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::{InferCtxt, InferOk, TyCtxtInferExt};
10 use rustc_middle::ty::fold::TypeFoldable;
11 use rustc_middle::ty::visit::TypeVisitable;
12 use rustc_middle::ty::{self, Ty, TyCtxt};
13 use rustc_span::def_id::LocalDefIdMap;
14 use rustc_span::{self, Span};
15 use rustc_trait_selection::infer::InferCtxtExt as _;
16 use rustc_trait_selection::traits::{
17 self, ObligationCause, ObligationCtxt, TraitEngine, TraitEngineExt as _,
20 use std::cell::RefCell;
23 /// Closures defined within the function. For example:
24 /// ```ignore (illustrative)
26 /// bar(move|| { ... })
29 /// Here, the function `foo()` and the closure passed to
30 /// `bar()` will each have their own `FnCtxt`, but they will
31 /// share the inherited fields.
32 pub struct Inherited<'a, 'tcx> {
33 pub(super) infcx: InferCtxt<'a, 'tcx>,
35 pub(super) typeck_results: &'a RefCell<ty::TypeckResults<'tcx>>,
37 pub(super) locals: RefCell<HirIdMap<super::LocalTy<'tcx>>>,
39 pub(super) fulfillment_cx: RefCell<Box<dyn TraitEngine<'tcx>>>,
41 // Some additional `Sized` obligations badly affect type inference.
42 // These obligations are added in a later stage of typeck.
43 // Removing these may also cause additional complications, see #101066.
44 pub(super) deferred_sized_obligations:
45 RefCell<Vec<(Ty<'tcx>, Span, traits::ObligationCauseCode<'tcx>)>>,
47 // When we process a call like `c()` where `c` is a closure type,
48 // we may not have decided yet whether `c` is a `Fn`, `FnMut`, or
49 // `FnOnce` closure. In that case, we defer full resolution of the
50 // call until upvar inference can kick in and make the
51 // decision. We keep these deferred resolutions grouped by the
52 // def-id of the closure, so that once we decide, we can easily go
53 // back and process them.
54 pub(super) deferred_call_resolutions: RefCell<LocalDefIdMap<Vec<DeferredCallResolution<'tcx>>>>,
56 pub(super) deferred_cast_checks: RefCell<Vec<super::cast::CastCheck<'tcx>>>,
58 pub(super) deferred_transmute_checks: RefCell<Vec<(Ty<'tcx>, Ty<'tcx>, Span)>>,
60 pub(super) deferred_asm_checks: RefCell<Vec<(&'tcx hir::InlineAsm<'tcx>, hir::HirId)>>,
62 pub(super) deferred_generator_interiors:
63 RefCell<Vec<(hir::BodyId, Ty<'tcx>, hir::GeneratorKind)>>,
65 pub(super) body_id: Option<hir::BodyId>,
67 /// Whenever we introduce an adjustment from `!` into a type variable,
68 /// we record that type variable here. This is later used to inform
69 /// fallback. See the `fallback` module for details.
70 pub(super) diverging_type_vars: RefCell<FxHashSet<Ty<'tcx>>>,
73 impl<'a, 'tcx> Deref for Inherited<'a, 'tcx> {
74 type Target = InferCtxt<'a, 'tcx>;
75 fn deref(&self) -> &Self::Target {
80 /// A temporary returned by `Inherited::build(...)`. This is necessary
81 /// for multiple `InferCtxt` to share the same `in_progress_typeck_results`
82 /// without using `Rc` or something similar.
83 pub struct InheritedBuilder<'tcx> {
84 infcx: infer::InferCtxtBuilder<'tcx>,
88 impl<'tcx> Inherited<'_, 'tcx> {
89 pub fn build(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> InheritedBuilder<'tcx> {
90 let hir_owner = tcx.hir().local_def_id_to_hir_id(def_id).owner;
96 .with_fresh_in_progress_typeck_results(hir_owner)
97 .with_normalize_fn_sig_for_diagnostic(Lrc::new(move |infcx, fn_sig| {
98 if fn_sig.has_escaping_bound_vars() {
102 let ocx = ObligationCtxt::new_in_snapshot(infcx);
103 let normalized_fn_sig = ocx.normalize(
104 ObligationCause::dummy(),
105 // FIXME(compiler-errors): This is probably not the right param-env...
106 infcx.tcx.param_env(def_id),
109 if ocx.select_all_or_error().is_empty() {
110 let normalized_fn_sig =
111 infcx.resolve_vars_if_possible(normalized_fn_sig);
112 if !normalized_fn_sig.needs_infer() {
113 return normalized_fn_sig;
124 impl<'tcx> InheritedBuilder<'tcx> {
125 pub fn enter<F, R>(&mut self, f: F) -> R
127 F: for<'a> FnOnce(Inherited<'a, 'tcx>) -> R,
129 let def_id = self.def_id;
130 self.infcx.enter(|infcx| f(Inherited::new(infcx, def_id)))
134 impl<'a, 'tcx> Inherited<'a, 'tcx> {
135 fn new(infcx: InferCtxt<'a, 'tcx>, def_id: LocalDefId) -> Self {
137 let body_id = tcx.hir().maybe_body_owned_by(def_id);
139 infcx.in_progress_typeck_results.expect("building `FnCtxt` without typeck results");
144 fulfillment_cx: RefCell::new(<dyn TraitEngine<'_>>::new(tcx)),
145 locals: RefCell::new(Default::default()),
146 deferred_sized_obligations: RefCell::new(Vec::new()),
147 deferred_call_resolutions: RefCell::new(Default::default()),
148 deferred_cast_checks: RefCell::new(Vec::new()),
149 deferred_transmute_checks: RefCell::new(Vec::new()),
150 deferred_asm_checks: RefCell::new(Vec::new()),
151 deferred_generator_interiors: RefCell::new(Vec::new()),
152 diverging_type_vars: RefCell::new(Default::default()),
157 #[instrument(level = "debug", skip(self))]
158 pub(super) fn register_predicate(&self, obligation: traits::PredicateObligation<'tcx>) {
159 if obligation.has_escaping_bound_vars() {
160 span_bug!(obligation.cause.span, "escaping bound vars in predicate {:?}", obligation);
162 self.fulfillment_cx.borrow_mut().register_predicate_obligation(self, obligation);
165 pub(super) fn register_predicates<I>(&self, obligations: I)
167 I: IntoIterator<Item = traits::PredicateObligation<'tcx>>,
169 for obligation in obligations {
170 self.register_predicate(obligation);
174 pub(super) fn register_infer_ok_obligations<T>(&self, infer_ok: InferOk<'tcx, T>) -> T {
175 self.register_predicates(infer_ok.obligations);
179 pub(super) fn normalize_associated_types_in<T>(
183 param_env: ty::ParamEnv<'tcx>,
187 T: TypeFoldable<'tcx>,
189 self.normalize_associated_types_in_with_cause(
190 ObligationCause::misc(span, body_id),
196 pub(super) fn normalize_associated_types_in_with_cause<T>(
198 cause: ObligationCause<'tcx>,
199 param_env: ty::ParamEnv<'tcx>,
203 T: TypeFoldable<'tcx>,
205 let ok = self.partially_normalize_associated_types_in(cause, param_env, value);
207 self.register_infer_ok_obligations(ok)