}
impl<'tcx> CanonicalVarValues<'tcx> {
+ /// Creates dummy var values which should not be used in a
+ /// canonical response.
+ pub fn dummy() -> CanonicalVarValues<'tcx> {
+ CanonicalVarValues { var_values: Default::default() }
+ }
+
#[inline]
pub fn len(&self) -> usize {
self.var_values.len()
///
/// It consists of both the `source`, which describes how that goal would be proven,
/// and the `result` when using the given `source`.
-///
-/// For the list of possible candidates, please look at the documentation of
-/// [super::trait_goals::CandidateSource] and [super::project_goals::CandidateSource].
#[derive(Debug, Clone)]
-pub(super) struct Candidate<'tcx, G: GoalKind<'tcx>> {
- pub(super) source: G::CandidateSource,
+pub(super) struct Candidate<'tcx> {
+ pub(super) source: CandidateSource,
pub(super) result: CanonicalResponse<'tcx>,
}
-pub(super) trait GoalKind<'tcx>: TypeFoldable<'tcx> + Copy {
- type CandidateSource: Debug + Copy;
+/// Possible ways the given goal can be proven.
+#[derive(Debug, Clone, Copy)]
+pub(super) enum CandidateSource {
+ /// A user written impl.
+ ///
+ /// ## Examples
+ ///
+ /// ```rust
+ /// fn main() {
+ /// let x: Vec<u32> = Vec::new();
+ /// // This uses the impl from the standard library to prove `Vec<T>: Clone`.
+ /// let y = x.clone();
+ /// }
+ /// ```
+ Impl(DefId),
+ /// A builtin impl generated by the compiler. When adding a new special
+ /// trait, try to use actual impls whenever possible. Builtin impls should
+ /// only be used in cases where the impl cannot be manually be written.
+ ///
+ /// Notable examples are auto traits, `Sized`, and `DiscriminantKind`.
+ /// For a list of all traits with builtin impls, check out the
+ /// [`EvalCtxt::assemble_builtin_impl_candidates`] method. Not
+ BuiltinImpl,
+ /// An assumption from the environment.
+ ///
+ /// More precicely we've used the `n-th` assumption in the `param_env`.
+ ///
+ /// ## Examples
+ ///
+ /// ```rust
+ /// fn is_clone<T: Clone>(x: T) -> (T, T) {
+ /// // This uses the assumption `T: Clone` from the `where`-bounds
+ /// // to prove `T: Clone`.
+ /// (x.clone(), x)
+ /// }
+ /// ```
+ ParamEnv(usize),
+ /// If the self type is an alias type, e.g. an opaque type or a projection,
+ /// we know the bounds on that alias to hold even without knowing its concrete
+ /// underlying type.
+ ///
+ /// More precisely this candidate is using the `n-th` bound in the `item_bounds` of
+ /// the self type.
+ ///
+ /// ## Examples
+ ///
+ /// ```rust
+ /// trait Trait {
+ /// type Assoc: Clone;
+ /// }
+ ///
+ /// fn foo<T: Trait>(x: <T as Trait>::Assoc) {
+ /// // We prove `<T as Trait>::Assoc` by looking at the bounds on `Assoc` in
+ /// // in the trait definition.
+ /// let _y = x.clone();
+ /// }
+ /// ```
+ AliasBound(usize),
+}
+pub(super) trait GoalKind<'tcx>: TypeFoldable<'tcx> + Copy {
fn self_ty(self) -> Ty<'tcx>;
fn with_self_ty(self, tcx: TyCtxt<'tcx>, self_ty: Ty<'tcx>) -> Self;
fn trait_def_id(self, tcx: TyCtxt<'tcx>) -> DefId;
fn consider_impl_candidate(
- acx: &mut AssemblyCtxt<'_, '_, 'tcx, Self>,
+ ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, Self>,
impl_def_id: DefId,
- );
-}
+ ) -> Result<Certainty, NoSolution>;
-/// An abstraction which correctly deals with the canonical results for candidates.
