| use super::callee::DeferredCallResolution; |
| |
| use rustc_data_structures::fx::{FxHashMap, FxHashSet}; |
| use rustc_hir as hir; |
| use rustc_hir::def_id::LocalDefId; |
| use rustc_hir::HirIdMap; |
| use rustc_infer::infer; |
| use rustc_infer::infer::{DefiningAnchor, InferCtxt, InferOk, TyCtxtInferExt}; |
| use rustc_middle::ty::visit::TypeVisitableExt; |
| use rustc_middle::ty::{self, Ty, TyCtxt}; |
| use rustc_span::def_id::LocalDefIdMap; |
| use rustc_span::{self, Span}; |
| use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt; |
| use rustc_trait_selection::traits::{self, PredicateObligation, TraitEngine, TraitEngineExt as _}; |
| |
| use std::cell::RefCell; |
| use std::ops::Deref; |
| |
| /// Closures defined within the function. For example: |
| /// ```ignore (illustrative) |
| /// fn foo() { |
| /// bar(move|| { ... }) |
| /// } |
| /// ``` |
| /// Here, the function `foo()` and the closure passed to |
| /// `bar()` will each have their own `FnCtxt`, but they will |
| /// share the inherited fields. |
| pub struct Inherited<'tcx> { |
| pub(super) infcx: InferCtxt<'tcx>, |
| |
| pub(super) typeck_results: RefCell<ty::TypeckResults<'tcx>>, |
| |
| pub(super) locals: RefCell<HirIdMap<super::LocalTy<'tcx>>>, |
| |
| pub(super) fulfillment_cx: RefCell<Box<dyn TraitEngine<'tcx>>>, |
| |
| /// Some additional `Sized` obligations badly affect type inference. |
| /// These obligations are added in a later stage of typeck. |
| /// Removing these may also cause additional complications, see #101066. |
| pub(super) deferred_sized_obligations: |
| RefCell<Vec<(Ty<'tcx>, Span, traits::ObligationCauseCode<'tcx>)>>, |
| |
| /// When we process a call like `c()` where `c` is a closure type, |
| /// we may not have decided yet whether `c` is a `Fn`, `FnMut`, or |
| /// `FnOnce` closure. In that case, we defer full resolution of the |
| /// call until upvar inference can kick in and make the |
| /// decision. We keep these deferred resolutions grouped by the |
| /// def-id of the closure, so that once we decide, we can easily go |
| /// back and process them. |
| pub(super) deferred_call_resolutions: RefCell<LocalDefIdMap<Vec<DeferredCallResolution<'tcx>>>>, |
| |
| pub(super) deferred_cast_checks: RefCell<Vec<super::cast::CastCheck<'tcx>>>, |
| |
| pub(super) deferred_transmute_checks: RefCell<Vec<(Ty<'tcx>, Ty<'tcx>, hir::HirId)>>, |
| |
| pub(super) deferred_asm_checks: RefCell<Vec<(&'tcx hir::InlineAsm<'tcx>, hir::HirId)>>, |
| |
| pub(super) deferred_generator_interiors: |
| RefCell<Vec<(LocalDefId, hir::BodyId, Ty<'tcx>, hir::GeneratorKind)>>, |
| |
| pub(super) body_id: Option<hir::BodyId>, |
| |
| /// Whenever we introduce an adjustment from `!` into a type variable, |
| /// we record that type variable here. This is later used to inform |
| /// fallback. See the `fallback` module for details. |
| pub(super) diverging_type_vars: RefCell<FxHashSet<Ty<'tcx>>>, |
| |
| pub(super) infer_var_info: RefCell<FxHashMap<ty::TyVid, ty::InferVarInfo>>, |
| } |
| |
| impl<'tcx> Deref for Inherited<'tcx> { |
| type Target = InferCtxt<'tcx>; |
| fn deref(&self) -> &Self::Target { |
| &self.infcx |
| } |
| } |
| |
| /// A temporary returned by `Inherited::build(...)`. This is necessary |
| /// for multiple `InferCtxt` to share the same `typeck_results` |
| /// without using `Rc` or something similar. |
| pub struct InheritedBuilder<'tcx> { |
| infcx: infer::InferCtxtBuilder<'tcx>, |
| def_id: LocalDefId, |
| typeck_results: RefCell<ty::TypeckResults<'tcx>>, |
| } |
| |
| impl<'tcx> Inherited<'tcx> { |
| pub fn build(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> InheritedBuilder<'tcx> { |
| let hir_owner = tcx.hir().local_def_id_to_hir_id(def_id).owner; |
| |
| InheritedBuilder { |
| infcx: tcx |
