Refactor ty_var and ty_var_integral into one ty_infer variant

17 files changed, 182 insertions, 174 deletions

diff --git a/src/rustc/metadata/tydecode.rs b/src/rustc/metadata/tydecode.rs
index 3bd4cdd47db..24f706eeb46 100644
--- a/src/rustc/metadata/tydecode.rs
+++ b/src/rustc/metadata/tydecode.rs
@@ -274,7 +274,7 @@ fn parse_ty(st: @pstate, conv: conv_did) -> ty::t {
         parse_ty_rust_fn(st, conv)
       }
       'X' => {
-        return ty::mk_var(st.tcx, ty::tv_vid(parse_int(st) as uint));
+        return ty::mk_var(st.tcx, ty::ty_vid(parse_int(st) as uint));
       }
       'Y' => return ty::mk_type(st.tcx),
       'C' => {
diff --git a/src/rustc/metadata/tyencode.rs b/src/rustc/metadata/tyencode.rs
index 42a258e836f..0ecb9dc3dc0 100644
--- a/src/rustc/metadata/tyencode.rs
+++ b/src/rustc/metadata/tyencode.rs
@@ -274,11 +274,11 @@ fn enc_sty(w: io::Writer, cx: @ctxt, st: ty::sty) {
       ty::ty_fn(f) => {
         enc_ty_fn(w, cx, f);
       }
-      ty::ty_var(id) => {
+      ty::ty_infer(ty::TyVar(id)) => {
         w.write_char('X');
         w.write_uint(id.to_uint());
       }
-      ty::ty_var_integral(id) => {
+      ty::ty_infer(ty::IntVar(id)) => {
         w.write_char('X');
         w.write_char('I');
         w.write_uint(id.to_uint());
diff --git a/src/rustc/middle/trans/reflect.rs b/src/rustc/middle/trans/reflect.rs
index c6d35e85826..5aeddac8ab3 100644
--- a/src/rustc/middle/trans/reflect.rs
+++ b/src/rustc/middle/trans/reflect.rs
@@ -272,8 +272,7 @@ impl reflector {
 
           // Miscallaneous extra types
           ty::ty_trait(_, _, _) => self.leaf(~"trait"),
-          ty::ty_var(_) => self.leaf(~"var"),
-          ty::ty_var_integral(_) => self.leaf(~"var_integral"),
+          ty::ty_infer(_) => self.leaf(~"infer"),
           ty::ty_param(p) => self.visit(~"param", ~[self.c_uint(p.idx)]),
           ty::ty_self => self.leaf(~"self"),
           ty::ty_type => self.leaf(~"type"),
diff --git a/src/rustc/middle/trans/shape.rs b/src/rustc/middle/trans/shape.rs
index 0ff538b3f90..92ee4e5dc90 100644
--- a/src/rustc/middle/trans/shape.rs
+++ b/src/rustc/middle/trans/shape.rs
@@ -363,7 +363,7 @@ fn shape_of(ccx: @crate_ctxt, t: ty::t) -> ~[u8] {
         ~[shape_bare_fn],
       ty::ty_opaque_closure_ptr(_) =>
         ~[shape_opaque_closure_ptr],
-      ty::ty_var(_) | ty::ty_var_integral(_) | ty::ty_self =>
+      ty::ty_infer(_) | ty::ty_self =>
         ccx.sess.bug(~"shape_of: unexpected type struct found")
     }
 }
diff --git a/src/rustc/middle/trans/type_of.rs b/src/rustc/middle/trans/type_of.rs
index 40bf644c626..3cdb132f26c 100644
--- a/src/rustc/middle/trans/type_of.rs
+++ b/src/rustc/middle/trans/type_of.rs
@@ -171,11 +171,8 @@ fn type_of(cx: @crate_ctxt, t: ty::t) -> TypeRef {
         common::T_named_struct(llvm_type_name(cx, a_class, did, substs.tps))
       }
       ty::ty_self => cx.tcx.sess.unimpl(~"type_of: ty_self"),
-      ty::ty_var(_) => cx.tcx.sess.bug(~"type_of with ty_var"),
+      ty::ty_infer(*) => cx.tcx.sess.bug(~"type_of with ty_infer"),
       ty::ty_param(*) => cx.tcx.sess.bug(~"type_of with ty_param"),
-      ty::ty_var_integral(_) => {
-        cx.tcx.sess.bug(~"type_of shouldn't see a ty_var_integral");
-      }
     };
 
     cx.lltypes.insert(t, llty);
diff --git a/src/rustc/middle/ty.rs b/src/rustc/middle/ty.rs
index 85ef0797437..2f352efc864 100644
--- a/src/rustc/middle/ty.rs
+++ b/src/rustc/middle/ty.rs
@@ -21,7 +21,7 @@ use util::ppaux::{ty_to_str, proto_ty_to_str, tys_to_str};
 use std::serialization::{serialize_Option,
                             deserialize_Option};
 
-export tv_vid, tvi_vid, region_vid, vid;
+export ty_vid, int_vid, region_vid, vid;
 export br_hashmap;
 export is_instantiable;
 export node_id_to_type;
@@ -99,8 +99,8 @@ export ty_tup, mk_tup;
 export ty_type, mk_type;
 export ty_uint, mk_uint, mk_mach_uint;
 export ty_uniq, mk_uniq, mk_imm_uniq, type_is_unique_box;
-export ty_var, mk_var, type_is_var;
-export ty_var_integral, mk_var_integral, type_is_var_integral;
+export ty_infer, mk_infer, type_is_ty_var, mk_var, mk_int_var;
+export InferTy, TyVar, IntVar;
 export ty_self, mk_self, type_has_self;
 export ty_class;
 export region, bound_region, encl_region;
@@ -510,12 +510,11 @@ enum sty {
     ty_class(def_id, substs),
     ty_tup(~[t]),
 
-    ty_var(tv_vid), // type variable during typechecking
-    ty_var_integral(tvi_vid), // type variable during typechecking, for
-                              // integral types only
     ty_param(param_ty), // type parameter
     ty_self, // special, implicit `self` type parameter
 
+    ty_infer(InferTy), // soething used only during inference/typeck
+
     // "Fake" types, used for trans purposes
     ty_type, // type_desc*
     ty_opaque_box, // used by monomorphizer to represent any @ box
@@ -568,21 +567,26 @@ enum param_bound {
     bound_trait(t),
 }
 
