diff options
Diffstat (limited to 'compiler/rustc_trait_selection/src/traits/fulfill.rs')
| -rw-r--r-- | compiler/rustc_trait_selection/src/traits/fulfill.rs | 164 |
1 files changed, 76 insertions, 88 deletions
diff --git a/compiler/rustc_trait_selection/src/traits/fulfill.rs b/compiler/rustc_trait_selection/src/traits/fulfill.rs index a417e1440..76a755ed9 100644 --- a/compiler/rustc_trait_selection/src/traits/fulfill.rs +++ b/compiler/rustc_trait_selection/src/traits/fulfill.rs @@ -4,13 +4,12 @@ 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::traits::ProjectionCacheKey; -use rustc_infer::traits::{SelectionError, TraitEngine, TraitEngineExt as _, TraitObligation}; +use rustc_infer::traits::{SelectionError, TraitEngine, TraitObligation}; use rustc_middle::mir::interpret::ErrorHandled; use rustc_middle::ty::abstract_const::NotConstEvaluatable; use rustc_middle::ty::error::{ExpectedFound, TypeError}; use rustc_middle::ty::subst::SubstsRef; -use rustc_middle::ty::ToPredicate; -use rustc_middle::ty::{self, Binder, Const, Ty, TypeVisitable}; +use rustc_middle::ty::{self, Binder, Const, TypeVisitable}; use std::marker::PhantomData; use super::const_evaluatable; @@ -21,9 +20,9 @@ use super::CodeAmbiguity; use super::CodeProjectionError; use super::CodeSelectionError; use super::EvaluationResult; +use super::PredicateObligation; use super::Unimplemented; use super::{FulfillmentError, FulfillmentErrorCode}; -use super::{ObligationCause, PredicateObligation}; use crate::traits::project::PolyProjectionObligation; use crate::traits::project::ProjectionCacheKeyExt as _; @@ -85,7 +84,7 @@ static_assert_size!(PendingPredicateObligation<'_>, 72); impl<'a, 'tcx> FulfillmentContext<'tcx> { /// Creates a new fulfillment context. - pub fn new() -> FulfillmentContext<'tcx> { + pub(super) fn new() -> FulfillmentContext<'tcx> { FulfillmentContext { predicates: ObligationForest::new(), relationships: FxHashMap::default(), @@ -93,7 +92,7 @@ impl<'a, 'tcx> FulfillmentContext<'tcx> { } } - pub fn new_in_snapshot() -> FulfillmentContext<'tcx> { + pub(super) fn new_in_snapshot() -> FulfillmentContext<'tcx> { FulfillmentContext { predicates: ObligationForest::new(), relationships: FxHashMap::default(), @@ -127,42 +126,6 @@ impl<'a, 'tcx> FulfillmentContext<'tcx> { } impl<'tcx> TraitEngine<'tcx> for FulfillmentContext<'tcx> { - /// "Normalize" a projection type `<SomeType as SomeTrait>::X` by - /// creating a fresh type variable `$0` as well as a projection - /// predicate `<SomeType as SomeTrait>::X == $0`. When the - /// inference engine runs, it will attempt to find an impl of - /// `SomeTrait` or a where-clause that lets us unify `$0` with - /// something concrete. If this fails, we'll unify `$0` with - /// `projection_ty` again. - #[instrument(level = "debug", skip(self, infcx, param_env, cause))] - fn normalize_projection_type( - &mut self, - infcx: &InferCtxt<'tcx>, - param_env: ty::ParamEnv<'tcx>, - projection_ty: ty::ProjectionTy<'tcx>, - cause: ObligationCause<'tcx>, - ) -> Ty<'tcx> { - debug_assert!(!projection_ty.has_escaping_bound_vars()); - - // FIXME(#20304) -- cache - - let mut selcx = SelectionContext::new(infcx); - let mut obligations = vec![]; - let normalized_ty = project::normalize_projection_type( - &mut selcx, - param_env, - projection_ty, - cause, - 0, - &mut obligations, - ); - self.register_predicate_obligations(infcx, obligations); - - debug!