diff --git a/src/rustc/metadata/astencode.rs b/src/rustc/metadata/astencode.rs
index 5cd46fd67903..92ad024619ec 100644
--- a/src/rustc/metadata/astencode.rs
+++ b/src/rustc/metadata/astencode.rs
@@ -13,14 +13,19 @@ import std::serialization::serializer;
 import std::serialization::deserializer;
 import std::serialization::serializer_helpers;
 import std::serialization::deserializer_helpers;
+import std::prettyprint::serializer;
 import std::smallintmap::map;
 import middle::trans::common::maps;
 import middle::{ty, typeck, last_use, ast_map};
-import middle::typeck::method_origin;
-import middle::typeck::vtable_res;
-import middle::typeck::vtable_origin;
+import middle::typeck::{method_origin,
+                        serialize_method_origin,
+                        deserialize_method_origin,
+                        vtable_res,
+                        vtable_origin};
 import driver::session::session;
-import middle::freevars::freevar_entry;
+import middle::freevars::{freevar_entry,
+                          serialize_freevar_entry,
+                          deserialize_freevar_entry};
 import c = common;
 import e = encoder;
 
@@ -302,13 +307,13 @@ impl of tr for span {
 
 impl serializer_helpers<S: serializer> for S {
     fn emit_def_id(did: ast::def_id) {
-        astencode_gen::serialize_syntax_ast_def_id(self, did)
+        ast::serialize_def_id(self, did)
     }
 }
 
 impl deserializer_helpers<D: deserializer> for D {
     fn read_def_id(xcx: extended_decode_ctxt) -> ast::def_id {
-        let did = astencode_gen::deserialize_syntax_ast_def_id(self);
+        let did = ast::deserialize_def_id(self);
         did.tr(xcx)
     }
 }
@@ -330,7 +335,7 @@ impl deserializer_helpers<D: deserializer> for D {
 
 fn encode_ast(ebml_w: ebml::writer, item: ast::inlined_item) {
     ebml_w.wr_tag(c::tag_tree as uint) {||
-        astencode_gen::serialize_syntax_ast_inlined_item(ebml_w, item)
+        ast::serialize_inlined_item(ebml_w, item)
     }
 }
 
@@ -375,7 +380,7 @@ fn simplify_ast(ii: ast::inlined_item) -> ast::inlined_item {
 fn decode_ast(par_doc: ebml::doc) -> ast::inlined_item {
     let chi_doc = par_doc[c::tag_tree];
     let d = ebml::ebml_deserializer(chi_doc);
-    astencode_gen::deserialize_syntax_ast_inlined_item(d)
+    ast::deserialize_inlined_item(d)
 }
 
 fn renumber_ast(xcx: extended_decode_ctxt, ii: ast::inlined_item)
@@ -400,12 +405,12 @@ fn renumber_ast(xcx: extended_decode_ctxt, ii: ast::inlined_item)
 // Encoding and decoding of ast::def
 
 fn encode_def(ebml_w: ebml::writer, def: ast::def) {
-    astencode_gen::serialize_syntax_ast_def(ebml_w, def)
+    ast::serialize_def(ebml_w, def)
 }
 
 fn decode_def(xcx: extended_decode_ctxt, doc: ebml::doc) -> ast::def {
     let dsr = ebml::ebml_deserializer(doc);
-    let def = astencode_gen::deserialize_syntax_ast_def(dsr);
+    let def = ast::deserialize_def(dsr);
     def.tr(xcx)
 }
 
@@ -448,13 +453,12 @@ impl of tr for ast::def {
 // Encoding and decoding of freevar information
 
 fn encode_freevar_entry(ebml_w: ebml::writer, fv: freevar_entry) {
-    astencode_gen::serialize_middle_freevars_freevar_entry(ebml_w, fv)
+    serialize_freevar_entry(ebml_w, fv)
 }
 
 impl helper for ebml::ebml_deserializer {
     fn read_freevar_entry(xcx: extended_decode_ctxt) -> freevar_entry {
-        let fv =
-            astencode_gen::deserialize_middle_freevars_freevar_entry(self);
+        let fv = deserialize_freevar_entry(self);
         fv.tr(xcx)
     }
 }
@@ -469,16 +473,16 @@ impl of tr for freevar_entry {
 // Encoding and decoding of method_origin
 