-///
-/// It also deduplicates the behavior between trait and projection predicates.
-pub(super) struct AssemblyCtxt<'a, 'b, 'tcx, G: GoalKind<'tcx>> {
- pub(super) cx: &'a mut EvalCtxt<'b, 'tcx>,
- candidates: Vec<Candidate<'tcx, G>>,
-}
+ fn consider_builtin_sized_candidate(
+ ecx: &mut EvalCtxt<'_, 'tcx>,
+ goal: Goal<'tcx, Self>,
+ ) -> Result<Certainty, NoSolution>;
-impl<'a, 'b, 'tcx, G: GoalKind<'tcx>> AssemblyCtxt<'a, 'b, 'tcx, G> {
- pub(super) fn assemble_and_evaluate_candidates(
- cx: &'a mut EvalCtxt<'b, 'tcx>,
+ fn consider_assumption(
+ ecx: &mut EvalCtxt<'_, 'tcx>,
+ goal: Goal<'tcx, Self>,
+ assumption: ty::Predicate<'tcx>,
+ ) -> Result<Certainty, NoSolution>;
+}
+impl<'tcx> EvalCtxt<'_, 'tcx> {
+ pub(super) fn assemble_and_evaluate_candidates<G: GoalKind<'tcx>>(
+ &mut self,
goal: Goal<'tcx, G>,
- ) -> Vec<Candidate<'tcx, G>> {
- let mut acx = AssemblyCtxt { cx, candidates: Vec::new() };
+ ) -> Vec<Candidate<'tcx>> {
+ let mut candidates = Vec::new();
- acx.assemble_candidates_after_normalizing_self_ty(goal);
+ self.assemble_candidates_after_normalizing_self_ty(goal, &mut candidates);
- acx.assemble_impl_candidates(goal);
+ self.assemble_impl_candidates(goal, &mut candidates);
- acx.candidates
- }
+ self.assemble_builtin_impl_candidates(goal, &mut candidates);
- pub(super) fn try_insert_candidate(
- &mut self,
- source: G::CandidateSource,
- certainty: Certainty,
- ) {
- match self.cx.make_canonical_response(certainty) {
- Ok(result) => self.candidates.push(Candidate { source, result }),
- Err(NoSolution) => debug!(?source, ?certainty, "failed leakcheck"),
- }
+ self.assemble_param_env_candidates(goal, &mut candidates);
+
+ self.assemble_alias_bound_candidates(goal, &mut candidates);
+
+ candidates
}
/// If the self type of a goal is a projection, computing the relevant candidates is difficult.
/// To deal with this, we first try to normalize the self type and add the candidates for the normalized
/// self type to the list of candidates in case that succeeds. Note that we can't just eagerly return in
/// this case as projections as self types add `
- fn assemble_candidates_after_normalizing_self_ty(&mut self, goal: Goal<'tcx, G>) {
- let tcx = self.cx.tcx();
- let infcx = self.cx.infcx;
+ fn assemble_candidates_after_normalizing_self_ty<G: GoalKind<'tcx>>(
+ &mut self,
+ goal: Goal<'tcx, G>,
+ candidates: &mut Vec<Candidate<'tcx>>,
+ ) {
+ let tcx = self.tcx();
// FIXME: We also have to normalize opaque types, not sure where to best fit that in.
let &ty::Alias(ty::Projection, projection_ty) = goal.predicate.self_ty().kind() else {
return
};
- infcx.probe(|_| {
- let normalized_ty = infcx.next_ty_infer();
+ self.infcx.probe(|_| {
+ let normalized_ty = self.infcx.next_ty_infer();
let normalizes_to_goal = goal.with(
tcx,
ty::Binder::dummy(ty::ProjectionPredicate {
term: normalized_ty.into(),
}),
);
- let normalization_certainty = match self.cx.evaluate_goal(normalizes_to_goal) {
+ let normalization_certainty = match self.evaluate_goal(normalizes_to_goal) {
Ok((_, certainty)) => certainty,
Err(NoSolution) => return,
};
// NOTE: Alternatively we could call `evaluate_goal` here and only have a `Normalized` candidate.
