use crate::middle::region::{Scope, ScopeData, ScopeTree};
use rustc_hir as hir;
use rustc_hir::ItemLocalMap;
#[derive(TyEncodable, TyDecodable, Clone, Debug, Default, Eq, PartialEq, HashStable)]
pub struct RvalueScopes {
map: ItemLocalMap<Option<Scope>>,
}
impl RvalueScopes {
pub fn new() -> Self {
Self { map: <_>::default() }
}
pub fn temporary_scope(
&self,
region_scope_tree: &ScopeTree,
expr_id: hir::ItemLocalId,
) -> Option<Scope> {
if let Some(&s) = self.map.get(&expr_id) {
debug!("temporary_scope({expr_id:?}) = {s:?} [custom]");
return s;
}
let mut id = Scope { id: expr_id, data: ScopeData::Node };
while let Some(&(p, _)) = region_scope_tree.parent_map.get(&id) {
match p.data {
ScopeData::Destruction => {
debug!("temporary_scope({expr_id:?}) = {id:?} [enclosing]");
return Some(id);
}
_ => id = p,
}
}
debug!("temporary_scope({expr_id:?}) = None");
None
}
pub fn record_rvalue_scope(&mut self, var: hir::ItemLocalId, lifetime: Option<Scope>) {
debug!("record_rvalue_scope(var={var:?}, lifetime={lifetime:?})");
if let Some(lifetime) = lifetime {
assert!(var != lifetime.item_local_id());
}
self.map.insert(var, lifetime);
}
}