 fn encode_method_origin(ebml_w: ebml::writer, mo: method_origin) {
-    astencode_gen::serialize_middle_typeck_method_origin(ebml_w, mo)
+    serialize_method_origin(ebml_w, mo)
 }
 
 impl helper for ebml::ebml_deserializer {
     fn read_method_origin(xcx: extended_decode_ctxt) -> method_origin {
-        let fv = astencode_gen::deserialize_middle_typeck_method_origin(self);
+        let fv = deserialize_method_origin(self);
         fv.tr(xcx)
     }
     fn read_is_last_use(xcx: extended_decode_ctxt) -> last_use::is_last_use {
-        let lu = astencode_gen::deserialize_middle_last_use_is_last_use(self);
+        let lu = last_use::deserialize_is_last_use(self);
         lu.tr(xcx)
     }
 }
@@ -692,7 +696,7 @@ fn encode_side_tables_for_id(ecx: @e::encode_ctxt,
         ebml_w.tag(c::tag_table_def) {||
             ebml_w.id(id);
             ebml_w.tag(c::tag_table_val) {||
-                astencode_gen::serialize_syntax_ast_def(ebml_w, def)
+                ast::serialize_def(ebml_w, def)
             }
         }
     }
@@ -774,7 +778,7 @@ fn encode_side_tables_for_id(ecx: @e::encode_ctxt,
         ebml_w.tag(c::tag_table_last_use) {||
             ebml_w.id(id);
             ebml_w.tag(c::tag_table_val) {||
-               astencode_gen::serialize_middle_last_use_is_last_use(ebml_w, m)
+                last_use::serialize_is_last_use(ebml_w, m)
             }
         }
     }
@@ -786,8 +790,7 @@ fn encode_side_tables_for_id(ecx: @e::encode_ctxt,
         ebml_w.tag(c::tag_table_method_map) {||
             ebml_w.id(id);
             ebml_w.tag(c::tag_table_val) {||
-                astencode_gen::
-                    serialize_middle_typeck_method_origin(ebml_w, mo)
+                serialize_method_origin(ebml_w, mo)
             }
         }
     }
@@ -901,3 +904,128 @@ fn decode_side_tables(xcx: extended_decode_ctxt,
         #debug[">< Side table doc loaded"];
     }
 }
+
+// ______________________________________________________________________
+// Testing of astencode_gen
+
+#[cfg(test)]
+fn encode_item_ast(ebml_w: ebml::writer, item: @ast::item) {
+    ebml_w.wr_tag(c::tag_tree as uint) {||
+        ast::serialize_item(ebml_w, *item);
+    }
+}
+
+#[cfg(test)]
+fn decode_item_ast(par_doc: ebml::doc) -> @ast::item {
+    let chi_doc = par_doc[c::tag_tree];
+    let d = ebml::ebml_deserializer(chi_doc);
+    @ast::deserialize_item(d)
+}
+
+#[cfg(test)]
+fn new_parse_sess() -> parser::parse_sess {
+    let cm = codemap::new_codemap();
+    let handler = diagnostic::mk_handler(option::none);
+    let sess = @{
+        cm: cm,
+        mutable next_id: 1,
+        span_diagnostic: diagnostic::mk_span_handler(handler, cm),
+        mutable chpos: 0u,
+        mutable byte_pos: 0u
+    };
+    ret sess;
+}
+
+#[cfg(test)]
+iface fake_ext_ctxt {
+    fn session() -> fake_session;
+}
+
+#[cfg(test)]
+type fake_options = {cfg: ast::crate_cfg};
+
+#[cfg(test)]
+type fake_session = {opts: @fake_options,
+                     parse_sess: parser::parse_sess};
+
+#[cfg(test)]
+impl of fake_ext_ctxt for fake_session {
+    fn session() -> fake_session {self}
+}
+
+#[cfg(test)]
+fn mk_ctxt() -> fake_ext_ctxt {
+    let opts : fake_options = {cfg: []};
+    {opts: @opts, parse_sess: new_parse_sess()} as fake_ext_ctxt
+}
+
+#[cfg(test)]
+fn roundtrip(in_item: @ast::item) {
+    #debug["in_item = %s", pprust::item_to_str(in_item)];
+    let mbuf = io::mem_buffer();
+    let ebml_w = ebml::writer(io::mem_buffer_writer(mbuf));
+    encode_item_ast(ebml_w, in_item);
+    let ebml_doc = ebml::doc(@io::mem_buffer_buf(mbuf));
+    let out_item = decode_item_ast(ebml_doc);
+    #debug["out_item = %s", pprust::item_to_str(out_item)];
+
+    let exp_str =
+        io::with_str_writer {|w| ast::serialize_item(w, *in_item) };
+    let out_str =
+        io::with_str_writer {|w| ast::serialize_item(w, *out_item) };
+
+    #debug["expected string: %s", exp_str];
+    #debug["actual string  : %s", out_str];
+
+    assert exp_str == out_str;
+}
+
+#[test]
+fn test_basic() {
+    let ext_cx = mk_ctxt();
+    roundtrip(#ast(item){
+        fn foo() {}
+    });
+}
+
+#[test]
+fn test_smalltalk() {
+    let ext_cx = mk_ctxt();
+    roundtrip(#ast(item){
+        fn foo() -> int { 3 + 4 } // first smalltalk program ever executed.
+    });
+}
+
+#[test]
+fn test_more() {
+    let ext_cx = mk_ctxt();
+    roundtrip(#ast(item){
+        fn foo(x: uint, y: uint) -> uint {
+            let z = x + y;
+            ret z;
+        }
+    });
+}
+
+#[test]
+fn test_simplification() {
+    let ext_cx = mk_ctxt();
+    let item_in = ast::ii_item(#ast(item) {
+        fn new_int_alist<B: copy>() -> alist<int, B> {
+            fn eq_int(&&a: int, &&b: int) -> bool { a == b }
+            ret {eq_fn: eq_int, mut data: []};
+        }
+    });
+    let item_out = simplify_ast(item_in);
+    let item_exp = ast::ii_item(#ast(item) {
+        fn new_int_alist<B: copy>() -> alist<int, B> {
+            ret {eq_fn: eq_int, mut data: []};
+        }
+    });
+    alt (item_out, item_exp) {
+      (ast::ii_item(item_out), ast::ii_item(item_exp)) {
+        assert pprust::item_to_str(item_out) == pprust::item_to_str(item_exp);
+      }
+      _ { fail; }
+    }
+}
diff --git a/src/rustc/middle/freevars.rs b/src/rustc/middle/freevars.rs
index 37f32f657f7a..f6dd7d991026 100644
--- a/src/rustc/middle/freevars.rs
+++ b/src/rustc/middle/freevars.rs
@@ -5,18 +5,20 @@ import syntax::print::pprust::path_to_str;
 import std::map::*;
 import option::*;
 import syntax::{ast, ast_util, visit};
+import syntax::ast::{serialize_span, deserialize_span};
 import middle::resolve;
 import syntax::codemap::span;
 