- // This doesn't work as long as we use `CandidateSource` in both winnowing and to resolve associated items.
+ // This doesn't work as long as we use `CandidateSource` in winnowing.
let goal = goal.with(tcx, goal.predicate.with_self_ty(tcx, normalized_ty));
- let normalized_candidates =
- AssemblyCtxt::assemble_and_evaluate_candidates(self.cx, goal);
+ // FIXME: This is broken if we care about the `usize` of `AliasBound` because the self type
+ // could be normalized to yet another projection with different item bounds.
+ let normalized_candidates = self.assemble_and_evaluate_candidates(goal);
for mut normalized_candidate in normalized_candidates {
normalized_candidate.result =
normalized_candidate.result.unchecked_map(|mut response| {
+ // FIXME: This currently hides overflow in the normalization step of the self type
+ // which is probably wrong. Maybe `unify_and` should actually keep overflow as
+ // we treat it as non-fatal anyways.
response.certainty = response.certainty.unify_and(normalization_certainty);
response
});
- self.candidates.push(normalized_candidate);
+ candidates.push(normalized_candidate);
}
})
}
- fn assemble_impl_candidates(&mut self, goal: Goal<'tcx, G>) {
- let tcx = self.cx.tcx();
+ fn assemble_impl_candidates<G: GoalKind<'tcx>>(
+ &mut self,
+ goal: Goal<'tcx, G>,
+ candidates: &mut Vec<Candidate<'tcx>>,
+ ) {
+ let tcx = self.tcx();
tcx.for_each_relevant_impl(
goal.predicate.trait_def_id(tcx),
goal.predicate.self_ty(),
- |impl_def_id| G::consider_impl_candidate(self, goal, impl_def_id),
+ |impl_def_id| match G::consider_impl_candidate(self, goal, impl_def_id)
+ .and_then(|certainty| self.make_canonical_response(certainty))
+ {
+ Ok(result) => candidates
+ .push(Candidate { source: CandidateSource::Impl(impl_def_id), result }),
+ Err(NoSolution) => (),
+ },
);
}
+
+ fn assemble_builtin_impl_candidates<G: GoalKind<'tcx>>(
+ &mut self,
+ goal: Goal<'tcx, G>,
+ candidates: &mut Vec<Candidate<'tcx>>,
+ ) {
+ let lang_items = self.tcx().lang_items();
+ let trait_def_id = goal.predicate.trait_def_id(self.tcx());
+ let result = if lang_items.sized_trait() == Some(trait_def_id) {
+ G::consider_builtin_sized_candidate(self, goal)
+ } else {
+ Err(NoSolution)
+ };
+
+ match result.and_then(|certainty| self.make_canonical_response(certainty)) {
+ Ok(result) => {
+ candidates.push(Candidate { source: CandidateSource::BuiltinImpl, result })
+ }
+ Err(NoSolution) => (),
+ }
+ }
+
+ fn assemble_param_env_candidates<G: GoalKind<'tcx>>(
+ &mut self,
+ goal: Goal<'tcx, G>,
+ candidates: &mut Vec<Candidate<'tcx>>,
+ ) {
+ for (i, assumption) in goal.param_env.caller_bounds().iter().enumerate() {
+ match G::consider_assumption(self, goal, assumption)
+ .and_then(|certainty| self.make_canonical_response(certainty))
+ {
+ Ok(result) => {
+ candidates.push(Candidate { source: CandidateSource::ParamEnv(i), result })
+ }
+ Err(NoSolution) => (),
+ }
+ }
+ }
+
+ fn assemble_alias_bound_candidates<G: GoalKind<'tcx>>(
+ &mut self,
+ goal: Goal<'tcx, G>,
+ candidates: &mut Vec<Candidate<'tcx>>,
+ ) {
+ let alias_ty = match goal.predicate.self_ty().kind() {
+ ty::Bool
+ | ty::Char
+ | ty::Int(_)
+ | ty::Uint(_)
+ | ty::Float(_)
+ | ty::Adt(_, _)
+ | ty::Foreign(_)
+ | ty::Str
+ | ty::Array(_, _)
+ | ty::Slice(_)
+ | ty::RawPtr(_)
+ | ty::Ref(_, _, _)
+ | ty::FnDef(_, _)
+ | ty::FnPtr(_)
+ | ty::Dynamic(..)
