diff options
Diffstat (limited to 'compiler/rustc_traits/src/implied_outlives_bounds.rs')
| -rw-r--r-- | compiler/rustc_traits/src/implied_outlives_bounds.rs | 49 |
1 files changed, 24 insertions, 25 deletions
diff --git a/compiler/rustc_traits/src/implied_outlives_bounds.rs b/compiler/rustc_traits/src/implied_outlives_bounds.rs index 7d36b9558..010233d77 100644 --- a/compiler/rustc_traits/src/implied_outlives_bounds.rs +++ b/compiler/rustc_traits/src/implied_outlives_bounds.rs @@ -5,16 +5,15 @@ use rustc_hir as hir; use rustc_infer::infer::canonical::{self, Canonical}; use rustc_infer::infer::outlives::components::{push_outlives_components, Component}; -use rustc_infer::infer::{InferCtxt, TyCtxtInferExt}; +use rustc_infer::infer::TyCtxtInferExt; use rustc_infer::traits::query::OutlivesBound; -use rustc_infer::traits::TraitEngineExt as _; use rustc_middle::ty::query::Providers; use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitable}; use rustc_span::source_map::DUMMY_SP; use rustc_trait_selection::infer::InferCtxtBuilderExt; use rustc_trait_selection::traits::query::{CanonicalTyGoal, Fallible, NoSolution}; use rustc_trait_selection::traits::wf; -use rustc_trait_selection::traits::{TraitEngine, TraitEngineExt}; +use rustc_trait_selection::traits::ObligationCtxt; use smallvec::{smallvec, SmallVec}; pub(crate) fn provide(p: &mut Providers) { @@ -28,18 +27,18 @@ fn implied_outlives_bounds<'tcx>( &'tcx Canonical<'tcx, canonical::QueryResponse<'tcx, Vec<OutlivesBound<'tcx>>>>, NoSolution, > { - tcx.infer_ctxt().enter_canonical_trait_query(&goal, |infcx, _fulfill_cx, key| { + tcx.infer_ctxt().enter_canonical_trait_query(&goal, |ocx, key| { let (param_env, ty) = key.into_parts(); - compute_implied_outlives_bounds(&infcx, param_env, ty) + compute_implied_outlives_bounds(ocx, param_env, ty) }) } fn compute_implied_outlives_bounds<'tcx>( - infcx: &InferCtxt<'tcx>, + ocx: &ObligationCtxt<'_, 'tcx>, param_env: ty::ParamEnv<'tcx>, ty: Ty<'tcx>, ) -> Fallible<Vec<OutlivesBound<'tcx>>> { - let tcx = infcx.tcx; + let tcx = ocx.infcx.tcx; // Sometimes when we ask what it takes for T: WF, we get back that // U: WF is required; in that case, we push U onto this stack and @@ -52,8 +51,6 @@ fn compute_implied_outlives_bounds<'tcx>( let mut outlives_bounds: Vec<ty::OutlivesPredicate<ty::GenericArg<'tcx>, ty::Region<'tcx>>> = vec![]; - let mut fulfill_cx = <dyn TraitEngine<'tcx>>::new(tcx); - while let Some(arg) = wf_args.pop() { if !checked_wf_args.insert(arg) { continue; @@ -70,15 +67,15 @@ fn compute_implied_outlives_bounds<'tcx>( // FIXME(@lcnr): It's not really "always fine", having fewer implied // bounds can be backward incompatible, e.g. #101951 was caused by // us not dealing with inference vars in `TypeOutlives` predicates. - let obligations = wf::obligations(infcx, param_env, hir::CRATE_HIR_ID, 0, arg, DUMMY_SP) - .unwrap_or_default(); + let obligations = + wf::obligations(ocx.infcx, param_env, hir::CRATE_HIR_ID, 0, arg, DUMMY_SP) + .unwrap_or_default(); // While these predicates should all be implied by other parts of // the program, they are still relevant as they may constrain // inference variables, which is necessary to add the correct // implied bounds in some cases, mostly when dealing with projections. - fulfill_cx.register_predicate_obligations( - infcx, + ocx.register_obligations( obligations.iter().filter(|o| o.predicate.has_non_region_infer()).cloned(), ); @@ -89,35 +86,37 @@ fn compute_implied_outlives_bounds<'tcx>( match obligation.predicate.kind().no_bound_vars() { None => None, Some(pred) => match pred { - ty::PredicateKind::Trait(..) + ty::PredicateKind::Clause(ty::Clause::Trait(..)) | ty::PredicateKind::Subtype(..) | ty::PredicateKind::Coerce(..) - | ty::PredicateKind::Projection(..) + | ty::PredicateKind::Clause(ty::Clause::Projection(..)) | ty::PredicateKind::ClosureKind(..) | ty::PredicateKind::ObjectSafe(..) | ty::PredicateKind::ConstEvaluatable(..) | ty::PredicateKind::ConstEquate(..) + | ty::PredicateKind::Ambiguous | ty::PredicateKind::TypeWellFormedFromEnv(..) => None, ty::PredicateKind::WellFormed(arg) => { wf_args.push(arg); None } - ty::PredicateKind::RegionOutlives(ty::OutlivesPredicate(r_a, r_b)) => { - Some(ty::OutlivesPredicate(r_a.into(), r_b)) - } + ty::PredicateKind::Clause(ty::Clause::RegionOutlives( + ty::OutlivesPredicate(r_a, r_b), + )) => Some(ty::OutlivesPredicate(r_a.into(), r_b)), - ty::PredicateKind::TypeOutlives(ty::OutlivesPredicate(ty_a, r_b)) => { - Some(ty::OutlivesPredicate(ty_a.into(), r_b)) - } + ty::PredicateKind::Clause(ty::Clause::TypeOutlives(ty::OutlivesPredicate( + ty_a, + r_b, + ))) => Some(ty::OutlivesPredicate(ty_a.into(), r_b)), }, } })); } - // Ensure that those obligations that we had to solve - // get solved *here*. - match fulfill_cx.select_all_or_error(infcx).as_slice() { + // This call to `select_all_or_error` is necessary to constrain inference variables, which we + // use further down when computing the implied bounds. + match ocx.select_all_or_error().as_slice() { [] => (), _ => return Err(NoSolution), } @@ -129,7 +128,7 @@ fn compute_implied_outlives_bounds<'tcx>( .flat_map(|ty::OutlivesPredicate(a, r_b)| match a.unpack() { ty::GenericArgKind::Lifetime(r_a) => vec![OutlivesBound::RegionSubRegion(r_b, r_a)], ty::GenericArgKind::Type(ty_a) => { - let ty_a = infcx.resolve_vars_if_possible(ty_a); + let ty_a = ocx.infcx.resolve_vars_if_possible(ty_a); let mut components = smallvec![]; push_outlives_components(tcx, ty_a, &mut components); implied_bounds_from_components(r_b, components) |