Convert ast::ident to istr. Issue #855

34 files changed, 403 insertions, 316 deletions

diff --git a/src/comp/back/link.rs b/src/comp/back/link.rs
index 2a4da724fba..3f09374309c 100644
--- a/src/comp/back/link.rs
+++ b/src/comp/back/link.rs
@@ -299,12 +299,12 @@ fn build_link_meta(sess: &session::session, c: &ast::crate, output: &str,
         let linkage_metas = attr::find_linkage_metas(c.node.attrs);
         attr::require_unique_names(sess, linkage_metas);
         for meta: @ast::meta_item in linkage_metas {
-            if attr::get_meta_item_name(meta) == "name" {
+            if attr::get_meta_item_name(meta) == ~"name" {
                 alt attr::get_meta_item_value_str(meta) {
                   some(v) { name = some(v); }
                   none. { cmh_items += [meta]; }
                 }
-            } else if attr::get_meta_item_name(meta) == "vers" {
+            } else if attr::get_meta_item_name(meta) == ~"vers" {
                 alt attr::get_meta_item_value_str(meta) {
                   some(v) { vers = some(v); }
                   none. { cmh_items += [meta]; }
@@ -334,11 +334,11 @@ fn build_link_meta(sess: &session::session, c: &ast::crate, output: &str,
             let m = m_;
             alt m.node {
               ast::meta_name_value(key, value) {
-                sha.input_str(len_and_str(istr::from_estr(key)));
+                sha.input_str(len_and_str(key));
                 sha.input_str(len_and_str_lit(value));
               }
               ast::meta_word(name) {
-                sha.input_str(len_and_str(istr::from_estr(name)));
+                sha.input_str(len_and_str(name));
               }
               ast::meta_list(_, _) {
                 // FIXME (#607): Implement this
diff --git a/src/comp/driver/rustc.rs b/src/comp/driver/rustc.rs
index 204b6ef0d51..18ff0559624 100644
--- a/src/comp/driver/rustc.rs
+++ b/src/comp/driver/rustc.rs
@@ -55,11 +55,11 @@ fn default_configuration(sess: session::session, argv0: str, input: str) ->
     let mk = attr::mk_name_value_item_str;
 
     ret [ // Target bindings.
-         mk("target_os", istr::to_estr(std::os::target_os())),
-        mk("target_arch", "x86"),
-         mk("target_libc", libc),
+         mk(~"target_os", istr::to_estr(std::os::target_os())),
+        mk(~"target_arch", "x86"),
+         mk(~"target_libc", libc),
          // Build bindings.
-         mk("build_compiler", argv0), mk("build_input", input)];
+         mk(~"build_compiler", argv0), mk(~"build_input", input)];
 }
 
 fn build_configuration(sess: session::session, argv0: str, input: str) ->
@@ -71,9 +71,9 @@ fn build_configuration(sess: session::session, argv0: str, input: str) ->
     // If the user wants a test runner, then add the test cfg
     let gen_cfg =
         {
-            if sess.get_opts().test && !attr::contains_name(user_cfg, "test")
-               {
-                [attr::mk_word_item("test")]
+            if sess.get_opts().test
+                && !attr::contains_name(user_cfg, ~"test") {
+                [attr::mk_word_item(~"test")]
             } else { [] }
         };
     ret user_cfg + gen_cfg + default_cfg;
@@ -84,7 +84,9 @@ fn parse_cfgspecs(cfgspecs: &[str]) -> ast::crate_cfg {
     // FIXME: It would be nice to use the parser to parse all varieties of
     // meta_item here. At the moment we just support the meta_word variant.
     let words = [];
-    for s: str in cfgspecs { words += [attr::mk_word_item(s)]; }
+    for s: str in cfgspecs {
+        words += [attr::mk_word_item(istr::from_estr(s))];
+    }
     ret words;
 }
 
@@ -655,7 +657,7 @@ mod test {
         let sessopts = build_session_options("whatever", match, "whatever");
         let sess = build_session(sessopts);
         let cfg = build_configuration(sess, "whatever", "whatever");
-        assert (attr::contains_name(cfg, "test"));
+        assert (attr::contains_name(cfg, ~"test"));
     }
 
