diff --git a/mk/stage3.mk b/mk/stage3.mk
index 70d3f26d309..d8604ed999e 100644
--- a/mk/stage3.mk
+++ b/mk/stage3.mk
@@ -1,13 +1,8 @@
-stage3/std.o: $(STDLIB_CRATE) $(STDLIB_INPUTS) \
+stage3/$(CFG_STDLIB): $(STDLIB_CRATE) $(STDLIB_INPUTS) \
               stage2/rustc$(X) stage2/$(CFG_STDLIB) stage2/intrinsics.bc \
               $(LREQ) $(MKFILES)
-	@$(call E, compile: $@)
-	$(STAGE2) -c --shared -o $@ $<
-
-stage3/$(CFG_STDLIB): stage2/std.o stage2/glue.o
-	@$(call E, link: $@)
-	$(Q)gcc $(CFG_GCCISH_CFLAGS) stage2/glue.o $(CFG_GCCISH_LINK_FLAGS) -o \
-        $@ $< -Lstage2 -Lrt -lrustrt
+	@$(call E, compile_and_link: $@)
+	$(STAGE2)  --shared -o $@ $<
 
 stage3/librustc.o: $(COMPILER_CRATE) $(COMPILER_INPUTS) $(SREQ2)
 	@$(call E, compile: $@)
diff --git a/src/comp/back/abi.rs b/src/comp/back/abi.rs
index 79039cb55d4..d79ff61748c 100644
--- a/src/comp/back/abi.rs
+++ b/src/comp/back/abi.rs
@@ -104,7 +104,7 @@ const int closure_elt_bindings = 2;
 
 const int closure_elt_ty_params = 3;
 
-const uint ivec_default_length = 8u;
+const uint ivec_default_length = 4u;
 
 const uint ivec_elt_len = 0u;
 
diff --git a/src/comp/back/link.rs b/src/comp/back/link.rs
index bb20d79d7c9..c986842e9ae 100644
--- a/src/comp/back/link.rs
+++ b/src/comp/back/link.rs
@@ -209,7 +209,7 @@ mod write {
  *
  * There are a few issues to handle:
  *
- *  - Linkers operate on a flat namespace, so we have to flatten names.
+ *  - Linnkers operate on a flat namespace, so we have to flatten names.
  *    We do this using the C++ namespace-mangling technique. Foo::bar
  *    symbols and such.
  *
@@ -221,7 +221,7 @@ mod write {
  *    symbols in the same process before you're even hitting birthday-paradox
  *    collision probability.
  *
- *  - Symbols in dirrerent crates but with same names "within" the crate need
+ *  - Symbols in different crates but with same names "within" the crate need
  *    to get different linkage-names.
  *
  * So here is what we do:
@@ -229,7 +229,7 @@ mod write {
  *  - Separate the meta tags into two sets: exported and local. Only work with
  *    the exported ones when considering linkage.
  *
- *  - Consider two exported tags as special (and madatory): name and vers.
+ *  - Consider two exported tags as special (and mandatory): name and vers.
  *    Every crate gets them; if it doesn't name them explicitly we infer them
  *    as basename(crate) and "0.1", respectively. Call these CNAME, CVERS.
  *
diff --git a/src/comp/driver/rustc.rs b/src/comp/driver/rustc.rs
index 9aef46058ee..e0a6d28f2b7 100644
--- a/src/comp/driver/rustc.rs
+++ b/src/comp/driver/rustc.rs
@@ -81,10 +81,10 @@ fn compile_input(session::session sess, eval::env env, str input,
     auto crate =
         time(time_passes, "parsing", bind parse_input(sess, p, input));
     if (sess.get_opts().output_type == link::output_type_none) { ret; }
-    auto def_map =
+    auto d =
         time(time_passes, "resolution",
              bind resolve::resolve_crate(sess, crate));
-    auto ty_cx = ty::mk_ctxt(sess, def_map);
+    auto ty_cx = ty::mk_ctxt(sess, d._0, d._1);
     time[()](time_passes, "typechecking",
              bind typeck::check_crate(ty_cx, crate));
     if (sess.get_opts().run_typestate) {
@@ -92,7 +92,7 @@ fn compile_input(session::session sess, eval::env env, str input,
              bind middle::tstate::ck::check_crate(ty_cx, crate));
     }
     time(time_passes, "alias checking",
-         bind middle::alias::check_crate(@ty_cx, def_map, crate));
+         bind middle::alias::check_crate(@ty_cx, crate));
     auto llmod =
         time[llvm::llvm::ModuleRef](time_passes, "translation",
                                     bind trans::trans_crate(sess, crate,
@@ -109,8 +109,8 @@ fn pretty_print_input(session::session sess, eval::env env, str input,
     auto mode;
     alt (ppm) {
         case (ppm_typed) {
-            auto def_map = resolve::resolve_crate(sess, crate);
-            auto ty_cx = ty::mk_ctxt(sess, def_map);
+            auto d = resolve::resolve_crate(sess, crate);
+            auto ty_cx = ty::mk_ctxt(sess, d._0, d._1);
             typeck::check_crate(ty_cx, crate);
             mode = ppaux::mo_typed(ty_cx);
         }
@@ -399,37 +399,34 @@ fn main(vec[str] args) {
         let str prog = "gcc";
         // The invocations of gcc share some flags across platforms
 
-        let vec[str] common_cflags =
-            ["-fno-strict-aliasing", "-fPIC", "-Wall", "-fno-rtti",
-             "-fno-exceptions", "-g"];
-        let vec[str] common_libs =
-            [stage, "-Lrustllvm", "-Lrt", "-lrustrt", "-lrustllvm", "-lstd",
-             "-lm"];
+        let vec[str] common_args = [stage, "-Lrt", "-lrustrt",
+         "-fno-strict-aliasing", "-fPIC", "-Wall",
+         "-fno-rtti", "-fno-exceptions", "-g", glu, "-o",
+         saved_out_filename, saved_out_filename + ".o"];
+
+       auto shared_cmd;
+
         alt (sess.get_targ_cfg().os) {
             case (session::os_win32) {
-                gcc_args =
-                    common_cflags +
-                        ["-march=i686", "-O2", glu, main, "-o",
-                         saved_out_filename, saved_out_filename + ".o"] +
-                        common_libs;
+                shared_cmd = "-shared";
+                gcc_args = common_args + ["-march=i686", "-O2"];
             }
             case (session::os_macos) {
-                gcc_args =
-                    common_cflags +
-                        ["-arch i386", "-O0", "-m32", glu, main, "-o",
-                         saved_out_filename, saved_out_filename + ".o"] +
-                        common_libs;
+                shared_cmd = "-dynamiclib";
+                gcc_args = common_args + ["-arch i386", "-O0", "-m32"];
             }
             case (session::os_linux) {
-                gcc_args =
-                    common_cflags +
-                        ["-march=i686", "-O2", "-m32", glu, main, "-o",
-                         saved_out_filename, saved_out_filename + ".o"] +
-                        common_libs;
+                shared_cmd = "-shared";
+                gcc_args = common_args + ["-march=i686", "-O2", "-m32"];
             }
         }
-        // We run 'gcc' here
+        if (sopts.shared) {
+           gcc_args += [shared_cmd];
+        } else {
+           gcc_args += ["-Lrustllvm", "-lrustllvm", "-lstd", "-lm", main];
+        }
 
+        // We run 'gcc' here
         run::run_program(prog, gcc_args);
         // Clean up on Darwin
 
diff --git a/src/comp/front/ast.rs b/src/comp/front/ast.rs
index 6a2f4d986ff..b66c286f325 100644
--- a/src/comp/front/ast.rs
+++ b/src/comp/front/ast.rs
@@ -359,19 +359,17 @@ tag constr_arg_general_[T] { carg_base; carg_ident(T); carg_lit(@lit); }
 
 type constr_arg = constr_arg_general[uint];
 
-type constr_arg_use = constr_arg_general[ident];
-
 type constr_arg_general[T] = spanned[constr_arg_general_[T]];
 
+type constr_ = rec(path path,
+                   vec[@constr_arg_general[uint]] args,
+                   ann ann);
 
-// The ann field is there so that using the def_map in the type
-// context, we can get the def_id for the path.
-type constr_general[T] =
-    rec(path path, vec[@constr_arg_general[T]] args, ann ann);
+type constr = spanned[constr_];
 
-type constr = spanned[constr_general[uint]];
-
-type constr_use = spanned[constr_general[ident]];
+/* The parser generates ast::constrs; resolve generates
+ a mapping from each function to a list of ty::constr_defs,
+ corresponding to these. */
 
 type arg = rec(mode mode, @ty ty, ident ident, def_id id);
 
diff --git a/src/comp/front/creader.rs b/src/comp/front/creader.rs
index 0270717edd9..98004bf6961 100644
--- a/src/comp/front/creader.rs
+++ b/src/comp/front/creader.rs
@@ -78,8 +78,8 @@ fn parse_ty_or_bang(@pstate st, str_def sd) -> ty_or_bang {
     }
 }
 
-fn parse_constrs(@pstate st, str_def sd) -> vec[@ast::constr] {
-    let vec[@ast::constr] res = [];
+fn parse_constrs(@pstate st, str_def sd) -> vec[@ty::constr_def] {
+    let vec[@ty::constr_def] res = [];
     alt (peek(st) as char) {
         case (':') {
             do  {
@@ -92,7 +92,7 @@ fn parse_constrs(@pstate st, str_def sd) -> vec[@ast::constr] {
     ret res;
 }
 
-fn parse_constr(@pstate st, str_def sd) -> @ast::constr {
+fn parse_constr(@pstate st, str_def sd) -> @ty::constr_def {
     st.tcx.sess.unimpl("Reading constraints " + " isn't implemented");
     /*
     let vec[@ast::constr_arg] args = [];
@@ -318,7 +318,7 @@ fn parse_hex(@pstate st) -> uint {
 }
 
 fn parse_ty_fn(@pstate st, str_def sd) ->
-   tup(vec[ty::arg], ty::t, ast::controlflow, vec[@ast::constr]) {
+   tup(vec[ty::arg], ty::t, ast::controlflow, vec[@ty::constr_def]) {
     assert (next(st) as char == '[');
     let vec[ty::arg] inputs = [];
     while (peek(st) as char != ']') {
diff --git a/src/comp/front/parser.rs b/src/comp/front/parser.rs
index 72eda8ca309..88d8516043b 100644
--- a/src/comp/front/parser.rs
+++ b/src/comp/front/parser.rs
@@ -5,6 +5,9 @@ import std::str;
 import std::option;
 import std::option::some;
 import std::option::none;
+import std::either;
+import std::either::left;
+import std::either::right;
 import std::map::hashmap;
 import driver::session;
 import util::common;
@@ -816,14 +819,9 @@ fn parse_bottom_expr(&parser p) -> @ast::expr {
         hi = es.span.hi;
         ex = ast::expr_bind(e, es.node, p.get_ann());
     } else if (p.peek() == token::POUND) {
-        p.bump();
-        auto pth = parse_path(p);
-        auto es =
-            parse_seq(token::LPAREN, token::RPAREN, some(token::COMMA),
-                      parse_expr, p);
-        hi = es.span.hi;
-        auto ext_span = rec(lo=lo, hi=hi);
-        ex = expand_syntax_ext(p, ext_span, pth, es.node, none);
+        auto ex_ext = parse_syntax_ext(p);
+        lo = ex_ext.span.lo;
+        ex = ex_ext.node;
     } else if (eat_word(p, "fail")) {
         auto msg;
         alt (p.peek()) {
@@ -917,6 +915,21 @@ fn parse_bottom_expr(&parser p) -> @ast::expr {
     ret @spanned(lo, hi, ex);
 }
 
+fn parse_syntax_ext(&parser p) -> @ast::expr {
+    auto lo = p.get_lo_pos();
+    expect(p, token::POUND);
+    ret parse_syntax_ext_inner(p, lo);
+}
+
+fn parse_syntax_ext_inner(&parser p, uint lo) -> @ast::expr {
+    auto pth = parse_path(p);
+    auto es = parse_seq(token::LPAREN, token::RPAREN,
+                        some(token::COMMA), parse_expr, p);
+    auto hi = es.span.hi;
+    auto ext_span = rec(lo=lo, hi=hi);
+    auto ex = expand_syntax_ext(p, ext_span, pth, es.node, none);
+    ret @spanned(lo, hi, ex);
+}
 
 /*
  * FIXME: This is a crude approximation of the syntax-extension system,
@@ -1423,7 +1436,22 @@ fn parse_source_stmt(&parser p) -> @ast::stmt {
         auto hi = p.get_span();
         ret @spanned(lo, decl.span.hi, ast::stmt_decl(decl, p.get_ann()));
     } else {
-        alt (parse_item(p, [])) {
+
+        auto item_attrs;
+        alt (parse_attrs_or_ext(p)) {
+            case (none) {
+                item_attrs = [];
+            }
+            case (some(left(?attrs))) {
+                item_attrs = attrs;
+            }
+            case (some(right(?ext))) {
+                ret @spanned(lo, ext.span.hi,
+                             ast::stmt_expr(ext, p.get_ann()));
+            }
+        }
+
+        alt (parse_item(p, item_attrs)) {
             case (got_item(?i)) {
                 auto hi = i.span.hi;
                 auto decl = @spanned(lo, hi, ast::decl_item(i));
@@ -1936,6 +1964,26 @@ fn parse_item(&parser p, vec[ast::attribute] attrs) -> parsed_item {
     } else { ret no_item; }
 }
 
+// A type to distingush between the parsing of item attributes or syntax
+// extensions, which both begin with token.POUND
+type attr_or_ext = option::t[either::t[vec[ast::attribute],
+                                       @ast::expr]];
+
+fn parse_attrs_or_ext(&parser p) -> attr_or_ext {
+    if (p.peek() == token::POUND) {
+        auto lo = p.get_lo_pos();
+        p.bump();
+        if (p.peek() == token::LBRACKET) {
+            auto first_attr = parse_attribute_inner(p, lo);
+            ret some(left([first_attr] + parse_attributes(p)));
+        } else {
+            ret some(right(parse_syntax_ext_inner(p, lo)));
+        }
+    } else {
+        ret none;
+    }
+}
+
 fn parse_attributes(&parser p) -> vec[ast::attribute] {
     let vec[ast::attribute] attrs = [];
     while (p.peek() == token::POUND) { attrs += [parse_attribute(p)]; }
@@ -1945,6 +1993,10 @@ fn parse_attributes(&parser p) -> vec[ast::attribute] {
 fn parse_attribute(&parser p) -> ast::attribute {
     auto lo = p.get_lo_pos();
     expect(p, token::POUND);
+    ret parse_attribute_inner(p, lo);
+}
+
+fn parse_attribute_inner(&parser p, uint lo) -> ast::attribute {
     expect(p, token::LBRACKET);
     auto meta_item = parse_meta_item(p);
     expect(p, token::RBRACKET);
@@ -2181,13 +2233,7 @@ fn parse_crate_directive(&parser p) -> ast::crate_directive {
         auto hi = p.get_hi_pos();
         expect(p, token::RBRACE);
         ret spanned(lo, hi, ast::cdir_let(id, x, v));
-    } else if (is_word(p, "use")) {
-        auto vi = parse_view_item(p);
-        ret spanned(lo, vi.span.hi, ast::cdir_view_item(vi));
-    } else if (is_word(p, "import")) {
-        auto vi = parse_view_item(p);
-        ret spanned(lo, vi.span.hi, ast::cdir_view_item(vi));
-    } else if (is_word(p, "export")) {
+    } else if (is_view_item(p)) {
         auto vi = parse_view_item(p);
         ret spanned(lo, vi.span.hi, ast::cdir_view_item(vi));
     } else {
diff --git a/src/comp/middle/alias.rs b/src/comp/middle/alias.rs
index d9ef386de62..57cb33b8af6 100644
--- a/src/comp/middle/alias.rs
+++ b/src/comp/middle/alias.rs
@@ -35,14 +35,11 @@ tag local_info { arg(ast::mode); objfield(ast::mutability); }
 
 type ctx =
     rec(@ty::ctxt tcx,
-        resolve::def_map dm,
         std::map::hashmap[def_num, local_info] local_map);
 