-enum tv_vid = uint;
-enum tvi_vid = uint;
+enum ty_vid = uint;
+enum int_vid = uint;
 enum region_vid = uint;
 
+enum InferTy {
+    TyVar(ty_vid),
+    IntVar(int_vid)
+}
+
 trait vid {
     pure fn to_uint() -> uint;
     pure fn to_str() -> ~str;
 }
 
-impl tv_vid: vid {
+impl ty_vid: vid {
     pure fn to_uint() -> uint { *self }
     pure fn to_str() -> ~str { fmt!("<V%u>", self.to_uint()) }
 }
 
-impl tvi_vid: vid {
+impl int_vid: vid {
     pure fn to_uint() -> uint { *self }
     pure fn to_str() -> ~str { fmt!("<VI%u>", self.to_uint()) }
 }
@@ -592,6 +596,22 @@ impl region_vid: vid {
     pure fn to_str() -> ~str { fmt!("%?", self) }
 }
 
+impl InferTy {
+    pure fn to_hash() -> uint {
+        match self {
+            TyVar(v) => v.to_uint() << 1,
+            IntVar(v) => (v.to_uint() << 1) + 1
+        }
+    }
+
+    pure fn to_str() -> ~str {
+        match self {
+            TyVar(v) => v.to_str(),
+            IntVar(v) => v.to_str()
+        }
+    }
+}
+
 trait purity_to_str {
     pure fn to_str() -> ~str;
 }
@@ -744,7 +764,7 @@ fn mk_t_with_id(cx: ctxt, +st: sty, o_def_id: Option<ast::def_id>) -> t {
       ty_estr(_) | ty_type | ty_opaque_closure_ptr(_) |
       ty_opaque_box => (),
       ty_param(_) => flags |= has_params as uint,
-      ty_var(_) | ty_var_integral(_) => flags |= needs_infer as uint,
+      ty_infer(_) => flags |= needs_infer as uint,
       ty_self => flags |= has_self as uint,
       ty_enum(_, ref substs) | ty_class(_, ref substs)
       | ty_trait(_, ref substs, _) => {
@@ -882,12 +902,14 @@ fn mk_class(cx: ctxt, class_id: ast::def_id, +substs: substs) -> t {
     mk_t(cx, ty_class(class_id, substs))
 }
 
-fn mk_var(cx: ctxt, v: tv_vid) -> t { mk_t(cx, ty_var(v)) }
+fn mk_var(cx: ctxt, v: ty_vid) -> t { mk_infer(cx, TyVar(v)) }
 
-fn mk_var_integral(cx: ctxt, v: tvi_vid) -> t {
-    mk_t(cx, ty_var_integral(v))
+fn mk_int_var(cx: ctxt, v: int_vid) -> t {
+    mk_infer(cx, IntVar(v))
 }
 
+fn mk_infer(cx: ctxt, it: InferTy) -> t { mk_t(cx, ty_infer(it)) }
+
 fn mk_self(cx: ctxt) -> t { mk_t(cx, ty_self) }
 
 fn mk_param(cx: ctxt, n: uint, k: def_id) -> t {
@@ -939,8 +961,7 @@ fn maybe_walk_ty(ty: t, f: fn(t) -> bool) {
     match get(ty).struct {
       ty_nil | ty_bot | ty_bool | ty_int(_) | ty_uint(_) | ty_float(_) |
       ty_estr(_) | ty_type | ty_opaque_box | ty_self |
-      ty_opaque_closure_ptr(_) | ty_var(_) | ty_var_integral(_) |
-      ty_param(_) => {
+      ty_opaque_closure_ptr(_) | ty_infer(_) | ty_param(_) => {
       }
       ty_box(tm) | ty_evec(tm, _) | ty_unboxed_vec(tm) |
       ty_ptr(tm) | ty_rptr(_, tm) => {
@@ -1023,8 +1044,7 @@ fn fold_sty(sty: &sty, fldop: fn(t) -> t) -> sty {
       }
       ty_nil | ty_bot | ty_bool | ty_int(_) | ty_uint(_) | ty_float(_) |
       ty_estr(_) | ty_type | ty_opaque_closure_ptr(_) |
-      ty_opaque_box | ty_var(_) | ty_var_integral(_) |
-      ty_param(*) | ty_self => {
+      ty_opaque_box | ty_infer(_) | ty_param(*) | ty_self => {
         *sty
       }
     }
@@ -1240,16 +1260,9 @@ fn type_is_nil(ty: t) -> bool { get(ty).struct == ty_nil }
 
 fn type_is_bot(ty: t) -> bool { get(ty).struct == ty_bot }
 
-fn type_is_var(ty: t) -> bool {
+fn type_is_ty_var(ty: t) -> bool {
     match get(ty).struct {
-      ty_var(_) => true,
-      _ => false
-    }
-}
-
-fn type_is_var_integral(ty: t) -> bool {
-    match get(ty).struct {
-      ty_var_integral(_) => true,
+      ty_infer(TyVar(_)) => true,
       _ => false
     }
 }
@@ -1370,7 +1383,7 @@ pure fn type_is_unique(ty: t) -> bool {
 pure fn type_is_scalar(ty: t) -> bool {
     match get(ty).struct {
       ty_nil | ty_bool | ty_int(_) | ty_float(_) | ty_uint(_) |
-      ty_var_integral(_) | ty_type | ty_ptr(_) => true,
+      ty_infer(IntVar(_)) | ty_type | ty_ptr(_) => true,
       _ => false
     }
 }
@@ -1852,7 +1865,7 @@ fn type_kind(cx: ctxt, ty: t) -> kind {
       // is never bounded in any way, hence it has the bottom kind.
       ty_self => kind_noncopyable(),
 
-      ty_var(_) | ty_var_integral(_) => {
+      ty_infer(_) => {
         cx.sess.bug(~"Asked to compute kind of a type variable");
       }
       ty_type | ty_opaque_closure_ptr(_)
@@ -1923,7 +1936,7 @@ fn type_size(cx: ctxt, ty: t) -> uint {
         1
       }
 