 export annotate_freevars;
 export freevar_map;
 export freevar_info;
-export freevar_entry;
+export freevar_entry, serialize_freevar_entry, deserialize_freevar_entry;
 export get_freevars;
 export has_freevars;
 
 // A vector of defs representing the free variables referred to in a function.
 // (The def_upvar will already have been stripped).
+#[auto_serialize]
 type freevar_entry = {
     def: ast::def, //< The variable being accessed free.
     span: span     //< First span where it is accessed (there can be multiple)
diff --git a/src/rustc/middle/last_use.rs b/src/rustc/middle/last_use.rs
index c8ced03175eb..cca276f9a739 100644
--- a/src/rustc/middle/last_use.rs
+++ b/src/rustc/middle/last_use.rs
@@ -25,6 +25,7 @@ import std::map::hashmap;
 // (by `break` or conditionals), and for handling loops.
 
 // Marks expr_paths that are last uses.
+#[auto_serialize]
 enum is_last_use {
     is_last_use,
     has_last_use,
diff --git a/src/rustc/middle/typeck.rs b/src/rustc/middle/typeck.rs
index 2df5d1b158e4..1e092a6eb78c 100644
--- a/src/rustc/middle/typeck.rs
+++ b/src/rustc/middle/typeck.rs
@@ -14,13 +14,17 @@ import middle::ty::{node_id_to_type, arg, block_ty,
 import util::ppaux::ty_to_str;
 import std::smallintmap;
 import std::map::{hashmap, int_hash};
+import std::serialization::{serialize_uint, deserialize_uint};
 import syntax::print::pprust::*;
 
 export check_crate;
-export method_map, method_origin, method_static, method_param, method_iface;
-export vtable_map, vtable_res, vtable_origin, vtable_static, vtable_param,
-       vtable_iface;
+export method_map;
+export method_origin, serialize_method_origin, deserialize_method_origin;
+export vtable_map;
+export vtable_res;
+export vtable_origin;
 