     // When the user supplies --test and --cfg test, don't implicitly add
@@ -669,7 +671,7 @@ mod test {
         let sessopts = build_session_options("whatever", match, "whatever");
         let sess = build_session(sessopts);
         let cfg = build_configuration(sess, "whatever", "whatever");
-        let test_items = attr::find_meta_items_by_name(cfg, "test");
+        let test_items = attr::find_meta_items_by_name(cfg, ~"test");
         assert (vec::len(test_items) == 1u);
     }
 }
diff --git a/src/comp/front/attr.rs b/src/comp/front/attr.rs
index 5701ff33f97..711f9f67039 100644
--- a/src/comp/front/attr.rs
+++ b/src/comp/front/attr.rs
@@ -2,6 +2,7 @@
 
 import std::vec;
 import std::str;
+import std::istr;
 import std::map;
 import std::option;
 import syntax::ast;
@@ -32,7 +33,7 @@ export mk_attr;
 // linkage
 fn find_linkage_metas(attrs: &[ast::attribute]) -> [@ast::meta_item] {
     let metas: [@ast::meta_item] = [];
-    for attr: ast::attribute in find_attrs_by_name(attrs, "link") {
+    for attr: ast::attribute in find_attrs_by_name(attrs, ~"link") {
         alt attr.node.value.node {
           ast::meta_list(_, items) { metas += items; }
           _ { log "ignoring link attribute that has incorrect type"; }
@@ -163,11 +164,11 @@ fn sort_meta_items(items: &[@ast::meta_item]) -> [@ast::meta_item] {
     ret v2;
 }
 
-fn remove_meta_items_by_name(items: &[@ast::meta_item], name: str) ->
+fn remove_meta_items_by_name(items: &[@ast::meta_item], name: &istr) ->
    [@ast::meta_item] {
 
     let filter =
-        bind fn (item: &@ast::meta_item, name: str) ->
+        bind fn (item: &@ast::meta_item, name: &istr) ->
                 option::t<@ast::meta_item> {
                  if get_meta_item_name(item) != name {
                      option::some(item)
@@ -178,12 +179,13 @@ fn remove_meta_items_by_name(items: &[@ast::meta_item], name: str) ->
 }
 
 fn require_unique_names(sess: &session::session, metas: &[@ast::meta_item]) {
-    let map = map::mk_hashmap::<str, ()>(str::hash, str::eq);
+    let map = map::new_str_hash();
     for meta: @ast::meta_item in metas {
         let name = get_meta_item_name(meta);
         if map.contains_key(name) {
             sess.span_fatal(meta.span,
-                            #fmt["duplicate meta item `%s`", name]);
+                            #fmt["duplicate meta item `%s`",
+                                 istr::to_estr(name)]);
         }
         map.insert(name, ());
     }
diff --git a/src/comp/front/config.rs b/src/comp/front/config.rs
index 526bf20ebb7..be02086cc01 100644
--- a/src/comp/front/config.rs
+++ b/src/comp/front/config.rs
@@ -94,7 +94,7 @@ fn native_item_in_cfg(cfg: &ast::crate_cfg, item: &@ast::native_item) ->
 fn in_cfg(cfg: &ast::crate_cfg, attrs: &[ast::attribute]) -> bool {
 
     // The "cfg" attributes on the item
-    let item_cfg_attrs = attr::find_attrs_by_name(attrs, "cfg");
+    let item_cfg_attrs = attr::find_attrs_by_name(attrs, ~"cfg");
     let item_has_cfg_attrs = vec::len(item_cfg_attrs) > 0u;
     if !item_has_cfg_attrs { ret true; }
 
@@ -108,7 +108,7 @@ fn in_cfg(cfg: &ast::crate_cfg, attrs: &[ast::attribute]) -> bool {
                [@ast::meta_item] {
                 alt cfg_item.node {
                   ast::meta_list(name, items) {
-                    assert (name == "cfg");
+                    assert (name == ~"cfg");
                     inner_items + items
                   }
                   _ { inner_items }
diff --git a/src/comp/front/test.rs b/src/comp/front/test.rs
index d76e26064a7..425736c2d5c 100644
--- a/src/comp/front/test.rs
+++ b/src/comp/front/test.rs
@@ -64,7 +64,7 @@ fn fold_mod(_cx: &test_ctxt, m: &ast::_mod, fld: fold::ast_fold) ->
     fn nomain(item: &@ast::item) -> option::t<@ast::item> {
         alt item.node {
           ast::item_fn(f, _) {
-            if item.ident == "main" {
+            if item.ident == ~"main" {
                 option::none
             } else { option::some(item) }
           }
@@ -107,7 +107,7 @@ fn fold_item(cx: &test_ctxt, i: &@ast::item, fld: fold::ast_fold) ->
 