-      ty_var(_) | ty_var_integral(_) => {
+      ty_infer(_) => {
         cx.sess.bug(~"Asked to compute kind of a type variable");
       }
       ty_type | ty_opaque_closure_ptr(_)
@@ -1969,8 +1982,7 @@ fn is_instantiable(cx: ctxt, r_ty: t) -> bool {
           ty_float(_) |
           ty_estr(_) |
           ty_fn(_) |
-          ty_var(_) |
-          ty_var_integral(_) |
+          ty_infer(_) |
           ty_param(_) |
           ty_self |
           ty_type |
@@ -2103,7 +2115,7 @@ fn type_structurally_contains_uniques(cx: ctxt, ty: t) -> bool {
 
 fn type_is_integral(ty: t) -> bool {
     match get(ty).struct {
-      ty_var_integral(_) | ty_int(_) | ty_uint(_) | ty_bool => true,
+      ty_infer(IntVar(_)) | ty_int(_) | ty_uint(_) | ty_bool => true,
       _ => false
     }
 }
@@ -2176,7 +2188,7 @@ fn type_is_pod(cx: ctxt, ty: t) -> bool {
         result = false;
       }
 
-      ty_var(*) | ty_var_integral(*) | ty_self(*) => {
+      ty_infer(*) | ty_self(*) => {
         cx.sess.bug(~"non concrete type in type_is_pod");
       }
     }
@@ -2353,8 +2365,7 @@ pure fn hash_type_structure(st: &sty) -> uint {
         hash_subty(h, f.output)
       }
       ty_self => 28u,
-      ty_var(v) => hash_uint(29u, v.to_uint()),
-      ty_var_integral(v) => hash_uint(30u, v.to_uint()),
+      ty_infer(v) => hash_uint(29u, v.to_hash()),
       ty_param(p) => hash_def(hash_uint(31u, p.idx), p.def_id),
       ty_type => 32u,
       ty_bot => 34u,
@@ -2462,21 +2473,23 @@ fn is_pred_ty(fty: t) -> bool {
     is_fn_ty(fty) && type_is_bool(ty_fn_ret(fty))
 }
 
-fn ty_var_id(typ: t) -> tv_vid {
+/*
+fn ty_var_id(typ: t) -> ty_vid {
     match get(typ).struct {
-      ty_var(vid) => return vid,
+      ty_infer(TyVar(vid)) => return vid,
       _ => { error!("ty_var_id called on non-var ty"); fail; }
     }
 }
 
-fn ty_var_integral_id(typ: t) -> tvi_vid {
+fn int_var_id(typ: t) -> int_vid {
     match get(typ).struct {
-      ty_var_integral(vid) => return vid,
+      ty_infer(IntVar(vid)) => return vid,
       _ => { error!("ty_var_integral_id called on ty other than \
                   ty_var_integral");
          fail; }
     }
 }
+*/
 
 // Type accessors for AST nodes
 fn block_ty(cx: ctxt, b: &ast::blk) -> t {
@@ -2752,15 +2765,15 @@ fn param_tys_in_type(ty: t) -> ~[param_ty] {
     rslt
 }
 
-fn occurs_check(tcx: ctxt, sp: span, vid: tv_vid, rt: t) {
+fn occurs_check(tcx: ctxt, sp: span, vid: ty_vid, rt: t) {
 
     // Returns a vec of all the type variables occurring in `ty`. It may
     // contain duplicates.  (Integral type vars aren't counted.)
-    fn vars_in_type(ty: t) -> ~[tv_vid] {
+    fn vars_in_type(ty: t) -> ~[ty_vid] {
         let mut rslt = ~[];
         do walk_ty(ty) |ty| {
             match get(ty).struct {
-              ty_var(v) => vec::push(rslt, v),
+              ty_infer(TyVar(v)) => vec::push(rslt, v),
               _ => ()
             }
         }
@@ -2876,8 +2889,8 @@ fn ty_sort_str(cx: ctxt, t: t) -> ~str {
       ty_trait(id, _, _) => fmt!("trait %s", item_path_str(cx, id)),
       ty_class(id, _) => fmt!("class %s", item_path_str(cx, id)),
       ty_tup(_) => ~"tuple",
-      ty_var(_) => ~"variable",
-      ty_var_integral(_) => ~"integral variable",
+      ty_infer(TyVar(_)) => ~"inferred type",
+      ty_infer(IntVar(_)) => ~"integral variable",
       ty_param(_) => ~"type parameter",
       ty_self => ~"self"
     }
@@ -3487,7 +3500,7 @@ fn is_binopable(_cx: ctxt, ty: t, op: ast::binop) -> bool {
     fn tycat(ty: t) -> int {
         match get(ty).struct {
           ty_bool => tycat_bool,
-          ty_int(_) | ty_uint(_) | ty_var_integral(_) => tycat_int,
+          ty_int(_) | ty_uint(_) | ty_infer(IntVar(_)) => tycat_int,
           ty_float(_) => tycat_float,
           ty_rec(_) | ty_tup(_) | ty_enum(_, _) => tycat_struct,
           ty_bot => tycat_bot,
@@ -3706,14 +3719,14 @@ impl fn_ty : cmp::Eq {
     }
 }
 
-impl tv_vid: cmp::Eq {
-    pure fn eq(&&other: tv_vid) -> bool {
+impl ty_vid: cmp::Eq {
+    pure fn eq(&&other: ty_vid) -> bool {
         *self == *other
     }
 }
 
-impl tvi_vid: cmp::Eq {
-    pure fn eq(&&other: tvi_vid) -> bool {
+impl int_vid: cmp::Eq {
+    pure fn eq(&&other: int_vid) -> bool {
         *self == *other
     }
 }
@@ -3800,6 +3813,12 @@ impl substs : cmp::Eq {
     }
 }
 
+impl InferTy : cmp::Eq {
+    pure fn eq(&&other: InferTy) -> bool {
+        self.to_hash() == other.to_hash()
+    }
+}
+
 impl sty : cmp::Eq {
     pure fn eq(&&other: sty) -> bool {
         match self {
@@ -3912,15 +3931,9 @@ impl sty : cmp::Eq {
                     _ => false
                 }
             }
-            ty_var(e0a) => {
-                match other {
-                    ty_var(e0b) => e0a == e0b,
-                    _ => false
-                }
-            }
-            ty_var_integral(e0a) => {
+            ty_infer(e0a) => {
                 match other {
-                    ty_var_integral(e0b) => e0a == e0b,
+                    ty_infer(e0b) => e0a == e0b,
                     _ => false
                 }
             }
diff --git a/src/rustc/middle/typeck/astconv.rs b/src/rustc/middle/typeck/astconv.rs
index df0b2e1c221..933629bdf91 100644
--- a/src/rustc/middle/typeck/astconv.rs
+++ b/src/rustc/middle/typeck/astconv.rs
@@ -422,7 +422,7 @@ fn ty_of_arg<AC: ast_conv, RS: region_scope copy owned>(
               // If the type is not specified, then this must be a fn expr.
               // Leave the mode as infer(_), it will get inferred based
               // on constraints elsewhere.
-              ty::ty_var(_) => a.mode,
+              ty::ty_infer(_) => a.mode,
 