-fn check_crate(@ty::ctxt tcx, resolve::def_map dm, &@ast::crate crate) {
+fn check_crate(@ty::ctxt tcx, &@ast::crate crate) {
     auto cx =
         @rec(tcx=tcx,
-             dm=dm,
-
              // Stores information about object fields and function
              // arguments that's otherwise not easily available.
              local_map=util::common::new_int_hash());
@@ -77,12 +74,18 @@ fn visit_item(@ctx cx, &@ast::item i, &scope sc, &vt[scope] v) {
 }
 
 fn visit_expr(@ctx cx, &@ast::expr ex, &scope sc, &vt[scope] v) {
-    auto handled = false;
+    auto handled = true;
     alt (ex.node) {
-        case (ast::expr_call(?f, ?args, _)) { check_call(*cx, f, args, sc); }
+        case (ast::expr_call(?f, ?args, _)) {
+            check_call(*cx, f, args, sc);
+            handled = false;
+        }
+        case (ast::expr_be(?cl, _)) {
+            check_tail_call(*cx, cl);
+            visit::visit_expr(cl, sc, v);
+        }
         case (ast::expr_alt(?input, ?arms, _)) {
             check_alt(*cx, input, arms, sc, v);
-            handled = true;
         }
         case (ast::expr_put(?val, _)) {
             alt (val) {
@@ -97,32 +100,27 @@ fn visit_expr(@ctx cx, &@ast::expr ex, &scope sc, &vt[scope] v) {
                 }
                 case (_) { }
             }
-            handled = true;
         }
         case (ast::expr_for_each(?decl, ?call, ?block, _)) {
             check_for_each(*cx, decl, call, block, sc, v);
-            handled = true;
         }
         case (ast::expr_for(?decl, ?seq, ?block, _)) {
             check_for(*cx, decl, seq, block, sc, v);
-            handled = true;
         }
         case (ast::expr_path(?pt, ?ann)) {
             check_var(*cx, ex, pt, ann, false, sc);
+            handled = false;
         }
         case (ast::expr_move(?dest, ?src, _)) {
             check_assign(cx, dest, src, sc, v);
-            handled = true;
         }
         case (ast::expr_assign(?dest, ?src, _)) {
             check_assign(cx, dest, src, sc, v);
-            handled = true;
         }
         case (ast::expr_assign_op(_, ?dest, ?src, _)) {
             check_assign(cx, dest, src, sc, v);
-            handled = true;
         }
-        case (_) { }
+        case (_) { handled = false; }
     }
     if (!handled) { visit::visit_expr(ex, sc, v); }
 }
@@ -130,11 +128,8 @@ fn visit_expr(@ctx cx, &@ast::expr ex, &scope sc, &vt[scope] v) {
 fn check_call(&ctx cx, &@ast::expr f, &vec[@ast::expr] args, &scope sc) ->
    rec(vec[def_num] root_vars, vec[ty::t] unsafe_ts) {
     auto fty = ty::expr_ty(*cx.tcx, f);
-    auto arg_ts =
-        alt (ty::struct(*cx.tcx, fty)) {
-            case (ty::ty_fn(_, ?args, _, _, _)) { args }
-            case (ty::ty_native_fn(_, ?args, _)) { args }
-        };
+    auto arg_ts = fty_args(cx, fty);
+
     let vec[def_num] roots = [];
     let vec[tup(uint, def_num)] mut_roots = [];
     let vec[ty::t] unsafe_ts = [];
@@ -175,11 +170,11 @@ fn check_call(&ctx cx, &@ast::expr f, &vec[@ast::expr] args, &scope sc) ->
     if (vec::len(unsafe_ts) > 0u) {
         alt (f.node) {
             case (ast::expr_path(_, ?ann)) {
-                if (def_is_local(cx.dm.get(ann.id))) {
-                    cx.tcx.sess.span_err(f.span,
-                                         #fmt("function may alias with \
-                         argument %u, which is not immutably rooted",
-                                              unsafe_t_offsets.(0)));
+                if (def_is_local(cx.tcx.def_map.get(ann.id), true)) {
+                    cx.tcx.sess.span_err
+                        (f.span, #fmt("function may alias with argument \
+                         %u, which is not immutably rooted",
+                         unsafe_t_offsets.(0)));
                 }
             }
             case (_) { }
@@ -221,8 +216,47 @@ fn check_call(&ctx cx, &@ast::expr f, &vec[@ast::expr] args, &scope sc) ->
     ret rec(root_vars=roots, unsafe_ts=unsafe_ts);
 }
 
-fn check_alt(&ctx cx, &@ast::expr input, &vec[ast::arm] arms, &scope sc,
-             &vt[scope] v) {
+fn check_tail_call(&ctx cx, &@ast::expr call) {
+    auto args;
+    auto f = alt (call.node) {
+        case (ast::expr_call(?f, ?args_, _)) { args = args_; f }
+    };
+    auto i = 0u;
+    for (ty::arg arg_t in fty_args(cx, ty::expr_ty(*cx.tcx, f))) {
+        if (arg_t.mode != ty::mo_val) {
+            auto mut_a = arg_t.mode == ty::mo_alias(true);
+            auto ok = true;
+            alt (args.(i).node) {
+                case (ast::expr_path(_, ?ann)) {
+                    auto def = cx.tcx.def_map.get(ann.id);
+                    auto dnum = ast::def_id_of_def(def)._1;
+                    alt (cx.local_map.find(dnum)) {
+                        case (some(arg(ast::alias(?mut)))) {
+                            if (mut_a && !mut) {
+                                cx.tcx.sess.span_warn
+                                    (args.(i).span, "passing an immutable \
+                                     alias by mutable alias");
+                            }
+                        }
+                        case (_) {
+                            ok = !def_is_local(def, false);
+                        }
+                    }
+                }
+                case (_) { ok = false; }
+            }
+            if (!ok) {
+                cx.tcx.sess.span_warn
+                    (args.(i).span, "can not pass a local value by alias to \
+                                     a tail call");
+            }
+        }
+        i += 1u;
+    }
+}
+
+fn check_alt(&ctx cx, &@ast::expr input, &vec[ast::arm] arms,
+             &scope sc, &vt[scope] v) {
     visit::visit_expr(input, sc, v);
     auto root = expr_root(cx, input, true);
     auto roots =
@@ -316,8 +350,8 @@ fn check_for(&ctx cx, &@ast::local local, &@ast::expr seq, &ast::block block,
 
 fn check_var(&ctx cx, &@ast::expr ex, &ast::path p, ast::ann ann, bool assign,
              &scope sc) {
-    auto def = cx.dm.get(ann.id);
-    if (!def_is_local(def)) { ret; }
+    auto def = cx.tcx.def_map.get(ann.id);
+    if (!def_is_local(def, true)) { ret; }
     auto my_defnum = ast::def_id_of_def(def)._1;
     auto var_t = ty::expr_ty(*cx.tcx, ex);
     for (restrict r in sc) {
@@ -342,7 +376,7 @@ fn check_assign(&@ctx cx, &@ast::expr dest, &@ast::expr src, &scope sc,
     visit_expr(cx, src, sc, v);
     alt (dest.node) {
         case (ast::expr_path(?p, ?ann)) {
-            auto dnum = ast::def_id_of_def(cx.dm.get(ann.id))._1;
+            auto dnum = ast::def_id_of_def(cx.tcx.def_map.get(ann.id))._1;
             if (is_immutable_alias(cx, sc, dnum)) {
                 cx.tcx.sess.span_err(dest.span,
                                      "assigning to immutable alias");
@@ -529,7 +563,7 @@ fn inner_mut(&vec[deref] ds) -> option::t[ty::t] {
 fn path_def_id(&ctx cx, &@ast::expr ex) -> option::t[ast::def_id] {
     alt (ex.node) {
         case (ast::expr_path(_, ?ann)) {
-            ret some(ast::def_id_of_def(cx.dm.get(ann.id)));
+            ret some(ast::def_id_of_def(cx.tcx.def_map.get(ann.id)));
         }
         case (_) { ret none; }
     }
@@ -594,15 +628,23 @@ fn ty_can_unsafely_include(&ctx cx, ty::t needle, ty::t haystack, bool mut) ->
     ret helper(*cx.tcx, needle, haystack, mut);
 }
 
-fn def_is_local(&ast::def d) -> bool {
+fn def_is_local(&ast::def d, bool objfields_count) -> bool {
     ret alt (d) {
-            case (ast::def_local(_)) { true }
-            case (ast::def_arg(_)) { true }
-            case (ast::def_obj_field(_)) { true }
-            case (ast::def_binding(_)) { true }
-            case (_) { false }
-        };
+        case (ast::def_local(_)) { true }
+        case (ast::def_arg(_)) { true }
+        case (ast::def_obj_field(_)) { objfields_count }
+        case (ast::def_binding(_)) { true }
+        case (_) { false }
+    };
 }
+
+fn fty_args(&ctx cx, ty::t fty) -> vec[ty::arg] {
+    ret alt (ty::struct(*cx.tcx, fty)) {
+        case (ty::ty_fn(_, ?args, _, _, _)) { args }
+        case (ty::ty_native_fn(_, ?args, _)) { args }
+    };
+}
+
 // Local Variables:
 // mode: rust
 // fill-column: 78;
diff --git a/src/comp/middle/metadata.rs b/src/comp/middle/metadata.rs
index b64bab69eaf..dc2acfa6ca7 100644
--- a/src/comp/middle/metadata.rs
+++ b/src/comp/middle/metadata.rs
@@ -221,8 +221,7 @@ mod Encode {
                     case (ast::native_abi_cdecl) { w.write_char('c'); }
                     case (ast::native_abi_llvm) { w.write_char('l'); }
                 }
-                let vec[@constr] res_constrs = [];
-                enc_ty_fn(w, cx, args, out, ast::return, res_constrs);
+                enc_ty_fn(w, cx, args, out, ast::return, []);
             }
             case (ty::ty_obj(?methods)) {
                 w.write_str("O[");
@@ -253,7 +252,7 @@ mod Encode {
         }
     }
     fn enc_ty_fn(&io::writer w, &@ctxt cx, &vec[ty::arg] args, &ty::t out,
-                 &ast::controlflow cf, &vec[@ast::constr] constrs) {
+                 &ast::controlflow cf, &vec[@ty::constr_def] constrs) {
         w.write_char('[');
         for (ty::arg arg in args) {
             alt (arg.mode) {
@@ -271,7 +270,7 @@ mod Encode {
             case (_) { enc_ty(w, cx, out); }
         }
         auto colon = true;
-        for (@ast::constr c in constrs) {
+        for (@ty::constr_def c in constrs) {
             if (colon) {
                 w.write_char(':');
                 colon = false;
@@ -279,7 +278,7 @@ mod Encode {
             enc_constr(w, cx, c);
         }
     }
-    fn enc_constr(&io::writer w, &@ctxt cx, &@ast::constr c) {
+    fn enc_constr(&io::writer w, &@ctxt cx, &@ty::constr_def c) {
         w.write_str(path_to_str(c.node.path));
         w.write_char('(');
         // FIXME
diff --git a/src/comp/middle/resolve.rs b/src/comp/middle/resolve.rs
index 1da8fa0d410..4d20216564c 100644
--- a/src/comp/middle/resolve.rs
+++ b/src/comp/middle/resolve.rs
@@ -11,7 +11,8 @@ import util::common::new_int_hash;
 import util::common::new_uint_hash;
 import util::common::new_str_hash;
 import util::common::span;
-import middle::tstate::ann::ts_ann;
+import util::common::respan;
+import middle::ty::constr_table;
 import visit::vt;
 import std::map::hashmap;
 import std::list;
@@ -111,6 +112,7 @@ type def_map = hashmap[uint, def];
 type env =
     rec(crate_map crate_map,
         def_map def_map,
+        constr_table fn_constrs,
         hashmap[def_id, @ast::item] ast_map,
         hashmap[ast::def_num, import_state] imports,
         hashmap[ast::def_num, @indexed_mod] mod_map,
@@ -118,17 +120,18 @@ type env =
         ext_hash ext_cache,
         session sess);
 
-
 // Used to distinguish between lookups from outside and from inside modules,
 // since export restrictions should only be applied for the former.
 tag dir { inside; outside; }
 
 tag namespace { ns_value; ns_type; ns_module; }
 
-fn resolve_crate(session sess, @ast::crate crate) -> def_map {
+fn resolve_crate(session sess, @ast::crate crate)
+    -> tup(def_map, constr_table) {
     auto e =
         @rec(crate_map=new_uint_hash[ast::crate_num](),
              def_map=new_uint_hash[def](),
+             fn_constrs = new_def_hash[vec[ty::constr_def]](),
              ast_map=new_def_hash[@ast::item](),
              imports=new_int_hash[import_state](),
              mod_map=new_int_hash[@indexed_mod](),
@@ -140,7 +143,7 @@ fn resolve_crate(session sess, @ast::crate crate) -> def_map {
     resolve_imports(*e);
     check_for_collisions(e, *crate);
     resolve_names(e, crate);
-    ret e.def_map;
+    ret tup(e.def_map, e.fn_constrs);
 }
 
 
@@ -266,8 +269,9 @@ fn resolve_names(&@env e, &@ast::crate c) {
              visit_arm=bind walk_arm(e, _, _, _),
              visit_expr=bind walk_expr(e, _, _, _),
              visit_ty=bind walk_ty(e, _, _, _),
-             visit_fn=visit_fn_with_scope,
-             visit_constr=bind walk_constr(e, _, _, _)
+             visit_constr = bind walk_constr(e, _, _, _),
+             visit_fn=bind visit_fn_with_scope
+                        (e, _, _, _, _, _, _, _, _)
              with *visit::default_visitor());
     visit::visit_crate(*c, cons(scope_crate(c), @nil), visit::vtor(v));
     fn walk_expr(@env e, &@ast::expr exp, &scopes sc, &vt[scopes] v) {
@@ -282,12 +286,7 @@ fn resolve_names(&@env e, &@ast::crate c) {
             case (_) { }
         }
     }
-    fn walk_constr(@env e, &@ast::constr c, &scopes sc, &vt[scopes] v) {
-        auto new_def =
-            lookup_path_strict(*e, sc, c.span, c.node.path.node.idents,
-                               ns_value);
-        e.def_map.insert(c.node.ann.id, new_def);
-    }
+
     fn walk_ty(@env e, &@ast::ty t, &scopes sc, &vt[scopes] v) {
         visit::visit_ty(t, sc, v);
         alt (t.node) {
@@ -300,6 +299,13 @@ fn resolve_names(&@env e, &@ast::crate c) {
             case (_) { }
         }
     }
+
+    fn walk_constr(@env e, &@ast::constr c, &scopes sc, &vt[scopes] v) {
+        auto new_def = lookup_path_strict(*e, sc, c.span,
+                                          c.node.path.node.idents, ns_value);
+        e.def_map.insert(c.node.ann.id, new_def);
+    }
+
     fn walk_arm(@env e, &ast::arm a, &scopes sc, &vt[scopes] v) {
         walk_pat(*e, sc, a.pat);
         visit_arm_with_scope(a, sc, v);
@@ -338,11 +344,16 @@ fn visit_native_item_with_scope(&@ast::native_item ni, &scopes sc,
     visit::visit_native_item(ni, cons(scope_native_item(ni), @sc), v);
 }
 
-fn visit_fn_with_scope(&ast::_fn f, &vec[ast::ty_param] tp, &span sp,
+fn visit_fn_with_scope(&@env e, &ast::_fn f, &vec[ast::ty_param] tp, &span sp,
                        &ident name, &def_id d_id, &ann a, &scopes sc,
                        &vt[scopes] v) {
-    visit::visit_fn(f, tp, sp, name, d_id, a, cons(scope_fn(f.decl, tp), @sc),
-                    v);
+    // here's where we need to set up the mapping
+    // for f's constrs in the table.
+    for (@ast::constr c in f.decl.constraints) {
+        resolve_constr(e, d_id, c, sc, v); 
+    }
+    visit::visit_fn(f, tp, sp, name, d_id, a,
+                    cons(scope_fn(f.decl, tp), @sc), v);
 }
 
 fn visit_block_with_scope(&ast::block b, &scopes sc, &vt[scopes] v) {
@@ -389,6 +400,37 @@ fn follow_import(&env e, &scopes sc, vec[ident] path, &span sp) -> def {
     }
 }
 
+fn resolve_constr(@env e, &def_id d_id, &@ast::constr c, &scopes sc,
+                  &vt[scopes] v) {
+    let def new_def = lookup_path_strict(*e, sc, c.span,
+                                         c.node.path.node.idents,
+                                         ns_value);
+    alt (new_def) {
+        case (ast::def_fn(?pred_id)) {
+            let ty::constr_general[uint] c_ = rec(path=c.node.path,
+                                                  args=c.node.args,
+                                                  id=pred_id);
+            let ty::constr_def new_constr = respan(c.span, c_);
+            add_constr(e, d_id, new_constr);
+        }
+        case (_) {
+            e.sess.span_err(c.span, "Non-predicate in constraint: "
+                            + ty::path_to_str(c.node.path));
+        }
+    }
+}
+
+fn add_constr(&@env e, &def_id d_id, &ty::constr_def c) {
+    e.fn_constrs.insert(d_id,
+       alt (e.fn_constrs.find(d_id)) {
+          case (none) {
+              [c]
+          }
+          case (some(?cs)) {
+              cs + [c]
+          }
+       });
+}
 
