1 use super::callee::DeferredCallResolution;
2 use super::MaybeInProgressTables;
4 use rustc_data_structures::fx::FxHashMap;
5 use rustc_data_structures::vec_map::VecMap;
7 use rustc_hir::def_id::{DefIdMap, LocalDefId};
8 use rustc_hir::HirIdMap;
9 use rustc_infer::infer;
10 use rustc_infer::infer::{InferCtxt, InferOk, TyCtxtInferExt};
11 use rustc_middle::ty::fold::TypeFoldable;
12 use rustc_middle::ty::{self, OpaqueTypeKey, Ty, TyCtxt};
13 use rustc_span::{self, Span};
14 use rustc_trait_selection::infer::InferCtxtExt as _;
15 use rustc_trait_selection::opaque_types::OpaqueTypeDecl;
16 use rustc_trait_selection::traits::{self, ObligationCause, TraitEngine, TraitEngineExt};
18 use std::cell::RefCell;
21 /// Closures defined within the function. For example:
24 /// bar(move|| { ... })
27 /// Here, the function `foo()` and the closure passed to
28 /// `bar()` will each have their own `FnCtxt`, but they will
29 /// share the inherited fields.
30 pub struct Inherited<'a, 'tcx> {
31 pub(super) infcx: InferCtxt<'a, 'tcx>,
33 pub(super) typeck_results: super::MaybeInProgressTables<'a, 'tcx>,
35 pub(super) locals: RefCell<HirIdMap<super::LocalTy<'tcx>>>,
37 pub(super) fulfillment_cx: RefCell<Box<dyn TraitEngine<'tcx>>>,
39 // Some additional `Sized` obligations badly affect type inference.
40 // These obligations are added in a later stage of typeck.
41 pub(super) deferred_sized_obligations:
42 RefCell<Vec<(Ty<'tcx>, Span, traits::ObligationCauseCode<'tcx>)>>,
44 // When we process a call like `c()` where `c` is a closure type,
45 // we may not have decided yet whether `c` is a `Fn`, `FnMut`, or
46 // `FnOnce` closure. In that case, we defer full resolution of the
47 // call until upvar inference can kick in and make the
48 // decision. We keep these deferred resolutions grouped by the
49 // def-id of the closure, so that once we decide, we can easily go
50 // back and process them.
51 pub(super) deferred_call_resolutions: RefCell<DefIdMap<Vec<DeferredCallResolution<'tcx>>>>,
53 pub(super) deferred_cast_checks: RefCell<Vec<super::cast::CastCheck<'tcx>>>,
55 pub(super) deferred_generator_interiors:
56 RefCell<Vec<(hir::BodyId, Ty<'tcx>, hir::GeneratorKind)>>,
58 // Opaque types found in explicit return types and their
59 // associated fresh inference variable. Writeback resolves these
60 // variables to get the concrete type, which can be used to
61 // 'de-opaque' OpaqueTypeDecl, after typeck is done with all functions.
62 pub(super) opaque_types: RefCell<VecMap<OpaqueTypeKey<'tcx>, OpaqueTypeDecl<'tcx>>>,
64 /// A map from inference variables created from opaque
65 /// type instantiations (`ty::Infer`) to the actual opaque
66 /// type (`ty::Opaque`). Used during fallback to map unconstrained
67 /// opaque type inference variables to their corresponding
69 pub(super) opaque_types_vars: RefCell<FxHashMap<Ty<'tcx>, Ty<'tcx>>>,
71 pub(super) body_id: Option<hir::BodyId>,
74 impl<'a, 'tcx> Deref for Inherited<'a, 'tcx> {
75 type Target = InferCtxt<'a, 'tcx>;
76 fn deref(&self) -> &Self::Target {
81 /// Helper type of a temporary returned by `Inherited::build(...)`.
82 /// Necessary because we can't write the following bound:
83 /// `F: for<'b, 'tcx> where 'tcx FnOnce(Inherited<'b, 'tcx>)`.
84 pub struct InheritedBuilder<'tcx> {
85 infcx: infer::InferCtxtBuilder<'tcx>,
89 impl Inherited<'_, 'tcx> {
90 pub fn build(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> InheritedBuilder<'tcx> {
91 let hir_owner = tcx.hir().local_def_id_to_hir_id(def_id).owner;
94 infcx: tcx.infer_ctxt().with_fresh_in_progress_typeck_results(hir_owner),
100 impl<'tcx> InheritedBuilder<'tcx> {
101 pub fn enter<F, R>(&mut self, f: F) -> R
103 F: for<'a> FnOnce(Inherited<'a, 'tcx>) -> R,
105 let def_id = self.def_id;
106 self.infcx.enter(|infcx| f(Inherited::new(infcx, def_id)))
110 impl Inherited<'a, 'tcx> {
111 pub(super) fn new(infcx: InferCtxt<'a, 'tcx>, def_id: LocalDefId) -> Self {
113 let item_id = tcx.hir().local_def_id_to_hir_id(def_id);
114 let body_id = tcx.hir().maybe_body_owned_by(item_id);
117 typeck_results: MaybeInProgressTables {
118 maybe_typeck_results: infcx.in_progress_typeck_results,
121 fulfillment_cx: RefCell::new(<dyn TraitEngine<'_>>::new(tcx)),
122 locals: RefCell::new(Default::default()),
123 deferred_sized_obligations: RefCell::new(Vec::new()),
124 deferred_call_resolutions: RefCell::new(Default::default()),
125 deferred_cast_checks: RefCell::new(Vec::new()),
126 deferred_generator_interiors: RefCell::new(Vec::new()),
127 opaque_types: RefCell::new(Default::default()),
128 opaque_types_vars: RefCell::new(Default::default()),
133 pub(super) fn register_predicate(&self, obligation: traits::PredicateObligation<'tcx>) {
134 debug!("register_predicate({:?})", obligation);
135 if obligation.has_escaping_bound_vars() {
136 span_bug!(obligation.cause.span, "escaping bound vars in predicate {:?}", obligation);
138 self.fulfillment_cx.borrow_mut().register_predicate_obligation(self, obligation);
141 pub(super) fn register_predicates<I>(&self, obligations: I)
143 I: IntoIterator<Item = traits::PredicateObligation<'tcx>>,
145 for obligation in obligations {
146 self.register_predicate(obligation);
150 pub(super) fn register_infer_ok_obligations<T>(&self, infer_ok: InferOk<'tcx, T>) -> T {
151 self.register_predicates(infer_ok.obligations);
155 pub(super) fn normalize_associated_types_in<T>(
159 param_env: ty::ParamEnv<'tcx>,
163 T: TypeFoldable<'tcx>,
165 self.normalize_associated_types_in_with_cause(
166 ObligationCause::misc(span, body_id),
172 pub(super) fn normalize_associated_types_in_with_cause<T>(
174 cause: ObligationCause<'tcx>,
175 param_env: ty::ParamEnv<'tcx>,
179 T: TypeFoldable<'tcx>,
181 let ok = self.partially_normalize_associated_types_in(cause, param_env, value);
183 self.register_infer_ok_obligations(ok)