               // If the type is known, then use the default for that type.
               // Here we unify m and the default.  This should update the
diff --git a/src/rustc/middle/typeck/check.rs b/src/rustc/middle/typeck/check.rs
index d74bf4f208e..52970baa547 100644
--- a/src/rustc/middle/typeck/check.rs
+++ b/src/rustc/middle/typeck/check.rs
@@ -60,7 +60,7 @@ type variable is rather an "instance" of a type parameter: that is,
 given a generic function `fn foo<T>(t: T)`: while checking the
 function `foo`, the type `ty_param(0)` refers to the type `T`, which
 is treated in abstract.  When `foo()` is called, however, `T` will be
-substituted for a fresh type variable `ty_var(N)`.  This variable will
+substituted for a fresh type variable `N`.  This variable will
 eventually be resolved to some concrete type (which might itself be
 type parameter).
 
@@ -68,7 +68,7 @@ type parameter).
 
 use astconv::{ast_conv, ast_path_to_ty, ast_ty_to_ty};
 use astconv::{ast_region_to_region};
-use middle::ty::{tv_vid, vid};
+use middle::ty::{ty_vid, vid};
 use regionmanip::{replace_bound_regions_in_fn_ty};
 use rscope::{anon_rscope, binding_rscope, empty_rscope, in_anon_rscope};
 use rscope::{in_binding_rscope, region_scope, type_rscope,
@@ -98,7 +98,7 @@ type self_info = {
 /// share the inherited fields.
 struct inherited {
     infcx: infer::infer_ctxt;
-    locals: hashmap<ast::node_id, tv_vid>;
+    locals: hashmap<ast::node_id, ty_vid>;
     node_types: hashmap<ast::node_id, ty::t>;
     node_type_substs: hashmap<ast::node_id, ty::substs>;
     borrowings: hashmap<ast::node_id, ty::borrow>;
@@ -749,33 +749,33 @@ fn do_autoderef(fcx: @fn_ctxt, sp: span, t: ty::t) -> ty::t {
 
         // Some extra checks to detect weird cycles and so forth:
         match sty {
-          ty::ty_box(inner) | ty::ty_uniq(inner) | ty::ty_rptr(_, inner) => {
-            match ty::get(t1).struct {
-              ty::ty_var(v1) => {
-                ty::occurs_check(fcx.ccx.tcx, sp, v1,
-                                 ty::mk_box(fcx.ccx.tcx, inner));
-              }
-              _ => ()
+            ty::ty_box(inner) | ty::ty_uniq(inner) | ty::ty_rptr(_, inner) => {
+                match ty::get(t1).struct {
+                    ty::ty_infer(ty::TyVar(v1)) => {
+                        ty::occurs_check(fcx.ccx.tcx, sp, v1,
+                                         ty::mk_box(fcx.ccx.tcx, inner));
+                    }
+                    _ => ()
+                }
             }
-          }
-          ty::ty_enum(did, _) => {
-            // Watch out for a type like `enum t = @t`.  Such a type would
-            // otherwise infinitely auto-deref.  This is the only autoderef
-            // loop that needs to be concerned with this, as an error will be
-            // reported on the enum definition as well because the enum is not
-            // instantiable.
-            if vec::contains(enum_dids, did) {
-                return t1;
+            ty::ty_enum(did, _) => {
+                // Watch out for a type like `enum t = @t`.  Such a type would
+                // otherwise infinitely auto-deref.  This is the only autoderef
+                // loop that needs to be concerned with this, as an error will be
+                // reported on the enum definition as well because the enum is not
+                // instantiable.
+                if vec::contains(enum_dids, did) {
+                    return t1;
+                }
+                vec::push(enum_dids, did);
             }
-            vec::push(enum_dids, did);
-          }
-          _ => { /*ok*/ }
+            _ => { /*ok*/ }
         }
 
         // Otherwise, deref if type is derefable:
         match ty::deref_sty(fcx.ccx.tcx, &sty, false) {
-          None => return t1,
-          Some(mt) => t1 = mt.ty
+            None => return t1,
+            Some(mt) => t1 = mt.ty
         }
     };
 }
@@ -791,7 +791,7 @@ fn check_lit(fcx: @fn_ctxt, lit: @ast::lit) -> ty::t {
       ast::lit_int_unsuffixed(_) => {
         // An unsuffixed integer literal could have any integral type,
         // so we create an integral type variable for it.
-        ty::mk_var_integral(tcx, fcx.infcx().next_ty_var_integral_id())
+        ty::mk_int_var(tcx, fcx.infcx().next_int_var_id())
       }
       ast::lit_float(_, t) => ty::mk_mach_float(tcx, t),
       ast::lit_nil => ty::mk_nil(tcx),
@@ -2304,7 +2304,7 @@ fn self_ref(fcx: @fn_ctxt, id: ast::node_id) -> bool {
                         ast_util::is_self)
 }
 