 fn is_test_fn(i: &@ast::item) -> bool {
     let has_test_attr =
-        vec::len(attr::find_attrs_by_name(i.attrs, "test")) > 0u;
+        vec::len(attr::find_attrs_by_name(i.attrs, ~"test")) > 0u;
 
     fn has_test_signature(i: &@ast::item) -> bool {
         alt i.node {
@@ -125,7 +125,7 @@ fn is_test_fn(i: &@ast::item) -> bool {
 }
 
 fn is_ignored(i: &@ast::item) -> bool {
-    attr::contains_name(attr::attr_metas(i.attrs), "ignore")
+    attr::contains_name(attr::attr_metas(i.attrs), ~"ignore")
 }
 
 fn add_test_module(cx: &test_ctxt, m: &ast::_mod) -> ast::_mod {
@@ -160,7 +160,7 @@ fn mk_test_module(cx: &test_ctxt) -> @ast::item {
     let testmod: ast::_mod = {view_items: [], items: [mainfn, testsfn]};
     let item_ = ast::item_mod(testmod);
     let item: ast::item =
-        {ident: "__test",
+        {ident: ~"__test",
          attrs: [],
          id: cx.next_node_id(),
          node: item_,
@@ -198,7 +198,7 @@ fn mk_tests(cx: &test_ctxt) -> @ast::item {
 
     let item_ = ast::item_fn(fn_, []);
     let item: ast::item =
-        {ident: "tests",
+        {ident: ~"tests",
          attrs: [],
          id: cx.next_node_id(),
          node: item_,
@@ -219,7 +219,7 @@ fn empty_fn_ty() -> ast::ty {
 fn mk_test_desc_vec_ty(cx: &test_ctxt) -> @ast::ty {
     let test_desc_ty_path: ast::path =
         nospan({global: false,
-                idents: ["std", "test", "test_desc"],
+                idents: [~"std", ~"test", ~"test_desc"],
                 types: []});
 
     let test_desc_ty: ast::ty =
@@ -256,7 +256,7 @@ fn mk_test_desc_rec(cx: &test_ctxt, test: test) -> @ast::expr {
          span: dummy_sp()};
 
     let name_field: ast::field =
-        nospan({mut: ast::imm, ident: "name", expr: @name_expr});
+        nospan({mut: ast::imm, ident: ~"name", expr: @name_expr});
 
     let fn_path: ast::path = nospan({global: false, idents: path, types: []});
 
@@ -266,7 +266,7 @@ fn mk_test_desc_rec(cx: &test_ctxt, test: test) -> @ast::expr {
          span: dummy_sp()};
 
     let fn_field: ast::field =
-        nospan({mut: ast::imm, ident: "fn", expr: @fn_expr});
+        nospan({mut: ast::imm, ident: ~"fn", expr: @fn_expr});
 
     let ignore_lit: ast::lit = nospan(ast::lit_bool(test.ignore));
 
@@ -276,7 +276,7 @@ fn mk_test_desc_rec(cx: &test_ctxt, test: test) -> @ast::expr {
          span: dummy_sp()};
 
     let ignore_field: ast::field =
-        nospan({mut: ast::imm, ident: "ignore", expr: @ignore_expr});
+        nospan({mut: ast::imm, ident: ~"ignore", expr: @ignore_expr});
 
     let desc_rec_: ast::expr_ =
         ast::expr_rec([name_field, fn_field, ignore_field], option::none);
@@ -291,7 +291,7 @@ fn mk_main(cx: &test_ctxt) -> @ast::item {
     let args_ty: ast::ty = nospan(ast::ty_vec(args_mt));
 
     let args_arg: ast::arg =
-        {mode: ast::val, ty: @args_ty, ident: "args", id: cx.next_node_id()};
+        {mode: ast::val, ty: @args_ty, ident: ~"args", id: cx.next_node_id()};
 
     let ret_ty = nospan(ast::ty_nil);
 