(?normalized_ty); - - normalized_ty.ty().unwrap() - } - fn register_predicate_obligation( &mut self, infcx: &InferCtxt<'tcx>, @@ -236,7 +199,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { // code is so hot. 1 and 0 dominate; 2+ is fairly rare. 1 => { let infer_var = pending_obligation.stalled_on[0]; - self.selcx.infcx().ty_or_const_infer_var_changed(infer_var) + self.selcx.infcx.ty_or_const_infer_var_changed(infer_var) } 0 => { // In this case we haven't changed, but wish to make a change. @@ -247,7 +210,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { // form was a perf win. See #64545 for details. (|| { for &infer_var in &pending_obligation.stalled_on { - if self.selcx.infcx().ty_or_const_infer_var_changed(infer_var) { + if self.selcx.infcx.ty_or_const_infer_var_changed(infer_var) { return true; } } @@ -277,13 +240,12 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { debug!(?obligation, "pre-resolve"); if obligation.predicate.has_non_region_infer() { - obligation.predicate = - self.selcx.infcx().resolve_vars_if_possible(obligation.predicate); + obligation.predicate = self.selcx.infcx.resolve_vars_if_possible(obligation.predicate); } let obligation = &pending_obligation.obligation; - let infcx = self.selcx.infcx(); + let infcx = self.selcx.infcx; if obligation.predicate.has_projections() { let mut obligations = Vec::new(); @@ -296,7 +258,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { &mut obligations, ); if predicate != obligation.predicate { - obligations.push(obligation.with(predicate)); + obligations.push(obligation.with(infcx.tcx, predicate)); return ProcessResult::Changed(mk_pending(obligations)); } } @@ -306,8 +268,8 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { // Evaluation will discard candidates using the leak check. // This means we need to pass it the bound version of our // predicate. - ty::PredicateKind::Trait(trait_ref) => { - let trait_obligation = obligation.with(binder.rebind(trait_ref)); + ty::PredicateKind::Clause(ty::Clause::Trait(trait_ref)) => { + let trait_obligation = obligation.with(infcx.tcx, binder.rebind(trait_ref)); self.process_trait_obligation( obligation, @@ -315,8 +277,8 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { &mut pending_obligation.stalled_on, ) } - ty::PredicateKind::Projection(data) => { - let project_obligation = obligation.with(binder.rebind(data)); + ty::PredicateKind::Clause(ty::Clause::Projection(data)) => { + let project_obligation = obligation.with(infcx.tcx, binder.rebind(data)); self.process_projection_obligation( obligation, @@ -324,8 +286,8 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { &mut pending_obligation.stalled_on, ) } - ty::PredicateKind::RegionOutlives(_) - | ty::PredicateKind::TypeOutlives(_) + ty::PredicateKind::Clause(ty::Clause::RegionOutlives(_)) + | ty::PredicateKind::Clause(ty::Clause::TypeOutlives(_)) | ty::PredicateKind::WellFormed(_) | ty::PredicateKind::ObjectSafe(_) | ty::PredicateKind::ClosureKind(..) @@ -335,17 +297,16 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { | ty::PredicateKind::ConstEquate(..) => { let pred = ty::Binder::dummy(infcx.replace_bound_vars_with_placeholders(binder)); - ProcessResult::Changed(mk_pending(vec![ - obligation.with(pred.to_predicate(self.selcx.tcx())), - ])) + ProcessResult::Changed(mk_pending(vec![obligation.with(infcx.tcx, pred)])) } + ty::PredicateKind::Ambiguous => ProcessResult::Unchanged, ty::PredicateKind::TypeWellFormedFromEnv(..) => { bug!