diff --git a/src/rustc/middle/pairwise.rs b/src/rustc/middle/pairwise.rs
deleted file mode 100644
index 802671e2c81c..000000000000
--- a/src/rustc/middle/pairwise.rs
+++ /dev/null
@@ -1,407 +0,0 @@
-iface lattice<T> {
-    fn lub(T, T) -> cres<T>;
-    fn glb(T, T) -> cres<T>;
-}
-
-iface lattice_op<T> {
-    fn bnd<V:copy>(b: bounds<V>) -> option<V>;
-    fn with_bnd<V:copy>(b: bounds<V>, v: V) -> bounds<V>;
-}
-
-iface pairwise {
-    fn infcx() -> infer_ctxt;
-    fn tag() -> str;
-
-    fn c_tys(t1: ty::t, t2: ty::t) -> cres<ty::t>;
-    fn c_flds(a: ty::field, b: ty::field) -> cres<ty::field>;
-    fn c_bot(b: ty::t) -> cres<ty::t>;
-    fn c_mts(a: ty::mt, b: ty::mt) -> cres<ty::mt>;
-    fn c_contratys(t1: ty::t, t2: ty::t) -> cres<ty::t>;
-    fn c_protos(p1: ast::proto, p2: ast::proto) -> cres<ast::proto>;
-    fn c_ret_styles(r1: ret_style, r2: ret_style) -> cres<ret_style>;
-
-    // Combining regions (along with some specific cases that are
-    // different for LUB/GLB):
-    fn c_regions(
-        a: ty::region, b: ty::region) -> cres<ty::region>;
-    fn c_regions_scope_scope(
-        a: ty::region, a_id: ast::node_id,
-        b: ty::region, b_id: ast::node_id) -> cres<ty::region>;
-    fn c_regions_free_scope(
-        a: ty::region, a_id: ast::node_id, a_br: ty::bound_region,
-        b: ty::region, b_id: ast::node_id) -> cres<ty::region>;
-}
-
-fn c_vars<V:copy vid, PW:pairwise, T:copy to_str st>(
-    self: PW, vb: vals_and_bindings<V, T>,
-    a_t: T, a_vid: V, b_vid: V,
-    c_ts: fn(T, T) -> cres<T>) -> cres<T> {
-
-    // The comments in this function are written for LUB and types,
-    // but they apply equally well to GLB and regions if you inverse
-    // upper/lower/sub/super/etc.
-
-    // Need to find a type that is a supertype of both a and b:
-    let {root: a_vid, bounds: a_bounds} = self.infcx().get(vb, a_vid);
-    let {root: b_vid, bounds: b_bounds} = self.infcx().get(vb, b_vid);
-
-    #debug["%s.c_vars(%s=%s <: %s=%s)",
-           self.tag(),
-           a_vid.to_str(), a_bounds.to_str(self.infcx()),
-           b_vid.to_str(), b_bounds.to_str(self.infcx())];
-
-    if a_vid == b_vid {
-        ret ok(a_t);
-    }
-
-    // If both A and B have an UB type, then we can just compute the
-    // LUB of those types:
-    let a_bnd = self.bnd(a_bounds), b_bnd = self.bnd(b_bounds);
-    alt (a_bnd, b_bnd) {
-      (some(a_ty), some(b_ty)) {
-        alt self.infcx().try {|| c_ts(a_ty, b_ty) } {
-            ok(t) { ret ok(t); }
-            err(_) { /*fallthrough */ }
-        }
-      }
-      _ {/*fallthrough*/}
-    }
-
-    // Otherwise, we need to merge A and B into one variable.  We can
-    // then use either variable as an upper bound:
-    self.infcx().vars(vb, a_vid, b_vid).then {||
-        ok(a_t)
-    }
-}
-
-fn c_var_t<V:copy vid, PW:pairwise, T:copy to_str st>(
-    self: PW, vb: vals_and_bindings<V, T>,
-    a_vid: V, b: T,
-    c_ts: fn(T, T) -> cres<T>) -> cres<T> {
-
-    let {root: a_id, bounds: a_bounds} = self.infcx().get(vb, a_vid);
-
-    // The comments in this function are written for LUB, but they
-    // apply equally well to GLB if you inverse upper/lower/sub/super/etc.
