use std::iter;
-use super::assembly::{self, AssemblyCtxt};
-use super::{CanonicalGoal, EvalCtxt, Goal, QueryResult};
+use super::assembly::{self, Candidate, CandidateSource};
+use super::infcx_ext::InferCtxtExt;
+use super::{Certainty, EvalCtxt, Goal, QueryResult};
use rustc_hir::def_id::DefId;
-use rustc_infer::infer::InferOk;
use rustc_infer::traits::query::NoSolution;
-use rustc_infer::traits::ObligationCause;
use rustc_middle::ty::fast_reject::{DeepRejectCtxt, TreatParams};
use rustc_middle::ty::TraitPredicate;
use rustc_middle::ty::{self, Ty, TyCtxt};
use rustc_span::DUMMY_SP;
-#[allow(dead_code)] // FIXME: implement and use all variants.
-#[derive(Debug, Clone, Copy)]
-pub(super) enum CandidateSource {
- /// Some user-defined impl with the given `DefId`.
- Impl(DefId),
- /// The n-th caller bound in the `param_env` of our goal.
- ///
- /// This is pretty much always a bound from the `where`-clauses of the
- /// currently checked item.
- ParamEnv(usize),
- /// A bound on the `self_ty` in case it is a projection or an opaque type.
- ///
- /// # Examples
- ///
- /// ```ignore (for syntax highlighting)
- /// trait Trait {
- /// type Assoc: OtherTrait;
- /// }
- /// ```
- ///
- /// We know that `<Whatever as Trait>::Assoc: OtherTrait` holds by looking at
- /// the bounds on `Trait::Assoc`.
- AliasBound(usize),
- /// A builtin implementation for some specific traits, used in cases
- /// where we cannot rely an ordinary library implementations.
- ///
- /// The most notable examples are `Sized`, `Copy` and `Clone`. This is also
- /// used for the `DiscriminantKind` and `Pointee` trait, both of which have
- /// an associated type.
- Builtin,
- /// An automatic impl for an auto trait, e.g. `Send`. These impls recursively look
- /// at the constituent types of the `self_ty` to check whether the auto trait
- /// is implemented for those.
- AutoImpl,
-}
-
-type Candidate<'tcx> = assembly::Candidate<'tcx, TraitPredicate<'tcx>>;
-
impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
- type CandidateSource = CandidateSource;
-
fn self_ty(self) -> Ty<'tcx> {
self.self_ty()
}
}
fn consider_impl_candidate(
- acx: &mut AssemblyCtxt<'_, 'tcx, Self>,
+ ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, TraitPredicate<'tcx>>,
impl_def_id: DefId,
- ) {
- let tcx = acx.cx.tcx;
+ ) -> Result<Certainty, NoSolution> {
+ let tcx = ecx.tcx();
let impl_trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap();
let drcx = DeepRejectCtxt { treat_obligation_params: TreatParams::AsPlaceholder };
if iter::zip(goal.predicate.trait_ref.substs, impl_trait_ref.skip_binder().substs)
.any(|(goal, imp)| !drcx.generic_args_may_unify(goal, imp))
{
- return;
+ return Err(NoSolution);
}
- acx.infcx.probe(|_| {
- let impl_substs = acx.infcx.fresh_substs_for_item(DUMMY_SP, impl_def_id);
+ ecx.infcx.probe(|_| {
+ let impl_substs = ecx.infcx.fresh_substs_for_item(DUMMY_SP, impl_def_id);
let impl_trait_ref = impl_trait_ref.subst(tcx, impl_substs);
- let Ok(InferOk { obligations, .. }) = acx
- .infcx
- .at(&ObligationCause::dummy(), goal.param_env)
- .define_opaque_types(false)
- .eq(goal.predicate.trait_ref, impl_trait_ref)
- .map_err(|e| debug!("failed to equate trait refs: {e:?}"))
- else {
- return
- };
+ let mut nested_goals =
+ ecx.infcx.eq(goal.param_env, goal.predicate.trait_ref, impl_trait_ref)?;
let where_clause_bounds = tcx
.predicates_of(impl_def_id)
.instantiate(tcx, impl_substs)
.predicates
.into_iter()
.map(|pred| goal.with(tcx, pred));
+ nested_goals.extend(where_clause_bounds);
+ ecx.evaluate_all(nested_goals)
+ })
+ }
- let nested_goals =
- obligations.into_iter().map(|o| o.into()).chain(where_clause_bounds).collect();
+ fn consider_builtin_sized_candidate(
+ _ecx: &mut EvalCtxt<'_, 'tcx>,
+ _goal: Goal<'tcx, Self>,
+ ) -> Result<Certainty, NoSolution> {
+ unimplemented!();
+ }
- let Ok(certainty) = acx.cx.evaluate_all(acx.infcx, nested_goals) else { return };
- acx.try_insert_candidate(CandidateSource::Impl(impl_def_id), certainty);
- })
+ fn consider_assumption(
+ _ecx: &mut EvalCtxt<'_, 'tcx>,
+ _goal: Goal<'tcx, Self>,
+ assumption: ty::Predicate<'tcx>,
+ ) -> Result<Certainty, NoSolution> {
+ if let Some(_poly_trait_pred) = assumption.to_opt_poly_trait_pred() {
+ unimplemented!()
+ } else {
+ Err(NoSolution)
+ }
}
}
-impl<'tcx> EvalCtxt<'tcx> {
+impl<'tcx> EvalCtxt<'_, 'tcx> {
pub(super) fn compute_trait_goal(
&mut self,
- goal: CanonicalGoal<'tcx, TraitPredicate<'tcx>>,
+ goal: Goal<'tcx, TraitPredicate<'tcx>>,
) -> QueryResult<'tcx> {
- let candidates = AssemblyCtxt::assemble_and_evaluate_candidates(self, goal);
+ let candidates = self.assemble_and_evaluate_candidates(goal);
self.merge_trait_candidates_discard_reservation_impls(candidates)
}
(CandidateSource::Impl(_), _)
| (CandidateSource::ParamEnv(_), _)
| (CandidateSource::AliasBound(_), _)
- | (CandidateSource::Builtin, _)
- | (CandidateSource::AutoImpl, _) => unimplemented!(),
+ | (CandidateSource::BuiltinImpl, _) => unimplemented!(),
}
}
fn discard_reservation_impl(&self, candidate: Candidate<'tcx>) -> Candidate<'tcx> {
if let CandidateSource::Impl(def_id) = candidate.source {
- if let ty::ImplPolarity::Reservation = self.tcx.impl_polarity(def_id) {
+ if let ty::ImplPolarity::Reservation = self.tcx().impl_polarity(def_id) {
debug!("Selected reservation impl");
// FIXME: reduce candidate to ambiguous
// FIXME: replace `var_values` with identity, yeet external constraints.
projects / rust.git / blobdiff