@@ -314,7 +314,7 @@ fn mk_main(cx: &test_ctxt) -> @ast::item {
 
     let item_ = ast::item_fn(fn_, []);
     let item: ast::item =
-        {ident: "main",
+        {ident: ~"main",
          attrs: [],
          id: cx.next_node_id(),
          node: item_,
@@ -326,7 +326,7 @@ fn mk_test_main_call(cx: &test_ctxt) -> @ast::expr {
 
     // Get the args passed to main so we can pass the to test_main
     let args_path: ast::path =
-        nospan({global: false, idents: ["args"], types: []});
+        nospan({global: false, idents: [~"args"], types: []});
 
     let args_path_expr_: ast::expr_ = ast::expr_path(args_path);
 
@@ -335,7 +335,7 @@ fn mk_test_main_call(cx: &test_ctxt) -> @ast::expr {
 
     // Call __test::test to generate the vector of test_descs
     let test_path: ast::path =
-        nospan({global: false, idents: ["tests"], types: []});
+        nospan({global: false, idents: [~"tests"], types: []});
 
     let test_path_expr_: ast::expr_ = ast::expr_path(test_path);
 
@@ -350,7 +350,7 @@ fn mk_test_main_call(cx: &test_ctxt) -> @ast::expr {
     // Call std::test::test_main
     let test_main_path: ast::path =
         nospan({global: false,
-                idents: ["std", "test", "test_main"],
+                idents: [~"std", ~"test", ~"test_main"],
                 types: []});
 
     let test_main_path_expr_: ast::expr_ = ast::expr_path(test_main_path);
diff --git a/src/comp/metadata/creader.rs b/src/comp/metadata/creader.rs
index 3f6d63cf577..1400fe98395 100644
--- a/src/comp/metadata/creader.rs
+++ b/src/comp/metadata/creader.rs
@@ -70,7 +70,7 @@ fn visit_item(e: env, i: &@ast::item) {
         let cstore = e.sess.get_cstore();
         if !cstore::add_used_library(cstore, m.native_name) { ret; }
         for a: ast::attribute in
-            attr::find_attrs_by_name(i.attrs, "link_args") {
+            attr::find_attrs_by_name(i.attrs, ~"link_args") {
             alt attr::get_meta_item_value_str(attr::attr_meta(a)) {
               some(linkarg) { cstore::add_used_link_args(cstore, linkarg); }
               none. {/* fallthrough */ }
@@ -128,15 +128,15 @@ fn find_library_crate(sess: &session::session, ident: &ast::ident,
     // is using the wrong type of meta item
     let crate_name =
         {
-            let name_items = attr::find_meta_items_by_name(metas, "name");
+            let name_items = attr::find_meta_items_by_name(metas, ~"name");
             alt vec::last(name_items) {
               some(i) {
                 alt attr::get_meta_item_value_str(i) {
                   some(n) { n }
-                  _ { ident }
+                  _ { istr::to_estr(ident) }
                 }
               }
-              none. { ident }
+              none. { istr::to_estr(ident) }
             }
         };
 
@@ -219,14 +219,15 @@ fn load_library_crate(sess: &session::session, span: span, ident: &ast::ident,
     alt find_library_crate(sess, ident, metas, library_search_paths) {
       some(t) { ret t; }
       none. {
-        sess.span_fatal(span, #fmt["can't find crate for '%s'", ident]);
+        sess.span_fatal(span, #fmt["can't find crate for '%s'",
+                                   istr::to_estr(ident)]);
       }
     }
 }
 
-fn resolve_crate(e: env, ident: ast::ident, metas: [@ast::meta_item],
+fn resolve_crate(e: env, ident: &ast::ident, metas: [@ast::meta_item],
                  span: span) -> ast::crate_num {
-    if !e.crate_cache.contains_key(istr::from_estr(ident)) {
+    if !e.crate_cache.contains_key(ident) {
         let cinfo =
             load_library_crate(e.sess, span, ident, metas,
                                e.library_search_paths);
@@ -236,19 +237,20 @@ fn resolve_crate(e: env, ident: ast::ident, metas: [@ast::meta_item],
 
