Turn `HirLocalId` into a `newtype_index`

6 files changed, 36 insertions, 42 deletions

diff --git a/src/librustc/dep_graph/dep_node.rs b/src/librustc/dep_graph/dep_node.rs
index 61996b5a8a7..3ff2545f78d 100644
--- a/src/librustc/dep_graph/dep_node.rs
+++ b/src/librustc/dep_graph/dep_node.rs
@@ -63,7 +63,7 @@
 use mir::interpret::GlobalId;
 use hir::def_id::{CrateNum, DefId, DefIndex, CRATE_DEF_INDEX};
 use hir::map::DefPathHash;
-use hir::{HirId, ItemLocalId};
+use hir::HirId;
 
 use ich::{Fingerprint, StableHashingContext};
 use rustc_data_structures::stable_hasher::{StableHasher, HashStable};
@@ -790,11 +790,11 @@ impl<'a, 'gcx: 'tcx + 'a, 'tcx: 'a> DepNodeParams<'a, 'gcx, 'tcx> for HirId {
     fn to_fingerprint(&self, tcx: TyCtxt<'_, '_, '_>) -> Fingerprint {
         let HirId {
             owner,
-            local_id: ItemLocalId(local_id),
+            local_id,
         } = *self;
 
         let def_path_hash = tcx.def_path_hash(DefId::local(owner));
-        let local_id = Fingerprint::from_smaller_hash(local_id as u64);
+        let local_id = Fingerprint::from_smaller_hash(local_id.as_u32().into());
 
         def_path_hash.0.combine(local_id)
     }
diff --git a/src/librustc/hir/lowering.rs b/src/librustc/hir/lowering.rs
index dd5d4b8f6af..e532b50a28b 100644
--- a/src/librustc/hir/lowering.rs
+++ b/src/librustc/hir/lowering.rs
@@ -588,7 +588,7 @@ impl<'a> LoweringContext<'a> {
             *local_id_counter += 1;
             hir::HirId {
                 owner: def_index,
-                local_id: hir::ItemLocalId(local_id),
+                local_id: hir::ItemLocalId::from_u32(local_id),
             }
         })
     }
@@ -616,7 +616,7 @@ impl<'a> LoweringContext<'a> {
 
             hir::HirId {
                 owner: def_index,
-                local_id: hir::ItemLocalId(local_id),
+                local_id: hir::ItemLocalId::from_u32(local_id),
             }
         })
     }
diff --git a/src/librustc/hir/map/hir_id_validator.rs b/src/librustc/hir/map/hir_id_validator.rs
index 501c17867f0..ac4119dc372 100644
--- a/src/librustc/hir/map/hir_id_validator.rs
+++ b/src/librustc/hir/map/hir_id_validator.rs
@@ -101,7 +101,7 @@ impl<'a, 'hir: 'a> HirIdValidator<'a, 'hir> {
         if max != self.hir_ids_seen.len() - 1 {
             // Collect the missing ItemLocalIds
             let missing: Vec<_> = (0 .. max as u32 + 1)
-              .filter(|&i| !self.hir_ids_seen.contains_key(&ItemLocalId(i)))
+              .filter(|&i| !self.hir_ids_seen.contains_key(&ItemLocalId::from_u32(i)))
               .collect();
 
             // Try to map those to something more useful
@@ -110,7 +110,7 @@ impl<'a, 'hir: 'a> HirIdValidator<'a, 'hir> {
             for local_id in missing {
                 let hir_id = HirId {
                     owner: owner_def_index,
-                    local_id: ItemLocalId(local_id as u32),
+                    local_id: ItemLocalId::from_u32(local_id),
                 };
 
                 trace!("missing hir id {:#?}", hir_id);
diff --git a/src/librustc/hir/mod.rs b/src/librustc/hir/mod.rs
index f57e3ff913b..bfe16493805 100644
--- a/src/librustc/hir/mod.rs
+++ b/src/librustc/hir/mod.rs
@@ -37,7 +37,6 @@ use syntax::util::parser::ExprPrecedence;
 use ty::AdtKind;
 use ty::query::Providers;
 
-use rustc_data_structures::indexed_vec;
 use rustc_data_structures::sync::{ParallelIterator, par_iter, Send, Sync, scope};
 use rustc_data_structures::thin_vec::ThinVec;
 
@@ -121,40 +120,28 @@ impl serialize::UseSpecializedDecodable for HirId {
     }
 }
 
-
-/// An `ItemLocalId` uniquely identifies something within a given "item-like",
-/// that is within a hir::Item, hir::TraitItem, or hir::ImplItem. There is no
-/// guarantee that the numerical value of a given `ItemLocalId` corresponds to
-/// the node's position within the owning item in any way, but there is a
-/// guarantee that the `LocalItemId`s within an owner occupy a dense range of
-/// integers starting at zero, so a mapping that maps all or most nodes within
-/// an "item-like" to something else can be implement by a `Vec` instead of a
-/// tree or hash map.
-#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug,
-         RustcEncodable, RustcDecodable)]
-pub struct ItemLocalId(pub u32);
-
-impl ItemLocalId {
-    pub fn as_usize(&self) -> usize {
-        self.0 as usize
+// hack to ensure that we don't try to access the private parts of `NodeId` in this module
+mod item_local_id_inner {
+    use rustc_data_structures::indexed_vec::Idx;
+    /// An `ItemLocalId` uniquely identifies something within a given "item-like",
+    /// that is within a hir::Item, hir::TraitItem, or hir::ImplItem. There is no
+    /// guarantee that the numerical value of a given `ItemLocalId` corresponds to
+    /// the node's position within the owning item in any way, but there is a
+    /// guarantee that the `LocalItemId`s within an owner occupy a dense range of
+    /// integers starting at zero, so a mapping that maps all or most nodes within
+    /// an "item-like" to something else can be implement by a `Vec` instead of a
+    /// tree or hash map.
+    newtype_index! {
+        pub struct ItemLocalId { .. }
     }
 }
 