-
-    #debug["%s.c_var_ty(%s=%s <: %s)",
-           self.tag(),
-           a_id.to_str(), a_bounds.to_str(self.infcx()),
-           b.to_str(self.infcx())];
-
-    alt self.bnd(a_bounds) {
-      some(a_bnd) {
-        // If a has an upper bound, return it.
-        ret c_ts(a_bnd, b);
-      }
-      none {
-        // If a does not have an upper bound, make b the upper bound of a
-        // and then return b.
-        let a_bounds = self.with_bnd(a_bounds, b);
-        self.infcx().bnds(a_bounds.lb, a_bounds.ub).then {||
-            self.infcx().set(vb, a_id, bounded(a_bounds));
-            ok(b)
-        }
-      }
-    }
-}
-
-fn c_tuptys<PW:pairwise>(self: PW, as: [ty::t], bs: [ty::t])
-    -> cres<[ty::t]> {
-
-    if check vec::same_length(as, bs) {
-        map2(as, bs) {|a, b| self.c_tys(a, b) }
-    } else {
-        err(ty::terr_tuple_size(as.len(), bs.len()))
-    }
-}
-
-fn c_tps<PW:pairwise>(self: PW, _did: ast::def_id, as: [ty::t], bs: [ty::t])
-    -> cres<[ty::t]> {
-    // FIXME #1973 lookup the declared variance of the type parameters
-    // based on did
-    if check vec::same_length(as, bs) {
-        map2(as, bs) {|a,b| self.c_tys(a, b) }
-    } else {
-        err(ty::terr_ty_param_size(as.len(), bs.len()))
-    }
-}
-
-fn c_fieldvecs<PW:pairwise>(
-    self: PW, as: [ty::field], bs: [ty::field])
-    -> cres<[ty::field]> {
-
-    if check vec::same_length(as, bs) {
-        map2(as, bs) {|a,b| self.c_flds(a, b) }
-    } else {
-        err(ty::terr_record_size(as.len(), bs.len()))
-    }
-}
-
-fn c_flds<PW:pairwise>(
-    self: PW, a: ty::field, b: ty::field) -> cres<ty::field> {
-
-    if a.ident == b.ident {
-        self.c_mts(a.mt, b.mt).chain {|mt|
-            ok({ident: a.ident, mt: mt})
-        }
-    } else {
-        err(ty::terr_record_fields(a.ident, b.ident))
-    }
-}
-
-fn c_modes<PW:pairwise>(
-    self: PW, a: ast::mode, b: ast::mode)
-    -> cres<ast::mode> {
-
-    let tcx = self.infcx().tcx;
-    ty::unify_mode(tcx, a, b)
-}
-
-fn c_args<PW:pairwise>(
-    self: PW, a: ty::arg, b: ty::arg)
-    -> cres<ty::arg> {
-
-    self.c_modes(a.mode, b.mode).chain {|m|
-        // Note: contravariant
-        self.c_contratys(b.ty, a.ty).chain {|t|
-            ok({mode: m, ty: t})
-        }
-    }
-}
-
-fn c_argvecs<PW:pairwise>(
-    self: PW, a_args: [ty::arg], b_args: [ty::arg]) -> cres<[ty::arg]> {
-
-    if check vec::same_length(a_args, b_args) {
-        map2(a_args, b_args) {|a, b| self.c_args(a, b) }
-    } else {
-        err(ty::terr_arg_count)
-    }
-}
-
-fn c_fns<PW:pairwise>(
-    self: PW, a_f: ty::fn_ty, b_f: ty::fn_ty) -> cres<ty::fn_ty> {
-
-    self.c_protos(a_f.proto, b_f.proto).chain {|p|
-        self.c_ret_styles(a_f.ret_style, b_f.ret_style).chain {|rs|
-            self.c_argvecs(a_f.inputs, b_f.inputs).chain {|inputs|
-                self.c_tys(a_f.output, b_f.output).chain {|output|
-                    //FIXME self.infcx().constrvecs(a_f.constraints,
-                    //FIXME                         b_f.constraints).then {||
-                        ok({proto: p,
-                            inputs: inputs,
-                            output: output,
-                            ret_style: rs,
-                            constraints: a_f.constraints})
-                    //FIXME }
-                }
-            }
-        }
-    }
-}
-
-fn c_tys<PW:pairwise>(
-    self: PW, a: ty::t, b: ty::t) -> cres<ty::t> {
-
-    let tcx = self.infcx().tcx;
-
-    #debug("%s.c_tys(%s, %s)",
-           self.tag(),
-           ty_to_str(tcx, a),
-           ty_to_str(tcx, b));
-
-    // Fast path.
