rustc_borrowck/
root_cx.rs

1use rustc_abi::FieldIdx;
2use rustc_data_structures::fx::FxHashMap;
3use rustc_hir::def_id::LocalDefId;
4use rustc_middle::bug;
5use rustc_middle::ty::{EarlyBinder, OpaqueHiddenType, Ty, TyCtxt, TypeVisitableExt};
6use rustc_span::ErrorGuaranteed;
7use smallvec::SmallVec;
8
9use crate::consumers::BorrowckConsumer;
10use crate::{ClosureRegionRequirements, ConcreteOpaqueTypes, PropagatedBorrowCheckResults};
11
12/// The shared context used by both the root as well as all its nested
13/// items.
14pub(super) struct BorrowCheckRootCtxt<'tcx> {
15    pub tcx: TyCtxt<'tcx>,
16    root_def_id: LocalDefId,
17    concrete_opaque_types: ConcreteOpaqueTypes<'tcx>,
18    nested_bodies: FxHashMap<LocalDefId, PropagatedBorrowCheckResults<'tcx>>,
19    tainted_by_errors: Option<ErrorGuaranteed>,
20    /// This should be `None` during normal compilation. See [`crate::consumers`] for more
21    /// information on how this is used.
22    pub consumer: Option<BorrowckConsumer<'tcx>>,
23}
24
25impl<'tcx> BorrowCheckRootCtxt<'tcx> {
26    pub(super) fn new(
27        tcx: TyCtxt<'tcx>,
28        root_def_id: LocalDefId,
29        consumer: Option<BorrowckConsumer<'tcx>>,
30    ) -> BorrowCheckRootCtxt<'tcx> {
31        BorrowCheckRootCtxt {
32            tcx,
33            root_def_id,
34            concrete_opaque_types: Default::default(),
35            nested_bodies: Default::default(),
36            tainted_by_errors: None,
37            consumer,
38        }
39    }
40
41    pub(super) fn root_def_id(&self) -> LocalDefId {
42        self.root_def_id
43    }
44
45    /// Collect all defining uses of opaque types inside of this typeck root. This
46    /// expects the hidden type to be mapped to the definition parameters of the opaque
47    /// and errors if we end up with distinct hidden types.
48    pub(super) fn add_concrete_opaque_type(
49        &mut self,
50        def_id: LocalDefId,
51        hidden_ty: OpaqueHiddenType<'tcx>,
52    ) {
53        // Sometimes two opaque types are the same only after we remap the generic parameters
54        // back to the opaque type definition. E.g. we may have `OpaqueType<X, Y>` mapped to
55        // `(X, Y)` and `OpaqueType<Y, X>` mapped to `(Y, X)`, and those are the same, but we
56        // only know that once we convert the generic parameters to those of the opaque type.
57        if let Some(prev) = self.concrete_opaque_types.0.get_mut(&def_id) {
58            if prev.ty != hidden_ty.ty {
59                let guar = hidden_ty.ty.error_reported().err().unwrap_or_else(|| {
60                    let (Ok(e) | Err(e)) =
61                        prev.build_mismatch_error(&hidden_ty, self.tcx).map(|d| d.emit());
62                    e
63                });
64                prev.ty = Ty::new_error(self.tcx, guar);
65            }
66            // Pick a better span if there is one.
67            // FIXME(oli-obk): collect multiple spans for better diagnostics down the road.
68            prev.span = prev.span.substitute_dummy(hidden_ty.span);
69        } else {
70            self.concrete_opaque_types.0.insert(def_id, hidden_ty);
71        }
72    }
73
74    pub(super) fn get_concrete_opaque_type(
75        &mut self,
76        def_id: LocalDefId,
77    ) -> Option<EarlyBinder<'tcx, OpaqueHiddenType<'tcx>>> {
78        self.concrete_opaque_types.0.get(&def_id).map(|ty| EarlyBinder::bind(*ty))
79    }
80
81    pub(super) fn set_tainted_by_errors(&mut self, guar: ErrorGuaranteed) {
82        self.tainted_by_errors = Some(guar);
83    }
84
85    pub(super) fn get_or_insert_nested(
86        &mut self,
87        def_id: LocalDefId,
88    ) -> &PropagatedBorrowCheckResults<'tcx> {
89        debug_assert_eq!(
90            self.tcx.typeck_root_def_id(def_id.to_def_id()),
91            self.root_def_id.to_def_id()
92        );
93        if !self.nested_bodies.contains_key(&def_id) {
94            let result = super::do_mir_borrowck(self, def_id);
95            if let Some(prev) = self.nested_bodies.insert(def_id, result) {
96                bug!("unexpected previous nested body: {prev:?}");
97            }
98        }
99
100        self.nested_bodies.get(&def_id).unwrap()
101    }
102
103    pub(super) fn closure_requirements(
104        &mut self,
105        nested_body_def_id: LocalDefId,
106    ) -> &Option<ClosureRegionRequirements<'tcx>> {
107        &self.get_or_insert_nested(nested_body_def_id).closure_requirements
108    }
109
110    pub(super) fn used_mut_upvars(
111        &mut self,
112        nested_body_def_id: LocalDefId,
113    ) -> &SmallVec<[FieldIdx; 8]> {
114        &self.get_or_insert_nested(nested_body_def_id).used_mut_upvars
115    }
116
117    pub(super) fn finalize(self) -> Result<&'tcx ConcreteOpaqueTypes<'tcx>, ErrorGuaranteed> {
118        if let Some(guar) = self.tainted_by_errors {
119            Err(guar)
120        } else {
121            Ok(self.tcx.arena.alloc(self.concrete_opaque_types))
122        }
123    }
124}
rustc_borrowck/root_cx.rs

rustc_borrowck/
root_cx.rs