-fn lookup_local(fcx: @fn_ctxt, sp: span, id: ast::node_id) -> tv_vid {
+fn lookup_local(fcx: @fn_ctxt, sp: span, id: ast::node_id) -> ty_vid {
     match fcx.inh.locals.find(id) {
         Some(x) => x,
         _ => {
@@ -2441,7 +2441,7 @@ fn instantiate_path(fcx: @fn_ctxt,
 // resolution is possible, then an error is reported.
 fn structurally_resolved_type(fcx: @fn_ctxt, sp: span, tp: ty::t) -> ty::t {
     match infer::resolve_type(fcx.infcx(), tp, force_tvar) {
-        Ok(t_s) if !ty::type_is_var(t_s) => return t_s,
+        Ok(t_s) if !ty::type_is_ty_var(t_s) => return t_s,
         _ => {
             fcx.ccx.tcx.sess.span_fatal
                 (sp, ~"the type of this value must be known in this context");
diff --git a/src/rustc/middle/typeck/coherence.rs b/src/rustc/middle/typeck/coherence.rs
index a01b0983e70..c1473f08b82 100644
--- a/src/rustc/middle/typeck/coherence.rs
+++ b/src/rustc/middle/typeck/coherence.rs
@@ -12,9 +12,9 @@ use middle::ty::{get, lookup_item_type, subst, t, ty_box};
 use middle::ty::{ty_uniq, ty_ptr, ty_rptr, ty_enum};
 use middle::ty::{ty_class, ty_nil, ty_bot, ty_bool, ty_int, ty_uint};
 use middle::ty::{ty_float, ty_estr, ty_evec, ty_rec};
-use middle::ty::{ty_fn, ty_trait, ty_tup, ty_var, ty_var_integral};
+use middle::ty::{ty_fn, ty_trait, ty_tup, ty_infer};
 use middle::ty::{ty_param, ty_self, ty_type, ty_opaque_box};
-use middle::ty::{ty_opaque_closure_ptr, ty_unboxed_vec, type_is_var};
+use middle::ty::{ty_opaque_closure_ptr, ty_unboxed_vec, type_is_ty_var};
 use middle::typeck::infer::{infer_ctxt, can_mk_subty};
 use middle::typeck::infer::{new_infer_ctxt, resolve_ivar, resolve_type};
 use syntax::ast::{crate, def_id, def_mod};
@@ -43,7 +43,7 @@ fn get_base_type(inference_context: infer_ctxt, span: span, original_type: t)
     match resolve_type(inference_context,
                      original_type,
                      resolve_ivar) {
-        Ok(resulting_type) if !type_is_var(resulting_type) => {
+        Ok(resulting_type) if !type_is_ty_var(resulting_type) => {
             resolved_type = resulting_type;
         }
         _ => {
@@ -72,7 +72,7 @@ fn get_base_type(inference_context: infer_ctxt, span: span, original_type: t)
 
         ty_nil | ty_bot | ty_bool | ty_int(*) | ty_uint(*) | ty_float(*) |
         ty_estr(*) | ty_evec(*) | ty_rec(*) |
-        ty_fn(*) | ty_tup(*) | ty_var(*) | ty_var_integral(*) |
+        ty_fn(*) | ty_tup(*) | ty_infer(*) |
         ty_param(*) | ty_self | ty_type | ty_opaque_box |
         ty_opaque_closure_ptr(*) | ty_unboxed_vec(*) => {
             debug!("(getting base type) no base type; found %?",
diff --git a/src/rustc/middle/typeck/infer.rs b/src/rustc/middle/typeck/infer.rs
index c630ae432ad..a658ef044df 100644
--- a/src/rustc/middle/typeck/infer.rs
+++ b/src/rustc/middle/typeck/infer.rs
@@ -250,8 +250,8 @@ use std::smallintmap;
 use std::smallintmap::smallintmap;
 use std::map::hashmap;
 use middle::ty;
-use middle::ty::{tv_vid, tvi_vid, region_vid, vid,
-                    ty_int, ty_uint, get, terr_fn};
+use middle::ty::{ty_vid, int_vid, region_vid, vid,
+                 ty_int, ty_uint, get, terr_fn, TyVar, IntVar};
 use syntax::{ast, ast_util};
 use syntax::ast::{ret_style, purity};
 use util::ppaux::{ty_to_str, mt_to_str};
@@ -312,25 +312,25 @@ enum infer_ctxt = @{
     // We instantiate vals_and_bindings with bounds<ty::t> because the
     // types that might instantiate a general type variable have an
     // order, represented by its upper and lower bounds.
-    ty_var_bindings: vals_and_bindings<ty::tv_vid, bounds<ty::t>>,
+    ty_var_bindings: vals_and_bindings<ty::ty_vid, bounds<ty::t>>,
 
     // The types that might instantiate an integral type variable are
     // represented by an int_ty_set.
-    ty_var_integral_bindings: vals_and_bindings<ty::tvi_vid, int_ty_set>,
+    int_var_bindings: vals_and_bindings<ty::int_vid, int_ty_set>,
 
     // For region variables.
     region_vars: RegionVarBindings,
 
     // For keeping track of existing type and region variables.
     ty_var_counter: @mut uint,
-    ty_var_integral_counter: @mut uint,
+    int_var_counter: @mut uint,
     region_var_counter: @mut uint
 };
 
 enum fixup_err {
-    unresolved_int_ty(tvi_vid),
-    unresolved_ty(tv_vid),
-    cyclic_ty(tv_vid),
+    unresolved_int_ty(int_vid),
+    unresolved_ty(ty_vid),
+    cyclic_ty(ty_vid),
     unresolved_region(region_vid),
     region_var_bound_by_region_var(region_vid, region_vid)
 }
@@ -358,10 +358,10 @@ fn new_vals_and_bindings<V:copy, T:copy>() -> vals_and_bindings<V, T> {
 fn new_infer_ctxt(tcx: ty::ctxt) -> infer_ctxt {
     infer_ctxt(@{tcx: tcx,
                  ty_var_bindings: new_vals_and_bindings(),
-                 ty_var_integral_bindings: new_vals_and_bindings(),
+                 int_var_bindings: new_vals_and_bindings(),
                  region_vars: RegionVarBindings(tcx),
                  ty_var_counter: @mut 0u,
-                 ty_var_integral_counter: @mut 0u,
+                 int_var_counter: @mut 0u,
                  region_var_counter: @mut 0u})}
 
 fn mk_subty(cx: infer_ctxt, a_is_expected: bool, span: span,
@@ -508,7 +508,7 @@ fn rollback_to<V:copy vid, T:copy>(
 
 struct Snapshot {
     ty_var_bindings_len: uint;
-    ty_var_integral_bindings_len: uint;
+    int_var_bindings_len: uint;
     region_vars_snapshot: uint;
 }
 
@@ -532,8 +532,8 @@ impl infer_ctxt {
         Snapshot {
             ty_var_bindings_len:
                 self.ty_var_bindings.bindings.len(),
-            ty_var_integral_bindings_len:
-                self.ty_var_integral_bindings.bindings.len(),
+            int_var_bindings_len:
+                self.int_var_bindings.bindings.len(),
             region_vars_snapshot:
                 self.region_vars.start_snapshot(),
         }
@@ -543,9 +543,9 @@ impl infer_ctxt {
         debug!("rollback!");
         rollback_to(&self.ty_var_bindings, snapshot.ty_var_bindings_len);
 
