diff --git a/src/comp/metadata/tydecode.rs b/src/comp/metadata/tydecode.rs
index 88d68d01b2b..a2c706610a3 100644
--- a/src/comp/metadata/tydecode.rs
+++ b/src/comp/metadata/tydecode.rs
@@ -65,13 +65,13 @@ fn parse_ty_or_bang(@pstate st, str_def sd) -> ty_or_bang {
     }
 }
 
-fn parse_constrs(@pstate st, str_def sd) -> vec[@ty::constr_def] {
-    let vec[@ty::constr_def] rslt = [];
+fn parse_constrs(@pstate st, str_def sd) -> (@ty::constr_def)[] {
+    let (@ty::constr_def)[] rslt = ~[];
     alt (peek(st) as char) {
         case (':') {
             do  {
                 next(st);
-                vec::push(rslt, parse_constr(st, sd));
+                rslt += ~[parse_constr(st, sd)];
             } while (peek(st) as char == ';')
         }
         case (_) { }
@@ -333,7 +333,7 @@ fn parse_hex(@pstate st) -> uint {
 }
 
 fn parse_ty_fn(@pstate st, str_def sd) ->
-   tup(ty::arg[], ty::t, ast::controlflow, vec[@ty::constr_def]) {
+   tup(ty::arg[], ty::t, ast::controlflow, (@ty::constr_def)[]) {
     assert (next(st) as char == '[');
     let ty::arg[] inputs = ~[];
     while (peek(st) as char != ']') {
diff --git a/src/comp/metadata/tyencode.rs b/src/comp/metadata/tyencode.rs
index f6ea1a89719..8cefd90e78f 100644
--- a/src/comp/metadata/tyencode.rs
+++ b/src/comp/metadata/tyencode.rs
@@ -162,7 +162,7 @@ fn enc_sty(&io::writer w, &@ctxt cx, &ty::sty st) {
                 case (native_abi_cdecl) { w.write_char('c'); }
                 case (native_abi_llvm) { w.write_char('l'); }
             }
-            enc_ty_fn(w, cx, args, out, return, []);
+            enc_ty_fn(w, cx, args, out, return, ~[]);
         }
         case (ty::ty_obj(?methods)) {
             w.write_str("O[");
@@ -205,7 +205,7 @@ fn enc_proto(&io::writer w, proto proto) {
     }
 }
 fn enc_ty_fn(&io::writer w, &@ctxt cx, &ty::arg[] args, &ty::t out,
-             &controlflow cf, &vec[@ty::constr_def] constrs) {
+             &controlflow cf, &(@ty::constr_def)[] constrs) {
     w.write_char('[');
     for (ty::arg arg in args) {
         alt (arg.mode) {
diff --git a/src/comp/middle/tstate/auxiliary.rs b/src/comp/middle/tstate/auxiliary.rs
index 0bc1ceb3951..04daaff3d4e 100644
--- a/src/comp/middle/tstate/auxiliary.rs
+++ b/src/comp/middle/tstate/auxiliary.rs
@@ -453,10 +453,10 @@ fn controlflow_expr(&crate_ctxt ccx, @expr e) -> controlflow {
     }
 }
 
-fn constraints_expr(&ty::ctxt cx, @expr e) -> vec[@ty::constr_def] {
+fn constraints_expr(&ty::ctxt cx, @expr e) -> (@ty::constr_def)[] {
     alt (ty::struct(cx, ty::node_id_to_type(cx, e.id))) {
         case (ty::ty_fn(_, _, _, _, ?cs)) { ret cs; }
-        case (_) { ret []; }
+        case (_) { ret ~[]; }
     }
 }
 
diff --git a/src/comp/middle/ty.rs b/src/comp/middle/ty.rs
index aea0a2c731f..8be2460f918 100644
--- a/src/comp/middle/ty.rs
+++ b/src/comp/middle/ty.rs
@@ -196,7 +196,7 @@ type method =
         arg[] inputs,
         t output,
         controlflow cf,
-        vec[@constr_def] constrs);
+        (@constr_def)[] constrs);
 
 type constr_table = hashmap[ast::node_id, vec[constr_def]]; 
 