+#[auto_serialize]
 enum method_origin {
     method_static(ast::def_id),
     // iface id, method num, param num, bound num
@@ -37,6 +41,7 @@ enum vtable_origin {
     vtable_param(uint, uint),
     vtable_iface(ast::def_id, [ty::t]),
 }
+
 type vtable_map = hashmap<ast::node_id, vtable_res>;
 
 type ty_table = hashmap<ast::def_id, ty::t>;
diff --git a/src/rustc/syntax/ast.rs b/src/rustc/syntax/ast.rs
index a925514b8fb0..43b0d5e03913 100644
--- a/src/rustc/syntax/ast.rs
+++ b/src/rustc/syntax/ast.rs
@@ -26,45 +26,45 @@ fn deserialize_span<D>(_d: D) -> span {
     ast_util::dummy_sp()
 }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type spanned<T> = {node: T, span: span};
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type ident = str;
 
 // Functions may or may not have names.
-/*#[auto_serialize]*/
+#[auto_serialize]
 type fn_ident = option<ident>;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type path_ = {global: bool, idents: [ident], types: [@ty]};
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type path = spanned<path_>;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type crate_num = int;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type node_id = int;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type def_id = {crate: crate_num, node: node_id};
 
 const local_crate: crate_num = 0;
 const crate_node_id: node_id = 0;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum ty_param_bound {
     bound_copy,
     bound_send,
     bound_iface(@ty),
 }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type ty_param = {ident: ident, id: node_id, bounds: @[ty_param_bound]};
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum def {
     def_fn(def_id, purity),
     def_self(node_id),
@@ -119,30 +119,30 @@ enum crate_directive_ {
 
 type crate_directive = spanned<crate_directive_>;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type meta_item = spanned<meta_item_>;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum meta_item_ {
     meta_word(ident),
     meta_list(ident, [@meta_item]),
     meta_name_value(ident, lit),
 }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type blk = spanned<blk_>;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type blk_ = {view_items: [@view_item], stmts: [@stmt], expr: option<@expr>,
              id: node_id, rules: blk_check_mode};
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type pat = {id: node_id, node: pat_, span: span};
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type field_pat = {ident: ident, pat: @pat};
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum pat_ {
     pat_wild,
     // A pat_ident may either be a new bound variable,
@@ -162,10 +162,10 @@ enum pat_ {
     pat_range(@expr, @expr),
 }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum mutability { m_mutbl, m_imm, m_const, }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum proto {
     proto_bare,    // native fn
     proto_any,     // fn
@@ -181,7 +181,7 @@ pure fn is_blockish(p: ast::proto) -> bool {
     }
 }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum binop {
     add,
     subtract,
@@ -204,7 +204,7 @@ enum binop {
     gt,
 }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum unop {
     box(mutability),
     uniq(mutability),
@@ -213,23 +213,23 @@ enum unop {
 
 // Generally, after typeck you can get the inferred value
 // using ty::resolved_T(...).
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum inferable<T> {
     expl(T), infer(node_id)
 }
 
 // "resolved" mode: the real modes.
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum rmode { by_ref, by_val, by_mutbl_ref, by_move, by_copy }
 
 // inferable mode.
-/*#[auto_serialize]*/
+#[auto_serialize]
 type mode = inferable<rmode>;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type stmt = spanned<stmt_>;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum stmt_ {
     stmt_decl(@decl, node_id),
 