+ | ty::Closure(..)
+ | ty::Generator(..)
+ | ty::GeneratorWitness(_)
+ | ty::Never
+ | ty::Tuple(_)
+ | ty::Param(_)
+ | ty::Placeholder(..)
+ | ty::Infer(_)
+ | ty::Error(_) => return,
+ ty::Bound(..) => bug!("unexpected bound type: {goal:?}"),
+ ty::Alias(_, alias_ty) => alias_ty,
+ };
+
+ for (i, (assumption, _)) in self
+ .tcx()
+ .bound_explicit_item_bounds(alias_ty.def_id)
+ .subst_iter_copied(self.tcx(), alias_ty.substs)
+ .enumerate()
+ {
+ match G::consider_assumption(self, goal, assumption)
+ .and_then(|certainty| self.make_canonical_response(certainty))
+ {
+ Ok(result) => {
+ candidates.push(Candidate { source: CandidateSource::AliasBound(i), result })
+ }
+ Err(NoSolution) => (),
+ }
+ }
+ }
}
use rustc_data_structures::fx::FxHashMap;
use rustc_infer::{
- infer::{canonical::OriginalQueryValues, InferCtxt},
+ infer::InferCtxt,
traits::{
query::NoSolution, FulfillmentError, FulfillmentErrorCode, PredicateObligation,
SelectionError, TraitEngine,
};
use rustc_middle::ty;
-use super::{Certainty, EvalCtxt};
+use super::{search_graph, Certainty, EvalCtxt};
/// A trait engine using the new trait solver.
///
let mut has_changed = false;
for obligation in mem::take(&mut self.obligations) {
let goal = obligation.clone().into();
-
- // FIXME: Add a better API for that '^^
- let mut orig_values = OriginalQueryValues::default();
- let canonical_goal = infcx.canonicalize_query(goal, &mut orig_values);
- let (changed, certainty) = match EvalCtxt::evaluate_canonical_goal(
- infcx.tcx,
- &mut super::search_graph::SearchGraph::new(infcx.tcx),
- canonical_goal,
- ) {
- Ok(canonical_response) => {
- (
- true, // FIXME: check whether `var_values` are an identity substitution.
- super::instantiate_canonical_query_response(
- infcx,
- &orig_values,
- canonical_response,
- ),
- )
- }
+ let search_graph = &mut search_graph::SearchGraph::new(infcx.tcx);
+ let mut ecx = EvalCtxt::new_outside_solver(infcx, search_graph);
+ let (changed, certainty) = match ecx.evaluate_goal(goal) {
+ Ok(result) => result,
Err(NoSolution) => {
errors.push(FulfillmentError {
obligation: obligation.clone(),
}
impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
+ fn tcx(&self) -> TyCtxt<'tcx> {
+ self.infcx.tcx
+ }
+
+ /// Creates a new evaluation context outside of the trait solver.
+ ///
+ /// With this solver making a canonical response doesn't make much sense.
+ /// The `search_graph` for this solver has to be completely empty.