         // Claim this crate number and cache it
         let cnum = e.next_crate_num;
-        e.crate_cache.insert(istr::from_estr(ident), cnum);
+        e.crate_cache.insert(ident, cnum);
         e.next_crate_num += 1;
 
         // Now resolve the crates referenced by this crate
         let cnum_map = resolve_crate_deps(e, cdata);
 
-        let cmeta = {name: ident, data: cdata, cnum_map: cnum_map};
+        let cmeta = {name: istr::to_estr(ident),
+                     data: cdata, cnum_map: cnum_map};
 
         let cstore = e.sess.get_cstore();
         cstore::set_crate_data(cstore, cnum, cmeta);
         cstore::add_used_crate_file(cstore, cfilename);
         ret cnum;
-    } else { ret e.crate_cache.get(istr::from_estr(ident)); }
+    } else { ret e.crate_cache.get(ident); }
 }
 
 // Go through the crate metadata and load any crates that it references
@@ -271,7 +273,9 @@ fn resolve_crate_deps(e: env, cdata: &@[u8]) -> cstore::cnum_map {
             // This is a new one so we've got to load it
             // FIXME: Need better error reporting than just a bogus span
             let fake_span = ast_util::dummy_sp();
-            let local_cnum = resolve_crate(e, cname, [], fake_span);
+            let local_cnum = resolve_crate(e,
+                                           istr::from_estr(cname),
+                                           [], fake_span);
             cnum_map.insert(extrn_cnum, local_cnum);
         }
     }
diff --git a/src/comp/metadata/decoder.rs b/src/comp/metadata/decoder.rs
index 97010e0d521..b91906063fc 100644
--- a/src/comp/metadata/decoder.rs
+++ b/src/comp/metadata/decoder.rs
@@ -153,7 +153,7 @@ fn resolve_path(path: &[ast::ident], data: @[u8]) -> [ast::def_id] {
     fn eq_item(data: &[u8], s: str) -> bool {
         ret str::eq(str::unsafe_from_bytes(data), s);
     }
-    let s = str::connect(path, "::");
+    let s = istr::to_estr(istr::connect(path, ~"::"));
     let md = ebml::new_doc(data);
     let paths = ebml::get_doc(md, tag_paths);
     let eqer = bind eq_item(_, s);
@@ -302,14 +302,14 @@ fn get_meta_items(md: &ebml::doc) -> [@ast::meta_item] {
     for each meta_item_doc: ebml::doc in
              ebml::tagged_docs(md, tag_meta_item_word) {
         let nd = ebml::get_doc(meta_item_doc, tag_meta_item_name);
-        let n = str::unsafe_from_bytes(ebml::doc_data(nd));
+        let n = istr::unsafe_from_bytes(ebml::doc_data(nd));
         items += [attr::mk_word_item(n)];
     }
     for each meta_item_doc: ebml::doc in
              ebml::tagged_docs(md, tag_meta_item_name_value) {
         let nd = ebml::get_doc(meta_item_doc, tag_meta_item_name);
         let vd = ebml::get_doc(meta_item_doc, tag_meta_item_value);
-        let n = str::unsafe_from_bytes(ebml::doc_data(nd));
+        let n = istr::unsafe_from_bytes(ebml::doc_data(nd));
         let v = str::unsafe_from_bytes(ebml::doc_data(vd));
         // FIXME (#611): Should be able to decode meta_name_value variants,
         // but currently they can't be encoded
@@ -318,7 +318,7 @@ fn get_meta_items(md: &ebml::doc) -> [@ast::meta_item] {
     for each meta_item_doc: ebml::doc in
              ebml::tagged_docs(md, tag_meta_item_list) {
         let nd = ebml::get_doc(meta_item_doc, tag_meta_item_name);
-        let n = str::unsafe_from_bytes(ebml::doc_data(nd));
+        let n = istr::unsafe_from_bytes(ebml::doc_data(nd));
         let subitems = get_meta_items(meta_item_doc);
         items += [attr::mk_list_item(n, subitems)];
     }
diff --git a/src/comp/metadata/encoder.rs b/src/comp/metadata/encoder.rs
index 1aa89d9a914..f803292d9ad 100644
--- a/src/comp/metadata/encoder.rs
+++ b/src/comp/metadata/encoder.rs
@@ -44,9 +44,9 @@ type entry<T> = {val: T, pos: uint};
 fn encode_tag_variant_paths(ebml_w: &ebml::writer, variants: &[variant],