@@ -240,48 +240,48 @@ enum stmt_ {
     stmt_semi(@expr, node_id),
 }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum init_op { init_assign, init_move, }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type initializer = {op: init_op, expr: @expr};
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type local_ =  // FIXME: should really be a refinement on pat
     {is_mutbl: bool, ty: @ty, pat: @pat,
      init: option<initializer>, id: node_id};
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type local = spanned<local_>;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type decl = spanned<decl_>;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum decl_ { decl_local([@local]), decl_item(@item), }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type arm = {pats: [@pat], guard: option<@expr>, body: blk};
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type field_ = {mutbl: mutability, ident: ident, expr: @expr};
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type field = spanned<field_>;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum blk_check_mode { default_blk, unchecked_blk, unsafe_blk, }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum expr_check_mode { claimed_expr, checked_expr, }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type expr = {id: node_id, node: expr_, span: span};
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum alt_mode { alt_check, alt_exhaustive, }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum expr_ {
     expr_vec([@expr], mutability),
     expr_rec([field], option<@expr>),
@@ -337,14 +337,14 @@ enum expr_ {
     expr_mac(mac),
 }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type capture_item = {
     id: int,
     name: ident, // Currently, can only capture a local var.
     span: span
 };
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type capture_clause = {
     copies: [@capture_item],
     moves: [@capture_item]
@@ -359,19 +359,19 @@ enum blk_sort {
 }
 */
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type mac = spanned<mac_>;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type mac_arg = option<@expr>;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type mac_body_ = {span: span};
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type mac_body = option<mac_body_>;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum mac_ {
     mac_invoc(@path, mac_arg, mac_body),
     mac_embed_type(@ty),
@@ -382,10 +382,10 @@ enum mac_ {
     mac_var(uint)
 }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type lit = spanned<lit_>;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum lit_ {
     lit_str(str),
     lit_int(i64, int_ty),
@@ -397,33 +397,33 @@ enum lit_ {
 
 // NB: If you change this, you'll probably want to change the corresponding
 // type structure in middle/ty.rs as well.
-/*#[auto_serialize]*/
+#[auto_serialize]
 type mt = {ty: @ty, mutbl: mutability};
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type ty_field_ = {ident: ident, mt: mt};
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type ty_field = spanned<ty_field_>;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type ty_method = {ident: ident, attrs: [attribute],
                   decl: fn_decl, tps: [ty_param], span: span};
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum int_ty { ty_i, ty_char, ty_i8, ty_i16, ty_i32, ty_i64, }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum uint_ty { ty_u, ty_u8, ty_u16, ty_u32, ty_u64, }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum float_ty { ty_f, ty_f32, ty_f64, }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type ty = {id: node_id, node: ty_, span: span};
 
 // Not represented directly in the AST, referred to by name through a ty_path.
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum prim_ty {
     ty_int(int_ty),
     ty_uint(uint_ty),
@@ -432,17 +432,17 @@ enum prim_ty {
     ty_bool,
 }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type region = {id: node_id, node: region_};
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum region_ {
     re_inferred,
     re_named(ident),
     re_self
 }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum ty_ {
     ty_nil,
     ty_bot, /* bottom type */
@@ -472,19 +472,19 @@ so that the typestate pass doesn't have to map a function name onto its decl.
 So, the constr_arg type is parameterized: it's instantiated with uint for
 declarations, and ident for uses.
 */
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum constr_arg_general_<T> { carg_base, carg_ident(T), carg_lit(@lit), }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type fn_constr_arg = constr_arg_general_<uint>;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type sp_constr_arg<T> = spanned<constr_arg_general_<T>>;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type ty_constr_arg = sp_constr_arg<@path>;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type constr_arg = spanned<fn_constr_arg>;
 
 // Constrained types' args are parameterized by paths, since
@@ -492,34 +492,34 @@ type constr_arg = spanned<fn_constr_arg>;
 // The implicit root of such path, in the constraint-list for a
 // constrained type, is * (referring to the base record)
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type constr_general_<ARG, ID> =
     {path: @path, args: [@spanned<constr_arg_general_<ARG>>], id: ID};
 
 // In the front end, constraints have a node ID attached.
 // Typeck turns this to a def_id, using the output of resolve.
-/*#[auto_serialize]*/
+#[auto_serialize]
 type constr_general<ARG> = spanned<constr_general_<ARG, node_id>>;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type constr_ = constr_general_<uint, node_id>;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type constr = spanned<constr_general_<uint, node_id>>;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type ty_constr_ = constr_general_<@path, node_id>;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type ty_constr = spanned<ty_constr_>;
 
