diff options
Diffstat (limited to 'compiler/rustc_trait_selection/src/traits/fulfill.rs')
| -rw-r--r-- | compiler/rustc_trait_selection/src/traits/fulfill.rs | 72 |
1 files changed, 51 insertions, 21 deletions
diff --git a/compiler/rustc_trait_selection/src/traits/fulfill.rs b/compiler/rustc_trait_selection/src/traits/fulfill.rs index 944436ab8..26cadab3e 100644 --- a/compiler/rustc_trait_selection/src/traits/fulfill.rs +++ b/compiler/rustc_trait_selection/src/traits/fulfill.rs @@ -2,6 +2,7 @@ use crate::infer::{InferCtxt, TyOrConstInferVar}; use rustc_data_structures::obligation_forest::ProcessResult; use rustc_data_structures::obligation_forest::{Error, ForestObligation, Outcome}; use rustc_data_structures::obligation_forest::{ObligationForest, ObligationProcessor}; +use rustc_infer::infer::DefineOpaqueTypes; use rustc_infer::traits::ProjectionCacheKey; use rustc_infer::traits::{SelectionError, TraitEngine, TraitObligation}; use rustc_middle::mir::interpret::ErrorHandled; @@ -132,8 +133,15 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentContext<'tcx> { .register_obligation(PendingPredicateObligation { obligation, stalled_on: vec![] }); } - fn collect_remaining_errors(&mut self) -> Vec<FulfillmentError<'tcx>> { - self.predicates.to_errors(CodeAmbiguity).into_iter().map(to_fulfillment_error).collect() + fn collect_remaining_errors( + &mut self, + _infcx: &InferCtxt<'tcx>, + ) -> Vec<FulfillmentError<'tcx>> { + self.predicates + .to_errors(CodeAmbiguity { overflow: false }) + .into_iter() + .map(to_fulfillment_error) + .collect() } fn select_where_possible(&mut self, infcx: &InferCtxt<'tcx>) -> Vec<FulfillmentError<'tcx>> { @@ -210,6 +218,29 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { type Error = FulfillmentErrorCode<'tcx>; type OUT = Outcome<Self::Obligation, Self::Error>; + /// Compared to `needs_process_obligation` this and its callees + /// contain some optimizations that come at the price of false negatives. + /// + /// They + /// - reduce branching by covering only the most common case + /// - take a read-only view of the unification tables which allows skipping undo_log + /// construction. + /// - bail out on value-cache misses in ena to avoid pointer chasing + /// - hoist RefCell locking out of the loop + #[inline] + fn skippable_obligations<'b>( + &'b self, + it: impl Iterator<Item = &'b Self::Obligation>, + ) -> usize { + let is_unchanged = self.selcx.infcx.is_ty_infer_var_definitely_unchanged(); + + it.take_while(|o| match o.stalled_on.as_slice() { + [o] => is_unchanged(*o), + _ => false, + }) + .count() + } + /// Identifies whether a predicate obligation needs processing. /// /// This is always inlined because it has a single callsite and it is @@ -337,8 +368,8 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { ty::PredicateKind::TypeWellFormedFromEnv(..) => { bug!("TypeWellFormedFromEnv is only used for Chalk") } - ty::PredicateKind::AliasEq(..) => { - bug!("AliasEq is only used for new solver") + ty::PredicateKind::AliasRelate(..) => { + bug!("AliasRelate is only used for new solver") } }, Some(pred) => match pred { @@ -515,7 +546,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { if let Ok(new_obligations) = infcx .at(&obligation.cause, obligation.param_env) .trace(c1, c2) - .eq(a.substs, b.substs) + .eq(DefineOpaqueTypes::No, a.substs, b.substs) { return ProcessResult::Changed(mk_pending( new_obligations.into_obligations(), @@ -524,8 +555,9 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { } (_, Unevaluated(_)) | (Unevaluated(_), _) => (), (_, _) => { - if let Ok(new_obligations) = - infcx.at(&obligation.cause, obligation.param_env).eq(c1, c2) + if let Ok(new_obligations) = infcx + .at(&obligation.cause, obligation.param_env) + .eq(DefineOpaqueTypes::No, c1, c2) { return ProcessResult::Changed(mk_pending( new_obligations.into_obligations(), @@ -565,12 +597,11 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { match (evaluate(c1), evaluate(c2)) { (Ok(c1), Ok(c2)) => { - match self - .selcx - .infcx - .at(&obligation.cause, obligation.param_env) - .eq(c1, c2) - { + match self.selcx.infcx.at(&obligation.cause, obligation.param_env).eq( + DefineOpaqueTypes::No, + c1, + c2, + ) { Ok(inf_ok) => { ProcessResult::Changed(mk_pending(inf_ok.into_obligations())) } @@ -606,16 +637,15 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { ty::PredicateKind::TypeWellFormedFromEnv(..) => { bug!("TypeWellFormedFromEnv is only used for Chalk") } - ty::PredicateKind::AliasEq(..) => { - bug!("AliasEq is only used for new solver") + ty::PredicateKind::AliasRelate(..) => { + bug!("AliasRelate is only used for new solver") } ty::PredicateKind::Clause(ty::Clause::ConstArgHasType(ct, ty)) => { - match self - .selcx - .infcx - .at(&obligation.cause, obligation.param_env) - .eq(ct.ty(), ty) - { + match self.selcx.infcx.at(&obligation.cause, obligation.param_env).eq( + DefineOpaqueTypes::No, + ct.ty(), + ty, + ) { Ok(inf_ok) => ProcessResult::Changed(mk_pending(inf_ok.into_obligations())), Err(_) => ProcessResult::Error(FulfillmentErrorCode::CodeSelectionError( SelectionError::Unimplemented, |