                             path: &[istr], index: &mutable [entry<istr>]) {
     for variant: variant in variants {
-        add_to_index(ebml_w, path, index, istr::from_estr(variant.node.name));
+        add_to_index(ebml_w, path, index, variant.node.name);
         ebml::start_tag(ebml_w, tag_paths_data_item);
-        encode_name(ebml_w, istr::from_estr(variant.node.name));
+        encode_name(ebml_w, variant.node.name);
         encode_def_id(ebml_w, local_def(variant.node.id));
         ebml::end_tag(ebml_w);
     }
@@ -63,9 +63,9 @@ fn encode_native_module_item_paths(ebml_w: &ebml::writer, nmod: &native_mod,
                                    path: &[istr],
                                    index: &mutable [entry<istr>]) {
     for nitem: @native_item in nmod.items {
-        add_to_index(ebml_w, path, index, istr::from_estr(nitem.ident));
+        add_to_index(ebml_w, path, index, nitem.ident);
         ebml::start_tag(ebml_w, tag_paths_data_item);
-        encode_name(ebml_w, istr::from_estr(nitem.ident));
+        encode_name(ebml_w, nitem.ident);
         encode_def_id(ebml_w, local_def(nitem.id));
         ebml::end_tag(ebml_w);
     }
@@ -77,76 +77,76 @@ fn encode_module_item_paths(ebml_w: &ebml::writer, module: &_mod,
         if !ast_util::is_exported(it.ident, module) { cont; }
         alt it.node {
           item_const(_, _) {
-            add_to_index(ebml_w, path, index, istr::from_estr(it.ident));
+            add_to_index(ebml_w, path, index, it.ident);
             ebml::start_tag(ebml_w, tag_paths_data_item);
-            encode_name(ebml_w, istr::from_estr(it.ident));
+            encode_name(ebml_w, it.ident);
             encode_def_id(ebml_w, local_def(it.id));
             ebml::end_tag(ebml_w);
           }
           item_fn(_, tps) {
-            add_to_index(ebml_w, path, index, istr::from_estr(it.ident));
+            add_to_index(ebml_w, path, index, it.ident);
             ebml::start_tag(ebml_w, tag_paths_data_item);
-            encode_name(ebml_w, istr::from_estr(it.ident));
+            encode_name(ebml_w, it.ident);
             encode_def_id(ebml_w, local_def(it.id));
             ebml::end_tag(ebml_w);
           }
           item_mod(_mod) {
-            add_to_index(ebml_w, path, index, istr::from_estr(it.ident));
+            add_to_index(ebml_w, path, index, it.ident);
             ebml::start_tag(ebml_w, tag_paths_data_mod);
-            encode_name(ebml_w, istr::from_estr(it.ident));
+            encode_name(ebml_w, it.ident);
             encode_def_id(ebml_w, local_def(it.id));
             encode_module_item_paths(ebml_w, _mod,
-                                     path + [istr::from_estr(it.ident)],
+                                     path + [it.ident],
                                      index);
             ebml::end_tag(ebml_w);
           }
           item_native_mod(nmod) {
-            add_to_index(ebml_w, path, index, istr::from_estr(it.ident));
+            add_to_index(ebml_w, path, index, it.ident);
             ebml::start_tag(ebml_w, tag_paths_data_mod);
-            encode_name(ebml_w, istr::from_estr(it.ident));
+            encode_name(ebml_w, it.ident);
             encode_def_id(ebml_w, local_def(it.id));
             encode_native_module_item_paths(
                 ebml_w, nmod,
-                path + [istr::from_estr(it.ident)],
+                path + [it.ident],
                 index);
             ebml::end_tag(ebml_w);
           }
           item_ty(_, tps) {
-            add_to_index(ebml_w, path, index, istr::from_estr(it.ident));
+            add_to_index(ebml_w, path, index, it.ident);
             ebml::start_tag(ebml_w, tag_paths_data_item);
-            encode_name(ebml_w, istr::from_estr(it.ident));