-    if a == b { ret ok(a); }
-
-    alt (ty::get(a).struct, ty::get(b).struct) {
-      (ty::ty_bot, _) { self.c_bot(b) }
-      (_, ty::ty_bot) { self.c_bot(b) }
-
-      (ty::ty_var(a_id), ty::ty_var(b_id)) {
-        self.c_vars(self.infcx().vb,
-               a, a_id, b_id,
-               {|x, y| self.c_tys(x, y) })
-      }
-
-      // Note that the LUB/GLB operations are commutative:
-      (ty::ty_var(v_id), _) {
-        self.c_var_t(self.infcx().vb,
-                v_id, b,
-                {|x, y| self.c_tys(x, y) })
-      }
-      (_, ty::ty_var(v_id)) {
-        self.c_var_t(self.infcx().vb,
-                v_id, a,
-                {|x, y| self.c_tys(x, y) })
-      }
-
-      (ty::ty_nil, _) |
-      (ty::ty_bool, _) |
-      (ty::ty_int(_), _) |
-      (ty::ty_uint(_), _) |
-      (ty::ty_float(_), _) |
-      (ty::ty_str, _) {
-        let cfg = tcx.sess.targ_cfg;
-        if ty::mach_sty(cfg, a) == ty::mach_sty(cfg, b) {
-            ok(a)
-        } else {
-            err(ty::terr_mismatch)
-        }
-      }
-
-      (ty::ty_param(a_n, _), ty::ty_param(b_n, _)) if a_n == b_n {
-        ok(a)
-      }
-
-      (ty::ty_enum(a_id, a_tps), ty::ty_enum(b_id, b_tps))
-      if a_id == b_id {
-        self.c_tps(a_id, a_tps, b_tps).chain {|tps|
-            ok(ty::mk_enum(tcx, a_id, tps))
-        }
-      }
-
-      (ty::ty_iface(a_id, a_tps), ty::ty_iface(b_id, b_tps))
-      if a_id == b_id {
-        self.c_tps(a_id, a_tps, b_tps).chain {|tps|
-            ok(ty::mk_iface(tcx, a_id, tps))
-        }
-      }
-
-      (ty::ty_class(a_id, a_tps), ty::ty_class(b_id, b_tps))
-      if a_id == b_id {
-        // FIXME variance
-        self.c_tps(a_id, a_tps, b_tps).chain {|tps|
-            ok(ty::mk_class(tcx, a_id, tps))
-        }
-      }
-
-      (ty::ty_box(a_mt), ty::ty_box(b_mt)) {
-        self.c_mts(a_mt, b_mt).chain {|mt|
-            ok(ty::mk_box(tcx, mt))
-        }
-      }
-
-      (ty::ty_uniq(a_mt), ty::ty_uniq(b_mt)) {
-        self.c_mts(a_mt, b_mt).chain {|mt|
-            ok(ty::mk_uniq(tcx, mt))
-        }
-      }
-
-      (ty::ty_vec(a_mt), ty::ty_vec(b_mt)) {
-        self.c_mts(a_mt, b_mt).chain {|mt|
-            ok(ty::mk_vec(tcx, mt))
-        }
-      }
-
-      (ty::ty_ptr(a_mt), ty::ty_ptr(b_mt)) {
-        self.c_mts(a_mt, b_mt).chain {|mt|
-            ok(ty::mk_ptr(tcx, mt))
-        }
-      }
-
-      (ty::ty_rptr(a_r, a_mt), ty::ty_rptr(b_r, b_mt)) {
-        self.c_regions(a_r, b_r).chain {|r|
-            self.c_mts(a_mt, b_mt).chain {|mt|
-                ok(ty::mk_rptr(tcx, r, mt))
-            }
-        }
-      }
-
-      (ty::ty_res(a_id, a_t, a_tps), ty::ty_res(b_id, b_t, b_tps))
-      if a_id == b_id {
-        self.c_tys(a_t, b_t).chain {|t|