 /* The parser generates ast::constrs; resolve generates
  a mapping from each function to a list of ty::constr_defs,
  corresponding to these. */
-/*#[auto_serialize]*/
+#[auto_serialize]
 type arg = {mode: mode, ty: @ty, ident: ident, id: node_id};
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type fn_decl =
     {inputs: [arg],
      output: @ty,
@@ -527,7 +527,7 @@ type fn_decl =
      cf: ret_style,
      constraints: [@constr]};
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum purity {
     pure_fn, // declared with "pure fn"
     unsafe_fn, // declared with "unsafe fn"
@@ -535,58 +535,58 @@ enum purity {
     crust_fn, // declared with "crust fn"
 }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum ret_style {
     noreturn, // functions with return type _|_ that always
               // raise an error or exit (i.e. never return to the caller)
     return_val, // everything else
 }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type method = {ident: ident, attrs: [attribute],
                tps: [ty_param], decl: fn_decl, body: blk,
                id: node_id, span: span, self_id: node_id};
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type _mod = {view_items: [@view_item], items: [@item]};
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum native_abi {
     native_abi_rust_intrinsic,
     native_abi_cdecl,
     native_abi_stdcall,
 }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type native_mod =
     {view_items: [@view_item],
      items: [@native_item]};
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type variant_arg = {ty: @ty, id: node_id};
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type variant_ = {name: ident, attrs: [attribute], args: [variant_arg],
                  id: node_id, disr_expr: option<@expr>};
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type variant = spanned<variant_>;
 
 // FIXME: May want to just use path here, which would allow things like
 // 'import ::foo'
-/*#[auto_serialize]*/
+#[auto_serialize]
 type simple_path = [ident];
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type path_list_ident_ = {name: ident, id: node_id};
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type path_list_ident = spanned<path_list_ident_>;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type view_path = spanned<view_path_>;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum view_path_ {
 
     // quux = foo::bar::baz
@@ -603,10 +603,10 @@ enum view_path_ {
     view_path_list(@simple_path, [path_list_ident], node_id)
 }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type view_item = spanned<view_item_>;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum view_item_ {
     view_item_use(ident, [@meta_item], node_id),
     view_item_import([@view_path]),
@@ -614,23 +614,23 @@ enum view_item_ {
 }
 
 // Meta-data associated with an item
-/*#[auto_serialize]*/
+#[auto_serialize]
 type attribute = spanned<attribute_>;
 
 // Distinguishes between attributes that decorate items and attributes that
 // are contained as statements within items. These two cases need to be
 // distinguished for pretty-printing.
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum attr_style { attr_outer, attr_inner, }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type attribute_ = {style: attr_style, value: meta_item};
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type item = {ident: ident, attrs: [attribute],
              id: node_id, node: item_, span: span};
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum item_ {
     item_const(@ty, @expr),
     item_fn(fn_decl, [ty_param], blk),
@@ -650,13 +650,13 @@ enum item_ {
               @ty /* self */, [@method]),
 }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type class_item_ = {privacy: privacy, decl: class_member};
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type class_item = spanned<class_item_>;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum class_member {
     instance_var(ident, @ty, class_mutability, node_id),
     class_method(@item) // FIXME: methods aren't allowed to be
@@ -665,21 +665,21 @@ enum class_member {
     // item to separate out things with type params?
 }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum class_mutability { class_mutable, class_immutable }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum privacy { priv, pub }
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type class_ctor = spanned<class_ctor_>;
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type class_ctor_ = {id: node_id,
                     dec: fn_decl,
                     body: blk};
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 type native_item =
     {ident: ident,
      attrs: [attribute],
@@ -687,7 +687,7 @@ type native_item =
      id: node_id,
      span: span};
 