+            encode_name(ebml_w, it.ident);
             encode_def_id(ebml_w, local_def(it.id));
             ebml::end_tag(ebml_w);
           }
           item_res(_, _, tps, ctor_id) {
-            add_to_index(ebml_w, path, index, istr::from_estr(it.ident));
+            add_to_index(ebml_w, path, index, it.ident);
             ebml::start_tag(ebml_w, tag_paths_data_item);
-            encode_name(ebml_w, istr::from_estr(it.ident));
+            encode_name(ebml_w, it.ident);
             encode_def_id(ebml_w, local_def(ctor_id));
             ebml::end_tag(ebml_w);
-            add_to_index(ebml_w, path, index, istr::from_estr(it.ident));
+            add_to_index(ebml_w, path, index, it.ident);
             ebml::start_tag(ebml_w, tag_paths_data_item);
-            encode_name(ebml_w, istr::from_estr(it.ident));
+            encode_name(ebml_w, it.ident);
             encode_def_id(ebml_w, local_def(it.id));
             ebml::end_tag(ebml_w);
           }
           item_tag(variants, tps) {
-            add_to_index(ebml_w, path, index, istr::from_estr(it.ident));
+            add_to_index(ebml_w, path, index, it.ident);
             ebml::start_tag(ebml_w, tag_paths_data_item);
-            encode_name(ebml_w, istr::from_estr(it.ident));
+            encode_name(ebml_w, it.ident);
             encode_def_id(ebml_w, local_def(it.id));
             ebml::end_tag(ebml_w);
             encode_tag_variant_paths(ebml_w, variants, path, index);
           }
           item_obj(_, tps, ctor_id) {
-            add_to_index(ebml_w, path, index, istr::from_estr(it.ident));
+            add_to_index(ebml_w, path, index, it.ident);
             ebml::start_tag(ebml_w, tag_paths_data_item);
-            encode_name(ebml_w, istr::from_estr(it.ident));
+            encode_name(ebml_w, it.ident);
             encode_def_id(ebml_w, local_def(ctor_id));
             ebml::end_tag(ebml_w);
-            add_to_index(ebml_w, path, index, istr::from_estr(it.ident));
+            add_to_index(ebml_w, path, index, it.ident);
             ebml::start_tag(ebml_w, tag_paths_data_item);
-            encode_name(ebml_w, istr::from_estr(it.ident));
+            encode_name(ebml_w, it.ident);
             encode_def_id(ebml_w, local_def(it.id));
             ebml::end_tag(ebml_w);
           }
@@ -453,7 +453,7 @@ fn encode_meta_item(ebml_w: &ebml::writer, mi: &meta_item) {
       meta_word(name) {
         ebml::start_tag(ebml_w, tag_meta_item_word);
         ebml::start_tag(ebml_w, tag_meta_item_name);
-        ebml_w.writer.write(str::bytes(name));
+        ebml_w.writer.write(istr::bytes(name));
         ebml::end_tag(ebml_w);
         ebml::end_tag(ebml_w);
       }
@@ -462,7 +462,7 @@ fn encode_meta_item(ebml_w: &ebml::writer, mi: &meta_item) {
           lit_str(value, _) {
             ebml::start_tag(ebml_w, tag_meta_item_name_value);
             ebml::start_tag(ebml_w, tag_meta_item_name);
-            ebml_w.writer.write(str::bytes(name));
+            ebml_w.writer.write(istr::bytes(name));
             ebml::end_tag(ebml_w);
             ebml::start_tag(ebml_w, tag_meta_item_value);
             ebml_w.writer.write(str::bytes(value));
@@ -475,7 +475,7 @@ fn encode_meta_item(ebml_w: &ebml::writer, mi: &meta_item) {
       meta_list(name, items) {
         ebml::start_tag(ebml_w, tag_meta_item_list);
         ebml::start_tag(ebml_w, tag_meta_item_name);
-        ebml_w.writer.write(str::bytes(name));
+        ebml_w.writer.write(istr::bytes(name));
         ebml::end_tag(ebml_w);
         for inner_item: @meta_item in items {
             encode_meta_item(ebml_w, *inner_item);
@@ -508,18 +508,18 @@ fn synthesize_crate_attrs(ecx: &@encode_ctxt, crate: &@crate) -> [attribute] {
         assert (ecx.ccx.link_meta.vers != "");
 