 // Import resolution
 fn resolve_import(&env e, &@ast::view_item it, &scopes sc) {
diff --git a/src/comp/middle/trans.rs b/src/comp/middle/trans.rs
index a01650dc1ac..7bde65f40d8 100644
--- a/src/comp/middle/trans.rs
+++ b/src/comp/middle/trans.rs
@@ -113,6 +113,7 @@ type stats =
         mutable uint n_null_glues,
         mutable uint n_real_glues);
 
+// Crate context.  Every crate we compile has one of these.
 type crate_ctxt =
     rec(session::session sess,
         ModuleRef llmod,
@@ -120,6 +121,10 @@ type crate_ctxt =
         type_names tn,
         hashmap[str, ValueRef] externs,
         hashmap[str, ValueRef] intrinsics,
+
+        // A mapping from the def_id of each item in this crate to the address
+        // of the first instruction of the item's definition in the executable
+        // we're generating.
         hashmap[ast::def_id, ValueRef] item_ids,
         hashmap[ast::def_id, @ast::item] items,
         hashmap[ast::def_id, @ast::native_item] native_items,
@@ -1110,7 +1115,7 @@ fn trans_non_gc_free(&@block_ctxt cx, ValueRef v) -> result {
 fn find_scope_cx(&@block_ctxt cx) -> @block_ctxt {
     if (cx.kind != NON_SCOPE_BLOCK) { ret cx; }
     alt (cx.parent) {
-        case (parent_some(?b)) { be find_scope_cx(b); }
+        case (parent_some(?b)) { ret find_scope_cx(b); }
         case (parent_none) {
             cx.fcx.lcx.ccx.sess.bug("trans::find_scope_cx() " +
                                         "called on parentless block_ctxt");
@@ -2369,7 +2374,7 @@ fn make_numerical_cmp_glue(&@block_ctxt cx, ValueRef lhs, ValueRef rhs,
 
 // Returns the length of an interior vector and a pointer to its first
 // element, in that order.
-fn get_ivec_len_and_data(&@block_ctxt bcx, ValueRef v, ty::t unit_ty) ->
+fn get_len_and_data(&@block_ctxt bcx, ValueRef v, ty::t unit_ty) ->
    tup(ValueRef, ValueRef, @block_ctxt) {
     auto llunitty = type_of_or_i8(bcx, unit_ty);
     auto stack_len =
@@ -2450,7 +2455,7 @@ fn iter_structural_ty(&@block_ctxt cx, ValueRef v, &ty::t t, val_and_ty_fn f)
                   ty::t t) -> result {
         ret f(cx, av, t);
     }
-    be iter_structural_ty_full(cx, v, v, t, bind adaptor_fn(f, _, _, _, _));
+    ret iter_structural_ty_full(cx, v, v, t, bind adaptor_fn(f, _, _, _, _));
 }
 
 fn iter_structural_ty_full(&@block_ctxt cx, ValueRef av, ValueRef bv,
@@ -2481,11 +2486,13 @@ fn iter_structural_ty_full(&@block_ctxt cx, ValueRef av, ValueRef bv,
         auto rslt = size_of(bcx, unit_ty);
         auto unit_sz = rslt.val;
         bcx = rslt.bcx;
-        auto a_len_and_data = get_ivec_len_and_data(bcx, av, unit_ty);
+
+        auto a_len_and_data = ivec::get_len_and_data(bcx, av, unit_ty);
         auto a_len = a_len_and_data._0;
         auto a_elem = a_len_and_data._1;
         bcx = a_len_and_data._2;
-        auto b_len_and_data = get_ivec_len_and_data(bcx, bv, unit_ty);
+
+        auto b_len_and_data = ivec::get_len_and_data(bcx, bv, unit_ty);
         auto b_len = b_len_and_data._0;
         auto b_elem = b_len_and_data._1;
         bcx = b_len_and_data._2;
@@ -2688,8 +2695,8 @@ fn iter_sequence_inner(&@block_ctxt cx, ValueRef src,
         ret f(cx, load_if_immediate(cx, p, elt_ty), elt_ty);
     }
     auto elt_sz = size_of(cx, elt_ty);
-    be iter_sequence_raw(elt_sz.bcx, src, src, src_lim, elt_sz.val,
-                         bind adaptor_fn(f, elt_ty, _, _, _));
+    ret iter_sequence_raw(elt_sz.bcx, src, src, src_lim, elt_sz.val,
+                          bind adaptor_fn(f, elt_ty, _, _, _));
 }
 
 
@@ -3209,209 +3216,292 @@ fn trans_vec_append(&@block_ctxt cx, &ty::t t, ValueRef lhs, ValueRef rhs) ->
 }
 
 
-// Returns a tuple consisting of a pointer to the newly-reserved space and a
-// block context. Updates the length appropriately.
-fn reserve_ivec_space(&@block_ctxt cx, TypeRef llunitty, ValueRef v,
-                      ValueRef len_needed) -> result {
-    auto stack_len_ptr =
-        cx.build.InBoundsGEP(v, [C_int(0), C_uint(abi::ivec_elt_len)]);
-    auto stack_len = cx.build.Load(stack_len_ptr);
-    auto alen =
-        cx.build.Load(cx.build.InBoundsGEP(v,
-                                           [C_int(0),
-                                            C_uint(abi::ivec_elt_alen)]));
-    // There are four cases we have to consider:
-    // (1) On heap, no resize necessary.
-    // (2) On heap, need to resize.
-    // (3) On stack, no resize necessary.
-    // (4) On stack, need to spill to heap.
-
-    auto maybe_on_heap =
-        cx.build.ICmp(lib::llvm::LLVMIntEQ, stack_len, C_int(0));
-    auto maybe_on_heap_cx = new_sub_block_ctxt(cx, "maybe_on_heap");
-    auto on_stack_cx = new_sub_block_ctxt(cx, "on_stack");
-    cx.build.CondBr(maybe_on_heap, maybe_on_heap_cx.llbb, on_stack_cx.llbb);
-    auto next_cx = new_sub_block_ctxt(cx, "next");
-    // We're possibly on the heap, unless the vector is zero-length.
-
-    auto stub_p = [C_int(0), C_uint(abi::ivec_heap_stub_elt_ptr)];
-
-    auto stub_ptr =
-        maybe_on_heap_cx.build.PointerCast(v, T_ptr(T_ivec_heap(llunitty)));
-    auto heap_ptr =
-        {
-            auto m = maybe_on_heap_cx.build.InBoundsGEP(stub_ptr, stub_p);
-            maybe_on_heap_cx.build.Load(m)
+mod ivec {
+    // Returns the length of an interior vector and a pointer to its first
+    // element, in that order.
+    fn get_len_and_data(&@block_ctxt bcx, ValueRef v, ty::t unit_ty) ->
+            tup(ValueRef, ValueRef, @block_ctxt) {
+        auto llunitty = type_of_or_i8(bcx, unit_ty);
+        auto stack_len =
+            bcx.build.Load(bcx.build.InBoundsGEP(v,
+                [C_int(0), C_uint(abi::ivec_elt_len)]));
+        auto stack_elem =
+            bcx.build.InBoundsGEP(v,
+                [C_int(0), C_uint(abi::ivec_elt_elems), C_int(0)]);
+        auto on_heap = bcx.build.ICmp(lib::llvm::LLVMIntEQ, stack_len,
+                                      C_int(0));
+        auto on_heap_cx = new_sub_block_ctxt(bcx, "on_heap");
+        auto next_cx = new_sub_block_ctxt(bcx, "next");
+        bcx.build.CondBr(on_heap, on_heap_cx.llbb, next_cx.llbb);
+        auto heap_stub =
+            on_heap_cx.build.PointerCast(v, T_ptr(T_ivec_heap(llunitty)));
+        auto heap_ptr = {
+            auto v = [C_int(0), C_uint(abi::ivec_heap_stub_elt_ptr)];
+            on_heap_cx.build.Load(on_heap_cx.build.InBoundsGEP(heap_stub, v))
         };
-    auto on_heap =
-        maybe_on_heap_cx.build.ICmp(lib::llvm::LLVMIntNE, heap_ptr,
-                                    C_null(val_ty(heap_ptr)));
-    auto on_heap_cx = new_sub_block_ctxt(cx, "on_heap");
-    maybe_on_heap_cx.build.CondBr(on_heap, on_heap_cx.llbb, on_stack_cx.llbb);
-    // We're definitely on the heap. Check whether we need to resize.
 
-    auto heap_len_ptr =
-        on_heap_cx.build.InBoundsGEP(heap_ptr,
-                                     [C_int(0),
-                                      C_uint(abi::ivec_heap_elt_len)]);
-    auto heap_len = on_heap_cx.build.Load(heap_len_ptr);
-    auto new_heap_len = on_heap_cx.build.Add(heap_len, len_needed);
-    auto heap_len_unscaled =
-        on_heap_cx.build.UDiv(heap_len, llsize_of(llunitty));
-    auto heap_no_resize_needed =
-        on_heap_cx.build.ICmp(lib::llvm::LLVMIntULE, new_heap_len, alen);
-    auto heap_no_resize_cx = new_sub_block_ctxt(cx, "heap_no_resize");
-    auto heap_resize_cx = new_sub_block_ctxt(cx, "heap_resize");
-    on_heap_cx.build.CondBr(heap_no_resize_needed, heap_no_resize_cx.llbb,
-                            heap_resize_cx.llbb);
-    // Case (1): We're on the heap and don't need to resize.
+        // Check whether the heap pointer is null. If it is, the vector length
+        // is truly zero.
 
-    auto heap_data_no_resize =
-        heap_no_resize_cx.build.InBoundsGEP(heap_ptr,
-                                            [C_int(0),
-                                             C_uint(abi::ivec_heap_elt_elems),
-                                             heap_len_unscaled]);
-    heap_no_resize_cx.build.Store(new_heap_len, heap_len_ptr);
-    heap_no_resize_cx.build.Br(next_cx.llbb);
-    // Case (2): We're on the heap and need to resize. This path is rare, so
-    // we delegate to cold glue.
+        auto llstubty = T_ivec_heap(llunitty);
+        auto llheapptrty = struct_elt(llstubty, abi::ivec_heap_stub_elt_ptr);
+        auto heap_ptr_is_null =
+            on_heap_cx.build.ICmp(lib::llvm::LLVMIntEQ, heap_ptr,
+                                  C_null(T_ptr(llheapptrty)));
+        auto zero_len_cx = new_sub_block_ctxt(bcx, "zero_len");
+        auto nonzero_len_cx = new_sub_block_ctxt(bcx, "nonzero_len");
+        on_heap_cx.build.CondBr(heap_ptr_is_null, zero_len_cx.llbb,
+                                nonzero_len_cx.llbb);
+        // Technically this context is unnecessary, but it makes this function
+        // clearer.
 
-    {
-        auto p = heap_resize_cx.build.PointerCast(v, T_ptr(T_opaque_ivec()));
-        heap_resize_cx.build.Call(cx.fcx.lcx.ccx.upcalls.ivec_resize,
-                                  [cx.fcx.lltaskptr, p, new_heap_len]);
+        auto zero_len = C_int(0);
+        auto zero_elem = C_null(T_ptr(llunitty));
+        zero_len_cx.build.Br(next_cx.llbb);
+        // If we're here, then we actually have a heapified vector.
+
+        auto heap_len = {
+            auto v = [C_int(0), C_uint(abi::ivec_heap_elt_len)];
+            auto m = nonzero_len_cx.build.InBoundsGEP(heap_ptr, v);
+            nonzero_len_cx.build.Load(m)
+        };
+        auto heap_elem =
+            nonzero_len_cx.build.InBoundsGEP(heap_ptr,
+                [C_int(0), C_uint(abi::ivec_heap_elt_elems), C_int(0)]);
+        nonzero_len_cx.build.Br(next_cx.llbb);
+
+        // Now we can figure out the length of `v` and get a pointer to its
+        // first element.
+
+        auto len =
+            next_cx.build.Phi(T_int(),
+                [stack_len, zero_len, heap_len],
+                [bcx.llbb, zero_len_cx.llbb, nonzero_len_cx.llbb]);
+        auto elem =
+            next_cx.build.Phi(T_ptr(llunitty),
+                [stack_elem, zero_elem, heap_elem],
+                [bcx.llbb, zero_len_cx.llbb, nonzero_len_cx.llbb]);
+        ret tup(len, elem, next_cx);
     }
 
-    auto heap_ptr_resize =
+    // Returns a tuple consisting of a pointer to the newly-reserved space and
+    // a block context. Updates the length appropriately.
+    fn reserve_space(&@block_ctxt cx, TypeRef llunitty, ValueRef v,
+                     ValueRef len_needed) -> result {
+        auto stack_len_ptr =
+            cx.build.InBoundsGEP(v, [C_int(0), C_uint(abi::ivec_elt_len)]);
+        auto stack_len = cx.build.Load(stack_len_ptr);
+        auto alen =
+            cx.build.Load(cx.build.InBoundsGEP(v,
+                                               [C_int(0),
+                                                C_uint(abi::ivec_elt_alen)]));
+        // There are four cases we have to consider:
+        // (1) On heap, no resize necessary.
+        // (2) On heap, need to resize.
+        // (3) On stack, no resize necessary.
+        // (4) On stack, need to spill to heap.
+
+        auto maybe_on_heap =
+            cx.build.ICmp(lib::llvm::LLVMIntEQ, stack_len, C_int(0));
+        auto maybe_on_heap_cx = new_sub_block_ctxt(cx, "maybe_on_heap");
+        auto on_stack_cx = new_sub_block_ctxt(cx, "on_stack");
+        cx.build.CondBr(maybe_on_heap, maybe_on_heap_cx.llbb,
+                        on_stack_cx.llbb);
+        auto next_cx = new_sub_block_ctxt(cx, "next");
+        // We're possibly on the heap, unless the vector is zero-length.
+
+        auto stub_p = [C_int(0), C_uint(abi::ivec_heap_stub_elt_ptr)];
+
+        auto stub_ptr = maybe_on_heap_cx.build.PointerCast(v,
+            T_ptr(T_ivec_heap(llunitty)));
+        auto heap_ptr =
+            {
+                auto m = maybe_on_heap_cx.build.InBoundsGEP(stub_ptr, stub_p);
+                maybe_on_heap_cx.build.Load(m)
+            };
+        auto on_heap =
+            maybe_on_heap_cx.build.ICmp(lib::llvm::LLVMIntNE, heap_ptr,
+                                        C_null(val_ty(heap_ptr)));
+        auto on_heap_cx = new_sub_block_ctxt(cx, "on_heap");
+        maybe_on_heap_cx.build.CondBr(on_heap, on_heap_cx.llbb,
+                                      on_stack_cx.llbb);
+
+        // We're definitely on the heap. Check whether we need to resize.
+        auto heap_len_ptr =
+            on_heap_cx.build.InBoundsGEP(heap_ptr,
+                                         [C_int(0),
+                                          C_uint(abi::ivec_heap_elt_len)]);
+        auto heap_len = on_heap_cx.build.Load(heap_len_ptr);
+        auto new_heap_len = on_heap_cx.build.Add(heap_len, len_needed);
+        auto heap_len_unscaled =
+            on_heap_cx.build.UDiv(heap_len, llsize_of(llunitty));
+        auto heap_no_resize_needed =
+            on_heap_cx.build.ICmp(lib::llvm::LLVMIntULE, new_heap_len, alen);
+        auto heap_no_resize_cx = new_sub_block_ctxt(cx, "heap_no_resize");
+        auto heap_resize_cx = new_sub_block_ctxt(cx, "heap_resize");
+        on_heap_cx.build.CondBr(heap_no_resize_needed, heap_no_resize_cx.llbb,
+                                heap_resize_cx.llbb);
+        // Case (1): We're on the heap and don't need to resize.
+
+        auto heap_data_no_resize =
+            heap_no_resize_cx.build.InBoundsGEP(heap_ptr,
+                [C_int(0),
+                 C_uint(abi::ivec_heap_elt_elems),
+                 heap_len_unscaled]);
+        heap_no_resize_cx.build.Store(new_heap_len, heap_len_ptr);
+        heap_no_resize_cx.build.Br(next_cx.llbb);
+
+        // Case (2): We're on the heap and need to resize. This path is rare,
+        // so we delegate to cold glue.
+
         {
+            auto p = heap_resize_cx.build.PointerCast(v,
+                                                      T_ptr(T_opaque_ivec()));
+            heap_resize_cx.build.Call(cx.fcx.lcx.ccx.upcalls.ivec_resize,
+                                      [cx.fcx.lltaskptr, p, new_heap_len]);
+        }
+
+        auto heap_ptr_resize = {
             auto m = heap_resize_cx.build.InBoundsGEP(stub_ptr, stub_p);
             heap_resize_cx.build.Load(m)
         };
-    auto heap_data_resize =
-        heap_resize_cx.build.InBoundsGEP(heap_ptr_resize,
-                                         [C_int(0),
-                                          C_uint(abi::ivec_heap_elt_elems),
-                                          heap_len_unscaled]);
-    heap_resize_cx.build.Br(next_cx.llbb);
-    // We're on the stack. Check whether we need to spill to the heap.
+        auto heap_data_resize =
+            heap_resize_cx.build.InBoundsGEP(heap_ptr_resize,
+                [C_int(0),
+                 C_uint(abi::ivec_heap_elt_elems),
+                 heap_len_unscaled]);
+        heap_resize_cx.build.Br(next_cx.llbb);
 
