49 lines
2.2 KiB
Rust
49 lines
2.2 KiB
Rust
use crate::def_id::{LocalDefId, CRATE_DEF_INDEX};
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use std::fmt;
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/// Uniquely identifies a node in the HIR of the current crate. It is
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/// composed of the `owner`, which is the `LocalDefId` of the directly enclosing
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/// `hir::Item`, `hir::TraitItem`, or `hir::ImplItem` (i.e., the closest "item-like"),
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/// and the `local_id` which is unique within the given owner.
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///
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/// This two-level structure makes for more stable values: One can move an item
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/// around within the source code, or add or remove stuff before it, without
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/// the `local_id` part of the `HirId` changing, which is a very useful property in
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/// incremental compilation where we have to persist things through changes to
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/// the code base.
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#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, PartialOrd, Ord, RustcEncodable, RustcDecodable)]
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pub struct HirId {
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pub owner: LocalDefId,
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pub local_id: ItemLocalId,
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}
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impl fmt::Display for HirId {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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write!(f, "{:?}", self)
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}
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}
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rustc_data_structures::define_id_collections!(HirIdMap, HirIdSet, HirId);
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rustc_data_structures::define_id_collections!(ItemLocalMap, ItemLocalSet, ItemLocalId);
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rustc_index::newtype_index! {
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/// An `ItemLocalId` uniquely identifies something within a given "item-like";
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/// that is, within a `hir::Item`, `hir::TraitItem`, or `hir::ImplItem`. There is no
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/// guarantee that the numerical value of a given `ItemLocalId` corresponds to
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/// the node's position within the owning item in any way, but there is a
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/// guarantee that the `LocalItemId`s within an owner occupy a dense range of
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/// integers starting at zero, so a mapping that maps all or most nodes within
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/// an "item-like" to something else can be implemented by a `Vec` instead of a
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/// tree or hash map.
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pub struct ItemLocalId { .. }
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}
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rustc_data_structures::impl_stable_hash_via_hash!(ItemLocalId);
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/// The `HirId` corresponding to `CRATE_NODE_ID` and `CRATE_DEF_INDEX`.
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pub const CRATE_HIR_ID: HirId = HirId {
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owner: LocalDefId { local_def_index: CRATE_DEF_INDEX },
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local_id: ItemLocalId::from_u32(0),
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};
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pub const DUMMY_ITEM_LOCAL_ID: ItemLocalId = ItemLocalId::MAX;
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