diff options
Diffstat (limited to 'compiler/rustc_middle/src/middle/resolve_lifetime.rs')
-rw-r--r-- | compiler/rustc_middle/src/middle/resolve_lifetime.rs | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/compiler/rustc_middle/src/middle/resolve_lifetime.rs b/compiler/rustc_middle/src/middle/resolve_lifetime.rs new file mode 100644 index 000000000..9b2f44567 --- /dev/null +++ b/compiler/rustc_middle/src/middle/resolve_lifetime.rs @@ -0,0 +1,54 @@ +//! Name resolution for lifetimes: type declarations. + +use crate::ty; + +use rustc_data_structures::fx::{FxHashMap, FxHashSet}; +use rustc_hir::def_id::{DefId, LocalDefId}; +use rustc_hir::ItemLocalId; +use rustc_macros::HashStable; + +#[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable, Debug, HashStable)] +pub enum Region { + Static, + EarlyBound(/* index */ u32, /* lifetime decl */ DefId), + LateBound(ty::DebruijnIndex, /* late-bound index */ u32, /* lifetime decl */ DefId), + Free(DefId, /* lifetime decl */ DefId), +} + +/// A set containing, at most, one known element. +/// If two distinct values are inserted into a set, then it +/// becomes `Many`, which can be used to detect ambiguities. +#[derive(Copy, Clone, PartialEq, Eq, TyEncodable, TyDecodable, Debug, HashStable)] +pub enum Set1<T> { + Empty, + One(T), + Many, +} + +impl<T: PartialEq> Set1<T> { + pub fn insert(&mut self, value: T) { + *self = match self { + Set1::Empty => Set1::One(value), + Set1::One(old) if *old == value => return, + _ => Set1::Many, + }; + } +} + +pub type ObjectLifetimeDefault = Set1<Region>; + +/// Maps the id of each lifetime reference to the lifetime decl +/// that it corresponds to. +#[derive(Default, HashStable, Debug)] +pub struct ResolveLifetimes { + /// Maps from every use of a named (not anonymous) lifetime to a + /// `Region` describing how that region is bound + pub defs: FxHashMap<LocalDefId, FxHashMap<ItemLocalId, Region>>, + + /// Set of lifetime def ids that are late-bound; a region can + /// be late-bound if (a) it does NOT appear in a where-clause and + /// (b) it DOES appear in the arguments. + pub late_bound: FxHashMap<LocalDefId, FxHashSet<LocalDefId>>, + + pub late_bound_vars: FxHashMap<LocalDefId, FxHashMap<ItemLocalId, Vec<ty::BoundVariableKind>>>, +} |