-    auto new_stack_len = on_stack_cx.build.Add(stack_len, len_needed);
-    auto stack_no_spill_needed =
-        on_stack_cx.build.ICmp(lib::llvm::LLVMIntULE, new_stack_len, alen);
-    auto stack_len_unscaled =
-        on_stack_cx.build.UDiv(stack_len, llsize_of(llunitty));
-    auto stack_no_spill_cx = new_sub_block_ctxt(cx, "stack_no_spill");
-    auto stack_spill_cx = new_sub_block_ctxt(cx, "stack_spill");
-    on_stack_cx.build.CondBr(stack_no_spill_needed, stack_no_spill_cx.llbb,
-                             stack_spill_cx.llbb);
-    // Case (3): We're on the stack and don't need to spill.
+        // We're on the stack. Check whether we need to spill to the heap.
+        auto new_stack_len = on_stack_cx.build.Add(stack_len, len_needed);
+        auto stack_no_spill_needed =
+            on_stack_cx.build.ICmp(lib::llvm::LLVMIntULE, new_stack_len,
+                                   alen);
+        auto stack_len_unscaled =
+            on_stack_cx.build.UDiv(stack_len, llsize_of(llunitty));
+        auto stack_no_spill_cx = new_sub_block_ctxt(cx, "stack_no_spill");
+        auto stack_spill_cx = new_sub_block_ctxt(cx, "stack_spill");
+        on_stack_cx.build.CondBr(stack_no_spill_needed,
+                                 stack_no_spill_cx.llbb,
+                                 stack_spill_cx.llbb);
 
-    auto stack_data_no_spill =
-        stack_no_spill_cx.build.InBoundsGEP(v,
-                                            [C_int(0),
-                                             C_uint(abi::ivec_elt_elems),
-                                             stack_len_unscaled]);
-    stack_no_spill_cx.build.Store(new_stack_len, stack_len_ptr);
-    stack_no_spill_cx.build.Br(next_cx.llbb);
-    // Case (4): We're on the stack and need to spill. Like case (2), this
-    // path is rare, so we delegate to cold glue.
+        // Case (3): We're on the stack and don't need to spill.
+        auto stack_data_no_spill =
+            stack_no_spill_cx.build.InBoundsGEP(v,
+                                                [C_int(0),
+                                                 C_uint(abi::ivec_elt_elems),
+                                                 stack_len_unscaled]);
+        stack_no_spill_cx.build.Store(new_stack_len, stack_len_ptr);
+        stack_no_spill_cx.build.Br(next_cx.llbb);
 
-    {
-        auto p = stack_spill_cx.build.PointerCast(v, T_ptr(T_opaque_ivec()));
-        stack_spill_cx.build.Call(cx.fcx.lcx.ccx.upcalls.ivec_spill,
-                                  [cx.fcx.lltaskptr, p, new_stack_len]);
-    }
-    auto spill_stub =
-        stack_spill_cx.build.PointerCast(v, T_ptr(T_ivec_heap(llunitty)));
-    auto heap_ptr_spill =
-        stack_spill_cx.build.Load(stack_spill_cx.build.InBoundsGEP(spill_stub,
-                                                                   stub_p));
-    auto heap_len_ptr_spill =
-        stack_spill_cx.build.InBoundsGEP(heap_ptr_spill,
-                                         [C_int(0),
-                                          C_uint(abi::ivec_heap_elt_len)]);
-    auto heap_data_spill =
-        stack_spill_cx.build.InBoundsGEP(heap_ptr_spill,
-                                         [C_int(0),
-                                          C_uint(abi::ivec_heap_elt_elems),
-                                          stack_len_unscaled]);
-    stack_spill_cx.build.Br(next_cx.llbb);
-    // Phi together the different data pointers to get the result.
-
-    auto data_ptr =
-        next_cx.build.Phi(T_ptr(llunitty),
-                          [heap_data_no_resize, heap_data_resize,
-                           stack_data_no_spill, heap_data_spill],
-                          [heap_no_resize_cx.llbb, heap_resize_cx.llbb,
-                           stack_no_spill_cx.llbb, stack_spill_cx.llbb]);
-    ret res(next_cx, data_ptr);
-}
-
-fn trans_ivec_append(&@block_ctxt cx, &ty::t t, ValueRef lhs, ValueRef rhs) ->
-   result {
-    auto unit_ty = ty::sequence_element_type(cx.fcx.lcx.ccx.tcx, t);
-    auto llunitty = type_of_or_i8(cx, unit_ty);
-    auto skip_null;
-    alt (ty::struct(cx.fcx.lcx.ccx.tcx, t)) {
-        case (ty::ty_istr) { skip_null = true; }
-        case (ty::ty_ivec(_)) { skip_null = false; }
-        case (_) {
-            cx.fcx.lcx.ccx.tcx.sess.bug("non-istr/ivec in trans_ivec_append");
+        // Case (4): We're on the stack and need to spill. Like case (2), this
+        // path is rare, so we delegate to cold glue.
+        {
+            auto p = stack_spill_cx.build.PointerCast(v,
+                T_ptr(T_opaque_ivec()));
+            stack_spill_cx.build.Call(cx.fcx.lcx.ccx.upcalls.ivec_spill,
+                                      [cx.fcx.lltaskptr, p, new_stack_len]);
         }
+
+        auto spill_stub =
+            stack_spill_cx.build.PointerCast(v, T_ptr(T_ivec_heap(llunitty)));
+        auto heap_ptr_spill =
+            stack_spill_cx.build.Load(
+                stack_spill_cx.build.InBoundsGEP(spill_stub, stub_p));
+        auto heap_len_ptr_spill =
+            stack_spill_cx.build.InBoundsGEP(heap_ptr_spill,
+                [C_int(0), C_uint(abi::ivec_heap_elt_len)]);
+        auto heap_data_spill =
+            stack_spill_cx.build.InBoundsGEP(heap_ptr_spill,
+                [C_int(0),
+                 C_uint(abi::ivec_heap_elt_elems),
+                 stack_len_unscaled]);
+        stack_spill_cx.build.Br(next_cx.llbb);
+
+        // Phi together the different data pointers to get the result.
+        auto data_ptr =
+            next_cx.build.Phi(T_ptr(llunitty),
+                              [heap_data_no_resize, heap_data_resize,
+                               stack_data_no_spill, heap_data_spill],
+                              [heap_no_resize_cx.llbb, heap_resize_cx.llbb,
+                               stack_no_spill_cx.llbb, stack_spill_cx.llbb]);
+        ret res(next_cx, data_ptr);
     }
-    // Gather the various type descriptors we'll need.
 
-    auto rslt = get_tydesc(cx, t, false, none);
-    auto vec_tydesc = rslt.val;
-    auto bcx = rslt.bcx;
-    rslt = get_tydesc(bcx, unit_ty, false, none);
-    auto unit_tydesc = rslt.val;
-    bcx = rslt.bcx;
-    lazily_emit_tydesc_glue(bcx, abi::tydesc_field_take_glue, none);
-    lazily_emit_tydesc_glue(bcx, abi::tydesc_field_drop_glue, none);
-    lazily_emit_tydesc_glue(bcx, abi::tydesc_field_free_glue, none);
-    auto rhs_len_and_data = get_ivec_len_and_data(bcx, rhs, unit_ty);
-    auto rhs_len = rhs_len_and_data._0;
-    auto rhs_data = rhs_len_and_data._1;
-    bcx = rhs_len_and_data._2;
-    rslt = reserve_ivec_space(bcx, llunitty, lhs, rhs_len);
-    auto lhs_data = rslt.val;
-    bcx = rslt.bcx;
-    // Work out the end pointer.
+    fn trans_append(&@block_ctxt cx, &ty::t t, ValueRef lhs, ValueRef rhs) ->
+       result {
+        auto unit_ty = ty::sequence_element_type(cx.fcx.lcx.ccx.tcx, t);
+        auto llunitty = type_of_or_i8(cx, unit_ty);
+        auto skip_null;
+        alt (ty::struct(cx.fcx.lcx.ccx.tcx, t)) {
+            case (ty::ty_istr) { skip_null = true; }
+            case (ty::ty_ivec(_)) { skip_null = false; }
+            case (_) {
+                cx.fcx.lcx.ccx.tcx.sess.bug("non-istr/ivec in trans_append");
+            }
+        }
+        // Gather the various type descriptors we'll need.
 
-    auto lhs_unscaled_idx = bcx.build.UDiv(rhs_len, llsize_of(llunitty));
-    auto lhs_end = bcx.build.InBoundsGEP(lhs_data, [lhs_unscaled_idx]);
-    // Now emit the copy loop.
+        auto rslt = get_tydesc(cx, t, false, none);
+        auto vec_tydesc = rslt.val;
+        auto bcx = rslt.bcx;
+        rslt = get_tydesc(bcx, unit_ty, false, none);
+        auto unit_tydesc = rslt.val;
+        bcx = rslt.bcx;
 
-    auto dest_ptr = alloca(bcx, T_ptr(llunitty));
-    bcx.build.Store(lhs_data, dest_ptr);
-    auto src_ptr = alloca(bcx, T_ptr(llunitty));
-    bcx.build.Store(rhs_data, src_ptr);
-    auto copy_loop_header_cx = new_sub_block_ctxt(bcx, "copy_loop_header");
-    bcx.build.Br(copy_loop_header_cx.llbb);
-    auto copy_dest_ptr = copy_loop_header_cx.build.Load(dest_ptr);
-    auto not_yet_at_end =
-        copy_loop_header_cx.build.ICmp(lib::llvm::LLVMIntNE, copy_dest_ptr,
-                                       lhs_end);
-    auto copy_loop_body_cx = new_sub_block_ctxt(bcx, "copy_loop_body");
-    auto next_cx = new_sub_block_ctxt(bcx, "next");
-    copy_loop_header_cx.build.CondBr(not_yet_at_end, copy_loop_body_cx.llbb,
-                                     next_cx.llbb);
-    auto copy_src_ptr = copy_loop_body_cx.build.Load(src_ptr);
-    rslt = copy_val(copy_loop_body_cx, INIT, copy_dest_ptr, copy_src_ptr, t);
-    auto post_copy_cx = rslt.bcx;
-    // Increment both pointers.
+        lazily_emit_tydesc_glue(bcx, abi::tydesc_field_take_glue, none);
+        lazily_emit_tydesc_glue(bcx, abi::tydesc_field_drop_glue, none);
+        lazily_emit_tydesc_glue(bcx, abi::tydesc_field_free_glue, none);
 
-    post_copy_cx.build.Store(post_copy_cx.build.InBoundsGEP(copy_dest_ptr,
-                                                            [C_int(1)]),
-                             dest_ptr);
-    post_copy_cx.build.Store(post_copy_cx.build.InBoundsGEP(copy_src_ptr,
-                                                            [C_int(1)]),
-                             src_ptr);
-    post_copy_cx.build.Br(copy_loop_header_cx.llbb);
-    ret res(next_cx, C_nil());
+        auto rhs_len_and_data = get_len_and_data(bcx, rhs, unit_ty);
+        auto rhs_len = rhs_len_and_data._0;
+        auto rhs_data = rhs_len_and_data._1;
+
+        bcx = rhs_len_and_data._2;
+        rslt = reserve_space(bcx, llunitty, lhs, rhs_len);
+        auto lhs_data = rslt.val;
+        bcx = rslt.bcx;
+
+        // Work out the end pointer.
+        auto lhs_unscaled_idx = bcx.build.UDiv(rhs_len, llsize_of(llunitty));
+        auto lhs_end = bcx.build.InBoundsGEP(lhs_data, [lhs_unscaled_idx]);
+
+        // Now emit the copy loop.
+        auto dest_ptr = alloca(bcx, T_ptr(llunitty));
+        bcx.build.Store(lhs_data, dest_ptr);
+        auto src_ptr = alloca(bcx, T_ptr(llunitty));
+        bcx.build.Store(rhs_data, src_ptr);
+        auto copy_loop_header_cx = new_sub_block_ctxt(bcx,
+                                                      "copy_loop_header");
+        bcx.build.Br(copy_loop_header_cx.llbb);
+        auto copy_dest_ptr = copy_loop_header_cx.build.Load(dest_ptr);
+        auto not_yet_at_end =
+            copy_loop_header_cx.build.ICmp(lib::llvm::LLVMIntNE,
+                                           copy_dest_ptr,
+                                           lhs_end);
+        auto copy_loop_body_cx = new_sub_block_ctxt(bcx, "copy_loop_body");
+        auto next_cx = new_sub_block_ctxt(bcx, "next");
+        copy_loop_header_cx.build.CondBr(not_yet_at_end,
+                                         copy_loop_body_cx.llbb,
+                                         next_cx.llbb);
+        auto copy_src_ptr = copy_loop_body_cx.build.Load(src_ptr);
+        rslt = copy_val(copy_loop_body_cx, INIT, copy_dest_ptr, copy_src_ptr,
+                        t);
+        auto post_copy_cx = rslt.bcx;
+        // Increment both pointers.
+
+        post_copy_cx.build.Store(post_copy_cx.build.InBoundsGEP(copy_dest_ptr,
+                                                                [C_int(1)]),
+                                 dest_ptr);
+        post_copy_cx.build.Store(post_copy_cx.build.InBoundsGEP(copy_src_ptr,
+                                                                [C_int(1)]),
+                                 src_ptr);
+        post_copy_cx.build.Br(copy_loop_header_cx.llbb);
+        ret res(next_cx, C_nil());
+    }
 }
 
+
 fn trans_vec_add(&@block_ctxt cx, &ty::t t, ValueRef lhs, ValueRef rhs) ->
    result {
     auto r = alloc_ty(cx, t);
@@ -4359,7 +4449,7 @@ fn trans_index(&@block_ctxt cx, &span sp, &@ast::expr base, &@ast::expr idx,
     maybe_name_value(cx.fcx.lcx.ccx, scaled_ix, "scaled_ix");
     auto interior_len_and_data;
     if (is_interior) {
-        auto rslt = get_ivec_len_and_data(bcx, v, unit_ty);
+        auto rslt = get_len_and_data(bcx, v, unit_ty);
         interior_len_and_data = some(tup(rslt._0, rslt._1));
         bcx = rslt._2;
     } else { interior_len_and_data = none; }
@@ -5081,7 +5171,7 @@ fn trans_vec(&@block_ctxt cx, &vec[@ast::expr] args, &ast::ann ann) ->
 }
 
 fn trans_ivec(@block_ctxt bcx, &vec[@ast::expr] args, &ast::ann ann) ->
-   result {
+        result {
     auto typ = node_ann_type(bcx.fcx.lcx.ccx, ann);
     auto unit_ty;
     alt (ty::struct(bcx.fcx.lcx.ccx.tcx, typ)) {
@@ -5325,9 +5415,9 @@ fn trans_expr_out(&@block_ctxt cx, &@ast::expr e, out_method output) ->
                 alt (op) {
                     case (ast::add) {
                         if (ty::sequence_is_interior(cx.fcx.lcx.ccx.tcx, t)) {
-                            ret trans_ivec_append(rhs_res.bcx, t,
-                                                  lhs_res.res.val,
-                                                  rhs_res.val);
+                            ret ivec::trans_append(rhs_res.bcx, t,
+                                                   lhs_res.res.val,
+                                                   rhs_res.val);
                         }
                         ret trans_vec_append(rhs_res.bcx, t, lhs_res.res.val,
                                              rhs_res.val);
@@ -5967,24 +6057,26 @@ fn recv_val(&@block_ctxt cx, ValueRef lhs, &@ast::expr rhs, &ty::t unit_ty,
 
 */
 
-// trans_anon_obj: create (and return!) an LLVM function that is the object
-// constructor for the anonymous object being translated.  
-//
-// This code differs from trans_obj in that, rather than creating an object
-// constructor function and putting it in the generated code as an object
-// item, we are instead "inlining" the construction of the object.
-fn trans_anon_obj(@block_ctxt cx, &span sp, &ast::anon_obj anon_obj,
+// trans_anon_obj: create and return a pointer to an object.  This code
+// differs from trans_obj in that, rather than creating an object constructor
+// function and putting it in the generated code as an object item, we are
+// instead "inlining" the construction of the object and returning the object
+// itself.
+fn trans_anon_obj(@block_ctxt bcx, &span sp, &ast::anon_obj anon_obj, 
                   &vec[ast::ty_param] ty_params, ast::def_id oid,
                   &ast::ann ann) -> result {
-    auto ccx = cx.fcx.lcx.ccx;
-    // A crate_ctxt has an item_ids hashmap, which has all of the def_ids of
-    // everything in the crate.  By looking up a def_id, you can get the
-    // ValueRef of that item.
 
