use rustc_hir as hir;
use rustc_hir::def_id::DefId;
use rustc_infer::infer::LateBoundRegionConversionTime;
+use rustc_infer::traits::TraitEngine;
+use rustc_infer::traits::TraitEngineExt;
use rustc_middle::dep_graph::{DepKind, DepNodeIndex};
use rustc_middle::mir::interpret::ErrorHandled;
use rustc_middle::ty::abstract_const::NotConstEvaluatable;
use rustc_middle::ty::SubstsRef;
use rustc_middle::ty::{self, EarlyBinder, PolyProjectionPredicate, ToPolyTraitRef, ToPredicate};
use rustc_middle::ty::{Ty, TyCtxt, TypeFoldable, TypeVisitable};
+use rustc_session::config::TraitSolver;
use rustc_span::symbol::sym;
use std::cell::{Cell, RefCell};
// impl<T:Clone> Vec<T> { fn push_clone(...) { ... } }
//
// and we were to see some code `foo.push_clone()` where `boo`
- // is a `Vec<Bar>` and `Bar` does not implement `Clone`. If
+ // is a `Vec<Bar>` and `Bar` does not implement `Clone`. If
// we were to winnow, we'd wind up with zero candidates.
// Instead, we select the right impl now but report "`Bar` does
// not implement `Clone`".
obligation: &PredicateObligation<'tcx>,
) -> Result<EvaluationResult, OverflowError> {
self.evaluation_probe(|this| {
- this.evaluate_predicate_recursively(
- TraitObligationStackList::empty(&ProvisionalEvaluationCache::default()),
- obligation.clone(),
- )
+ if this.tcx().sess.opts.unstable_opts.trait_solver != TraitSolver::Next {
+ this.evaluate_predicate_recursively(
+ TraitObligationStackList::empty(&ProvisionalEvaluationCache::default()),
+ obligation.clone(),
+ )
+ } else {
+ this.evaluate_predicates_recursively_in_new_solver([obligation.clone()])
+ }
})
}
where
I: IntoIterator<Item = PredicateObligation<'tcx>> + std::fmt::Debug,
{
- let mut result = EvaluatedToOk;
- for obligation in predicates {
- let eval = self.evaluate_predicate_recursively(stack, obligation.clone())?;
- if let EvaluatedToErr = eval {
- // fast-path - EvaluatedToErr is the top of the lattice,
- // so we don't need to look on the other predicates.
- return Ok(EvaluatedToErr);
- } else {
- result = cmp::max(result, eval);
+ if self.tcx().sess.opts.unstable_opts.trait_solver != TraitSolver::Next {
+ let mut result = EvaluatedToOk;
+ for obligation in predicates {
+ let eval = self.evaluate_predicate_recursively(stack, obligation.clone())?;
+ if let EvaluatedToErr = eval {
+ // fast-path - EvaluatedToErr is the top of the lattice,
+ // so we don't need to look on the other predicates.
+ return Ok(EvaluatedToErr);
+ } else {
+ result = cmp::max(result, eval);
+ }
}
+ Ok(result)
+ } else {
+ self.evaluate_predicates_recursively_in_new_solver(predicates)
}
- Ok(result)
+ }
+
+ /// Evaluates the predicates using the new solver when `-Ztrait-solver=next` is enabled
+ fn evaluate_predicates_recursively_in_new_solver(
+ &mut self,
+ predicates: impl IntoIterator<Item = PredicateObligation<'tcx>>,
+ ) -> Result<EvaluationResult, OverflowError> {
+ let mut fulfill_cx = crate::solve::FulfillmentCtxt::new();
+ fulfill_cx.register_predicate_obligations(self.infcx, predicates);
+ // True errors
+ if !fulfill_cx.select_where_possible(self.infcx).is_empty() {
+ return Ok(EvaluatedToErr);
+ }
+ if !fulfill_cx.select_all_or_error(self.infcx).is_empty() {
+ return Ok(EvaluatedToAmbig);
+ }
+ // Regions and opaques are handled in the `evaluation_probe` by looking at the snapshot
+ Ok(EvaluatedToOk)
}
#[instrument(
}
ty::PredicateKind::ObjectSafe(trait_def_id) => {
- if self.tcx().is_object_safe(trait_def_id) {
+ if self.tcx().check_is_object_safe(trait_def_id) {
Ok(EvaluatedToOk)
} else {
Ok(EvaluatedToErr)
);
}
};
- let bounds = tcx.bound_item_bounds(def_id).subst(tcx, substs);
+ let bounds = tcx.item_bounds(def_id).subst(tcx, substs);
// The bounds returned by `item_bounds` may contain duplicates after
// normalization, so try to deduplicate when possible to avoid
| ty::Ref(..)
| ty::Generator(..)
| ty::GeneratorWitness(..)