+ fn new_outside_solver(
+ infcx: &'a InferCtxt<'tcx>,
+ search_graph: &'a mut search_graph::SearchGraph<'tcx>,
+ ) -> EvalCtxt<'a, 'tcx> {
+ assert!(search_graph.is_empty());
+ EvalCtxt { infcx, var_values: CanonicalVarValues::dummy(), search_graph }
+ }
+
+ #[instrument(level = "debug", skip(tcx, search_graph), ret)]
fn evaluate_canonical_goal(
tcx: TyCtxt<'tcx>,
search_graph: &'a mut search_graph::SearchGraph<'tcx>,
}
}
- fn tcx(&self) -> TyCtxt<'tcx> {
- self.infcx.tcx
- }
-
fn make_canonical_response(&self, certainty: Certainty) -> QueryResult<'tcx> {
let external_constraints = take_external_constraints(self.infcx)?;
use crate::traits::{specialization_graph, translate_substs};
-use super::assembly::{self, AssemblyCtxt};
-use super::{EvalCtxt, Goal, QueryResult};
+use super::assembly::{self, Candidate, CandidateSource};
+use super::{Certainty, EvalCtxt, Goal, QueryResult};
use rustc_errors::ErrorGuaranteed;
use rustc_hir::def::DefKind;
use rustc_hir::def_id::DefId;
use rustc_span::DUMMY_SP;
use std::iter;
-#[allow(dead_code)] // FIXME: implement and use all variants.
-#[derive(Debug, Clone, Copy)]
-pub(super) enum CandidateSource {
- Impl(DefId),
- ParamEnv(usize),
- Builtin,
-}
-
-type Candidate<'tcx> = assembly::Candidate<'tcx, ProjectionPredicate<'tcx>>;
-
impl<'tcx> EvalCtxt<'_, 'tcx> {
pub(super) fn compute_projection_goal(
&mut self,
goal: Goal<'tcx, ProjectionPredicate<'tcx>>,
) -> QueryResult<'tcx> {
- let candidates = AssemblyCtxt::assemble_and_evaluate_candidates(self, goal);
+ let candidates = self.assemble_and_evaluate_candidates(goal);
self.merge_project_candidates(candidates)
}
match (candidate.source, other.source) {
(CandidateSource::Impl(_), _)
| (CandidateSource::ParamEnv(_), _)
- | (CandidateSource::Builtin, _) => unimplemented!(),
+ | (CandidateSource::BuiltinImpl, _)
+ | (CandidateSource::AliasBound(_), _) => unimplemented!(),
}
}
}
impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> {
- type CandidateSource = CandidateSource;
-
fn self_ty(self) -> Ty<'tcx> {
self.self_ty()
}
}
fn consider_impl_candidate(
- acx: &mut AssemblyCtxt<'_, '_, 'tcx, ProjectionPredicate<'tcx>>,
+ ecx: &mut EvalCtxt<'_, 'tcx>,
goal: Goal<'tcx, ProjectionPredicate<'tcx>>,
impl_def_id: DefId,
- ) {
- let tcx = acx.cx.tcx();
- let infcx = acx.cx.infcx;
+ ) -> Result<Certainty, NoSolution> {
+ let tcx = ecx.tcx();
let goal_trait_ref = goal.predicate.projection_ty.trait_ref(tcx);
let impl_trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap();
if iter::zip(goal_trait_ref.substs, impl_trait_ref.skip_binder().substs)
.any(|(goal, imp)| !drcx.generic_args_may_unify(goal, imp))
{
- return;
+ return Err(NoSolution);
}
- infcx.probe(|_| {
- let impl_substs = 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, .. }) = infcx
+ let Ok(InferOk { obligations, .. }) = ecx.infcx
.at(&ObligationCause::dummy(), goal.param_env)
.define_opaque_types(false)
.eq(goal_trait_ref, impl_trait_ref)
.map_err(|e| debug!("failed to equate trait refs: {e:?}"))
else {
- return
+ return Err(NoSolution)
};
let where_clause_bounds = tcx
.predicates_of(impl_def_id)
let nested_goals =
obligations.into_iter().map(|o| o.into()).chain(where_clause_bounds).collect();
- let Ok(trait_ref_certainty) = acx.cx.evaluate_all(nested_goals) else { return };
+ let trait_ref_certainty = ecx.evaluate_all(nested_goals)?;
let Some(assoc_def) = fetch_eligible_assoc_item_def(
- infcx,
+ ecx.infcx,
goal.param_env,
goal_trait_ref,
goal.predicate.def_id(),
impl_def_id
) else {
- return
+ return Err(NoSolution);