-    auto llctor_decl = ccx.item_ids.get(oid);
+    // Right now, we're assuming that anon objs don't take ty params, even
+    // though the AST supports it.  It's nonsensical to write an expression
+    // like "obj[T](){ ... with ... }", since T is never instantiated;
+    // nevertheless, such an expression will parse.  FIXME for the future:
+    // support typarams (issue #n).
+    assert vec::len(ty_params) == 0u;
+
+    auto ccx = bcx.fcx.lcx.ccx;
+
     // If with_obj (the object being extended) exists, translate it, producing
     // a result.
-
     let option::t[result] with_obj_val = none[result];
     alt (anon_obj.with_obj) {
         case (none) { }
@@ -5993,81 +6085,44 @@ fn trans_anon_obj(@block_ctxt cx, &span sp, &ast::anon_obj anon_obj,
             // value) wrapped in a result.  We want to allocate space for this
             // value in our outer object, then copy it into the outer object.
 
-            with_obj_val = some[result](trans_expr(cx, e));
+            with_obj_val = some[result](trans_expr(bcx, e));
         }
     }
-    // If the anonymous object we're translating adds any additional fields,
-    // they'll become the arguments to the function we're creating.
 
     // FIXME (part of issue #417): all of the following code is copypasta from
     // trans_obj for translating the anonymous wrapper object.  Eventually we
     // should abstract this code out of trans_anon_obj and trans_obj.
 
-    // For the anon obj's additional fields, if any exist, translate object
-    // constructor arguments to function arguments.
-
-    let vec[ast::obj_field] addtl_fields = [];
-    let vec[ast::arg] addtl_fn_args = [];
-    alt (anon_obj.fields) {
-        case (none) { }
-        case (some(?fields)) {
-            addtl_fields = fields;
-            for (ast::obj_field f in fields) {
-                addtl_fn_args +=
-                    [rec(mode=ast::alias(false),
-                         ty=f.ty,
-                         ident=f.ident,
-                         id=f.id)];
-            }
-        }
-    }
-    auto fcx = new_fn_ctxt(cx.fcx.lcx, sp, llctor_decl);
-    // Both regular arguments and type parameters are handled here.
-
-    create_llargs_for_fn_args(fcx, ast::proto_fn, none[ty_self_pair],
-                              ret_ty_of_fn(ccx, ann), addtl_fn_args,
-                              ty_params);
-    let vec[ty::arg] arg_tys = arg_tys_of_fn(ccx, ann);
-    copy_args_to_allocas(fcx, addtl_fn_args, arg_tys);
-    //  Create the first block context in the function and keep a handle on it
-    //  to pass to finish_fn later.
-
-    auto bcx = new_top_block_ctxt(fcx);
-    auto lltop = bcx.llbb;
-    // Pick up the type of this object by looking at our own output type, that
-    // is, the output type of the object constructor we're building.
-
-    auto self_ty = ret_ty_of_fn(ccx, ann);
+    auto self_ty = ty::ann_to_type(ccx.tcx, ann);
     auto llself_ty = type_of(ccx, sp, self_ty);
-    // Set up the two-word pair that we're going to return from the object
-    // constructor we're building.  The two elements of this pair will be a
-    // vtable pointer and a body pointer.  (llretptr already points to the
-    // place where this two-word pair should go; it was pre-allocated by the
-    // caller of the function.)
 
-    auto pair = bcx.fcx.llretptr;
+    // Allocate the object that we're going to return.  It's a two-word pair
+    // containing a vtable pointer and a body pointer.
+    auto pair = alloca(bcx, llself_ty);
+
     // Grab onto the first and second elements of the pair.
     // abi::obj_field_vtbl and abi::obj_field_box simply specify words 0 and 1
     // of 'pair'.
-
     auto pair_vtbl =
         bcx.build.GEP(pair, [C_int(0), C_int(abi::obj_field_vtbl)]);
     auto pair_box =
         bcx.build.GEP(pair, [C_int(0), C_int(abi::obj_field_box)]);
-    // Make a vtable for this object: a static array of pointers to functions.
-    // It will be located in the read-only memory of the executable we're
-    // creating and will contain ValueRefs for all of this object's methods.
-    // create_vtbl returns a pointer to the vtable, which we store.
 
-    // create_vtbl() wants an ast::_obj and all we have is an
-    // ast::anon_obj, so we need to roll our own.
+    // Make a vtable for the outer object.  create_vtbl() wants an ast::_obj
+    // and all we have is an ast::anon_obj, so we need to roll our own.
+    let vec[ast::obj_field] addtl_fields = [];
+    alt (anon_obj.fields) {
+        case (none) { }
+        case (some(?fields)) { addtl_fields = fields; }
+    }
+    let ast::_obj wrapper_obj = rec(
+        fields = addtl_fields,
+        methods = anon_obj.methods,
+        dtor = none[@ast::method]);
+
+    auto vtbl = create_vtbl(bcx.fcx.lcx, llself_ty, self_ty, wrapper_obj, 
+                            ty_params);
 
-    let ast::_obj wrapper_obj =
-        rec(fields=addtl_fields,
-            methods=anon_obj.methods,
-            dtor=none[@ast::method]);
-    auto vtbl =
-        create_vtbl(cx.fcx.lcx, llself_ty, self_ty, wrapper_obj, ty_params);
     bcx.build.Store(vtbl, pair_vtbl);
     // FIXME (part of issue #417): This vtable needs to contain "forwarding
     // slots" for the methods that exist in the with_obj, as well.  How do we
@@ -6081,127 +6136,29 @@ fn trans_anon_obj(@block_ctxt cx, &span sp, &ast::anon_obj anon_obj,
     // also have to fill in the with_obj field of this tuple.
 
     let TypeRef llbox_ty = T_opaque_obj_ptr(ccx.tn);
-    // FIXME: we should probably also allocate a box for empty objs that have
-    // a dtor, since otherwise they are never dropped, and the dtor never
-    // runs.
+    
+    alt (anon_obj.fields) {
+        case (none) { 
+            // If the object we're translating has no fields or type
+            // parameters, there's not much to do.
 
-    if (vec::len[ast::ty_param](ty_params) == 0u &&
-            vec::len[ty::arg](arg_tys) == 0u) {
-        // If the object we're translating has no fields or type parameters,
-        // there's not much to do.
+            // Store null into pair, if no args or typarams.
+            bcx.build.Store(C_null(llbox_ty), pair_box);
 
-        // Store null into pair, if no args or typarams.
-
-        bcx.build.Store(C_null(llbox_ty), pair_box);
-    } else {
-        // Otherwise, we have to synthesize a big structural type for the
-        // object body.
-
-        let vec[ty::t] obj_fields = [];
-        for (ty::arg a in arg_tys) { vec::push[ty::t](obj_fields, a.ty); }
-        // Tuple type for fields: [field, ...]
-
-        let ty::t fields_ty = ty::mk_imm_tup(ccx.tcx, obj_fields);
-        // Tuple type for typarams: [typaram, ...]
-
-        auto tydesc_ty = ty::mk_type(ccx.tcx);
-        let vec[ty::t] tps = [];
-        for (ast::ty_param tp in ty_params) {
-            vec::push[ty::t](tps, tydesc_ty);
         }
-        let ty::t typarams_ty = ty::mk_imm_tup(ccx.tcx, tps);
-        // Tuple type for body: [tydesc_ty, [typaram, ...], [field, ...]]
 
-        let ty::t body_ty =
-            ty::mk_imm_tup(ccx.tcx, [tydesc_ty, typarams_ty, fields_ty]);
-        // Hand this type we've synthesized off to trans_malloc_boxed, which
-        // allocates a box, including space for a refcount.
+        case (some(?fields)) {
+            // For the moment let's pretend that there are no additional
+            // fields.
+            bcx.fcx.lcx.ccx.sess.unimpl("anon objs don't support "
+                                        + "adding fields yet");
 
-        auto box = trans_malloc_boxed(bcx, body_ty);
-        bcx = box.bcx;
-        // mk_imm_box throws a refcount into the type we're synthesizing, so
-        // that it looks like: [rc, [tydesc_ty, [typaram, ...], [field, ...]]]
-
-        let ty::t boxed_body_ty = ty::mk_imm_box(ccx.tcx, body_ty);
-        // Grab onto the refcount and body parts of the box we allocated.
-
-        auto rc =
-            GEP_tup_like(bcx, boxed_body_ty, box.val,
-                         [0, abi::box_rc_field_refcnt]);
-        bcx = rc.bcx;
-        auto body =
-            GEP_tup_like(bcx, boxed_body_ty, box.val,
-                         [0, abi::box_rc_field_body]);
-        bcx = body.bcx;
-        bcx.build.Store(C_int(1), rc.val);
-        // Put together a tydesc for the body, so that the object can later be
-        // freed by calling through its tydesc.
-
-        // Every object (not just those with type parameters) needs to have a
-        // tydesc to describe its body, since all objects have unknown type to
-        // the user of the object.  So the tydesc is needed to keep track of
-        // the types of the object's fields, so that the fields can be freed
-        // later.
-
-        auto body_tydesc =
-            GEP_tup_like(bcx, body_ty, body.val,
-                         [0, abi::obj_body_elt_tydesc]);
-        bcx = body_tydesc.bcx;
-        auto ti = none[@tydesc_info];
-        auto body_td = get_tydesc(bcx, body_ty, true, ti);
-        lazily_emit_tydesc_glue(bcx, abi::tydesc_field_drop_glue, ti);
-        lazily_emit_tydesc_glue(bcx, abi::tydesc_field_free_glue, ti);
-        bcx = body_td.bcx;
-        bcx.build.Store(body_td.val, body_tydesc.val);
-        // Copy the object's type parameters and fields into the space we
-        // allocated for the object body.  (This is something like saving the
-        // lexical environment of a function in its closure: the "captured
-        // typarams" are any type parameters that are passed to the object
-        // constructor and are then available to the object's methods.
-        // Likewise for the object's fields.)
-
-        // Copy typarams into captured typarams.
-
-        auto body_typarams =
-            GEP_tup_like(bcx, body_ty, body.val,
-                         [0, abi::obj_body_elt_typarams]);
-        bcx = body_typarams.bcx;
-        let int i = 0;
-        for (ast::ty_param tp in ty_params) {
-            auto typaram = bcx.fcx.lltydescs.(i);
-            auto capture =
-                GEP_tup_like(bcx, typarams_ty, body_typarams.val, [0, i]);
-            bcx = capture.bcx;
-            bcx = copy_val(bcx, INIT, capture.val, typaram, tydesc_ty).bcx;
-            i += 1;
+            // FIXME (issue #417): drop these fields into the newly created
+            // object.
         }
-        // Copy args into body fields.
-
-        auto body_fields =
-            GEP_tup_like(bcx, body_ty, body.val,
-                         [0, abi::obj_body_elt_fields]);
-        bcx = body_fields.bcx;
-        i = 0;
-        for (ast::obj_field f in wrapper_obj.fields) {
-            auto arg = bcx.fcx.llargs.get(f.id);
-            arg = load_if_immediate(bcx, arg, arg_tys.(i).ty);
-            auto field =
-                GEP_tup_like(bcx, fields_ty, body_fields.val, [0, i]);
-            bcx = field.bcx;
-            bcx = copy_val(bcx, INIT, field.val, arg, arg_tys.(i).ty).bcx;
-            i += 1;
-        }
-        // Store box ptr in outer pair.
-
-        auto p = bcx.build.PointerCast(box.val, llbox_ty);
-        bcx.build.Store(p, pair_box);
     }
-    bcx.build.RetVoid();
-    // Insert the mandatory first few basic blocks before lltop.
 
-    finish_fn(fcx, lltop);
     // Return the object we built.
-
     ret res(bcx, pair);
 }
 
@@ -6658,6 +6615,10 @@ fn arg_tys_of_fn(&@crate_ctxt ccx, ast::ann ann) -> vec[ty::arg] {
 fn ret_ty_of_fn_ty(&@crate_ctxt ccx, ty::t t) -> ty::t {
     alt (ty::struct(ccx.tcx, t)) {
         case (ty::ty_fn(_, _, ?ret_ty, _, _)) { ret ret_ty; }
+        case (_) {
+            ccx.sess.bug("ret_ty_of_fn_ty() called on non-function type: "
+                         + ty_to_str(ccx.tcx, t));
+        }
     }
 }
 
@@ -6807,6 +6768,10 @@ fn create_vtbl(@local_ctxt cx, TypeRef llself_ty, ty::t self_ty,
         let str s = mangle_internal_name_by_path(mcx.ccx, mcx.path);
         let ValueRef llfn =
             decl_internal_fastcall_fn(cx.ccx.llmod, s, llfnty);
+
+        // Every method on an object gets its def_id inserted into the
+        // crate-wide item_ids map, together with the ValueRef that points to
+        // where that method's definition will be in the executable.
         cx.ccx.item_ids.insert(m.node.id, llfn);
         cx.ccx.item_symbols.insert(m.node.id, s);
         trans_fn(mcx, m.span, m.node.meth, llfn,
@@ -7157,6 +7122,11 @@ fn trans_item(@local_ctxt cx, &ast::item item) {
     }
 }
 
+// Translate a module.  Doing this amounts to translating the items in the
+// module; there ends up being no artifact (aside from linkage names) of
+// separate modules in the compiled program.  That's because modules exist
+// only as a convenience for humans working with the code, to organize names
+// and control visibility.
 fn trans_mod(@local_ctxt cx, &ast::_mod m) {
     for (@ast::item item in m.items) { trans_item(cx, *item); }
 }
diff --git a/src/comp/middle/tstate/auxiliary.rs b/src/comp/middle/tstate/auxiliary.rs
index 689d00b47ff..db61c9be189 100644
--- a/src/comp/middle/tstate/auxiliary.rs
+++ b/src/comp/middle/tstate/auxiliary.rs
@@ -198,8 +198,9 @@ to represent predicate *arguments* however. This type
 Both types store an ident and span, for error-logging purposes.
 */
 type pred_desc_ = rec(vec[@constr_arg_use] args, uint bit_num);
-
 type pred_desc = spanned[pred_desc_];
+type constr_arg_use = constr_arg_general[ident];
+
 
 tag constraint {
     cinit(uint, span, ident);
@@ -456,7 +457,7 @@ fn controlflow_expr(&crate_ctxt ccx, @expr e) -> controlflow {
     }
 }
 
-fn constraints_expr(&ty::ctxt cx, @expr e) -> vec[@ast::constr] {
+fn constraints_expr(&ty::ctxt cx, @expr e) -> vec[@ty::constr_def] {
     alt (ty::struct(cx, ty::ann_to_type(cx, expr_ann(e)))) {
         case (ty::ty_fn(_, _, _, _, ?cs)) { ret cs; }
         case (_) { ret []; }
@@ -511,9 +512,11 @@ fn constraints(&fn_ctxt fcx) -> vec[norm_constraint] {
 // FIXME:
 // this probably doesn't handle name shadowing well (or at all)
 // variables should really always be id'd by def_id and not ident
+
 fn match_args(&fn_ctxt fcx, vec[pred_desc] occs, vec[@constr_arg_use] occ) ->
    uint {
-    log "match_args: looking at " + pretty::ppaux::constr_args_to_str_1(occ);
+    log ("match_args: looking at " +
+         pretty::ppaux::constr_args_to_str(std::util::id[str], occ));
     for (pred_desc pd in occs) {
         log "match_args: candidate " + pred_desc_to_str(pd);
         if (ty::args_eq(str::eq, pd.node.args, occ)) { ret pd.node.bit_num; }
@@ -586,11 +589,13 @@ fn expr_to_constr(ty::ctxt tcx, &@expr e) -> constr {
 
 fn pred_desc_to_str(&pred_desc p) -> str {
     ret "<" + uistr(p.node.bit_num) + ", " +
-            pretty::ppaux::constr_args_to_str_1(p.node.args) + ">";
+         pretty::ppaux::constr_args_to_str(std::util::id[str], p.node.args)
+         + ">";
 }
 