("TypeWellFormedFromEnv is only used for Chalk") } }, Some(pred) => match pred { - ty::PredicateKind::Trait(data) => { - let trait_obligation = obligation.with(Binder::dummy(data)); + ty::PredicateKind::Clause(ty::Clause::Trait(data)) => { + let trait_obligation = obligation.with(infcx.tcx, Binder::dummy(data)); self.process_trait_obligation( obligation, @@ -354,7 +315,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { ) } - ty::PredicateKind::RegionOutlives(data) => { + ty::PredicateKind::Clause(ty::Clause::RegionOutlives(data)) => { if infcx.considering_regions { infcx.region_outlives_predicate(&obligation.cause, Binder::dummy(data)); } @@ -362,15 +323,18 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { ProcessResult::Changed(vec![]) } - ty::PredicateKind::TypeOutlives(ty::OutlivesPredicate(t_a, r_b)) => { + ty::PredicateKind::Clause(ty::Clause::TypeOutlives(ty::OutlivesPredicate( + t_a, + r_b, + ))) => { if infcx.considering_regions { infcx.register_region_obligation_with_cause(t_a, r_b, &obligation.cause); } ProcessResult::Changed(vec![]) } - ty::PredicateKind::Projection(ref data) => { - let project_obligation = obligation.with(Binder::dummy(*data)); + ty::PredicateKind::Clause(ty::Clause::Projection(ref data)) => { + let project_obligation = obligation.with(infcx.tcx, Binder::dummy(*data)); self.process_projection_obligation( obligation, @@ -388,7 +352,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { } ty::PredicateKind::ClosureKind(_, closure_substs, kind) => { - match self.selcx.infcx().closure_kind(closure_substs) { + match self.selcx.infcx.closure_kind(closure_substs) { Some(closure_kind) => { if closure_kind.extends(kind) { ProcessResult::Changed(vec![]) @@ -402,7 +366,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { ty::PredicateKind::WellFormed(arg) => { match wf::obligations( - self.selcx.infcx(), + self.selcx.infcx, obligation.param_env, obligation.cause.body_id, obligation.recursion_depth + 1, @@ -419,7 +383,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { } ty::PredicateKind::Subtype(subtype) => { - match self.selcx.infcx().subtype_predicate( + match self.selcx.infcx.subtype_predicate( &obligation.cause, obligation.param_env, Binder::dummy(subtype), @@ -443,7 +407,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { } ty::PredicateKind::Coerce(coerce) => { - match self.selcx.infcx().coerce_predicate( + match self.selcx.infcx.coerce_predicate( &obligation.cause, obligation.param_env, Binder::dummy(coerce), @@ -467,7 +431,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { ty::PredicateKind::ConstEvaluatable(uv) => { match const_evaluatable::is_const_evaluatable( - self.selcx.infcx(), + self.selcx.infcx, uv, obligation.param_env, obligation.cause.span, @@ -490,20 +454,47 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { } ty::PredicateKind::ConstEquate(c1, c2) => { + let tcx = self.selcx.tcx(); assert!( - self.selcx.tcx().features().generic_const_exprs, + tcx.features().generic_const_exprs, "`ConstEquate` without a feature gate: {c1:?} {c2:?}", ); - debug!(?c1, ?c2, "equating consts"); // FIXME: we probably should only try to unify abstract constants // if the constants depend on generic parameters. // // Let's just see where this breaks :shrug: - if let (ty::ConstKind::Unevaluated(a), ty::ConstKind::Unevaluated(b)) = - (c1.kind(), c2.kind()) { - if infcx.try_unify_abstract_consts(a, b, obligation.param_env) { - return ProcessResult::Changed(vec![]); + let c1 = tcx.expand_abstract_consts(c1); + let c2 = tcx.expand_abstract_consts(c2); + debug!("equating consts:\nc1= {:?}\nc2= {:?