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Rollup merge of rust-lang#72508 - ecstatic-morse:poly-self-ty, r=niko…
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…matsakis

Make `PolyTraitRef::self_ty` return `Binder<Ty>`

This came up during review of rust-lang#71618. The current implementation is the same as a call to `skip_binder` but harder to audit. Make it preserve binding levels and add a call to `skip_binder` at all use sites so they can be audited as part of rust-lang#72507.
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@RalfJung
RalfJung authored Jun 6, 2020
2 parents edb5cdc + b4e06b9 commit 00eda74
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Showing 7 changed files with 45 additions and 25 deletions.
4 changes: 2 additions & 2 deletions src/librustc_middle/ty/sty.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -765,8 +765,8 @@ impl<'tcx> TraitRef<'tcx> {
pub type PolyTraitRef<'tcx> = Binder<TraitRef<'tcx>>;

impl<'tcx> PolyTraitRef<'tcx> {
pub fn self_ty(&self) -> Ty<'tcx> {
self.skip_binder().self_ty()
pub fn self_ty(&self) -> Binder<Ty<'tcx>> {
self.map_bound_ref(|tr| tr.self_ty())
}

pub fn def_id(&self) -> DefId {
Expand Down
32 changes: 21 additions & 11 deletions src/librustc_trait_selection/traits/error_reporting/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -290,7 +290,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
(
Some(format!(
"`?` couldn't convert the error to `{}`",
trait_ref.self_ty(),
trait_ref.skip_binder().self_ty(),
)),
Some(
"the question mark operation (`?`) implicitly performs a \
Expand Down Expand Up @@ -340,7 +340,10 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
if let Some(ret_span) = self.return_type_span(obligation) {
err.span_label(
ret_span,
&format!("expected `{}` because of this", trait_ref.self_ty()),
&format!(
"expected `{}` because of this",
trait_ref.skip_binder().self_ty()
),
);
}
}
Expand All @@ -353,7 +356,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
"{}the trait `{}` is not implemented for `{}`",
pre_message,
trait_ref.print_only_trait_path(),
trait_ref.self_ty(),
trait_ref.skip_binder().self_ty(),
)
};

Expand Down Expand Up @@ -643,7 +646,10 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
return;
}

let found_trait_ty = found_trait_ref.self_ty();
let found_trait_ty = match found_trait_ref.self_ty().no_bound_vars() {
Some(ty) => ty,
None => return,
};

let found_did = match found_trait_ty.kind {
ty::Closure(did, _) | ty::Foreign(did) | ty::FnDef(did, _) => Some(did),
Expand Down Expand Up @@ -1360,11 +1366,15 @@ impl<'a, 'tcx> InferCtxtPrivExt<'tcx> for InferCtxt<'a, 'tcx> {
) {
let get_trait_impl = |trait_def_id| {
let mut trait_impl = None;
self.tcx.for_each_relevant_impl(trait_def_id, trait_ref.self_ty(), |impl_def_id| {
if trait_impl.is_none() {
trait_impl = Some(impl_def_id);
}
});
self.tcx.for_each_relevant_impl(
trait_def_id,
trait_ref.skip_binder().self_ty(),
|impl_def_id| {
if trait_impl.is_none() {
trait_impl = Some(impl_def_id);
}
},
);
trait_impl
};
let required_trait_path = self.tcx.def_path_str(trait_ref.def_id());
Expand Down Expand Up @@ -1435,7 +1445,7 @@ impl<'a, 'tcx> InferCtxtPrivExt<'tcx> for InferCtxt<'a, 'tcx> {
let mut err = match predicate.kind() {
ty::PredicateKind::Trait(ref data, _) => {
let trait_ref = data.to_poly_trait_ref();
let self_ty = trait_ref.self_ty();
let self_ty = trait_ref.skip_binder().self_ty();
debug!("self_ty {:?} {:?} trait_ref {:?}", self_ty, self_ty.kind, trait_ref);

if predicate.references_error() {
Expand Down Expand Up @@ -1564,7 +1574,7 @@ impl<'a, 'tcx> InferCtxtPrivExt<'tcx> for InferCtxt<'a, 'tcx> {
}
ty::PredicateKind::Projection(ref data) => {
let trait_ref = data.to_poly_trait_ref(self.tcx);
let self_ty = trait_ref.self_ty();
let self_ty = trait_ref.skip_binder().self_ty();
let ty = data.skip_binder().ty;
if predicate.references_error() {
return;
Expand Down
24 changes: 17 additions & 7 deletions src/librustc_trait_selection/traits/error_reporting/suggestions.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -318,7 +318,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
trait_ref: ty::PolyTraitRef<'tcx>,
body_id: hir::HirId,
) {
let self_ty = trait_ref.self_ty();
let self_ty = trait_ref.skip_binder().self_ty();
let (param_ty, projection) = match &self_ty.kind {
ty::Param(_) => (true, None),
ty::Projection(projection) => (false, Some(projection)),
Expand Down Expand Up @@ -524,7 +524,11 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
trait_ref: &ty::Binder<ty::TraitRef<'tcx>>,
points_at_arg: bool,
) {
let self_ty = trait_ref.self_ty();
let self_ty = match trait_ref.self_ty().no_bound_vars() {
None => return,
Some(ty) => ty,
};