| .infer_ctxt() |
| .ignoring_regions() |
| .with_opaque_type_inference(DefiningAnchor::Bind(hir_owner.def_id)), |
| def_id, |
| typeck_results: RefCell::new(ty::TypeckResults::new(hir_owner)), |
| } |
| } |
| } |
| |
| impl<'tcx> InheritedBuilder<'tcx> { |
| pub fn enter<F, R>(mut self, f: F) -> R |
| where |
| F: FnOnce(&Inherited<'tcx>) -> R, |
| { |
| let def_id = self.def_id; |
| f(&Inherited::new(self.infcx.build(), def_id, self.typeck_results)) |
| } |
| } |
| |
| impl<'tcx> Inherited<'tcx> { |
| fn new( |
| infcx: InferCtxt<'tcx>, |
| def_id: LocalDefId, |
| typeck_results: RefCell<ty::TypeckResults<'tcx>>, |
| ) -> Self { |
| let tcx = infcx.tcx; |
| let body_id = tcx.hir().maybe_body_owned_by(def_id); |
| |
| Inherited { |
| typeck_results, |
| infcx, |
| fulfillment_cx: RefCell::new(<dyn TraitEngine<'_>>::new(tcx)), |
| locals: RefCell::new(Default::default()), |
| deferred_sized_obligations: RefCell::new(Vec::new()), |
| deferred_call_resolutions: RefCell::new(Default::default()), |
| deferred_cast_checks: RefCell::new(Vec::new()), |
| deferred_transmute_checks: RefCell::new(Vec::new()), |
| deferred_asm_checks: RefCell::new(Vec::new()), |
| deferred_generator_interiors: RefCell::new(Vec::new()), |
| diverging_type_vars: RefCell::new(Default::default()), |
| body_id, |
| infer_var_info: RefCell::new(Default::default()), |
| } |
| } |
| |
| #[instrument(level = "debug", skip(self))] |
| pub(super) fn register_predicate(&self, obligation: traits::PredicateObligation<'tcx>) { |
| if obligation.has_escaping_bound_vars() { |
| span_bug!(obligation.cause.span, "escaping bound vars in predicate {:?}", obligation); |
| } |
| |
| self.update_infer_var_info(&obligation); |
| |
| self.fulfillment_cx.borrow_mut().register_predicate_obligation(self, obligation); |
| } |
| |
| pub(super) fn register_predicates<I>(&self, obligations: I) |
| where |
| I: IntoIterator<Item = traits::PredicateObligation<'tcx>>, |
| { |
| for obligation in obligations { |
| self.register_predicate(obligation); |
| } |
| } |
| |
| pub(super) fn register_infer_ok_obligations<T>(&self, infer_ok: InferOk<'tcx, T>) -> T { |
| self.register_predicates(infer_ok.obligations); |
| infer_ok.value |
| } |
| |
| pub fn update_infer_var_info(&self, obligation: &PredicateObligation<'tcx>) { |
| let infer_var_info = &mut self.infer_var_info.borrow_mut(); |
| |
| // (*) binder skipped |
| if let ty::PredicateKind::Clause(ty::Clause::Trait(tpred)) = obligation.predicate.kind().skip_binder() |
| && let Some(ty) = self.shallow_resolve(tpred.self_ty()).ty_vid().map(|t| self.root_var(t)) |
| && self.tcx.lang_items().sized_trait().map_or(false, |st| st != tpred.trait_ref.def_id) |
| { |
| let new_self_ty = self.tcx.types.unit; |
| |
| // Then construct a new obligation with Self = () added |
| // to the ParamEnv, and see if it holds. |
| let o = obligation.with(self.tcx, |
| obligation |
| .predicate |
| .kind() |
| .rebind( |
| // (*) binder moved here |
| ty::PredicateKind::Clause(ty::Clause::Trait(tpred.with_self_ty(self.tcx, new_self_ty))) |
| ), |
| ); |
| // Don't report overflow errors. Otherwise equivalent to may_hold. |
| if let Ok(result) = self.probe(|_| self.evaluate_obligation(&o)) && result.may_apply() { |
| infer_var_info.entry(ty).or_default().self_in_trait = true; |
| } |
| } |
| |
| if let ty::PredicateKind::Clause(ty::Clause::Projection(predicate)) = |
| obligation.predicate.kind().skip_binder() |
| { |
| // If the projection predicate (Foo::Bar == X) has X as a non-TyVid, |
| // we need to make it into one. |
| if let Some(vid) = predicate.term.ty().and_then(|ty| ty.ty_vid()) { |
| debug!("infer_var_info: {:?}.output = true", vid); |
| infer_var_info.entry(vid).or_default().output = true; |
| } |
| } |
| } |
| } |