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum native_item_ {
     native_item_fn(fn_decl, [ty_param]),
 }
@@ -695,7 +695,7 @@ enum native_item_ {
 // The data we save and restore about an inlined item or method.  This is not
 // part of the AST that we parse from a file, but it becomes part of the tree
 // that we trans.
-/*#[auto_serialize]*/
+#[auto_serialize]
 enum inlined_item {
     ii_item(@item),
     ii_method(def_id /* impl id */, @method)
diff --git a/src/rustc/syntax/fold.rs b/src/rustc/syntax/fold.rs
index 62de1f881ef8..0a3e42aee344 100644
--- a/src/rustc/syntax/fold.rs
+++ b/src/rustc/syntax/fold.rs
@@ -117,13 +117,14 @@ fn fold_meta_item_(&&mi: @meta_item, fld: ast_fold) -> @meta_item {
                   meta_name_value(fld.fold_ident(id), s)
                 }
               },
-          span: mi.span};
+          span: fld.new_span(mi.span)};
 }
 //used in noop_fold_item and noop_fold_crate
-fn fold_attribute_(at: attribute, fmi: fn@(&&@meta_item) -> @meta_item) ->
+fn fold_attribute_(at: attribute, fld: ast_fold) ->
    attribute {
-    ret {node: {style: at.node.style, value: *fmi(@at.node.value)},
-         span: at.span};
+    ret {node: {style: at.node.style,
+                value: *fold_meta_item_(@at.node.value, fld)},
+         span: fld.new_span(at.span)};
 }
 //used in noop_fold_native_item and noop_fold_fn_decl
 fn fold_arg_(a: arg, fld: ast_fold) -> arg {
@@ -148,7 +149,7 @@ fn fold_mac_(m: mac, fld: ast_fold) -> mac {
                mac_aq(_,_) { /* fixme */ m.node }
                mac_var(_) { /* fixme */ m.node }
              },
-         span: m.span};
+         span: fld.new_span(m.span)};
 }
 
 fn fold_fn_decl(decl: ast::fn_decl, fld: ast_fold) -> ast::fn_decl {
@@ -178,7 +179,7 @@ fn fold_ty_params(tps: [ty_param], fld: ast_fold) -> [ty_param] {
 
 fn noop_fold_crate(c: crate_, fld: ast_fold) -> crate_ {
     let fold_meta_item = bind fold_meta_item_(_, fld);
-    let fold_attribute = bind fold_attribute_(_, fold_meta_item);
+    let fold_attribute = bind fold_attribute_(_, fld);
 
     ret {directives: vec::map(c.directives, fld.fold_crate_directive),
          module: fld.fold_mod(c.module),
@@ -208,8 +209,7 @@ fn noop_fold_view_item(vi: view_item_, _fld: ast_fold) -> view_item_ {
 
 fn noop_fold_native_item(&&ni: @native_item, fld: ast_fold) -> @native_item {
     let fold_arg = bind fold_arg_(_, fld);
-    let fold_meta_item = bind fold_meta_item_(_, fld);
-    let fold_attribute = bind fold_attribute_(_, fold_meta_item);
+    let fold_attribute = bind fold_attribute_(_, fld);
 
     ret @{ident: fld.fold_ident(ni.ident),
           attrs: vec::map(ni.attrs, fold_attribute),
@@ -231,8 +231,7 @@ fn noop_fold_native_item(&&ni: @native_item, fld: ast_fold) -> @native_item {
 }
 
 fn noop_fold_item(&&i: @item, fld: ast_fold) -> @item {
-    let fold_meta_item = bind fold_meta_item_(_, fld);
-    let fold_attribute = bind fold_attribute_(_, fold_meta_item);
+    let fold_attribute = bind fold_attribute_(_, fld);
 
     ret @{ident: fld.fold_ident(i.ident),
           attrs: vec::map(i.attrs, fold_attribute),
@@ -252,7 +251,7 @@ fn noop_fold_class_item(&&ci: @class_item, fld: ast_fold)
         }
         class_method(i) { class_method(fld.fold_item(i)) }
          }},
-       span: ci.span}
+       span: fld.new_span(ci.span)}
 }
 
 fn noop_fold_item_underscore(i: item_, fld: ast_fold) -> item_ {
@@ -374,7 +373,7 @@ fn noop_fold_expr(e: expr_, fld: ast_fold) -> expr_ {
                  {mutbl: field.node.mutbl,
                   ident: fld.fold_ident(field.node.ident),
                   expr: fld.fold_expr(field.node.expr)},
-             span: field.span};
+             span: fld.new_span(field.span)};
     }
     let fold_field = bind fold_field_(_, fld);
 
@@ -519,8 +518,7 @@ fn noop_fold_variant(v: variant_, fld: ast_fold) -> variant_ {
     let fold_variant_arg = bind fold_variant_arg_(_, fld);
     let args = vec::map(v.args, fold_variant_arg);
 
-    let fold_meta_item = bind fold_meta_item_(_, fld);
-    let fold_attribute = bind fold_attribute_(_, fold_meta_item);
+    let fold_attribute = bind fold_attribute_(_, fld);
     let attrs = vec::map(v.attrs, fold_attribute);
 
     let de = alt v.disr_expr {