1 use crate::def_id::{DefId, DefIndex, LocalDefId, CRATE_DEF_INDEX};
2 use rustc_serialize::{self, Decodable, Decoder, Encodable, Encoder};
5 /// Uniquely identifies a node in the HIR of the current crate. It is
6 /// composed of the `owner`, which is the `DefIndex` of the directly enclosing
7 /// `hir::Item`, `hir::TraitItem`, or `hir::ImplItem` (i.e., the closest "item-like"),
8 /// and the `local_id` which is unique within the given owner.
10 /// This two-level structure makes for more stable values: One can move an item
11 /// around within the source code, or add or remove stuff before it, without
12 /// the `local_id` part of the `HirId` changing, which is a very useful property in
13 /// incremental compilation where we have to persist things through changes to
15 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, PartialOrd, Ord)]
18 pub local_id: ItemLocalId,
22 pub fn owner_def_id(self) -> DefId {
23 DefId::local(self.owner)
26 pub fn owner_local_def_id(self) -> LocalDefId {
27 LocalDefId::from_def_id(DefId::local(self.owner))
31 impl rustc_serialize::UseSpecializedEncodable for HirId {
32 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
33 let HirId { owner, local_id } = *self;
41 impl rustc_serialize::UseSpecializedDecodable for HirId {
42 fn default_decode<D: Decoder>(d: &mut D) -> Result<HirId, D::Error> {
43 let owner = DefIndex::decode(d)?;
44 let local_id = ItemLocalId::decode(d)?;
46 Ok(HirId { owner, local_id })
50 impl fmt::Display for HirId {
51 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
52 write!(f, "{:?}", self)
56 rustc_data_structures::define_id_collections!(HirIdMap, HirIdSet, HirId);
57 rustc_data_structures::define_id_collections!(ItemLocalMap, ItemLocalSet, ItemLocalId);
59 rustc_index::newtype_index! {
60 /// An `ItemLocalId` uniquely identifies something within a given "item-like";
61 /// that is, within a `hir::Item`, `hir::TraitItem`, or `hir::ImplItem`. There is no
62 /// guarantee that the numerical value of a given `ItemLocalId` corresponds to
63 /// the node's position within the owning item in any way, but there is a
64 /// guarantee that the `LocalItemId`s within an owner occupy a dense range of
65 /// integers starting at zero, so a mapping that maps all or most nodes within
66 /// an "item-like" to something else can be implemented by a `Vec` instead of a
68 pub struct ItemLocalId { .. }
70 rustc_data_structures::impl_stable_hash_via_hash!(ItemLocalId);
72 /// The `HirId` corresponding to `CRATE_NODE_ID` and `CRATE_DEF_INDEX`.
73 pub const CRATE_HIR_ID: HirId =
74 HirId { owner: CRATE_DEF_INDEX, local_id: ItemLocalId::from_u32_const(0) };
76 pub const DUMMY_HIR_ID: HirId = HirId { owner: CRATE_DEF_INDEX, local_id: DUMMY_ITEM_LOCAL_ID };
78 pub const DUMMY_ITEM_LOCAL_ID: ItemLocalId = ItemLocalId::MAX;