-fn substitute_constr_args(&ty::ctxt cx, &vec[@expr] actuals, &@ast::constr c)
-   -> constr__ {
+fn substitute_constr_args(&ty::ctxt cx,
+                          &vec[@expr] actuals, &@ty::constr_def c)
+    -> constr__ {
     let vec[@constr_arg_use] res = [];
     for (@constr_arg a in c.node.args) {
         res += [substitute_arg(cx, actuals, a)];
diff --git a/src/comp/middle/tstate/collect_locals.rs b/src/comp/middle/tstate/collect_locals.rs
index 3c7efcdbe1e..f669afa965d 100644
--- a/src/comp/middle/tstate/collect_locals.rs
+++ b/src/comp/middle/tstate/collect_locals.rs
@@ -37,30 +37,16 @@ fn collect_pred(&ctxt cx, &@expr e) {
         case (expr_check(?e, _)) {
             vec::push(*cx.cs, expr_to_constr(cx.tcx, e));
         }
-        case (
-             // If it's a call, generate appropriate instances of the
-             // call's constraints.
-             expr_call(?operator, ?operands, ?a)) {
-            for (@ast::constr c in constraints_expr(cx.tcx, operator)) {
-                auto d_id = ann_to_def_strict(cx.tcx, c.node.ann);
-                alt (d_id) {
-                    case (def_fn(?an_id)) {
-                        let aux::constr ct =
-                            respan(c.span,
-                                   rec(id=an_id,
-                                       c=aux::substitute_constr_args(cx.tcx,
-                                                                     operands,
-                                                                     c)));
-                        vec::push(*cx.cs, ct);
-                    }
-                    case (_) {
-                        cx.tcx.sess.span_err(c.span,
-                                             "Non-pred in constraint");
-                    }
-                }
+        // If it's a call, generate appropriate instances of the
+        // call's constraints.
+        case (expr_call(?operator, ?operands, ?a)) {
+            for (@ty::constr_def c in constraints_expr(cx.tcx, operator)) {
+                let aux::constr ct = respan(c.span,
+                      rec(id=c.node.id,
+                          c=aux::substitute_constr_args(cx.tcx,
+                                                        operands, c)));
+                vec::push(*cx.cs, ct);
             }
-            // FIXME: constraints on result type
-
         }
         case (_) { }
     }
diff --git a/src/comp/middle/tstate/pre_post_conditions.rs b/src/comp/middle/tstate/pre_post_conditions.rs
index 98c7821235a..a355c9f3f12 100644
--- a/src/comp/middle/tstate/pre_post_conditions.rs
+++ b/src/comp/middle/tstate/pre_post_conditions.rs
@@ -208,38 +208,16 @@ fn find_pre_post_expr(&fn_ctxt fcx, @expr e) {
             auto args = vec::clone[@expr](operands);
             vec::push[@expr](args, operator);
             find_pre_post_exprs(fcx, args, a);
-            /* should test higher-order constrained functions */
-
-            /* FIXME */
-
-            /* see if the call has any constraints on its in type */
-
-            log "a function: ";
+            /* see if the call has any constraints on its type */
+            log("a function: " );
             log_expr(*operator);
             auto pp = expr_pp(fcx.ccx, e);
-            for (@constr c in constraints_expr(fcx.ccx.tcx, operator)) {
-                auto id = ann_to_def(fcx.ccx, c.node.ann);
-                alt (id) {
-                    case (some(def_fn(?d_id))) {
-                        auto i =
-                            bit_num(fcx,
-                                    rec(id=d_id,
-                                        c=substitute_constr_args(fcx.ccx.tcx,
-                                                                 operands,
-                                                                 c)));
-                        require(i, pp);
-                    }
-                    case (_) {
-                        fcx.ccx.tcx.sess.span_err(c.span,
-                                                  "Unbound pred " +
-                                                      " or pred that's not \
-                                                        bound to a function");
-                    }
-                }
+            for (@ty::constr_def c in 
+                     constraints_expr(fcx.ccx.tcx, operator)) {
+                auto i = bit_num(fcx, rec(id=c.node.id,
+                  c=substitute_constr_args(fcx.ccx.tcx, operands, c)));
+                require(i, pp);
             }
-
-            // FIXME: constraints on result type
-
             /* if this is a failing call, its postcondition sets everything */
             alt (controlflow_expr(fcx.ccx, operator)) {
                 case (noreturn) { set_postcond_false(fcx.ccx, a); }
diff --git a/src/comp/middle/ty.rs b/src/comp/middle/ty.rs
index 027c8b333ae..6ef2384d8f1 100644
--- a/src/comp/middle/ty.rs
+++ b/src/comp/middle/ty.rs
@@ -13,23 +13,14 @@ import std::option::some;
 import std::smallintmap;
 import driver::session;
 import front::ast;
+import front::ast::def_id;
+import front::ast::constr_arg_general;
 import front::ast::mutability;
 import front::ast::controlflow;
 import front::creader;
 import middle::metadata;
-import util::common;
-import util::common::ty_u8;
-import util::common::ty_u16;
-import util::common::ty_u32;
-import util::common::ty_u64;
-import util::common::ty_i8;
-import util::common::ty_i16;
-import util::common::ty_i32;
-import util::common::ty_i64;
-import util::common::ty_f32;
-import util::common::ty_f64;
-import util::common::new_def_hash;
-import util::common::span;
+import util::common::*;
+
 import util::data::interner;
 
 
@@ -46,7 +37,7 @@ type method =
         vec[arg] inputs,
         t output,
         controlflow cf,
-        vec[@ast::constr] constrs);
+        vec[@constr_def] constrs);
 
 tag any_item {
     any_item_rust(@ast::item);
@@ -54,12 +45,14 @@ tag any_item {
 }
 
 type item_table = hashmap[ast::def_id, any_item];
+type constr_table = hashmap[ast::def_id, vec[constr_def]]; 
 
 type mt = rec(t ty, ast::mutability mut);
 
 
 // Contains information needed to resolve types and (in the future) look up
 // the types of AST nodes.
+
 type creader_cache = hashmap[tup(int, uint, uint), ty::t];
 
 type ctxt =
@@ -68,7 +61,7 @@ type ctxt =
         resolve::def_map def_map,
         node_type_table node_types,
         item_table items, // Only contains type items
-
+        constr_table fn_constrs,
         type_cache tcache,
         creader_cache rcache,
         hashmap[t, str] short_names_cache,
@@ -83,7 +76,6 @@ type ty_ctxt = ctxt;
      ret mk_fn(cx, m.proto, m.inputs, m.output, m.cf, m.constrs);
  }
 
-
 // Never construct these manually. These are interned.
 //
 // TODO: It'd be really nice to be able to hide this definition from the
@@ -107,11 +99,11 @@ tag sty {
     ty_int;
     ty_float;
     ty_uint;
-    ty_machine(util::common::ty_mach);
+    ty_machine(ty_mach);
     ty_char;
     ty_str;
     ty_istr;
-    ty_tag(ast::def_id, vec[t]);
+    ty_tag(def_id, vec[t]);
     ty_box(mt);
     ty_vec(mt);
     ty_ivec(mt);
@@ -121,7 +113,7 @@ tag sty {
     ty_task;
     ty_tup(vec[mt]);
     ty_rec(vec[field]);
-    ty_fn(ast::proto, vec[arg], t, controlflow, vec[@ast::constr]);
+    ty_fn(ast::proto, vec[arg], t, controlflow, vec[@constr_def]);
     ty_native_fn(ast::native_abi, vec[arg], t);
     ty_obj(vec[method]);
     ty_var(int); // type variable
@@ -134,6 +126,10 @@ tag sty {
 
 }
 
+type constr_def = spanned[constr_general[uint]];
+type constr_general[T] =  rec(path path,
+                              vec[@constr_arg_general[T]] args,
+                              def_id id);
 
 // Data structures used in type unification
 tag type_err {
@@ -247,12 +243,13 @@ fn mk_rcache() -> creader_cache {
     ret map::mk_hashmap[tup(int, uint, uint), t](h, e);
 }
 
-fn mk_ctxt(session::session s, resolve::def_map dm) -> ctxt {
+fn mk_ctxt(session::session s, resolve::def_map dm, constr_table cs) -> ctxt {
+
     let vec[mutable option::t[ty::ty_param_substs_opt_and_ty]] ntt_sub =
         [mutable ];
     let node_type_table ntt = @mutable ntt_sub;
-    auto tcache = common::new_def_hash[ty::ty_param_count_and_ty]();
-    auto items = common::new_def_hash[any_item]();
+    auto tcache = new_def_hash[ty::ty_param_count_and_ty]();
+    auto items = new_def_hash[any_item]();
     auto ts = @interner::mk[raw_t](hash_raw_ty, eq_raw_ty);
     auto cx =
         rec(ts=ts,
@@ -260,6 +257,7 @@ fn mk_ctxt(session::session s, resolve::def_map dm) -> ctxt {
             def_map=dm,
             node_types=ntt,
             items=items,
+            fn_constrs = cs,
             tcache=tcache,
             rcache=mk_rcache(),
             short_names_cache=map::mk_hashmap[ty::t,
@@ -379,7 +377,7 @@ fn mk_float(&ctxt cx) -> t { ret idx_float; }
 
 fn mk_uint(&ctxt cx) -> t { ret idx_uint; }
 
-fn mk_mach(&ctxt cx, &util::common::ty_mach tm) -> t {
+fn mk_mach(&ctxt cx, &ty_mach tm) -> t {
     alt (tm) {
         case (ty_u8) { ret idx_u8; }
         case (ty_u16) { ret idx_u16; }
@@ -439,7 +437,7 @@ fn mk_imm_tup(&ctxt cx, &vec[t] tys) -> t {
 fn mk_rec(&ctxt cx, &vec[field] fs) -> t { ret gen_ty(cx, ty_rec(fs)); }
 
 fn mk_fn(&ctxt cx, &ast::proto proto, &vec[arg] args, &t ty, &controlflow cf,
-         &vec[@ast::constr] constrs) -> t {
+         &vec[@constr_def] constrs) -> t {
     ret gen_ty(cx, ty_fn(proto, args, ty, cf, constrs));
 }
 
@@ -759,8 +757,8 @@ fn sequence_is_interior(&ctxt cx, &t ty) -> bool {
 
 fn sequence_element_type(&ctxt cx, &t ty) -> t {
     alt (struct(cx, ty)) {
-        case (ty_str) { ret mk_mach(cx, common::ty_u8); }
-        case (ty_istr) { ret mk_mach(cx, common::ty_u8); }
+        case (ty_str) { ret mk_mach(cx, ty_u8); }
+        case (ty_istr) { ret mk_mach(cx, ty_u8); }
         case (ty_vec(?mt)) { ret mt.ty; }
         case (ty_ivec(?mt)) { ret mt.ty; }
         case (_) {
@@ -915,14 +913,14 @@ fn type_is_integral(&ctxt cx, &t ty) -> bool {
         case (ty_uint) { ret true; }
         case (ty_machine(?m)) {
             alt (m) {
-                case (common::ty_i8) { ret true; }
-                case (common::ty_i16) { ret true; }
-                case (common::ty_i32) { ret true; }
-                case (common::ty_i64) { ret true; }
-                case (common::ty_u8) { ret true; }
-                case (common::ty_u16) { ret true; }
-                case (common::ty_u32) { ret true; }
-                case (common::ty_u64) { ret true; }
+                case (ty_i8) { ret true; }
+                case (ty_i16) { ret true; }
+                case (ty_i32) { ret true; }
+                case (ty_i64) { ret true; }
+                case (ty_u8) { ret true; }
+                case (ty_u16) { ret true; }
+                case (ty_u32) { ret true; }
+                case (ty_u64) { ret true; }
                 case (_) { ret false; }
             }
         }
@@ -935,8 +933,8 @@ fn type_is_fp(&ctxt cx, &t ty) -> bool {
     alt (struct(cx, ty)) {
         case (ty_machine(?tm)) {
             alt (tm) {
-                case (common::ty_f32) { ret true; }
-                case (common::ty_f64) { ret true; }
+                case (ty_f32) { ret true; }
+                case (ty_f64) { ret true; }
                 case (_) { ret false; }
             }
         }
@@ -950,10 +948,10 @@ fn type_is_signed(&ctxt cx, &t ty) -> bool {
         case (ty_int) { ret true; }
         case (ty_machine(?tm)) {
             alt (tm) {
-                case (common::ty_i8) { ret true; }
-                case (common::ty_i16) { ret true; }
-                case (common::ty_i32) { ret true; }
-                case (common::ty_i64) { ret true; }
+                case (ty_i8) { ret true; }
+                case (ty_i16) { ret true; }
+                case (ty_i32) { ret true; }
+                case (ty_i64) { ret true; }
                 case (_) { ret false; }
             }
         }
@@ -1005,16 +1003,16 @@ fn hash_type_structure(&sty st) -> uint {
         case (ty_uint) { ret 4u; }
         case (ty_machine(?tm)) {
             alt (tm) {
-                case (common::ty_i8) { ret 5u; }
-                case (common::ty_i16) { ret 6u; }
-                case (common::ty_i32) { ret 7u; }
-                case (common::ty_i64) { ret 8u; }
-                case (common::ty_u8) { ret 9u; }
-                case (common::ty_u16) { ret 10u; }
-                case (common::ty_u32) { ret 11u; }
-                case (common::ty_u64) { ret 12u; }
-                case (common::ty_f32) { ret 13u; }
-                case (common::ty_f64) { ret 14u; }
+                case (ty_i8) { ret 5u; }
+                case (ty_i16) { ret 6u; }
+                case (ty_i32) { ret 7u; }
+                case (ty_i64) { ret 8u; }
+                case (ty_u8) { ret 9u; }
+                case (ty_u16) { ret 10u; }
+                case (ty_u32) { ret 11u; }
+                case (ty_u64) { ret 12u; }
+                case (ty_f32) { ret 13u; }
+                case (ty_f64) { ret 14u; }
             }
         }
         case (ty_char) { ret 15u; }
@@ -1096,7 +1094,7 @@ fn arg_eq[T](&fn(&T, &T) -> bool  eq, @ast::constr_arg_general[T] a,
         }
         case (ast::carg_lit(?l)) {
             alt (b.node) {
-                case (ast::carg_lit(?m)) { ret util::common::lit_eq(l, m); }
+                case (ast::carg_lit(?m)) { ret lit_eq(l, m); }
                 case (_) { ret false; }
             }
         }
@@ -1113,18 +1111,18 @@ fn args_eq[T](fn(&T, &T) -> bool  eq, vec[@ast::constr_arg_general[T]] a,
     ret true;
 }
 
-fn constr_eq(&@ast::constr c, &@ast::constr d) -> bool {
+fn constr_eq(&@constr_def c, &@constr_def d) -> bool {
     ret path_to_str(c.node.path) == path_to_str(d.node.path) &&
              // FIXME: hack
             args_eq(eq_int, c.node.args, d.node.args);
 }
 
-fn constrs_eq(&vec[@ast::constr] cs, &vec[@ast::constr] ds) -> bool {
+fn constrs_eq(&vec[@constr_def] cs, &vec[@constr_def] ds) -> bool {
     if (vec::len(cs) != vec::len(ds)) { ret false; }
-    auto i = 0;
-    for (@ast::constr c in cs) {
+    auto i = 0u;
+    for (@constr_def c in cs) {
         if (!constr_eq(c, ds.(i))) { ret false; }
-        i += 1;
+        i += 1u;
     }
     ret true;
 }
@@ -1829,8 +1827,8 @@ mod unify {
                 &t expected, &t actual, &vec[arg] expected_inputs,
                 &t expected_output, &vec[arg] actual_inputs, &t actual_output,
                 &controlflow expected_cf, &controlflow actual_cf,
-                &vec[@ast::constr] expected_constrs,
-                &vec[@ast::constr] actual_constrs) -> result {
+                &vec[@constr_def] expected_constrs,
+                &vec[@constr_def] actual_constrs) -> result {
         if (e_proto != a_proto) { ret ures_err(terr_mismatch); }
         alt (expected_cf) {
             case (ast::return) { }
@@ -2473,7 +2471,7 @@ fn tag_variant_with_id(&ctxt cx, &ast::def_id tag_id, &ast::def_id variant_id)
     auto i = 0u;
     while (i < vec::len[variant_info](variants)) {
         auto variant = variants.(i);
-        if (common::def_eq(variant.id, variant_id)) { ret variant; }
+        if (def_eq(variant.id, variant_id)) { ret variant; }
         i += 1u;
     }
     cx.sess.bug("tag_variant_with_id(): no variant exists with that ID");
diff --git a/src/comp/middle/typeck.rs b/src/comp/middle/typeck.rs
index d86aa74c1bd..bd804b97bd2 100644
--- a/src/comp/middle/typeck.rs
+++ b/src/comp/middle/typeck.rs
@@ -6,6 +6,7 @@ import front::creader;
 import driver::session;
 import util::common;
 import util::common::span;
+import util::common::respan;
 import util::common::new_def_hash;
 import util::common::log_expr_err;
 import middle::ty;
@@ -312,7 +313,10 @@ fn ast_ty_to_ty(&ty::ctxt tcx, &ty_getter getter, &@ast::ty ast_ty) -> ty::t {
             auto f = bind ast_arg_to_arg(tcx, getter, _);
             auto i = vec::map[ast::ty_arg, arg](f, inputs);
             auto out_ty = ast_ty_to_ty(tcx, getter, output);
-            typ = ty::mk_fn(tcx, proto, i, out_ty, cf, constrs);
+            let fn(&@ast::constr) -> @ty::constr_def g =
+                bind ast_constr_to_constr(tcx, _);
+            let vec[@ty::constr_def] out_constrs = vec::map(g, constrs);
+            typ = ty::mk_fn(tcx, proto, i, out_ty, cf, out_constrs);
         }
         case (ast::ty_path(?path, ?ann)) {
             alt (tcx.def_map.get(ann.id)) {
@@ -341,13 +345,17 @@ fn ast_ty_to_ty(&ty::ctxt tcx, &ty_getter getter, &@ast::ty ast_ty) -> ty::t {
             for (ast::ty_method m in meths) {
                 auto ins = vec::map[ast::ty_arg, arg](f, m.node.inputs);
                 auto out = ast_ty_to_ty(tcx, getter, m.node.output);
+                let fn(&@ast::constr) -> @ty::constr_def g =
+                    bind ast_constr_to_constr(tcx, _);
+                let vec[@ty::constr_def] out_constrs =
+                       vec::map(g, m.node.constrs);
                 let ty::method new_m =
                     rec(proto=m.node.proto,
                         ident=m.node.ident,
                         inputs=ins,
                         output=out,
                         cf=m.node.cf,
-                        constrs=m.node.constrs);
+                        constrs=out_constrs);
                 vec::push[ty::method](tmeths, new_m);
             }
             typ = ty::mk_obj(tcx, ty::sort_methods(tmeths));
@@ -388,7 +396,7 @@ mod write {
     // Writes a type parameter count and type pair into the node type table.
     fn ty(&ty::ctxt tcx, uint node_id, &ty_param_substs_opt_and_ty tpot) {
         assert (!ty::type_contains_vars(tcx, tpot._1));
-        be inner(tcx.node_types, node_id, tpot);
+        ret inner(tcx.node_types, node_id, tpot);
     }
 