-        // FIXME(#3211) -- ty_var_integral not transactional
-        //rollback_to(&self.ty_var_integral_bindings,
-        //            snapshot.ty_var_integral_bindings_len);
+        // FIXME(#3211) -- int_var not transactional
+        //rollback_to(&self.int_var_bindings,
+        //            snapshot.int_var_bindings_len);
 
         self.region_vars.rollback_to(
             snapshot.region_vars_snapshot);
@@ -563,7 +563,7 @@ impl infer_ctxt {
             // destructors but kept the vec at its currently allocated
             // length
             self.ty_var_bindings.bindings = ~[];
-            self.ty_var_integral_bindings.bindings = ~[];
+            self.int_var_bindings.bindings = ~[];
             self.region_vars.commit();
             r
         }
@@ -596,12 +596,12 @@ impl infer_ctxt {
 }
 
 impl infer_ctxt {
-    fn next_ty_var_id() -> tv_vid {
+    fn next_ty_var_id() -> ty_vid {
         let id = *self.ty_var_counter;
         *self.ty_var_counter += 1u;
         self.ty_var_bindings.vals.insert(id,
                                          root({lb: None, ub: None}, 0u));
-        return tv_vid(id);
+        return ty_vid(id);
     }
 
     fn next_ty_var() -> ty::t {
@@ -612,17 +612,17 @@ impl infer_ctxt {
         vec::from_fn(n, |_i| self.next_ty_var())
     }
 
-    fn next_ty_var_integral_id() -> tvi_vid {
-        let id = *self.ty_var_integral_counter;
-        *self.ty_var_integral_counter += 1u;
+    fn next_int_var_id() -> int_vid {
+        let id = *self.int_var_counter;
+        *self.int_var_counter += 1u;
 
-        self.ty_var_integral_bindings.vals.insert(id,
+        self.int_var_bindings.vals.insert(id,
                               root(int_ty_set_all(), 0u));
-        return tvi_vid(id);
+        return int_vid(id);
     }
 
-    fn next_ty_var_integral() -> ty::t {
-        ty::mk_var_integral(self.tcx, self.next_ty_var_integral_id())
+    fn next_int_var() -> ty::t {
+        ty::mk_int_var(self.tcx, self.next_int_var_id())
     }
 
     fn next_region_var_nb(span: span) -> ty::region {
diff --git a/src/rustc/middle/typeck/infer/assignment.rs b/src/rustc/middle/typeck/infer/assignment.rs
index 6faee7ad411..42dc90156f9 100644
--- a/src/rustc/middle/typeck/infer/assignment.rs
+++ b/src/rustc/middle/typeck/infer/assignment.rs
@@ -75,7 +75,7 @@ impl Assign {
                 Ok(None)
             }
 
-            (ty::ty_var(a_id), ty::ty_var(b_id)) => {
+            (ty::ty_infer(TyVar(a_id)), ty::ty_infer(TyVar(b_id))) => {
                 let nde_a = self.infcx.get(&self.infcx.ty_var_bindings, a_id);
                 let nde_b = self.infcx.get(&self.infcx.ty_var_bindings, b_id);
                 let a_bounds = nde_a.possible_types;
@@ -86,7 +86,7 @@ impl Assign {
                 self.assign_tys_or_sub(a, b, a_bnd, b_bnd)
             }
 
-            (ty::ty_var(a_id), _) => {
+            (ty::ty_infer(TyVar(a_id)), _) => {
                 let nde_a = self.infcx.get(&self.infcx.ty_var_bindings, a_id);
                 let a_bounds = nde_a.possible_types;
 
@@ -94,7 +94,7 @@ impl Assign {
                 self.assign_tys_or_sub(a, b, a_bnd, Some(b))
             }
 
-            (_, ty::ty_var(b_id)) => {
+            (_, ty::ty_infer(TyVar(b_id))) => {
                 let nde_b = self.infcx.get(&self.infcx.ty_var_bindings, b_id);
                 let b_bounds = nde_b.possible_types;
 
diff --git a/src/rustc/middle/typeck/infer/combine.rs b/src/rustc/middle/typeck/infer/combine.rs
index 4585be3e74a..2b194ebdf17 100644
--- a/src/rustc/middle/typeck/infer/combine.rs
+++ b/src/rustc/middle/typeck/infer/combine.rs
@@ -345,8 +345,8 @@ fn super_tys<C:combine>(
       // The "subtype" ought to be handling cases involving bot or var:
       (ty::ty_bot, _) |
       (_, ty::ty_bot) |
-      (ty::ty_var(_), _) |
-      (_, ty::ty_var(_)) => {
+      (ty::ty_infer(TyVar(_)), _) |
+      (_, ty::ty_infer(TyVar(_))) => {
         tcx.sess.bug(
             fmt!("%s: bot and var types should have been handled (%s,%s)",
                  self.tag(),
@@ -355,16 +355,16 @@ fn super_tys<C:combine>(
       }
 
       // Relate integral variables to other types
-      (ty::ty_var_integral(a_id), ty::ty_var_integral(b_id)) => {
-        self.infcx().vars_integral(a_id, b_id).then(|| Ok(a) )
+      (ty::ty_infer(IntVar(a_id)), ty::ty_infer(IntVar(b_id))) => {
+        self.infcx().int_vars(a_id, b_id).then(|| Ok(a) )
       }
-      (ty::ty_var_integral(a_id), ty::ty_int(_)) |
-      (ty::ty_var_integral(a_id), ty::ty_uint(_)) => {
-        self.infcx().var_integral_sub_t(a_id, b).then(|| Ok(a) )
+      (ty::ty_infer(IntVar(a_id)), ty::ty_int(_)) |
+      (ty::ty_infer(IntVar(a_id)), ty::ty_uint(_)) => {
+        self.infcx().int_var_sub_t(a_id, b).then(|| Ok(a) )
       }
-      (ty::ty_int(_), ty::ty_var_integral(b_id)) |
-      (ty::ty_uint(_), ty::ty_var_integral(b_id)) => {
-        self.infcx().t_sub_var_integral(a, b_id).then(|| Ok(a) )
+      (ty::ty_int(_), ty::ty_infer(IntVar(b_id))) |
+      (ty::ty_uint(_), ty::ty_infer(IntVar(b_id))) => {
+        self.infcx().t_sub_int_var(a, b_id).then(|| Ok(a) )
       }
 