};
if !assoc_def.item.defaultness(tcx).has_value() {
impl_substs,
);
let substs = translate_substs(
- infcx,
+ ecx.infcx,
goal.param_env,
impl_def_id,
impl_substs_with_gat,
ty.map_bound(|ty| ty.into())
};
- let Ok(InferOk { obligations, .. }) = infcx
+ let Ok(InferOk { obligations, .. }) = ecx.infcx
.at(&ObligationCause::dummy(), goal.param_env)
.define_opaque_types(false)
.eq(goal.predicate.term, term.subst(tcx, substs))
.map_err(|e| debug!("failed to equate trait refs: {e:?}"))
else {
- return
+ return Err(NoSolution);
};
let nested_goals = obligations.into_iter().map(|o| o.into()).collect();
- let Ok(rhs_certainty) = acx.cx.evaluate_all(nested_goals) else { return };
+ let rhs_certainty = ecx.evaluate_all(nested_goals)?;
- let certainty = trait_ref_certainty.unify_and(rhs_certainty);
- acx.try_insert_candidate(CandidateSource::Impl(impl_def_id), certainty);
+ Ok(trait_ref_certainty.unify_and(rhs_certainty))
})
}
+
+ fn consider_builtin_sized_candidate(
+ _ecx: &mut EvalCtxt<'_, 'tcx>,
+ goal: Goal<'tcx, Self>,
+ ) -> Result<Certainty, NoSolution> {
+ bug!("`Sized` does not have an associated type: {:?}", goal);
+ }
+
+ fn consider_assumption(
+ _ecx: &mut EvalCtxt<'_, 'tcx>,
+ _goal: Goal<'tcx, Self>,
+ assumption: ty::Predicate<'tcx>,
+ ) -> Result<Certainty, NoSolution> {
+ if let Some(_poly_projection_pred) = assumption.to_opt_poly_projection_pred() {
+ unimplemented!()
+ } else {
+ Err(NoSolution)
+ }
+ }
}
/// This behavior is also implemented in `rustc_ty_utils` and in the old `project` code.
ProvisionalCache { entries: Default::default(), lookup_table: Default::default() }
}
+ pub(super) fn is_empty(&self) -> bool {
+ self.entries.is_empty() && self.lookup_table.is_empty()
+ }
+
/// Adds a dependency from the current leaf to `target` in the cache
/// to prevent us from moving any goals which depend on the current leaf
/// to the global cache while we're still computing `target`.
}
}
+ pub(super) fn is_empty(&self) -> bool {
+ self.stack.is_empty()
+ && self.provisional_cache.is_empty()
+ && !self.overflow_data.did_overflow()
+ }
+
/// Tries putting the new goal on the stack, returning an error if it is already cached.
///
/// This correctly updates the provisional cache if there is a cycle.
use std::iter;
-use super::assembly::{self, AssemblyCtxt};
-use super::{EvalCtxt, Goal, QueryResult};
+use super::assembly::{self, Candidate, CandidateSource};
+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_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();
- let infcx = acx.cx.infcx;
+ ) -> 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);
}
- infcx.probe(|_| {
- let impl_substs = 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, .. }) = infcx
+ let Ok(InferOk { obligations, .. }) = ecx.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
+ return Err(NoSolution);
};
let where_clause_bounds = tcx
.predicates_of(impl_def_id)
let nested_goals =
obligations.into_iter().map(|o| o.into()).chain(where_clause_bounds).collect();
- let Ok(certainty) = acx.cx.evaluate_all(nested_goals) else { return };
- acx.try_insert_candidate(CandidateSource::Impl(impl_def_id), certainty);
+ ecx.evaluate_all(nested_goals)
})
}
+
+ fn consider_builtin_sized_candidate(
+ _ecx: &mut EvalCtxt<'_, 'tcx>,
+ _goal: Goal<'tcx, Self>,
+ ) -> Result<Certainty, NoSolution> {
+ unimplemented!();
+ }
+
+ 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> {
&mut self,
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!(),
}
}
projects / rust.git / commitdiff