Revert "change skolemizations to use universe index"

This reverts commit 35e78b5.

src/librustc/ty/mod.rs

@@ -67,7 +67,7 @@ pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
 pub use self::sty::{ExistentialProjection, PolyExistentialProjection, Const};
 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
 pub use self::sty::RegionKind;
-pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid};
+pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid, SkolemizedRegionVid};
 pub use self::sty::BoundRegion::*;
 pub use self::sty::InferTy::*;
 pub use self::sty::RegionKind::*;
@@ -1328,7 +1328,7 @@ impl<'tcx> InstantiatedPredicates<'tcx> {
 /// type name in a non-zero universe is a skolemized type -- an
 /// idealized representative of "types in general" that we use for
 /// checking generic functions.
-#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct UniverseIndex(u32);
 
 impl UniverseIndex {
@@ -1348,19 +1348,7 @@ impl UniverseIndex {
     /// region `'a`, but that region was not nameable from `U` because
     /// it was not in scope there.
     pub fn subuniverse(self) -> UniverseIndex {
-        UniverseIndex(self.0.checked_add(1).unwrap())
-    }
-
-    pub fn from(v: u32) -> UniverseIndex {
-        UniverseIndex(v)
-    }
-
-    pub fn as_u32(&self) -> u32 {
-        self.0
-    }
-
-    pub fn as_usize(&self) -> usize {
-        self.0 as usize
+        UniverseIndex(self.0 + 1)
     }
 
     /// Gets the "depth" of this universe in the universe tree. This

src/librustc/ty/sty.rs

@@ -1028,7 +1028,7 @@ pub enum RegionKind {
 
     /// A skolemized region - basically the higher-ranked version of ReFree.
     /// Should not exist after typeck.
-    ReSkolemized(ty::UniverseIndex, BoundRegion),
+    ReSkolemized(SkolemizedRegionVid, BoundRegion),
 
     /// Empty lifetime is for data that is never accessed.
     /// Bottom in the region lattice. We treat ReEmpty somewhat
@@ -1082,6 +1082,11 @@ newtype_index!(RegionVid
         DEBUG_FORMAT = custom,
     });
 
+#[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, PartialOrd, Ord)]
+pub struct SkolemizedRegionVid {
+    pub index: u32,
+}
+
 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
 pub enum InferTy {
     TyVar(TyVid),

src/librustc/util/ppaux.rs

@@ -793,7 +793,7 @@ define_print! {
                 }
 
                 ty::ReSkolemized(id, ref bound_region) => {
-                    write!(f, "ReSkolemized({:?}, {:?})", id, bound_region)
+                    write!(f, "ReSkolemized({}, {:?})", id.index, bound_region)
                 }
 
                 ty::ReEmpty => write!(f, "ReEmpty"),