       (ty::ty_int(_), _) |
diff --git a/src/rustc/middle/typeck/infer/lattice.rs b/src/rustc/middle/typeck/infer/lattice.rs
index 998d32bdad3..5fc9ee8d1a7 100644
--- a/src/rustc/middle/typeck/infer/lattice.rs
+++ b/src/rustc/middle/typeck/infer/lattice.rs
@@ -46,17 +46,17 @@ fn lattice_tys<L:lattice_ops combine>(
           (ty::ty_bot, _) => self.ty_bot(b),
           (_, ty::ty_bot) => self.ty_bot(a),
 
-          (ty::ty_var(a_id), ty::ty_var(b_id)) => {
+          (ty::ty_infer(TyVar(a_id)), ty::ty_infer(TyVar(b_id))) => {
             lattice_vars(self, a, a_id, b_id,
                          |x, y| self.tys(x, y) )
           }
 
-          (ty::ty_var(a_id), _) => {
+          (ty::ty_infer(TyVar(a_id)), _) => {
             lattice_var_and_t(self, a_id, b,
                               |x, y| self.tys(x, y) )
           }
 
-          (_, ty::ty_var(b_id)) => {
+          (_, ty::ty_infer(TyVar(b_id))) => {
             lattice_var_and_t(self, b_id, a,
                               |x, y| self.tys(x, y) )
           }
@@ -68,7 +68,7 @@ fn lattice_tys<L:lattice_ops combine>(
 }
 
 fn lattice_vars<L:lattice_ops combine>(
-    self: &L, +a_t: ty::t, +a_vid: ty::tv_vid, +b_vid: ty::tv_vid,
+    self: &L, +a_t: ty::t, +a_vid: ty::ty_vid, +b_vid: ty::ty_vid,
     c_ts: fn(ty::t, ty::t) -> cres<ty::t>) -> cres<ty::t> {
 
     // The comments in this function are written for LUB and types,
@@ -112,7 +112,7 @@ fn lattice_vars<L:lattice_ops combine>(
 }
 
 fn lattice_var_and_t<L:lattice_ops combine>(
-    self: &L, a_id: ty::tv_vid, b: ty::t,
+    self: &L, a_id: ty::ty_vid, b: ty::t,
     c_ts: fn(ty::t, ty::t) -> cres<ty::t>) -> cres<ty::t> {
 
     let vb = &self.infcx().ty_var_bindings;
diff --git a/src/rustc/middle/typeck/infer/resolve.rs b/src/rustc/middle/typeck/infer/resolve.rs
index 7364b744527..8d6841357c0 100644
--- a/src/rustc/middle/typeck/infer/resolve.rs
+++ b/src/rustc/middle/typeck/infer/resolve.rs
@@ -55,7 +55,7 @@ type resolve_state_ = {
     infcx: infer_ctxt,
     modes: uint,
     mut err: Option<fixup_err>,
-    mut v_seen: ~[tv_vid]
+    mut v_seen: ~[ty_vid]
 };
 
 enum resolve_state {
@@ -113,11 +113,11 @@ impl resolve_state {
             if !ty::type_needs_infer(typ) { return typ; }
 
             match ty::get(typ).struct {
-              ty::ty_var(vid) => {
+              ty::ty_infer(TyVar(vid)) => {
                 self.resolve_ty_var(vid)
               }
-              ty::ty_var_integral(vid) => {
-                self.resolve_ty_var_integral(vid)
+              ty::ty_infer(IntVar(vid)) => {
+                self.resolve_int_var(vid)
               }
               _ => {
                 if !self.should(resolve_rvar) &&
@@ -169,7 +169,7 @@ impl resolve_state {
         }
     }
 
-    fn resolve_ty_var(vid: tv_vid) -> ty::t {
+    fn resolve_ty_var(vid: ty_vid) -> ty::t {
         if vec::contains(self.v_seen, vid) {
             self.err = Some(cyclic_ty(vid));
             return ty::mk_var(self.infcx.tcx, vid);
@@ -202,12 +202,12 @@ impl resolve_state {
         }
     }
 
-    fn resolve_ty_var_integral(vid: tvi_vid) -> ty::t {
+    fn resolve_int_var(vid: int_vid) -> ty::t {
         if !self.should(resolve_ivar) {
-            return ty::mk_var_integral(self.infcx.tcx, vid);
+            return ty::mk_int_var(self.infcx.tcx, vid);
         }
 
-        let nde = self.infcx.get(&self.infcx.ty_var_integral_bindings, vid);
+        let nde = self.infcx.get(&self.infcx.int_var_bindings, vid);
         let pt = nde.possible_types;
 
         // If there's only one type in the set of possible types, then
@@ -219,13 +219,13 @@ impl resolve_state {
                 // As a last resort, default to int.
                 let ty = ty::mk_int(self.infcx.tcx);
                 self.infcx.set(
-                    &self.infcx.ty_var_integral_bindings, vid,
+                    &self.infcx.int_var_bindings, vid,
                     root(convert_integral_ty_to_int_ty_set(self.infcx.tcx,
                                                            ty),
                         nde.rank));
                 ty
             } else {
-                ty::mk_var_integral(self.infcx.tcx, vid)
+                ty::mk_int_var(self.infcx.tcx, vid)
             }
           }
         }
diff --git a/src/rustc/middle/typeck/infer/sub.rs b/src/rustc/middle/typeck/infer/sub.rs
index 1163c75c7fe..f3853134a37 100644
--- a/src/rustc/middle/typeck/infer/sub.rs
+++ b/src/rustc/middle/typeck/infer/sub.rs
@@ -105,13 +105,13 @@ impl Sub: combine {
               (ty::ty_bot, _) => {
                 Ok(a)
               }
-              (ty::ty_var(a_id), ty::ty_var(b_id)) => {
+              (ty::ty_infer(TyVar(a_id)), ty::ty_infer(TyVar(b_id))) => {
                 var_sub_var(&self, a_id, b_id).then(|| Ok(a) )
               }
-              (ty::ty_var(a_id), _) => {
+              (ty::ty_infer(TyVar(a_id)), _) => {
                 var_sub_t(&self, a_id, b).then(|| Ok(a) )
               }
-              (_, ty::ty_var(b_id)) => {
+              (_, ty::ty_infer(TyVar(b_id))) => {
                 t_sub_var(&self, a, b_id).then(|| Ok(a) )
               }
               (_, ty::ty_bot) => {
diff --git a/src/rustc/middle/typeck/infer/unify.rs b/src/rustc/middle/typeck/infer/unify.rs
index f5c0892219f..e8e834cfc57 100644
--- a/src/rustc/middle/typeck/infer/unify.rs
+++ b/src/rustc/middle/typeck/infer/unify.rs
@@ -113,7 +113,7 @@ fn merge_bnds<C: combine>(
 
