//! https://rustc-dev-guide.rust-lang.org/traits/resolution.html#confirmation
use rustc_data_structures::stack::ensure_sufficient_stack;
use rustc_hir::lang_items::LangItem;
-use rustc_index::bit_set::GrowableBitSet;
use rustc_infer::infer::InferOk;
use rustc_infer::infer::LateBoundRegionConversionTime::HigherRankedType;
use rustc_middle::ty::{
- self, Binder, GenericArg, GenericArgKind, GenericParamDefKind, InternalSubsts, SubstsRef,
- ToPolyTraitRef, ToPredicate, TraitRef, Ty, TyCtxt,
+ self, Binder, GenericParamDefKind, InternalSubsts, SubstsRef, ToPolyTraitRef, ToPredicate,
+ TraitRef, Ty, TyCtxt, TypeVisitable,
};
use rustc_session::config::TraitSolver;
use rustc_span::def_id::DefId;
// `T` -> `Trait`
(_, &ty::Dynamic(ref data, r, ty::Dyn)) => {
let mut object_dids = data.auto_traits().chain(data.principal_def_id());
- if let Some(did) = object_dids.find(|did| !tcx.is_object_safe(*did)) {
+ if let Some(did) = object_dids.find(|did| !tcx.check_is_object_safe(*did)) {
return Err(TraitNotObjectSafe(did));
}
// `Struct<T>` -> `Struct<U>`
(&ty::Adt(def, substs_a), &ty::Adt(_, substs_b)) => {
- let maybe_unsizing_param_idx = |arg: GenericArg<'tcx>| match arg.unpack() {
- GenericArgKind::Type(ty) => match ty.kind() {
- ty::Param(p) => Some(p.index),
- _ => None,
- },
-
- // Lifetimes aren't allowed to change during unsizing.
- GenericArgKind::Lifetime(_) => None,
-
- GenericArgKind::Const(ct) => match ct.kind() {
- ty::ConstKind::Param(p) => Some(p.index),
- _ => None,
- },
- };
-
- // FIXME(eddyb) cache this (including computing `unsizing_params`)
- // by putting it in a query; it would only need the `DefId` as it
- // looks at declared field types, not anything substituted.
-
- // The last field of the structure has to exist and contain type/const parameters.
- let (tail_field, prefix_fields) =
- def.non_enum_variant().fields.split_last().ok_or(Unimplemented)?;
- let tail_field_ty = tcx.bound_type_of(tail_field.did);
-
- let mut unsizing_params = GrowableBitSet::new_empty();
- for arg in tail_field_ty.0.walk() {
- if let Some(i) = maybe_unsizing_param_idx(arg) {
- unsizing_params.insert(i);
- }
- }
-
- // Ensure none of the other fields mention the parameters used
- // in unsizing.
- for field in prefix_fields {
- for arg in tcx.type_of(field.did).walk() {
- if let Some(i) = maybe_unsizing_param_idx(arg) {
- unsizing_params.remove(i);
- }
- }
- }
-
+ let unsizing_params = tcx.unsizing_params_for_adt(def.did());
if unsizing_params.is_empty() {
return Err(Unimplemented);
}
+ let tail_field = def
+ .non_enum_variant()
+ .fields
+ .last()
+ .expect("expected unsized ADT to have a tail field");
+ let tail_field_ty = tcx.bound_type_of(tail_field.did);
+
// Extract `TailField<T>` and `TailField<U>` from `Struct<T>` and `Struct<U>`,
// normalizing in the process, since `type_of` returns something directly from
// astconv (which means it's un-normalized).
ty::GeneratorWitness(tys) => {
stack.extend(tcx.erase_late_bound_regions(tys).to_vec());
}
+ ty::GeneratorWitnessMIR(def_id, substs) => {
+ let tcx = self.tcx();
+ stack.extend(tcx.generator_hidden_types(def_id).map(|bty| {
+ let ty = bty.subst(tcx, substs);
+ debug_assert!(!ty.has_late_bound_regions());
+ ty
+ }))
+ }
// If we have a projection type, make sure to normalize it so we replace it
// with a fresh infer variable