@@ -267,9 +267,9 @@ tag sty {
     ty_task;
     ty_tup(mt[]);
     ty_rec(field[]);
-    ty_fn(ast::proto, arg[], t, controlflow, vec[@constr_def]);
+    ty_fn(ast::proto, arg[], t, controlflow, (@constr_def)[]);
     ty_native_fn(ast::native_abi, arg[], t);
-    ty_obj(method[]);
+    ty_obj(vec[method]);
     ty_res(def_id, t, t[]);
     ty_var(int); // type variable
     ty_param(uint); // fn/tag type param
@@ -596,7 +596,7 @@ fn mk_imm_tup(&ctxt cx, &t[] tys) -> t {
 fn mk_rec(&ctxt cx, &field[] fs) -> t { ret gen_ty(cx, ty_rec(fs)); }
 
 fn mk_fn(&ctxt cx, &ast::proto proto, &arg[] args, &t ty, &controlflow cf,
-         &vec[@constr_def] constrs) -> t {
+         &(@constr_def)[] constrs) -> t {
     ret gen_ty(cx, ty_fn(proto, args, ty, cf, constrs));
 }
 
@@ -1454,8 +1454,8 @@ fn constr_eq(&@constr_def c, &@constr_def d) -> bool {
             args_eq(eq_int, c.node.args, d.node.args);
 }
 
-fn constrs_eq(&vec[@constr_def] cs, &vec[@constr_def] ds) -> bool {
-    if (vec::len(cs) != vec::len(ds)) { ret false; }
+fn constrs_eq(&(@constr_def)[] cs, &(@constr_def)[] ds) -> bool {
+    if (ivec::len(cs) != ivec::len(ds)) { ret false; }
     auto i = 0u;
     for (@constr_def c in cs) {
         if (!constr_eq(c, ds.(i))) { ret false; }
@@ -2139,8 +2139,8 @@ mod unify {
                 &t expected, &t actual, &arg[] expected_inputs,
                 &t expected_output, &arg[] actual_inputs, &t actual_output,
                 &controlflow expected_cf, &controlflow actual_cf,
-                &vec[@constr_def] expected_constrs,
-                &vec[@constr_def] actual_constrs) -> result {
+                &(@constr_def)[] expected_constrs,
+                &(@constr_def)[] actual_constrs) -> result {
         if (e_proto != a_proto) { ret ures_err(terr_mismatch); }
         alt (expected_cf) {
             case (ast::return) { }
diff --git a/src/comp/middle/typeck.rs b/src/comp/middle/typeck.rs
index 188d9cb6ebf..470b4bedccd 100644
--- a/src/comp/middle/typeck.rs
+++ b/src/comp/middle/typeck.rs
@@ -337,9 +337,10 @@ fn ast_ty_to_ty(&ty::ctxt tcx, &ty_getter getter, &@ast::ty ast_ty) -> ty::t {
             }
             auto out_ty = ast_ty_to_ty(tcx, getter, 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, constrs);
+            auto out_constrs = ~[];
+            for (@ast::constr constr in constrs) {
+                out_constrs += ~[ast_constr_to_constr(tcx, constr)];
+            }
             typ = ty::mk_fn(tcx, proto, i, out_ty, cf, out_constrs);
         }
         case (ast::ty_path(?path, ?id)) {
@@ -373,10 +374,10 @@ fn ast_ty_to_ty(&ty::ctxt tcx, &ty_getter getter, &@ast::ty ast_ty) -> ty::t {
                 }
                 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);
+                auto out_constrs = ~[];
+                for (@ast::constr constr in m.node.constrs) {
+                    out_constrs += ~[ast_constr_to_constr(tcx, constr)];
+                }
                 let ty::method new_m =
                     rec(proto=m.node.proto,
                         ident=m.node.ident,
@@ -492,9 +493,10 @@ mod collect {
         for (ast::arg a in decl.inputs) { input_tys += ~[ty_of_arg(a)]; }
         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 out_constrs = ~[];
+        for (@ast::constr constr in decl.constraints) {
+            out_constrs += ~[ast_constr_to_constr(cx.tcx, constr)];
+        }
         auto t_fn =
             ty::mk_fn(cx.tcx, proto, input_tys, output_ty, decl.cf,
                       out_constrs);
@@ -570,10 +572,11 @@ mod collect {
         }
 
         auto output = convert(m.node.meth.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, m.node.meth.decl.constraints);
+
+        auto out_constrs = ~[];
+        for (@ast::constr constr in m.node.meth.decl.constraints) {
+            out_constrs += ~[ast_constr_to_constr(cx.tcx, constr)];
+        }
         ret rec(proto=m.node.meth.proto, ident=m.node.ident,
                 inputs=inputs, output=output, cf=m.node.meth.decl.cf,
                 constrs=out_constrs);
@@ -598,7 +601,7 @@ mod collect {
         }
 