     // Writes a type parameter count and type pair into the node type table.
@@ -404,23 +412,23 @@ mod write {
 
     // Writes a type with no type parameters into the node type table.
     fn ty_only(&ty::ctxt tcx, uint node_id, ty::t typ) {
-        be ty(tcx, node_id, tup(none[vec[ty::t]], typ));
+        ret ty(tcx, node_id, tup(none[vec[ty::t]], typ));
     }
 
     // Writes a type with no type parameters into the node type table. This
     // function allows for the possibility of type variables.
     fn ty_only_fixup(@fn_ctxt fcx, uint node_id, ty::t typ) {
-        be ty_fixup(fcx, node_id, tup(none[vec[ty::t]], typ));
+        ret ty_fixup(fcx, node_id, tup(none[vec[ty::t]], typ));
     }
 
     // Writes a nil type into the node type table.
     fn nil_ty(&ty::ctxt tcx, uint node_id) {
-        be ty(tcx, node_id, tup(none[vec[ty::t]], ty::mk_nil(tcx)));
+        ret ty(tcx, node_id, tup(none[vec[ty::t]], ty::mk_nil(tcx)));
     }
 
     // Writes the bottom type into the node type table.
     fn bot_ty(&ty::ctxt tcx, uint node_id) {
-        be ty(tcx, node_id, tup(none[vec[ty::t]], ty::mk_bot(tcx)));
+        ret ty(tcx, node_id, tup(none[vec[ty::t]], ty::mk_bot(tcx)));
     }
 }
 
@@ -449,9 +457,12 @@ mod collect {
        ty::ty_param_count_and_ty {
         auto input_tys = vec::map[ast::arg, arg](ty_of_arg, decl.inputs);
         auto output_ty = convert(decl.output);
+        let fn(&@ast::constr) -> @ty::constr_def g =
+            bind ast_constr_to_constr(cx.tcx, _);
+        let vec[@ty::constr_def] out_constrs = vec::map(g, decl.constraints);
         auto t_fn =
             ty::mk_fn(cx.tcx, proto, input_tys, output_ty, decl.cf,
-                      decl.constraints);
+                      out_constrs);
         auto ty_param_count = vec::len[ast::ty_param](ty_params);
         auto tpt = tup(ty_param_count, t_fn);
         alt (def_id) {
@@ -512,12 +523,13 @@ mod collect {
         auto f = bind ty_of_arg(cx, _);
         auto inputs = vec::map[ast::arg, arg](f, m.node.meth.decl.inputs);
         auto output = convert(m.node.meth.decl.output);
-        ret rec(proto=m.node.meth.proto,
-                ident=m.node.ident,
-                inputs=inputs,
-                output=output,
-                cf=m.node.meth.decl.cf,
-                constrs=m.node.meth.decl.constraints);
+        let fn(&@ast::constr) -> @ty::constr_def g =
+            bind ast_constr_to_constr(cx.tcx, _);
+        let vec[@ty::constr_def] out_constrs =
+            vec::map(g, m.node.meth.decl.constraints);
+        ret rec(proto=m.node.meth.proto, ident=m.node.ident,
+                inputs=inputs, output=output, cf=m.node.meth.decl.cf,
+                constrs=out_constrs);
     }
     fn ty_of_obj(@ctxt cx, &ast::ident id, &ast::_obj obj_info,
                  &vec[ast::ty_param] ty_params) -> ty::ty_param_count_and_ty {
@@ -537,10 +549,8 @@ mod collect {
             auto t_field = ast_ty_to_ty(cx.tcx, g, f.ty);
             vec::push(t_inputs, rec(mode=ty::mo_alias(false), ty=t_field));
         }
-        let vec[@ast::constr] constrs = [];
-        auto t_fn =
-            ty::mk_fn(cx.tcx, ast::proto_fn, t_inputs, t_obj._1, ast::return,
-                      constrs);
+        auto t_fn = ty::mk_fn(cx.tcx, ast::proto_fn, t_inputs, t_obj._1,
+                              ast::return, []);
         auto tpt = tup(t_obj._0, t_fn);
         cx.tcx.tcache.insert(ctor_id, tpt);
         ret tpt;
@@ -652,11 +662,8 @@ mod collect {
                 }
                 auto tag_t = ty::mk_tag(cx.tcx, tag_id, ty_param_tys);
                 // FIXME: this will be different for constrained types
-
-                let vec[@ast::constr] res_constrs = [];
-                result_ty =
-                    ty::mk_fn(cx.tcx, ast::proto_fn, args, tag_t, ast::return,
-                              res_constrs);
+                result_ty = ty::mk_fn(cx.tcx, ast::proto_fn, args, tag_t,
+                                      ast::return, []);
             }
             auto tpt = tup(ty_param_count, result_ty);
             cx.tcx.tcache.insert(variant.node.id, tpt);
@@ -752,12 +759,8 @@ mod collect {
                 alt (object.dtor) {
                     case (none) {/* nothing to do */ }
                     case (some(?m)) {
-                        let vec[@ast::constr] constrs = [];
-                        let vec[arg] res_inputs = [];
-                        auto t =
-                            ty::mk_fn(cx.tcx, ast::proto_fn, res_inputs,
-                                      ty::mk_nil(cx.tcx), ast::return,
-                                      constrs);
+                        auto t = ty::mk_fn(cx.tcx, ast::proto_fn, [],
+                                   ty::mk_nil(cx.tcx), ast::return, []);
                         write::ty_only(cx.tcx, m.node.ann.id, t);
                     }
                 }
@@ -1421,9 +1424,8 @@ fn check_expr(&@fn_ctxt fcx, &@ast::expr expr) {
                         &@ast::expr rhs, &ast::ann a) {
         check_expr(fcx, lhs);
         check_expr(fcx, rhs);
-        auto typ =
-            demand::simple(fcx, sp, expr_ty(fcx.ccx.tcx, lhs),
-                           expr_ty(fcx.ccx.tcx, rhs));
+        demand::simple(fcx, sp, expr_ty(fcx.ccx.tcx, lhs),
+                       expr_ty(fcx.ccx.tcx, rhs));
         write::ty_only_fixup(fcx, a.id, ty::mk_nil(fcx.ccx.tcx));
     }
     // A generic function for checking call expressions
@@ -2123,12 +2125,13 @@ fn check_expr(&@fn_ctxt fcx, &@ast::expr expr) {
                 auto inputs =
                     vec::map[ast::arg, arg](f, m.node.meth.decl.inputs);
                 auto output = convert(m.node.meth.decl.output);
-                ret rec(proto=m.node.meth.proto,
-                        ident=m.node.ident,
-                        inputs=inputs,
-                        output=output,
-                        cf=m.node.meth.decl.cf,
-                        constrs=m.node.meth.decl.constraints);
+                let fn(&@ast::constr) -> @ty::constr_def g =
+                    bind ast_constr_to_constr(ccx.tcx, _);
+                let vec[@ty::constr_def] out_constrs =
+                    vec::map(g, m.node.meth.decl.constraints);
+                ret rec(proto=m.node.meth.proto, ident=m.node.ident,
+                        inputs=inputs, output=output, cf=m.node.meth.decl.cf,
+                        constrs=out_constrs);
             }
             fn get_anon_obj_method_types(@crate_ctxt ccx,
                                          &ast::anon_obj anon_obj) ->
@@ -2180,6 +2183,21 @@ fn get_obj_info(&@crate_ctxt ccx) -> option::t[obj_info] {
     ret vec::last[obj_info](ccx.obj_infos);
 }
 
+fn ast_constr_to_constr(ty::ctxt tcx, &@ast::constr c)
+    -> @ty::constr_def {
+    alt (tcx.def_map.find(c.node.ann.id)) {
+        case (some(ast::def_fn(?pred_id))) {
+            ret @respan(c.span, rec(path=c.node.path, args=c.node.args,
+                                    id=pred_id));
+        }
+        case (_) {
+            tcx.sess.span_err(c.span, "Predicate "
+                              + path_to_str(c.node.path)
+                              + " is unbound or bound to a non-function");
+        }
+    }
+}
+
 fn check_decl_initializer(&@fn_ctxt fcx, &ast::def_id lid,
                           &ast::initializer init) {
     check_expr(fcx, init.expr);
diff --git a/src/comp/pretty/ppaux.rs b/src/comp/pretty/ppaux.rs
index f1a85287c7f..929bfdcc25c 100644
--- a/src/comp/pretty/ppaux.rs
+++ b/src/comp/pretty/ppaux.rs
@@ -1,7 +1,6 @@
 
 import std::io;
 import middle::ty::*;
-import front::ast::constr_arg;
 import front::lexer;
 import pp::word;
 import pp::eof;
@@ -21,9 +20,10 @@ fn ty_to_str(&ctxt cx, &t typ) -> str {
             };
         ret s + ty_to_str(cx, input.ty);
     }
+
     fn fn_to_str(&ctxt cx, ast::proto proto, option::t[ast::ident] ident,
                  vec[arg] inputs, t output, ast::controlflow cf,
-                 &vec[@ast::constr] constrs) -> str {
+                 &vec[@constr_def] constrs) -> str {
         auto f = bind fn_input_to_str(cx, _);
         auto s;
         alt (proto) {
@@ -69,7 +69,7 @@ fn ty_to_str(&ctxt cx, &t typ) -> str {
         case (ty_int) { s += "int"; }
         case (ty_float) { s += "float"; }
         case (ty_uint) { s += "uint"; }
-        case (ty_machine(?tm)) { s += common::ty_mach_to_str(tm); }
+        case (ty_machine(?tm)) { s += ty_mach_to_str(tm); }
         case (ty_char) { s += "char"; }
         case (ty_str) { s += "str"; }
         case (ty_istr) { s += "istr"; }
@@ -92,10 +92,8 @@ fn ty_to_str(&ctxt cx, &t typ) -> str {
         }
         case (ty_tag(?id, ?tps)) {
             // The user should never see this if the cname is set properly!
-
             s +=
-                "<tag#" + util::common::istr(id._0) + ":" +
-                    util::common::istr(id._1) + ">";
+                "<tag#" + istr(id._0) + ":" + istr(id._1) + ">";
             if (vec::len[t](tps) > 0u) {
                 auto f = bind ty_to_str(cx, _);
                 auto strs = vec::map[t, str](f, tps);
@@ -104,21 +102,20 @@ fn ty_to_str(&ctxt cx, &t typ) -> str {
         }
         case (ty_fn(?proto, ?inputs, ?output, ?cf, ?constrs)) {
             s +=
-                fn_to_str(cx, proto, none[ast::ident], inputs, output, cf,
+                fn_to_str(cx, proto, none, inputs, output, cf,
                           constrs);
         }
         case (ty_native_fn(_, ?inputs, ?output)) {
-            let vec[@ast::constr] constrs = [];
             s +=
-                fn_to_str(cx, ast::proto_fn, none[ast::ident], inputs, output,
-                          ast::return, constrs);
+                fn_to_str(cx, ast::proto_fn, none, inputs, output,
+                          ast::return, []);
         }
         case (ty_obj(?meths)) {
             auto f = bind method_to_str(cx, _);
             auto m = vec::map[method, str](f, meths);
             s += "obj {\n\t" + str::connect(m, "\n\t") + "\n}";
         }
-        case (ty_var(?v)) { s += "<T" + util::common::istr(v) + ">"; }
+        case (ty_var(?v)) { s += "<T" + istr(v) + ">"; }
         case (ty_param(?id)) {
             s += "'" + str::unsafe_from_bytes([('a' as u8) + (id as u8)]);
         }
@@ -144,7 +141,7 @@ fn constr_arg_to_str[T](fn(&T) -> str  f, &ast::constr_arg_general_[T] c) ->
     }
 }
 
-fn constr_arg_to_str_1(&ast::constr_arg_general_[str] c) -> str {
+fn constr_arg_to_str_1(&front::ast::constr_arg_general_[str] c) -> str {
     alt (c) {
         case (ast::carg_base) { ret "*"; }
         case (ast::carg_ident(?i)) { ret i; }
@@ -164,18 +161,7 @@ fn constr_args_to_str[T](fn(&T) -> str  f,
     ret s;
 }
 
-fn constr_args_to_str_1(&vec[@ast::constr_arg_use] args) -> str {
-    auto comma = false;
-    auto s = "(";
-    for (@ast::constr_arg_use a in args) {
-        if (comma) { s += ", "; } else { comma = true; }
-        s += constr_arg_to_str_1(a.node);
-    }
-    s += ")";
-    ret s;
-}
-
-fn print_literal(&ps s, &@ast::lit lit) {
+fn print_literal(&ps s, &@front::ast::lit lit) {
     maybe_print_comment(s, lit.span.lo);
     alt (next_lit(s)) {
         case (some(?lt)) {
@@ -196,18 +182,18 @@ fn print_literal(&ps s, &@ast::lit lit) {
             word(s.s,
                  "'" + escape_str(str::from_bytes([ch as u8]), '\'') + "'");
         }
-        case (ast::lit_int(?val)) { word(s.s, common::istr(val)); }
-        case (ast::lit_uint(?val)) { word(s.s, common::uistr(val) + "u"); }
+        case (ast::lit_int(?val)) { word(s.s, istr(val)); }
+        case (ast::lit_uint(?val)) { word(s.s, uistr(val) + "u"); }
         case (ast::lit_float(?fstr)) { word(s.s, fstr); }
         case (ast::lit_mach_int(?mach, ?val)) {
-            word(s.s, common::istr(val as int));
-            word(s.s, common::ty_mach_to_str(mach));
+            word(s.s, istr(val as int));
+            word(s.s, ty_mach_to_str(mach));
         }
         case (ast::lit_mach_float(?mach, ?val)) {
             // val is already a str
 
             word(s.s, val);
-            word(s.s, common::ty_mach_to_str(mach));
+            word(s.s, ty_mach_to_str(mach));
         }
         case (ast::lit_nil) { word(s.s, "()"); }
         case (ast::lit_bool(?val)) {
@@ -216,7 +202,7 @@ fn print_literal(&ps s, &@ast::lit lit) {
     }
 }
 
-fn lit_to_str(&@ast::lit l) -> str { be to_str(l, print_literal); }
+fn lit_to_str(&@front::ast::lit l) -> str { be to_str(l, print_literal); }
 
 fn next_lit(&ps s) -> option::t[lexer::lit] {
     alt (s.literals) {
@@ -360,22 +346,46 @@ const uint default_columns = 78u;
 // needed b/c constr_args_to_str needs
 // something that takes an alias
 // (argh)
-fn uint_to_str(&uint i) -> str { ret util::common::uistr(i); }
 
-fn constr_to_str(&@ast::constr c) -> str {
-    ret path_to_str(c.node.path) +
-            constr_args_to_str(uint_to_str, c.node.args);
+fn uint_to_str(&uint i) -> str { ret uistr(i); }
+
+fn constr_to_str(&@constr_def c) -> str {
+  ret path_to_str(c.node.path)
+      + constr_args_to_str(uint_to_str, c.node.args);
 }
 
