Declare DebruijnIndex via newtype_index macro

Author: fdrinck

src/librustc/infer/error_reporting/nice_region_error/find_anon_type.rs

@@ -77,7 +77,7 @@ impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
             tcx: self.tcx,
             bound_region: *br,
             found_type: None,
-            current_index: ty::DebruijnIndex::INNERMOST,
+            current_index: ty::INNERMOST,
         };
         nested_visitor.visit_ty(arg);
         nested_visitor.found_type

src/librustc/infer/higher_ranked/mod.rs

@@ -417,8 +417,7 @@ impl<'a, 'gcx, 'tcx> CombineFields<'a, 'gcx, 'tcx> {
         {
             for (a_br, a_r) in a_map {
                 if *a_r == r {
-                    return infcx.tcx.mk_region(ty::ReLateBound(ty::DebruijnIndex::INNERMOST,
-                                                               *a_br));
+                    return infcx.tcx.mk_region(ty::ReLateBound(ty::INNERMOST, *a_br));
                 }
             }
             span_bug!(
@@ -735,7 +734,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                     // trait checking, and all of the skolemized regions
                     // appear inside predicates, which always have
                     // binders, so this assert is satisfied.
-                    assert!(current_depth > ty::DebruijnIndex::INNERMOST);
+                    assert!(current_depth > ty::INNERMOST);
 
                     // since leak-check passed, this skolemized region
                     // should only have incoming edges from variables

src/librustc/middle/resolve_lifetime.rs

@@ -98,7 +98,7 @@ impl Region {
     }
 
     fn late(hir_map: &Map, def: &hir::LifetimeDef) -> (hir::LifetimeName, Region) {
-        let depth = ty::DebruijnIndex::INNERMOST;
+        let depth = ty::INNERMOST;
         let def_id = hir_map.local_def_id(def.lifetime.id);
         let origin = LifetimeDefOrigin::from_is_in_band(def.in_band);
         debug!(
@@ -114,7 +114,7 @@ impl Region {
     fn late_anon(index: &Cell<u32>) -> Region {
         let i = index.get();
         index.set(i + 1);
-        let depth = ty::DebruijnIndex::INNERMOST;
+        let depth = ty::INNERMOST;
         Region::LateBoundAnon(depth, i)
     }
 
@@ -1861,7 +1861,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
             .map(|(i, input)| {
                 let mut gather = GatherLifetimes {
                     map: self.map,
-                    outer_index: ty::DebruijnIndex::INNERMOST,
+                    outer_index: ty::INNERMOST,
                     have_bound_regions: false,
                     lifetimes: FxHashSet(),
                 };

src/librustc/ty/flags.rs

@@ -24,7 +24,7 @@ impl FlagComputation {
     fn new() -> FlagComputation {
         FlagComputation {
             flags: TypeFlags::empty(),
-            outer_exclusive_binder: ty::DebruijnIndex::INNERMOST,
+            outer_exclusive_binder: ty::INNERMOST,
         }
     }
 
@@ -60,7 +60,7 @@ impl FlagComputation {
         // a region binder, so subtract one from the region depth
         // within when adding the depth to `self`.
         let outer_exclusive_binder = computation.outer_exclusive_binder;
-        if outer_exclusive_binder > ty::DebruijnIndex::INNERMOST {
+        if outer_exclusive_binder > ty::INNERMOST {
             self.add_exclusive_binder(outer_exclusive_binder.shifted_out(1));
         } else {
             // otherwise, this binder captures nothing

src/librustc/ty/fold.rs

@@ -78,7 +78,7 @@ pub trait TypeFoldable<'tcx>: fmt::Debug + Clone {
     }
 
     fn has_escaping_regions(&self) -> bool {
-        self.has_regions_bound_at_or_above(ty::DebruijnIndex::INNERMOST)
+        self.has_regions_bound_at_or_above(ty::INNERMOST)
     }
 
     fn has_type_flags(&self, flags: TypeFlags) -> bool {
@@ -246,7 +246,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
               T: TypeFoldable<'tcx>,
     {
         value.visit_with(&mut RegionVisitor {
-            outer_index: ty::DebruijnIndex::INNERMOST,
+            outer_index: ty::INNERMOST,
             callback
         });
 