-            self.c_tps(a_id, a_tps, b_tps).chain {|tps|
-                ok(ty::mk_res(tcx, a_id, t, tps))
-            }
-        }
-      }
-
-      (ty::ty_rec(a_fields), ty::ty_rec(b_fields)) {
-        self.c_fieldvecs(a_fields, b_fields).chain {|fs|
-            ok(ty::mk_rec(tcx, fs))
-        }
-      }
-
-      (ty::ty_tup(a_tys), ty::ty_tup(b_tys)) {
-        self.c_tuptys(a_tys, b_tys).chain {|ts|
-            ok(ty::mk_tup(tcx, ts))
-        }
-      }
-
-      (ty::ty_fn(a_fty), ty::ty_fn(b_fty)) {
-        self.c_fns(a_fty, b_fty).chain {|fty|
-            ok(ty::mk_fn(tcx, fty))
-        }
-      }
-
-      (ty::ty_constr(a_t, a_constrs), ty::ty_constr(b_t, b_constrs)) {
-        self.c_tys(a_t, b_t).chain {|t|
-            self.infcx().constrvecs(a_constrs, b_constrs).then {||
-                ok(ty::mk_constr(tcx, t, a_constrs))
-            }
-        }
-      }
-
-      _ { err(ty::terr_mismatch) }
-    }
-}
-
-fn c_regions<PW:pairwise>(
-    self: PW, a: ty::region, b: ty::region) -> cres<ty::region> {
-
-    #debug["%s.c_regions(%?, %?)",
-           self.tag(),
-           a.to_str(self.infcx()),
-           b.to_str(self.infcx())];
-
-    alt (a, b) {
-      (ty::re_var(a_id), ty::re_var(b_id)) {
-        self.c_vars(self.infcx().rb,
-               a, a_id, b_id,
-               {|x, y| self.c_regions(x, y) })
-      }
-
-      (ty::re_var(v_id), r) |
-      (r, ty::re_var(v_id)) {
-        self.c_var_t(self.infcx().rb,
-                v_id, r,
-                {|x, y| self.c_regions(x, y) })
-      }
-
-      (f @ ty::re_free(f_id, f_br), s @ ty::re_scope(s_id)) |
-      (s @ ty::re_scope(s_id), f @ ty::re_free(f_id, f_br)) {
-        self.c_regions_free_scope(f, f_id, f_br, s, s_id)
-      }
-
-      (ty::re_scope(a_id), ty::re_scope(b_id)) {
-        self.c_regions_scope_scope(a, a_id, b, b_id)
-      }
-
-      // For these types, we cannot define any additional relationship:
-      (ty::re_free(_, _), ty::re_free(_, _)) |
-      (ty::re_bound(_), ty::re_bound(_)) |
-      (ty::re_bound(_), ty::re_free(_, _)) |
-      (ty::re_bound(_), ty::re_scope(_)) |
-      (ty::re_free(_, _), ty::re_bound(_)) |
-      (ty::re_scope(_), ty::re_bound(_)) {
-        if a == b {
-            #debug["... yes, %s == %s.",
-                   a.to_str(self.infcx()),
-                   b.to_str(self.infcx())];
-            ok(a)
-        } else {
-            #debug["... no, %s != %s.",
-                   a.to_str(self.infcx()),
-                   b.to_str(self.infcx())];
-            err(ty::terr_regions_differ(false, b, a))
-        }
-      }
-
-      (ty::re_default, _) |
-      (_, ty::re_default) {
-        // actually a compiler bug, I think.
-        err(ty::terr_regions_differ(false, b, a))
-      }
-    }
-}