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Rollup merge of #89001 - jackh726:binder-cleanup, r=nikomatsakis

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Be explicit about using Binder::dummy

This is somewhat of a late followup to the binder refactor PR. It removes `ToPredicate` and `ToPolyTraitImpls` that hide the use of `Binder::dummy`. While this does make code a bit more verbose, it allows us be more careful about where we create binders.

Another alternative here might be to add a new trait `ToBinder` or something with a `dummy()` fn. Which could still allow grepping but allows doing something like `trait_ref.dummy()` (but I also wonder if longer-term, it would be better to be even more explicit with a `bind_with_vars(ty::List::empty())` *but* that's not clear yet.

r? ``@nikomatsakis``
This commit is contained in:
Jubilee
2021-09-24 11:40:11 -07:00
committed by GitHub
parent 2de7f1075f 553f6496f2
commit ee2e97c416
34 changed files with 127 additions and 121 deletions
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9
compiler/rustc_trait_selection/src/traits/select/confirmation.rs
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@@ -141,6 +141,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
let placeholder_trait_predicate =
self.infcx().replace_bound_vars_with_placeholders(trait_predicate);
let placeholder_self_ty = placeholder_trait_predicate.self_ty();
let placeholder_trait_predicate = ty::Binder::dummy(placeholder_trait_predicate);
let (def_id, substs) = match *placeholder_self_ty.kind() {
ty::Projection(proj) => (proj.item_def_id, proj.substs),
ty::Opaque(def_id, substs) => (def_id, substs),
@@ -164,7 +165,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
obligations.extend(self.infcx.commit_if_ok(|_| {
self.infcx
.at(&obligation.cause, obligation.param_env)
.sup(placeholder_trait_predicate.trait_ref.to_poly_trait_ref(), candidate.value)
.sup(placeholder_trait_predicate.to_poly_trait_ref(), candidate.value)
.map(|InferOk { obligations, .. }| obligations)
.map_err(|_| Unimplemented)
})?);
@@ -646,7 +647,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
obligations.push(Obligation::new(
obligation.cause.clone(),
obligation.param_env,
ty::PredicateKind::ClosureKind(closure_def_id, substs, kind)
ty::Binder::dummy(ty::PredicateKind::ClosureKind(closure_def_id, substs, kind))
.to_predicate(self.tcx()),
));
}
@@ -898,10 +899,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
);
// We can only make objects from sized types.
let tr = ty::TraitRef::new(
let tr = ty::Binder::dummy(ty::TraitRef::new(
tcx.require_lang_item(LangItem::Sized, None),
tcx.mk_substs_trait(source, &[]),
);
));
nested.push(predicate_to_obligation(tr.without_const().to_predicate(tcx)));
// If the type is `Foo + 'a`, ensure that the type