 fn set_var_to_merged_bounds<C: combine>(
     self: &C,
-    v_id: ty::tv_vid,
+    v_id: ty::ty_vid,
     a: bounds<ty::t>,
     b: bounds<ty::t>,
     rank: uint) -> ures {
@@ -175,8 +175,8 @@ fn set_var_to_merged_bounds<C: combine>(
 /// subtle and tricky process, as described in detail at the top
 /// of infer.rs
 fn var_sub_var<C: combine>(self: &C,
-                           a_id: ty::tv_vid,
-                           b_id: ty::tv_vid) -> ures {
+                           a_id: ty::ty_vid,
+                           b_id: ty::ty_vid) -> ures {
     let vb = &self.infcx().ty_var_bindings;
 
     // Need to make sub_id a subtype of sup_id.
@@ -241,7 +241,7 @@ fn var_sub_var<C: combine>(self: &C,
 }
 
 /// make variable a subtype of T
-fn var_sub_t<C: combine>(self: &C, a_id: ty::tv_vid, b: ty::t) -> ures {
+fn var_sub_t<C: combine>(self: &C, a_id: ty::ty_vid, b: ty::t) -> ures {
 
     let vb = &self.infcx().ty_var_bindings;
     let nde_a = self.infcx().get(vb, a_id);
@@ -257,7 +257,7 @@ fn var_sub_t<C: combine>(self: &C, a_id: ty::tv_vid, b: ty::t) -> ures {
 }
 
 /// make T a subtype of variable
-fn t_sub_var<C: combine>(self: &C, a: ty::t, b_id: ty::tv_vid) -> ures {
+fn t_sub_var<C: combine>(self: &C, a: ty::t, b_id: ty::ty_vid) -> ures {
 
     let vb = &self.infcx().ty_var_bindings;
     let a_bounds = {lb: Some(a), ub: None};
@@ -294,8 +294,8 @@ fn bnds<C: combine>(
 // Integral variables
 
 impl infer_ctxt {
-    fn vars_integral(a_id: ty::tvi_vid, b_id: ty::tvi_vid) -> ures {
-        let vb = &self.ty_var_integral_bindings;
+    fn int_vars(a_id: ty::int_vid, b_id: ty::int_vid) -> ures {
+        let vb = &self.int_var_bindings;
 
         let nde_a = self.get(vb, a_id);
         let nde_b = self.get(vb, b_id);
@@ -317,18 +317,18 @@ impl infer_ctxt {
 
         // Rank optimization
         if nde_a.rank > nde_b.rank {
-            debug!("vars_integral(): a has smaller rank");
+            debug!("int_vars(): a has smaller rank");
             // a has greater rank, so a should become b's parent,
             // i.e., b should redirect to a.
             self.set(vb, a_id, root(intersection, nde_a.rank));
             self.set(vb, b_id, redirect(a_id));
         } else if nde_a.rank < nde_b.rank {
-            debug!("vars_integral(): b has smaller rank");
+            debug!("int_vars(): b has smaller rank");
             // b has greater rank, so a should redirect to b.
             self.set(vb, b_id, root(intersection, nde_b.rank));
             self.set(vb, a_id, redirect(b_id));
         } else {
-            debug!("vars_integral(): a and b have equal rank");
+            debug!("int_vars(): a and b have equal rank");
             assert nde_a.rank == nde_b.rank;
             // If equal, just redirect one to the other and increment
             // the other's rank.  We choose arbitrarily to redirect b
@@ -340,10 +340,10 @@ impl infer_ctxt {
         uok()
     }
 
-    fn var_integral_sub_t(a_id: ty::tvi_vid, b: ty::t) -> ures {
+    fn int_var_sub_t(a_id: ty::int_vid, b: ty::t) -> ures {
         assert ty::type_is_integral(b);
 
-        let vb = &self.ty_var_integral_bindings;
+        let vb = &self.int_var_bindings;
         let nde_a = self.get(vb, a_id);
         let a_id = nde_a.root;
         let a_pt = nde_a.possible_types;
@@ -358,9 +358,9 @@ impl infer_ctxt {
         uok()
     }
 
-    fn t_sub_var_integral(a: ty::t, b_id: ty::tvi_vid) -> ures {
+    fn t_sub_int_var(a: ty::t, b_id: ty::int_vid) -> ures {
         assert ty::type_is_integral(a);
-        let vb = &self.ty_var_integral_bindings;
+        let vb = &self.int_var_bindings;
 
         let nde_b = self.get(vb, b_id);
         let b_id = nde_b.root;
diff --git a/src/rustc/util/ppaux.rs b/src/rustc/util/ppaux.rs
index ba7b9ffa478..bb54e9df19b 100644
--- a/src/rustc/util/ppaux.rs
+++ b/src/rustc/util/ppaux.rs
@@ -9,7 +9,7 @@ use middle::ty::{ty_bool, ty_bot, ty_box, ty_class, ty_enum};
 use middle::ty::{ty_estr, ty_evec, ty_float, ty_fn, ty_trait, ty_int};
 use middle::ty::{ty_nil, ty_opaque_box, ty_opaque_closure_ptr, ty_param};
 use middle::ty::{ty_ptr, ty_rec, ty_rptr, ty_self, ty_tup};
-use middle::ty::{ty_type, ty_uniq, ty_uint, ty_var, ty_var_integral};
+use middle::ty::{ty_type, ty_uniq, ty_uint, ty_infer};
 use middle::ty::{ty_unboxed_vec, vid};
 use metadata::encoder;
 use syntax::codemap;
@@ -335,8 +335,7 @@ fn ty_to_str(cx: ctxt, typ: t) -> ~str {
         fn_to_str(cx, f.purity, f.proto, None, f.inputs,
                   f.output, f.ret_style)
       }
-      ty_var(v) => v.to_str(),
-      ty_var_integral(v) => v.to_str(),
+      ty_infer(infer_ty) => infer_ty.to_str(),
       ty_param({idx: id, _}) => {
         ~"'" + str::from_bytes(~[('a' as u8) + (id as u8)])
       }