@@ -260,7 +260,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
             /// ^          ^          ^     ^
             /// |          |          |     | here, would be shifted in 1
             /// |          |          | here, would be shifted in 2
-            /// |          | here, would be INNTERMOST shifted in by 1
+            /// |          | here, would be INNERMOST shifted in by 1
             /// | here, initially, binder would be INNERMOST
             /// ```
             ///
@@ -333,7 +333,7 @@ impl<'a, 'gcx, 'tcx> RegionFolder<'a, 'gcx, 'tcx> {
         RegionFolder {
             tcx,
             skipped_regions,
-            current_index: ty::DebruijnIndex::INNERMOST,
+            current_index: ty::INNERMOST,
             fold_region_fn,
         }
     }
@@ -495,7 +495,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         let mut counter = 0;
         Binder::bind(self.replace_late_bound_regions(sig, |_| {
             counter += 1;
-            self.mk_region(ty::ReLateBound(ty::DebruijnIndex::INNERMOST, ty::BrAnon(counter)))
+            self.mk_region(ty::ReLateBound(ty::INNERMOST, ty::BrAnon(counter)))
         }).0)
     }
 }
@@ -507,7 +507,7 @@ impl<'a, 'gcx, 'tcx> RegionReplacer<'a, 'gcx, 'tcx> {
     {
         RegionReplacer {
             tcx,
-            current_index: ty::DebruijnIndex::INNERMOST,
+            current_index: ty::INNERMOST,
             fld_r,
             map: BTreeMap::default()
         }
@@ -542,7 +542,7 @@ impl<'a, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for RegionReplacer<'a, 'gcx, 'tcx> {
                     // that region should always use the INNERMOST
                     // debruijn index. Then we adjust it to the
                     // correct depth.
-                    assert_eq!(debruijn1, ty::DebruijnIndex::INNERMOST);
+                    assert_eq!(debruijn1, ty::INNERMOST);
                     self.tcx.mk_region(ty::ReLateBound(debruijn, br))
                 } else {
                     region
@@ -701,7 +701,7 @@ struct LateBoundRegionsCollector {
 impl LateBoundRegionsCollector {
     fn new(just_constrained: bool) -> Self {
         LateBoundRegionsCollector {
-            current_index: ty::DebruijnIndex::INNERMOST,
+            current_index: ty::INNERMOST,
             regions: FxHashSet(),
             just_constrained,
         }

src/librustc/ty/mod.rs

@@ -60,7 +60,7 @@ use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
 
 use hir;
 
-pub use self::sty::{Binder, CanonicalVar, DebruijnIndex};
+pub use self::sty::{Binder, CanonicalVar, DebruijnIndex, INNERMOST};
 pub use self::sty::{FnSig, GenSig, PolyFnSig, PolyGenSig};
 pub use self::sty::{InferTy, ParamTy, ProjectionTy, ExistentialPredicate};
 pub use self::sty::{ClosureSubsts, GeneratorSubsts, UpvarSubsts, TypeAndMut};

src/librustc/ty/sty.rs

@@ -1021,12 +1021,10 @@ impl<'a, 'gcx, 'tcx> ParamTy {
 /// is the outer fn.
 ///
 /// [dbi]: http://en.wikipedia.org/wiki/De_Bruijn_index
-#[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, Debug, Copy, PartialOrd, Ord)]
-pub struct DebruijnIndex {
-    /// We maintain the invariant that this is never 0. So 1 indicates
-    /// the innermost binder.
-    index: u32,
-}
+newtype_index!(DebruijnIndex
+    {
+        const INNERMOST = 0,
+    });
 
 pub type Region<'tcx> = &'tcx RegionKind;
 
