Implement Idx for OwnerId.

Author: cjgillot

compiler/rustc_hir/src/hir_id.rs

@@ -1,4 +1,4 @@
-use crate::def_id::{DefId, LocalDefId, CRATE_DEF_ID};
+use crate::def_id::{DefId, DefIndex, LocalDefId, CRATE_DEF_ID};
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher, ToStableHashKey};
 use rustc_span::{def_id::DefPathHash, HashStableContext};
 use std::fmt;
@@ -22,6 +22,18 @@ impl OwnerId {
     }
 }
 
+impl rustc_index::vec::Idx for OwnerId {
+    #[inline]
+    fn new(idx: usize) -> Self {
+        OwnerId { def_id: LocalDefId { local_def_index: DefIndex::from_usize(idx) } }
+    }
+
+    #[inline]
+    fn index(self) -> usize {
+        self.def_id.local_def_index.as_usize()
+    }
+}
+
 impl<CTX: HashStableContext> HashStable<CTX> for OwnerId {
     #[inline]
     fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {

compiler/rustc_index/src/vec.rs

@@ -17,10 +17,12 @@ pub trait Idx: Copy + 'static + Eq + PartialEq + Debug + Hash {
 
     fn index(self) -> usize;
 
+    #[inline]
     fn increment_by(&mut self, amount: usize) {
         *self = self.plus(amount);
     }
 
+    #[inline]
     fn plus(self, amount: usize) -> Self {
         Self::new(self.index() + amount)
     }