let (def_id, output_ty, callable) = match self_ty.kind {
ty::Closure(def_id, substs) => (def_id, substs.as_closure().sig().output(), "closure"),
ty::FnDef(def_id, _) => (def_id, self_ty.fn_sig(self.tcx).output(), "function"),
Expand Down Expand Up @@ -707,7 +711,10 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
return;
}

let mut suggested_ty = trait_ref.self_ty();
let mut suggested_ty = match trait_ref.self_ty().no_bound_vars() {
Some(ty) => ty,
None => return,
};

for refs_remaining in 0..refs_number {
if let ty::Ref(_, inner_ty, _) = suggested_ty.kind {
Expand Down Expand Up @@ -829,6 +836,9 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
span: Span,
trait_ref: &ty::Binder<ty::TraitRef<'tcx>>,
) {
let is_empty_tuple =
|ty: ty::Binder<Ty<'_>>| ty.skip_binder().kind == ty::Tuple(ty::List::empty());

let hir = self.tcx.hir();
let parent_node = hir.get_parent_node(obligation.cause.body_id);
let node = hir.find(parent_node);
Expand All @@ -840,7 +850,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
if let hir::ExprKind::Block(blk, _) = &body.value.kind {
if sig.decl.output.span().overlaps(span)
&& blk.expr.is_none()
&& "()" == &trait_ref.self_ty().to_string()
&& is_empty_tuple(trait_ref.self_ty())
{
// FIXME(estebank): When encountering a method with a trait
// bound not satisfied in the return type with a body that has
Expand Down Expand Up @@ -1271,7 +1281,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
ObligationCauseCode::DerivedObligation(derived_obligation)
| ObligationCauseCode::BuiltinDerivedObligation(derived_obligation)
| ObligationCauseCode::ImplDerivedObligation(derived_obligation) => {
let ty = derived_obligation.parent_trait_ref.self_ty();
let ty = derived_obligation.parent_trait_ref.skip_binder().self_ty();
debug!(
"maybe_note_obligation_cause_for_async_await: \
parent_trait_ref={:?} self_ty.kind={:?}",
Expand Down Expand Up @@ -1917,7 +1927,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {

let impls_future = self.tcx.type_implements_trait((
future_trait,
self_ty,
self_ty.skip_binder(),
ty::List::empty(),
obligation.param_env,
));
Expand All @@ -1933,7 +1943,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
let projection_ty = ty::ProjectionTy {
// `T`
substs: self.tcx.mk_substs_trait(
trait_ref.self_ty(),
trait_ref.self_ty().skip_binder(),
self.fresh_substs_for_item(span, item_def_id),
),
// `Future::Output`
Expand Down
2 changes: 1 addition & 1 deletion src/librustc_trait_selection/traits/specialize/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -496,7 +496,7 @@ fn to_pretty_impl_header(tcx: TyCtxt<'_>, impl_def_id: DefId) -> Option<String>
for (p, _) in predicates {
if let Some(poly_trait_ref) = p.to_opt_poly_trait_ref() {
if Some(poly_trait_ref.def_id()) == sized_trait {
types_without_default_bounds.remove(poly_trait_ref.self_ty());
types_without_default_bounds.remove(poly_trait_ref.self_ty().skip_binder());
continue;
}
}
Expand Down
2 changes: 1 addition & 1 deletion src/librustc_typeck/check/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -3813,7 +3813,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
trait_ref: ty::PolyTraitRef<'tcx>,
expected_vid: ty::TyVid,
) -> bool {
let self_ty = self.shallow_resolve(trait_ref.self_ty());
let self_ty = self.shallow_resolve(trait_ref.skip_binder().self_ty());
debug!(
"self_type_matches_expected_vid(trait_ref={:?}, self_ty={:?}, expected_vid={:?})",
trait_ref, self_ty, expected_vid
Expand Down
4 changes: 2 additions & 2 deletions src/librustdoc/clean/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -500,7 +500,7 @@ impl<'a> Clean<WherePredicate> for ty::PolyTraitPredicate<'a> {
fn clean(&self, cx: &DocContext<'_>) -> WherePredicate {
let poly_trait_ref = self.map_bound(|pred| pred.trait_ref);
WherePredicate::BoundPredicate {
ty: poly_trait_ref.self_ty().clean(cx),
ty: poly_trait_ref.skip_binder().self_ty().clean(cx),
bounds: vec![poly_trait_ref.clean(cx)],
}
}
Expand Down Expand Up @@ -755,7 +755,7 @@ impl<'a, 'tcx> Clean<Generics> for (&'a ty::Generics, ty::GenericPredicates<'tcx
let mut projection = None;
let param_idx = (|| {
if let Some(trait_ref) = p.to_opt_poly_trait_ref() {
if let ty::Param(param) = trait_ref.self_ty().kind {
if let ty::Param(param) = trait_ref.skip_binder().self_ty().kind {
return Some(param.index);
}
} else if let Some(outlives) = p.to_opt_type_outlives() {
Expand Down
2 changes: 1 addition & 1 deletion src/tools/clippy/clippy_lints/src/future_not_send.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -95,7 +95,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for FutureNotSend {
let trait_ref = trait_pred.to_poly_trait_ref();
db.note(&*format!(
"`{}` doesn't implement `{}`",
trait_ref.self_ty(),
trait_ref.skip_binder().self_ty(),
trait_ref.print_only_trait_path(),
));
}
Expand Down

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