-impl indexed_vec::Idx for ItemLocalId {
-    fn new(idx: usize) -> Self {
-        debug_assert!((idx as u32) as usize == idx);
-        ItemLocalId(idx as u32)
-    }
-
-    fn index(self) -> usize {
-        self.0 as usize
-    }
-}
+pub use self::item_local_id_inner::ItemLocalId;
 
 /// The `HirId` corresponding to CRATE_NODE_ID and CRATE_DEF_INDEX
 pub const CRATE_HIR_ID: HirId = HirId {
     owner: CRATE_DEF_INDEX,
-    local_id: ItemLocalId(0)
+    local_id: ItemLocalId::from_u32_const(0)
 };
 
 pub const DUMMY_HIR_ID: HirId = HirId {
@@ -162,7 +149,7 @@ pub const DUMMY_HIR_ID: HirId = HirId {
     local_id: DUMMY_ITEM_LOCAL_ID,
 };
 
-pub const DUMMY_ITEM_LOCAL_ID: ItemLocalId = ItemLocalId(!0);
+pub const DUMMY_ITEM_LOCAL_ID: ItemLocalId = ItemLocalId::MAX;
 
 #[derive(Clone, RustcEncodable, RustcDecodable, Copy)]
 pub struct Label {
diff --git a/src/librustc/ich/impls_hir.rs b/src/librustc/ich/impls_hir.rs
index b220634d0d9..ae0d78d2958 100644
--- a/src/librustc/ich/impls_hir.rs
+++ b/src/librustc/ich/impls_hir.rs
@@ -79,7 +79,14 @@ impl<'a> ToStableHashKey<StableHashingContext<'a>> for CrateNum {
     }
 }
 
-impl_stable_hash_for!(tuple_struct hir::ItemLocalId { index });
+impl<'a> HashStable<StableHashingContext<'a>> for hir::ItemLocalId {
+    #[inline]
+    fn hash_stable<W: StableHasherResult>(&self,
+                                          hcx: &mut StableHashingContext<'a>,
+                                          hasher: &mut StableHasher<W>) {
+        self.as_u32().hash_stable(hcx, hasher);
+    }
+}
 
 impl<'a> ToStableHashKey<StableHashingContext<'a>>
 for hir::ItemLocalId {
@@ -800,7 +807,7 @@ impl<'a> HashStable<StableHashingContext<'a>> for hir::Mod {
             .iter()
             .map(|id| {
                 let (def_path_hash, local_id) = id.id.to_stable_hash_key(hcx);
-                debug_assert_eq!(local_id, hir::ItemLocalId(0));
+                debug_assert_eq!(local_id, hir::ItemLocalId::from_u32(0));
                 def_path_hash.0
             }).fold(Fingerprint::ZERO, |a, b| {
                 a.combine_commutative(b)
diff --git a/src/librustc_driver/pretty.rs b/src/librustc_driver/pretty.rs
index b26d4fd09e9..c7ba31e3395 100644
--- a/src/librustc_driver/pretty.rs
+++ b/src/librustc_driver/pretty.rs
@@ -425,7 +425,7 @@ impl<'hir> pprust_hir::PpAnn for IdentifiedAnnotation<'hir> {
             pprust_hir::AnnNode::Item(item) => {
                 s.s.space()?;
                 s.synth_comment(format!("node_id: {} hir local_id: {}",
-                                        item.id, item.hir_id.local_id.0))
+                                        item.id, item.hir_id.local_id.as_u32()))
             }
             pprust_hir::AnnNode::SubItem(id) => {
                 s.s.space()?;
@@ -434,18 +434,18 @@ impl<'hir> pprust_hir::PpAnn for IdentifiedAnnotation<'hir> {
             pprust_hir::AnnNode::Block(blk) => {
                 s.s.space()?;
                 s.synth_comment(format!("block node_id: {} hir local_id: {}",
-                                        blk.id, blk.hir_id.local_id.0))
+                                        blk.id, blk.hir_id.local_id.as_u32()))
             }
             pprust_hir::AnnNode::Expr(expr) => {
                 s.s.space()?;
                 s.synth_comment(format!("node_id: {} hir local_id: {}",
-                                        expr.id, expr.hir_id.local_id.0))?;
+                                        expr.id, expr.hir_id.local_id.as_u32()))?;
                 s.pclose()
             }
             pprust_hir::AnnNode::Pat(pat) => {
                 s.s.space()?;
                 s.synth_comment(format!("pat node_id: {} hir local_id: {}",
-                                        pat.id, pat.hir_id.local_id.0))
+                                        pat.id, pat.hir_id.local_id.as_u32()))
             }
         }
     }