+ | ty::GeneratorWitnessMIR(..)
| ty::Array(..)
| ty::Closure(..)
| ty::Never
Where(ty::Binder::bind_with_vars(witness_tys.to_vec(), all_vars))
}
+ ty::GeneratorWitnessMIR(def_id, ref substs) => {
+ let hidden_types = bind_generator_hidden_types_above(
+ self.infcx,
+ def_id,
+ substs,
+ obligation.predicate.bound_vars(),
+ );
+ Where(hidden_types)
+ }
+
ty::Closure(_, substs) => {
// (*) binder moved here
let ty = self.infcx.shallow_resolve(substs.as_closure().tupled_upvars_ty());
types.map_bound(|types| types.to_vec())
}
+ ty::GeneratorWitnessMIR(def_id, ref substs) => {
+ bind_generator_hidden_types_above(self.infcx, def_id, substs, t.bound_vars())
+ }
+
// For `PhantomData<T>`, we pass `T`.
ty::Adt(def, substs) if def.is_phantom_data() => t.rebind(substs.types().collect()),
// Matching
//
// Matching is a common path used for both evaluation and
- // confirmation. It basically unifies types that appear in impls
+ // confirmation. It basically unifies types that appear in impls
// and traits. This does affect the surrounding environment;
// therefore, when used during evaluation, match routines must be
// run inside of a `probe()` so that their side-effects are
/// In Issue #60010, we found a bug in rustc where it would cache
/// these intermediate results. This was fixed in #60444 by disabling
/// *all* caching for things involved in a cycle -- in our example,
-/// that would mean we don't cache that `Bar<T>: Send`. But this led
+/// that would mean we don't cache that `Bar<T>: Send`. But this led
/// to large slowdowns.
///
/// Specifically, imagine this scenario, where proving `Baz<T>: Send`
/// a result at `reached_depth`, so it marks the *current* solution as
/// provisional as well. If an error is encountered, we toss out any
/// provisional results added from the subtree that encountered the
-/// error. When we pop the node at `reached_depth` from the stack, we
+/// error. When we pop the node at `reached_depth` from the stack, we
/// can commit all the things that remain in the provisional cache.
struct ProvisionalEvaluationCache<'tcx> {
/// next "depth first number" to issue -- just a counter
}
/// Invoked when the node with dfn `dfn` does not get a successful
- /// result. This will clear out any provisional cache entries
+ /// result. This will clear out any provisional cache entries
/// that were added since `dfn` was created. This is because the
/// provisional entries are things which must assume that the
/// things on the stack at the time of their creation succeeded --
Ambiguous,
No,
}
+
+/// Replace all regions inside the generator interior with late bound regions.
+/// Note that each region slot in the types gets a new fresh late bound region, which means that
+/// none of the regions inside relate to any other, even if typeck had previously found constraints
+/// that would cause them to be related.
+#[instrument(level = "trace", skip(infcx), ret)]
+fn bind_generator_hidden_types_above<'tcx>(
+ infcx: &InferCtxt<'tcx>,
+ def_id: DefId,
+ substs: ty::SubstsRef<'tcx>,
+ bound_vars: &ty::List<ty::BoundVariableKind>,
+) -> ty::Binder<'tcx, Vec<Ty<'tcx>>> {
+ let tcx = infcx.tcx;
+ let mut seen_tys = FxHashSet::default();
+
+ let considering_regions = infcx.considering_regions;
+
+ let num_bound_variables = bound_vars.len() as u32;
+ let mut counter = num_bound_variables;
+
+ let hidden_types: Vec<_> = tcx
+ .generator_hidden_types(def_id)
+ // Deduplicate tys to avoid repeated work.
+ .filter(|bty| seen_tys.insert(*bty))
+ .map(|bty| {
+ let mut ty = bty.subst(tcx, substs);
+
+ // Only remap erased regions if we use them.
+ if considering_regions {
+ ty = tcx.fold_regions(ty, |mut r, current_depth| {
+ if let ty::ReErased = r.kind() {
+ let br = ty::BoundRegion {
+ var: ty::BoundVar::from_u32(counter),
+ kind: ty::BrAnon(counter, None),
+ };
+ counter += 1;
+ r = tcx.mk_region(ty::ReLateBound(current_depth, br));
+ }
+ r
+ })
+ }
+
+ ty
+ })
+ .collect();
+ if considering_regions {
+ debug_assert!(!hidden_types.has_erased_regions());
+ }
+ let bound_vars = tcx.mk_bound_variable_kinds(bound_vars.iter().chain(
+ (num_bound_variables..counter).map(|i| ty::BoundVariableKind::Region(ty::BrAnon(i, None))),
+ ));
+ ty::Binder::bind_with_vars(hidden_types, bound_vars)
+}
projects / rust.git / blobdiff