}", c1, c2); + + use rustc_hir::def::DefKind; + use ty::ConstKind::Unevaluated; + match (c1.kind(), c2.kind()) { + (Unevaluated(a), Unevaluated(b)) + if a.def.did == b.def.did + && tcx.def_kind(a.def.did) == DefKind::AssocConst => + { + if let Ok(new_obligations) = infcx + .at(&obligation.cause, obligation.param_env) + .trace(c1, c2) + .eq(a.substs, b.substs) + { + return ProcessResult::Changed(mk_pending( + new_obligations.into_obligations(), + )); + } + } + (_, Unevaluated(_)) | (Unevaluated(_), _) => (), + (_, _) => { + if let Ok(new_obligations) = + infcx.at(&obligation.cause, obligation.param_env).eq(c1, c2) + { + return ProcessResult::Changed(mk_pending( + new_obligations.into_obligations(), + )); + } + } } } @@ -511,7 +502,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { let mut evaluate = |c: Const<'tcx>| { if let ty::ConstKind::Unevaluated(unevaluated) = c.kind() { - match self.selcx.infcx().try_const_eval_resolve( + match self.selcx.infcx.try_const_eval_resolve( obligation.param_env, unevaluated, c.ty(), @@ -539,11 +530,13 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { (Ok(c1), Ok(c2)) => { match self .selcx - .infcx() + .infcx .at(&obligation.cause, obligation.param_env) .eq(c1, c2) { - Ok(_) => ProcessResult::Changed(vec![]), + Ok(inf_ok) => { + ProcessResult::Changed(mk_pending(inf_ok.into_obligations())) + } Err(err) => ProcessResult::Error( FulfillmentErrorCode::CodeConstEquateError( ExpectedFound::new(true, c1, c2), @@ -558,12 +551,6 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { NotConstEvaluatable::Error(reported), )), ), - (Err(ErrorHandled::Linted), _) | (_, Err(ErrorHandled::Linted)) => { - span_bug!( - obligation.cause.span(), - "ConstEquate: const_eval_resolve returned an unexpected error" - ) - } (Err(ErrorHandled::TooGeneric), _) | (_, Err(ErrorHandled::TooGeneric)) => { if c1.has_non_region_infer() || c2.has_non_region_infer() { ProcessResult::Unchanged @@ -578,6 +565,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { } } } + ty::PredicateKind::Ambiguous => ProcessResult::Unchanged, ty::PredicateKind::TypeWellFormedFromEnv(..) => { bug!("TypeWellFormedFromEnv is only used for Chalk") } @@ -612,7 +600,7 @@ impl<'a, 'tcx> FulfillProcessor<'a, 'tcx> { trait_obligation: TraitObligation<'tcx>, stalled_on: &mut Vec<TyOrConstInferVar<'tcx>>, ) -> ProcessResult<PendingPredicateObligation<'tcx>, FulfillmentErrorCode<'tcx>> { - let infcx = self.selcx.infcx(); + let infcx = self.selcx.infcx; if obligation.predicate.is_global() { // no type variables present, can use evaluation for better caching. // FIXME: consider caching errors too. @@ -670,7 +658,7 @@ impl<'a, 'tcx> FulfillProcessor<'a, 'tcx> { if obligation.predicate.is_global() { // no type variables present, can use evaluation for better caching. // FIXME: consider caching errors too. - if self.selcx.infcx().predicate_must_hold_considering_regions(obligation) { + if self.selcx.infcx.predicate_must_hold_considering_regions(obligation) { if let Some(key) = ProjectionCacheKey::from_poly_projection_predicate( &mut self.selcx, project_obligation.predicate, @@ -679,7 +667,7 @@ impl<'a, 'tcx> FulfillProcessor<'a, 'tcx> { // evaluated all sub-obligations. We can therefore mark the 'root' // obligation as complete, and skip evaluating sub-obligations. self.selcx - .infcx() + .infcx .inner .borrow_mut() .projection_cache() @@ -703,7 +691,7 @@ impl<'a, 'tcx> FulfillProcessor<'a, 'tcx> { } // Let the caller handle the recursion ProjectAndUnifyResult::Recursive => ProcessResult::Changed(mk_pending(vec![ - project_obligation.with(project_obligation.predicate.to_predicate(tcx)), + project_obligation.with(tcx, project_obligation.predicate), ])), ProjectAndUnifyResult::MismatchedProjectionTypes(e) => { ProcessResult::Error(CodeProjectionError(e)) @@ -718,7 +706,7 @@ fn substs_infer_vars<'a, 'tcx>( substs: ty::Binder<'tcx, SubstsRef<'tcx>>, ) -> impl Iterator<Item = TyOrConstInferVar<'tcx>> { selcx - .infcx() + .infcx .resolve_vars_if_possible(substs) .skip_binder() // ok because this check doesn't care about regions .iter() |