-fn constrs_str(&vec[@ast::constr] constrs) -> str {
+
+fn ast_constr_to_str(&@front::ast::constr c) -> str {
+  ret path_to_str(c.node.path)
+      + constr_args_to_str(uint_to_str, c.node.args);
+}
+
+fn constrs_str(&vec[@constr_def] constrs) -> str {
     auto s = "";
     auto colon = true;
-    for (@ast::constr c in constrs) {
+    for (@constr_def c in constrs) {
         if (colon) { s += " : "; colon = false; } else { s += ", "; }
         s += constr_to_str(c);
     }
     ret s;
 }
+
+fn ast_constrs_str(&vec[@ast::constr] constrs) -> str {
+  auto s = "";
+  auto colon = true;
+  for (@ast::constr c in constrs) {
+    if (colon) {
+      s += " : ";
+      colon = false;
+    }
+    else {
+      s += ", ";
+    }
+    s += ast_constr_to_str(c);
+  }
+  ret s;
+}
+
 //
 // Local Variables:
 // mode: rust
diff --git a/src/comp/pretty/pprust.rs b/src/comp/pretty/pprust.rs
index 1c2b40c3212..8db88541c2f 100644
--- a/src/comp/pretty/pprust.rs
+++ b/src/comp/pretty/pprust.rs
@@ -802,7 +802,7 @@ fn print_expr(&ps s, &@ast::expr expr) {
         }
         case (ast::expr_anon_obj(_, _, _, _)) {
             word(s.s, "anon obj");
-            // TODO: nicer pretty-printing of anon objs
+            // FIXME (issue #499): nicer pretty-printing of anon objs
 
         }
     }
@@ -1094,7 +1094,7 @@ fn print_ty_fn(&ps s, &ast::proto proto, &option::t[str] id,
         }
         end(s);
     }
-    word_space(s, constrs_str(constrs));
+    word_space(s, ast_constrs_str(constrs));
     end(s);
 }
 
diff --git a/src/lib/either.rs b/src/lib/either.rs
new file mode 100644
index 00000000000..12ccbb2bbfb
--- /dev/null
+++ b/src/lib/either.rs
@@ -0,0 +1,64 @@
+import option;
+import option::some;
+import option::none;
+
+tag t[T, U] {
+    left(T);
+    right(U);
+}
+
+type operator[T, U] = fn(&T) -> U;
+
+fn either[T, U, V](&operator[T, V] f_left,
+                   &operator[U, V] f_right,
+                   &t[T, U] value) -> V {
+    alt (value) {
+        case (left(?l)) { f_left(l) }
+        case (right(?r)) { f_right(r) }
+    }
+}
+
+fn lefts[T, U](&vec[t[T, U]] eithers) -> vec[T] {
+    let vec[T] result = [];
+    for (t[T, U] elt in eithers) {
+        alt (elt) {
+            case (left(?l)) { result += [l] }
+            case (_) { /* fallthrough */ }
+        }
+    }
+    ret result;
+}
+
+fn rights[T, U](&vec[t[T, U]] eithers) -> vec[U] {
+    let vec[U] result = [];
+    for (t[T, U] elt in eithers) {
+        alt (elt) {
+            case (right(?r)) { result += [r] }
+            case (_) { /* fallthrough */ }
+        }
+    }
+    ret result;
+}
+
+fn partition[T, U](&vec[t[T, U]] eithers) -> tup(vec[T], vec[U]) {
+    let vec[T] lefts = [];
+    let vec[U] rights = [];
+    for (t[T, U] elt in eithers) {
+        alt (elt) {
+            case (left(?l)) { lefts += [l] }
+            case (right(?r)) { rights += [r] }
+        }
+    }
+    ret tup(lefts, rights);
+}
+
+//
+// Local Variables:
+// mode: rust
+// fill-column: 78;
+// indent-tabs-mode: nil
+// c-basic-offset: 4
+// buffer-file-coding-system: utf-8-unix
+// compile-command: "make -k -C $RBUILD 2>&1 | sed -e 's/\\/x\\//x:\\//g'";
+// End:
+//
diff --git a/src/lib/list.rs b/src/lib/list.rs
index edd14a30133..a752e005b5e 100644
--- a/src/lib/list.rs
+++ b/src/lib/list.rs
@@ -18,35 +18,52 @@ fn from_vec[T](vec[T] v) -> list[T] {
     ret l;
 }
 
-fn foldl[T, U](&list[T] ls, &U u, fn(&T, &U) -> U  f) -> U {
-    alt (ls) {
-        case (cons(?hd, ?tl)) {
-            auto u_ = f(hd, u);
-            be foldl[T, U](*tl, u_, f);
-        }
-        case (nil) { ret u; }
-    }
-}
-
-fn find[T, U](&list[T] ls, fn(&T) -> option::t[U]  f) -> option::t[U] {
-    alt (ls) {
-        case (cons(?hd, ?tl)) {
-            alt (f(hd)) {
-                case (none) { be find[T, U](*tl, f); }
-                case (some(?res)) { ret some[U](res); }
+fn foldl[T, U](&list[T] ls_, &U u, fn(&T, &U) -> U  f) -> U {
+    let U accum = u;
+    auto ls = ls_;
+    while (true) {
+        alt (ls) {
+            case (cons(?hd, ?tl)) {
+                accum = f(hd, accum);
+                ls = *tl;
             }
+            case (nil) { break; }
         }
-        case (nil) { ret none[U]; }
     }
+    ret accum;
 }
 
-fn has[T](&list[T] ls, &T elt) -> bool {
-    alt (ls) {
-        case (cons(?hd, ?tl)) {
-            if (elt == hd) { ret true; } else { be has(*tl, elt); }
+fn find[T, U](&list[T] ls_, fn(&T) -> option::t[U]  f) -> option::t[U] {
+    auto ls = ls_;
+    while (true) {
+        alt (ls) {
+            case (cons(?hd, ?tl)) {
+                alt (f(hd)) {
+                    case (none) { ls = *tl; }
+                    case (some(?res)) { ret some(res); }
+                }
+            }
+            case (nil) { break; }
         }
-        case (nil) { ret false; }
     }
+    ret none;
+}
+
+fn has[T](&list[T] ls_, &T elt) -> bool {
+    auto ls = ls_;
+    while (true) {
+        alt (ls) {
+            case (cons(?hd, ?tl)) {
+                if (elt == hd) {
+                    ret true;
+                } else {
+                    ls = *tl;
+                }
+            }
+            case (nil) { ret false; }
+        }
+    }
+    ret false; // Typestate checker doesn't understand infinite loops
 }
 
 fn length[T](&list[T] ls) -> uint {
diff --git a/src/lib/std.rc b/src/lib/std.rc
index 60cecd7cf68..26d36257bd5 100644
--- a/src/lib/std.rc
+++ b/src/lib/std.rc
@@ -22,6 +22,7 @@ mod task;
 
 // Utility modules.
 
+mod either;
 mod option;
 mod util;
 
diff --git a/src/lib/term.rs b/src/lib/term.rs
index 33ca245551c..14fddb55633 100644
--- a/src/lib/term.rs
+++ b/src/lib/term.rs
@@ -48,7 +48,17 @@ fn reset(io::buf_writer writer) {
 }
 
 fn color_supported() -> bool {
-    ret generic_os::getenv("TERM") == option::some[str]("xterm-color");
+    auto supported_terms = ["xterm-color",
+                            "xterm",
+                            "screen-bce"];
+    ret alt (generic_os::getenv("TERM")) {
+        case (option::some(?env)) {
+            vec::member(env, supported_terms)
+        }
+        case (option::none) {
+            false
+        }
+    };
 }
 
 fn set_color(io::buf_writer writer, u8 first_char, u8 color) {
@@ -67,3 +77,11 @@ fn bg(io::buf_writer writer, u8 color) {
 }
 // export fg;
 // export bg;
+
+// Local Variables:
+// fill-column: 78;
+// indent-tabs-mode: nil
+// c-basic-offset: 4
+// buffer-file-coding-system: utf-8-unix
+// compile-command: "make -k -C $RBUILD 2>&1 | sed -e 's/\\/x\\//x:\\//g'";
+// End:
diff --git a/src/test/compile-fail/ext-after-attrib.rs b/src/test/compile-fail/ext-after-attrib.rs
new file mode 100644
index 00000000000..31786fcaf65
--- /dev/null
+++ b/src/test/compile-fail/ext-after-attrib.rs
@@ -0,0 +1,8 @@
+// xfail-stage0
+// error-pattern:expecting \[, found fmt
+
+// Don't know how to deal with a syntax extension appearing after an
+// item attribute. Probably could use a better error message.
+#[foo = "bar"]
+#fmt("baz")
+fn main() { }
\ No newline at end of file
diff --git a/src/test/compile-fail/not-a-pred.rs b/src/test/compile-fail/not-a-pred.rs
index 4a899512e31..ae8068d05e1 100644
--- a/src/test/compile-fail/not-a-pred.rs
+++ b/src/test/compile-fail/not-a-pred.rs
@@ -1,6 +1,6 @@
 // -*- rust -*-
-
-// error-pattern: mismatched types
+// xfail-stage0
+// error-pattern: Non-predicate in constraint: lt
 
 fn f(int a, int b) : lt(a,b) {
 }
diff --git a/src/test/run-pass/anon-objs.rs b/src/test/run-pass/anon-objs.rs
index 94a14b89e77..5c7df451bf2 100644
--- a/src/test/run-pass/anon-objs.rs
+++ b/src/test/run-pass/anon-objs.rs
@@ -5,18 +5,30 @@
 use std;
 
 fn main() {
+
     obj a() {
-        fn foo() -> int { ret 2; }
-        fn bar() -> int { ret self.foo(); }
+        fn foo() -> int {
+            ret 2;
+        }
+        fn bar() -> int {
+            ret self.foo();
+        }
     }
+
     auto my_a = a();
+
     // Extending an object with a new method
+    auto my_b = obj { 
+        fn baz() -> int { 
+            ret self.foo(); 
+        } 
+        with my_a 
+    };
 
-    auto my_b = anon obj;
     // Extending an object with a new field
+    auto my_c = obj(int quux) { with my_a } ;
 
-    auto my_c = anon obj;
     // Should this be legal?
-
-    auto my_d = anon obj;
-}
\ No newline at end of file
+    auto my_d = obj() { with my_a } ;
+    
+}
diff --git a/src/test/run-pass/item-attributes.rs b/src/test/run-pass/item-attributes.rs
index df18f786f05..c407a386d60 100644
--- a/src/test/run-pass/item-attributes.rs
+++ b/src/test/run-pass/item-attributes.rs
@@ -1,14 +1,16 @@
-
-
-
 // xfail-stage0
+
 mod test_single_attr_outer {
 
     #[attr = "val"]
     const int x = 10;
 
     #[attr = "val"]
-    mod mod1 { }
+    fn f() {}
+
+    #[attr = "val"]
+    mod mod1 {
+    }
 
     #[attr = "val"]
     native "rust" mod rustrt { }
@@ -29,7 +31,12 @@ mod test_multi_attr_outer {
 
     #[attr1 = "val"]
     #[attr2 = "val"]
-    mod mod1 { }
+    fn f() {}
+
+    #[attr1 = "val"]
+    #[attr2 = "val"]
+    mod mod1 {
+    }
 
     #[attr1 = "val"]
     #[attr2 = "val"]
@@ -45,4 +52,69 @@ mod test_multi_attr_outer {
     obj o() { }
 }
 
-fn main() { }
\ No newline at end of file
+mod test_stmt_single_attr_outer {
+
+    fn f() {
+
+        #[attr = "val"]
+        const int x = 10;
+
+        #[attr = "val"]
+        fn f() {}
+
+        /* FIXME: Issue #493
+        #[attr = "val"]
+        mod mod1 {
+        }
+
+        #[attr = "val"]
+        native "rust" mod rustrt {
+        }
+        */
+
+        #[attr = "val"]
+        type t = obj { };
+
+        #[attr = "val"]
+        obj o() { }
+
+    }
+}
+
+mod test_stmt_multi_attr_outer {
+
+    fn f() {
+
+        #[attr1 = "val"]
+        #[attr2 = "val"]
+        const int x = 10;
+
+        #[attr1 = "val"]
+        #[attr2 = "val"]
+        fn f() {}
+
+        /* FIXME: Issue #493
+        #[attr1 = "val"]
+        #[attr2 = "val"]
+        mod mod1 {
+        }
+
+        #[attr1 = "val"]
+        #[attr2 = "val"]
+        native "rust" mod rustrt {
+        }
+        */
+
+        #[attr1 = "val"]
+        #[attr2 = "val"]
+        type t = obj { };
+
+        #[attr1 = "val"]
+        #[attr2 = "val"]
+        obj o() { }
+
+    }
+}
+
+fn main() {
+}
diff --git a/src/test/run-pass/lib-either.rs b/src/test/run-pass/lib-either.rs
new file mode 100644
index 00000000000..0ece8be64e9
--- /dev/null
+++ b/src/test/run-pass/lib-either.rs
@@ -0,0 +1,117 @@
+// xfail-stage0
+
+use std;
+import std::either::*;
+import std::vec::len;
+
+fn test_either_left() {
+  auto val = left(10);
+  fn f_left(&int x) -> bool { x == 10 }
+  fn f_right(&uint x) -> bool { false }
+  assert (either(f_left, f_right, val));
+}
+
+fn test_either_right() {
+  auto val = right(10u);
+  fn f_left(&int x) -> bool { false }
+  fn f_right(&uint x) -> bool { x == 10u }
+  assert (either(f_left, f_right, val));
+}
+
+fn test_lefts() {
+  auto input = [left(10),
+                right(11),
+                left(12),
+                right(13),
+                left(14)];
+  auto result = lefts(input);
+  assert (result == [10, 12, 14]);
+}
+
+fn test_lefts_none() {
+  let vec[t[int, int]] input = [right(10),
+                                right(10)];
+  auto result = lefts(input);
+  assert (len(result) == 0u);
+}
+
+fn test_lefts_empty() {
+  let vec[t[int, int]] input = [];
+  auto result = lefts(input);
+  assert (len(result) == 0u);
+}
+
+fn test_rights() {
+  auto input = [left(10),
+                right(11),
+                left(12),
+                right(13),
+                left(14)];
+  auto result = rights(input);
+  assert (result == [11, 13]);
+}
+
+fn test_rights_none() {
+  let vec[t[int, int]] input = [left(10),
+                                left(10)];
+  auto result = rights(input);
+  assert (len(result) == 0u);
+}
+
+fn test_rights_empty() {
+    let vec[t[int, int]] input = [];
+    auto result = rights(input);
+    assert (len(result) == 0u);
+}
+
+fn test_partition() {
+  auto input = [left(10),
+                right(11),
+                left(12),
+                right(13),
+                left(14)];
+  auto result = partition(input);
+  assert (result._0.(0) == 10);
+  assert (result._0.(1) == 12);
+  assert (result._0.(2) == 14);
+  assert (result._1.(0) == 11);
+  assert (result._1.(1) == 13);
+}
+
+fn test_partition_no_lefts() {
+  let vec[t[int, int]] input = [right(10),
+                                right(11)];
+  auto result = partition(input);
+  assert (len(result._0) == 0u);
+  assert (len(result._1) == 2u);
+}
+
+fn test_partition_no_rights() {
+  let vec[t[int, int]] input = [left(10),
+                                left(11)];
+  auto result = partition(input);
+  assert (len(result._0) == 2u);
+  assert (len(result._1) == 0u);
+}
+
+fn test_partition_empty() {
+  let vec[t[int, int]] input = [];
+  auto result = partition(input);
+  assert (len(result._0) == 0u);
+  assert (len(result._1) == 0u);
+}
+
+fn main() {
+  test_either_left();
+  test_either_right();
+  test_lefts();
+  test_lefts_none();
+  test_lefts_empty();
+  test_rights();
+  test_rights_none();
+  test_rights_empty();
+  test_partition();
+  test_partition_no_lefts();
+  test_partition_no_rights();
+  test_partition_empty();
+}
\ No newline at end of file
diff --git a/src/test/run-pass/simple-anon-objs.rs b/src/test/run-pass/simple-anon-objs.rs
index 323c427e485..df56f4810ee 100644
--- a/src/test/run-pass/simple-anon-objs.rs
+++ b/src/test/run-pass/simple-anon-objs.rs
@@ -1,7 +1,6 @@
 
 
 // xfail-stage0
-// xfail-stage1
 use std;
 
 fn main() {
@@ -11,10 +10,24 @@ fn main() {
     auto my_a = a();
     // Extending an object with a new method
 
-    auto my_b = anon obj;
-    assert (my_a.foo() == 2);
-    // FIXME: these raise a runtime error
-    //assert my_b.foo() == 2;
+    auto my_b = obj { 
+        fn bar() -> int { 
+            ret 3;
+        }
+        with my_a 
+    };
 
+    assert (my_a.foo() == 2);
     assert (my_b.bar() == 3);
-}
\ No newline at end of file
+
+    auto my_c = obj {
+        fn baz() -> int {
+            ret 4;
+        }
+        with my_b
+    };
+
+    assert (my_c.baz() == 4);
+
+}
+