@@ -1259,8 +1257,6 @@ impl<'a, 'tcx, 'gcx> PolyExistentialProjection<'tcx> {
 }
 
 impl DebruijnIndex {
-    pub const INNERMOST: DebruijnIndex = DebruijnIndex { index: 0 };
-
     /// Returns the resulting index when this value is moved into
     /// `amount` number of new binders. So e.g. if you had
     ///
@@ -1272,8 +1268,8 @@ impl DebruijnIndex {
     ///
     /// you would need to shift the index for `'a` into 1 new binder.
     #[must_use]
-    pub const fn shifted_in(self, amount: u32) -> DebruijnIndex {
-        DebruijnIndex { index: self.index + amount }
+    pub fn shifted_in(self, amount: u32) -> DebruijnIndex {
+        DebruijnIndex::new(self.index() + amount as usize)
     }
 
     /// Update this index in place by shifting it "in" through
@@ -1285,8 +1281,8 @@ impl DebruijnIndex {
     /// Returns the resulting index when this value is moved out from
     /// `amount` number of new binders.
     #[must_use]
-    pub const fn shifted_out(self, amount: u32) -> DebruijnIndex {
-        DebruijnIndex { index: self.index - amount }
+    pub fn shifted_out(self, amount: u32) -> DebruijnIndex {
+        DebruijnIndex::new(self.index() - amount as usize)
     }
 
     /// Update in place by shifting out from `amount` binders.
@@ -1315,13 +1311,11 @@ impl DebruijnIndex {
     /// bound by one of the binders we are shifting out of, that is an
     /// error (and should fail an assertion failure).
     pub fn shifted_out_to_binder(self, to_binder: DebruijnIndex) -> Self {
-        self.shifted_out(to_binder.index - Self::INNERMOST.index)
+        self.shifted_out((to_binder.index() - INNERMOST.index()) as u32)
     }
 }
 
-impl_stable_hash_for!(struct DebruijnIndex {
-    index
-});
+impl_stable_hash_for!(tuple_struct DebruijnIndex { index });
 
 /// Region utilities
 impl RegionKind {

src/librustc/ty/util.rs

@@ -555,7 +555,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
                           -> Option<ty::Binder<Ty<'tcx>>>
     {
         let closure_ty = self.mk_closure(closure_def_id, closure_substs);
-        let env_region = ty::ReLateBound(ty::DebruijnIndex::INNERMOST, ty::BrEnv);
+        let env_region = ty::ReLateBound(ty::INNERMOST, ty::BrEnv);
         let closure_kind_ty = closure_substs.closure_kind_ty(closure_def_id, self);
         let closure_kind = closure_kind_ty.to_opt_closure_kind()?;
         let env_ty = match closure_kind {

src/librustc/util/ppaux.rs

@@ -526,7 +526,7 @@ impl PrintContext {
                     ty::BrNamed(tcx.hir.local_def_id(CRATE_NODE_ID), name)
                 }
             };
-            tcx.mk_region(ty::ReLateBound(ty::DebruijnIndex::INNERMOST, br))
+            tcx.mk_region(ty::ReLateBound(ty::INNERMOST, br))
         }).0;
         start_or_continue(f, "", "> ")?;
 

src/librustc_codegen_llvm/common.rs

@@ -425,7 +425,7 @@ pub fn ty_fn_sig<'a, 'tcx>(cx: &CodegenCx<'a, 'tcx>,
             let tcx = cx.tcx;
             let sig = substs.poly_sig(def_id, cx.tcx);
 
-            let env_region = ty::ReLateBound(ty::DebruijnIndex::INNERMOST, ty::BrEnv);
+            let env_region = ty::ReLateBound(ty::INNERMOST, ty::BrEnv);
             let env_ty = tcx.mk_mut_ref(tcx.mk_region(env_region), ty);
 
             sig.map_bound(|sig| {