def.is_struct() => match def.struct_tail_ty(cx) {
@ -603,15 +616,14 @@ where
todo!()
}
ty::Infer(
ty::TyVar(_) | ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_),
)
ty::Infer(ty::TyVar(_) | ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_))
| ty::Bound(..) => panic!(
"unexpected self ty `{:?}` when normalizing `<T as Pointee>::Metadata`",
goal.predicate.self_ty()
),
};
ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc).enter(|ecx| {
ecx.instantiate_normalizes_to_term(goal, metadata_ty.into());
ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
})