rustc_hir_typeck/
typeck_root_ctxt.rs

1use std::cell::{Cell, RefCell};
2use std::ops::Deref;
3
4use rustc_data_structures::unord::UnordSet;
5use rustc_hir::def_id::LocalDefId;
6use rustc_hir::{self as hir, HirId, HirIdMap};
7use rustc_infer::infer::{InferCtxt, InferOk, OpaqueTypeStorageEntries, TyCtxtInferExt};
8use rustc_middle::span_bug;
9use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitableExt, TypingMode};
10use rustc_span::Span;
11use rustc_span::def_id::LocalDefIdMap;
12use rustc_trait_selection::traits::{self, FulfillmentError, TraitEngine, TraitEngineExt as _};
13use tracing::instrument;
14
15use super::callee::DeferredCallResolution;
16
17/// Data shared between a "typeck root" and its nested bodies,
18/// e.g. closures defined within the function. For example:
19/// ```ignore (illustrative)
20/// fn foo() {
21///     bar(move || { ... })
22/// }
23/// ```
24/// Here, the function `foo()` and the closure passed to
25/// `bar()` will each have their own `FnCtxt`, but they will
26/// share the inference context, will process obligations together,
27/// can access each other's local types (scoping permitted), etc.
28pub(crate) struct TypeckRootCtxt<'tcx> {
29    pub(super) infcx: InferCtxt<'tcx>,
30
31    pub(super) typeck_results: RefCell<ty::TypeckResults<'tcx>>,
32
33    pub(super) locals: RefCell<HirIdMap<Ty<'tcx>>>,
34
35    pub(super) fulfillment_cx: RefCell<Box<dyn TraitEngine<'tcx, FulfillmentError<'tcx>>>>,
36
37    // Used to detect opaque types uses added after we've already checked them.
38    //
39    // See [FnCtxt::detect_opaque_types_added_during_writeback] for more details.
40    pub(super) checked_opaque_types_storage_entries: Cell<Option<OpaqueTypeStorageEntries>>,
41
42    /// Some additional `Sized` obligations badly affect type inference.
43    /// These obligations are added in a later stage of typeck.
44    /// Removing these may also cause additional complications, see #101066.
45    pub(super) deferred_sized_obligations:
46        RefCell<Vec<(Ty<'tcx>, Span, traits::ObligationCauseCode<'tcx>)>>,
47
48    /// When we process a call like `c()` where `c` is a closure type,
49    /// we may not have decided yet whether `c` is a `Fn`, `FnMut`, or
50    /// `FnOnce` closure. In that case, we defer full resolution of the
51    /// call until upvar inference can kick in and make the
52    /// decision. We keep these deferred resolutions grouped by the
53    /// def-id of the closure, so that once we decide, we can easily go
54    /// back and process them.
55    pub(super) deferred_call_resolutions: RefCell<LocalDefIdMap<Vec<DeferredCallResolution<'tcx>>>>,
56
57    pub(super) deferred_cast_checks: RefCell<Vec<super::cast::CastCheck<'tcx>>>,
58
59    pub(super) deferred_transmute_checks: RefCell<Vec<(Ty<'tcx>, Ty<'tcx>, HirId)>>,
60
61    pub(super) deferred_asm_checks: RefCell<Vec<(&'tcx hir::InlineAsm<'tcx>, HirId)>>,
62
63    pub(super) deferred_repeat_expr_checks:
64        RefCell<Vec<(&'tcx hir::Expr<'tcx>, Ty<'tcx>, ty::Const<'tcx>)>>,
65
66    /// Whenever we introduce an adjustment from `!` into a type variable,
67    /// we record that type variable here. This is later used to inform
68    /// fallback. See the `fallback` module for details.
69    pub(super) diverging_type_vars: RefCell<UnordSet<Ty<'tcx>>>,
70}
71
72impl<'tcx> Deref for TypeckRootCtxt<'tcx> {
73    type Target = InferCtxt<'tcx>;
74    fn deref(&self) -> &Self::Target {
75        &self.infcx
76    }
77}
78
79impl<'tcx> TypeckRootCtxt<'tcx> {
80    pub(crate) fn new(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> Self {
81        let hir_owner = tcx.local_def_id_to_hir_id(def_id).owner;
82
83        let infcx = tcx
84            .infer_ctxt()
85            .ignoring_regions()
86            .in_hir_typeck()
87            .build(TypingMode::typeck_for_body(tcx, def_id));
88        let typeck_results = RefCell::new(ty::TypeckResults::new(hir_owner));
89        let fulfillment_cx = RefCell::new(<dyn TraitEngine<'_, _>>::new(&infcx));
90
91        TypeckRootCtxt {
92            infcx,
93            typeck_results,
94            locals: RefCell::new(Default::default()),
95            fulfillment_cx,
96            checked_opaque_types_storage_entries: Cell::new(None),
97            deferred_sized_obligations: RefCell::new(Vec::new()),
98            deferred_call_resolutions: RefCell::new(Default::default()),
99            deferred_cast_checks: RefCell::new(Vec::new()),
100            deferred_transmute_checks: RefCell::new(Vec::new()),
101            deferred_asm_checks: RefCell::new(Vec::new()),
102            deferred_repeat_expr_checks: RefCell::new(Vec::new()),
103            diverging_type_vars: RefCell::new(Default::default()),
104        }
105    }
106
107    #[instrument(level = "debug", skip(self))]
108    pub(super) fn register_predicate(&self, obligation: traits::PredicateObligation<'tcx>) {
109        if obligation.has_escaping_bound_vars() {
110            span_bug!(obligation.cause.span, "escaping bound vars in predicate {:?}", obligation);
111        }
112
113        self.fulfillment_cx.borrow_mut().register_predicate_obligation(self, obligation);
114    }
115
116    pub(super) fn register_predicates<I>(&self, obligations: I)
117    where
118        I: IntoIterator<Item = traits::PredicateObligation<'tcx>>,
119    {
120        for obligation in obligations {
121            self.register_predicate(obligation);
122        }
123    }
124
125    pub(super) fn register_infer_ok_obligations<T>(&self, infer_ok: InferOk<'tcx, T>) -> T {
126        self.register_predicates(infer_ok.obligations);
127        infer_ok.value
128    }
129}
rustc_hir_typeck/typeck_root_ctxt.rs

rustc_hir_typeck/
typeck_root_ctxt.rs
