rustc: make LocalDefId's index field public like DefId's is.

src/librustc/hir/map/mod.rs

@@ -263,7 +263,7 @@ impl<'hir> Map<'hir> {
 
     #[inline]
     pub fn local_def_id_to_hir_id(&self, def_id: LocalDefId) -> HirId {
-        self.tcx.definitions.def_index_to_hir_id(def_id.to_def_id().index)
+        self.tcx.definitions.def_index_to_hir_id(def_id.local_def_index)
     }
 
     pub fn def_kind(&self, hir_id: HirId) -> Option<DefKind> {

src/librustc/ty/context.rs

@@ -735,7 +735,7 @@ impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for TypeckTables<'tcx> {
                 let var_owner_def_id =
                     DefId { krate: local_id_root.krate, index: var_path.hir_id.owner };
                 let closure_def_id =
-                    DefId { krate: local_id_root.krate, index: closure_expr_id.to_def_id().index };
+                    DefId { krate: local_id_root.krate, index: closure_expr_id.local_def_index };
                 (
                     hcx.def_path_hash(var_owner_def_id),
                     var_path.hir_id.local_id,

src/librustc_hir/hir_id.rs

@@ -24,7 +24,7 @@ impl HirId {
     }
 
     pub fn owner_local_def_id(self) -> LocalDefId {
-        LocalDefId::from_def_id(DefId::local(self.owner))
+        LocalDefId { local_def_index: self.owner }
     }
 }
 

src/librustc_span/def_id.rs

@@ -211,18 +211,20 @@ rustc_data_structures::define_id_collections!(DefIdMap, DefIdSet, DefId);
 /// and a DefId from a different crate would signify a bug somewhere. This
 /// is when LocalDefId comes in handy.
 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
-pub struct LocalDefId(DefIndex);
+pub struct LocalDefId {
+    pub local_def_index: DefIndex,
+}
 
 impl LocalDefId {
     #[inline]
     pub fn from_def_id(def_id: DefId) -> LocalDefId {
         assert!(def_id.is_local());
-        LocalDefId(def_id.index)
+        LocalDefId { local_def_index: def_id.index }
     }
 
     #[inline]
     pub fn to_def_id(self) -> DefId {
-        DefId { krate: LOCAL_CRATE, index: self.0 }
+        DefId { krate: LOCAL_CRATE, index: self.local_def_index }
     }
 }