         auto t_fn = ty::mk_fn(cx.tcx, ast::proto_fn, t_inputs, t_obj._1,
-                              ast::return, []);
+                              ast::return, ~[]);
         auto tpt = tup(t_obj._0, t_fn);
         cx.tcx.tcache.insert(local_def(ctor_id), tpt);
         ret tpt;
@@ -709,7 +712,7 @@ mod collect {
                 auto tag_t = ty::mk_tag(cx.tcx, tag_id, ty_param_tys);
                 // FIXME: this will be different for constrained types
                 result_ty = ty::mk_fn(cx.tcx, ast::proto_fn, args, tag_t,
-                                      ast::return, []);
+                                      ast::return, ~[]);
             }
             auto tpt = tup(ty_param_count, result_ty);
             cx.tcx.tcache.insert(local_def(variant.node.id), tpt);
@@ -780,7 +783,7 @@ mod collect {
                     case (none) {/* nothing to do */ }
                     case (some(?m)) {
                         auto t = ty::mk_fn(cx.tcx, ast::proto_fn, ~[],
-                                   ty::mk_nil(cx.tcx), ast::return, []);
+                                   ty::mk_nil(cx.tcx), ast::return, ~[]);
                         write::ty_only(cx.tcx, m.node.id, t);
                     }
                 }
@@ -790,9 +793,9 @@ mod collect {
                 auto t_res = ty::mk_res(cx.tcx, local_def(it.id), t_arg.ty,
                                         mk_ty_params(cx, vec::len(tps)));
                 auto t_ctor = ty::mk_fn(cx.tcx, ast::proto_fn, ~[t_arg],
-                                        t_res, ast::return, []);
+                                        t_res, ast::return, ~[]);
                 auto t_dtor = ty::mk_fn(cx.tcx, ast::proto_fn, ~[t_arg],
-                                        ty::mk_nil(cx.tcx), ast::return, []);
+                                        ty::mk_nil(cx.tcx), ast::return, ~[]);
                 write::ty_only(cx.tcx, it.id, t_res);
                 write::ty_only(cx.tcx, ctor_id, t_ctor);
                 cx.tcx.tcache.insert(local_def(ctor_id),
@@ -2285,10 +2288,12 @@ fn check_expr(&@fn_ctxt fcx, &@ast::expr expr) {
                 }
 
                 auto output = convert(m.node.meth.decl.output);
-                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);
+
+                auto out_constrs = ~[];
+                for (@ast::constr constr in m.node.meth.decl.constraints) {
+                    out_constrs += ~[ast_constr_to_constr(ccx.tcx, constr)];
+                }
+
                 ret rec(proto=m.node.meth.proto, ident=m.node.ident,
                         inputs=inputs, output=output, cf=m.node.meth.decl.cf,
                         constrs=out_constrs);
diff --git a/src/comp/util/ppaux.rs b/src/comp/util/ppaux.rs
index 58ed9b6157c..854b1a4adcb 100644
--- a/src/comp/util/ppaux.rs
+++ b/src/comp/util/ppaux.rs
@@ -47,7 +47,7 @@ fn ty_to_str(&ctxt cx, &t typ) -> str {
     }
     fn fn_to_str(&ctxt cx, ast::proto proto, option::t[ast::ident] ident,
                  &arg[] inputs, t output, ast::controlflow cf,
-                 &vec[@constr_def] constrs) -> str {
+                 &(@constr_def)[] constrs) -> str {
         auto s;
         alt (proto) {
             case (ast::proto_iter) { s = "iter"; }
@@ -130,7 +130,7 @@ fn ty_to_str(&ctxt cx, &t typ) -> str {
         }
         case (ty_native_fn(_, ?inputs, ?output)) {
             s += fn_to_str(cx, ast::proto_fn, none, inputs, output,
-                           ast::return, []);
+                           ast::return, ~[]);
         }
         case (ty_obj(?meths)) {
             auto f = bind method_to_str(cx, _);
@@ -162,7 +162,7 @@ fn constr_to_str(&@constr_def c) -> str {
         pprust::constr_args_to_str(pprust::uint_to_str, c.node.args);
 }
 
-fn constrs_str(&vec[@constr_def] constrs) -> str {
+fn constrs_str(&(@constr_def)[] constrs) -> str {
     auto s = "";
     auto colon = true;
     for (@constr_def c in constrs) {