1 use super::callee::DeferredCallResolution;
3 use rustc_data_structures::fx::FxHashSet;
4 use rustc_data_structures::sync::Lrc;
6 use rustc_hir::def_id::LocalDefId;
7 use rustc_hir::HirIdMap;
8 use rustc_infer::infer;
9 use rustc_infer::infer::{DefiningAnchor, InferCtxt, InferOk, TyCtxtInferExt};
10 use rustc_middle::ty::visit::TypeVisitable;
11 use rustc_middle::ty::{self, Ty, TyCtxt};
12 use rustc_span::def_id::LocalDefIdMap;
13 use rustc_span::{self, Span};
14 use rustc_trait_selection::traits::{
15 self, ObligationCause, ObligationCtxt, TraitEngine, TraitEngineExt as _,
18 use std::cell::RefCell;
21 /// Closures defined within the function. For example:
22 /// ```ignore (illustrative)
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<'tcx> {
31 pub(super) infcx: InferCtxt<'tcx>,
33 pub(super) typeck_results: RefCell<ty::TypeckResults<'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 /// Removing these may also cause additional complications, see #101066.
42 pub(super) deferred_sized_obligations:
43 RefCell<Vec<(Ty<'tcx>, Span, traits::ObligationCauseCode<'tcx>)>>,
45 /// When we process a call like `c()` where `c` is a closure type,
46 /// we may not have decided yet whether `c` is a `Fn`, `FnMut`, or
47 /// `FnOnce` closure. In that case, we defer full resolution of the
48 /// call until upvar inference can kick in and make the
49 /// decision. We keep these deferred resolutions grouped by the
50 /// def-id of the closure, so that once we decide, we can easily go
51 /// back and process them.
52 pub(super) deferred_call_resolutions: RefCell<LocalDefIdMap<Vec<DeferredCallResolution<'tcx>>>>,
54 pub(super) deferred_cast_checks: RefCell<Vec<super::cast::CastCheck<'tcx>>>,
56 pub(super) deferred_transmute_checks: RefCell<Vec<(Ty<'tcx>, Ty<'tcx>, hir::HirId)>>,
58 pub(super) deferred_asm_checks: RefCell<Vec<(&'tcx hir::InlineAsm<'tcx>, hir::HirId)>>,
60 pub(super) deferred_generator_interiors:
61 RefCell<Vec<(hir::BodyId, Ty<'tcx>, hir::GeneratorKind)>>,
63 pub(super) body_id: Option<hir::BodyId>,
65 /// Whenever we introduce an adjustment from `!` into a type variable,
66 /// we record that type variable here. This is later used to inform
67 /// fallback. See the `fallback` module for details.
68 pub(super) diverging_type_vars: RefCell<FxHashSet<Ty<'tcx>>>,
71 impl<'tcx> Deref for Inherited<'tcx> {
72 type Target = InferCtxt<'tcx>;
73 fn deref(&self) -> &Self::Target {
78 /// A temporary returned by `Inherited::build(...)`. This is necessary
79 /// for multiple `InferCtxt` to share the same `typeck_results`
80 /// without using `Rc` or something similar.
81 pub struct InheritedBuilder<'tcx> {
82 infcx: infer::InferCtxtBuilder<'tcx>,
84 typeck_results: RefCell<ty::TypeckResults<'tcx>>,
87 impl<'tcx> Inherited<'tcx> {
88 pub fn build(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> InheritedBuilder<'tcx> {
89 let hir_owner = tcx.hir().local_def_id_to_hir_id(def_id).owner;
95 .with_opaque_type_inference(DefiningAnchor::Bind(hir_owner.def_id))
96 .with_normalize_fn_sig_for_diagnostic(Lrc::new(move |infcx, fn_sig| {
97 if fn_sig.has_escaping_bound_vars() {
101 let ocx = ObligationCtxt::new_in_snapshot(infcx);
102 let normalized_fn_sig = ocx.normalize(
103 &ObligationCause::dummy(),
104 // FIXME(compiler-errors): This is probably not the right param-env...
105 infcx.tcx.param_env(def_id),
108 if ocx.select_all_or_error().is_empty() {
109 let normalized_fn_sig =
110 infcx.resolve_vars_if_possible(normalized_fn_sig);
111 if !normalized_fn_sig.needs_infer() {
112 return normalized_fn_sig;
119 typeck_results: RefCell::new(ty::TypeckResults::new(hir_owner)),
124 impl<'tcx> InheritedBuilder<'tcx> {
125 pub fn enter<F, R>(mut self, f: F) -> R
127 F: FnOnce(&Inherited<'tcx>) -> R,
129 let def_id = self.def_id;
130 f(&Inherited::new(self.infcx.build(), def_id, self.typeck_results))
134 impl<'tcx> Inherited<'tcx> {
136 infcx: InferCtxt<'tcx>,
138 typeck_results: RefCell<ty::TypeckResults<'tcx>>,
141 let body_id = tcx.hir().maybe_body_owned_by(def_id);
146 fulfillment_cx: RefCell::new(<dyn TraitEngine<'_>>::new(tcx)),
147 locals: RefCell::new(Default::default()),
148 deferred_sized_obligations: RefCell::new(Vec::new()),
149 deferred_call_resolutions: RefCell::new(Default::default()),
150 deferred_cast_checks: RefCell::new(Vec::new()),
151 deferred_transmute_checks: RefCell::new(Vec::new()),
152 deferred_asm_checks: RefCell::new(Vec::new()),
153 deferred_generator_interiors: RefCell::new(Vec::new()),
154 diverging_type_vars: RefCell::new(Default::default()),
159 #[instrument(level = "debug", skip(self))]
160 pub(super) fn register_predicate(&self, obligation: traits::PredicateObligation<'tcx>) {
161 if obligation.has_escaping_bound_vars() {
162 span_bug!(obligation.cause.span, "escaping bound vars in predicate {:?}", obligation);
164 self.fulfillment_cx.borrow_mut().register_predicate_obligation(self, obligation);
167 pub(super) fn register_predicates<I>(&self, obligations: I)
169 I: IntoIterator<Item = traits::PredicateObligation<'tcx>>,
171 for obligation in obligations {
172 self.register_predicate(obligation);
176 pub(super) fn register_infer_ok_obligations<T>(&self, infer_ok: InferOk<'tcx, T>) -> T {
177 self.register_predicates(infer_ok.obligations);