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Diffstat (limited to '')
-rw-r--r-- | compiler/rustc_typeck/src/check/inherited.rs | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/compiler/rustc_typeck/src/check/inherited.rs b/compiler/rustc_typeck/src/check/inherited.rs new file mode 100644 index 000000000..cd152eb97 --- /dev/null +++ b/compiler/rustc_typeck/src/check/inherited.rs @@ -0,0 +1,183 @@ +use super::callee::DeferredCallResolution; + +use rustc_data_structures::fx::FxHashSet; +use rustc_hir as hir; +use rustc_hir::def_id::LocalDefId; +use rustc_hir::HirIdMap; +use rustc_infer::infer; +use rustc_infer::infer::{InferCtxt, InferOk, TyCtxtInferExt}; +use rustc_middle::ty::fold::TypeFoldable; +use rustc_middle::ty::visit::TypeVisitable; +use rustc_middle::ty::{self, Ty, TyCtxt}; +use rustc_span::def_id::LocalDefIdMap; +use rustc_span::{self, Span}; +use rustc_trait_selection::infer::InferCtxtExt as _; +use rustc_trait_selection::traits::{self, ObligationCause, TraitEngine, TraitEngineExt}; + +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<'a, 'tcx> { + pub(super) infcx: InferCtxt<'a, 'tcx>, + + pub(super) typeck_results: &'a 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. + 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>, Span)>>, + + pub(super) deferred_asm_checks: RefCell<Vec<(&'tcx hir::InlineAsm<'tcx>, hir::HirId)>>, + + pub(super) deferred_generator_interiors: + RefCell<Vec<(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>>>, +} + +impl<'a, 'tcx> Deref for Inherited<'a, 'tcx> { + type Target = InferCtxt<'a, 'tcx>; + fn deref(&self) -> &Self::Target { + &self.infcx + } +} + +/// A temporary returned by `Inherited::build(...)`. This is necessary +/// for multiple `InferCtxt` to share the same `in_progress_typeck_results` +/// without using `Rc` or something similar. +pub struct InheritedBuilder<'tcx> { + infcx: infer::InferCtxtBuilder<'tcx>, + def_id: LocalDefId, +} + +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_fresh_in_progress_typeck_results(hir_owner), + def_id, + } + } +} + +impl<'tcx> InheritedBuilder<'tcx> { + pub fn enter<F, R>(&mut self, f: F) -> R + where + F: for<'a> FnOnce(Inherited<'a, 'tcx>) -> R, + { + let def_id = self.def_id; + self.infcx.enter(|infcx| f(Inherited::new(infcx, def_id))) + } +} + +impl<'a, 'tcx> Inherited<'a, 'tcx> { + fn new(infcx: InferCtxt<'a, 'tcx>, def_id: LocalDefId) -> Self { + let tcx = infcx.tcx; + let body_id = tcx.hir().maybe_body_owned_by(def_id); + let typeck_results = + infcx.in_progress_typeck_results.expect("building `FnCtxt` without typeck results"); + + 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, + } + } + + #[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.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(super) fn normalize_associated_types_in<T>( + &self, + span: Span, + body_id: hir::HirId, + param_env: ty::ParamEnv<'tcx>, + value: T, + ) -> T + where + T: TypeFoldable<'tcx>, + { + self.normalize_associated_types_in_with_cause( + ObligationCause::misc(span, body_id), + param_env, + value, + ) + } + + pub(super) fn normalize_associated_types_in_with_cause<T>( + &self, + cause: ObligationCause<'tcx>, + param_env: ty::ParamEnv<'tcx>, + value: T, + ) -> T + where + T: TypeFoldable<'tcx>, + { + let ok = self.partially_normalize_associated_types_in(cause, param_env, value); + debug!(?ok); + self.register_infer_ok_obligations(ok) + } +} |