         let name_item =
-            attr::mk_name_value_item_str("name", ecx.ccx.link_meta.name);
+            attr::mk_name_value_item_str(~"name", ecx.ccx.link_meta.name);
         let vers_item =
-            attr::mk_name_value_item_str("vers", ecx.ccx.link_meta.vers);
+            attr::mk_name_value_item_str(~"vers", ecx.ccx.link_meta.vers);
 
         let other_items =
             {
-                let tmp = attr::remove_meta_items_by_name(items, "name");
-                attr::remove_meta_items_by_name(tmp, "vers")
+                let tmp = attr::remove_meta_items_by_name(items, ~"name");
+                attr::remove_meta_items_by_name(tmp, ~"vers")
             };
 
         let meta_items = [name_item, vers_item] + other_items;
-        let link_item = attr::mk_list_item("link", meta_items);
+        let link_item = attr::mk_list_item(~"link", meta_items);
 
         ret attr::mk_attr(link_item);
     }
@@ -528,7 +528,7 @@ fn synthesize_crate_attrs(ecx: &@encode_ctxt, crate: &@crate) -> [attribute] {
     let found_link_attr = false;
     for attr: attribute in crate.node.attrs {
         attrs +=
-            if attr::get_attr_name(attr) != "link" {
+            if attr::get_attr_name(attr) != ~"link" {
                 [attr]
             } else {
                 alt attr.node.value.node {
diff --git a/src/comp/metadata/tydecode.rs b/src/comp/metadata/tydecode.rs
index f632e5ed28b..1ab9ed93126 100644
--- a/src/comp/metadata/tydecode.rs
+++ b/src/comp/metadata/tydecode.rs
@@ -2,6 +2,7 @@
 
 import std::vec;
 import std::str;
+import std::istr;
 import std::uint;
 import std::option;
 import std::option::none;
@@ -42,9 +43,9 @@ fn parse_ident(st: @pstate, sd: str_def, last: char) -> ast::ident {
 
 fn parse_ident_(st: @pstate, _sd: str_def, is_last: fn(char) -> bool) ->
    ast::ident {
-    let rslt = "";
+    let rslt = ~"";
     while !is_last(peek(st) as char) {
-        rslt += str::unsafe_from_byte(next(st));
+        rslt += istr::unsafe_from_byte(next(st));
     }
     ret rslt;
 }
@@ -225,9 +226,9 @@ fn parse_ty(st: @pstate, sd: str_def) -> ty::t {
         assert (next(st) as char == '[');
         let fields: [ty::field] = [];
         while peek(st) as char != ']' {
-            let name = "";
+            let name = ~"";
             while peek(st) as char != '=' {
-                name += str::unsafe_from_byte(next(st));
+                name += istr::unsafe_from_byte(next(st));
             }
             st.pos = st.pos + 1u;
             fields += [{ident: name, mt: parse_mt(st, sd)}];
@@ -278,9 +279,9 @@ fn parse_ty(st: @pstate, sd: str_def) -> ty::t {
               'W' { proto = ast::proto_iter; }
               'F' { proto = ast::proto_fn; }
             }
-            let name = "";
+            let name = ~"";
             while peek(st) as char != '[' {
-                name += str::unsafe_from_byte(next(st));
+                name += istr::unsafe_from_byte(next(st));
             }
             let func = parse_ty_fn(st, sd);
             methods +=
diff --git a/src/comp/metadata/tyencode.rs b/src/comp/metadata/tyencode.rs
index bdb5db6758d..df2c83593d1 100644
--- a/src/comp/metadata/tyencode.rs
+++ b/src/comp/metadata/tyencode.rs
@@ -134,7 +134,7 @@ fn enc_sty(w: &io::writer, cx: &@ctxt, st: &ty::sty) {
       ty::ty_rec(fields) {
         w.write_str(~"R[");
         for field: ty::field in fields {
-            w.write_str(istr::from_estr(field.ident));
+            w.write_str(field.ident);
             w.write_char('=');
             enc_mt(w, cx, field.mt);
         }
@@ -159,7 +159,7 @@ fn enc_sty(w: &io::writer, cx: &@ctxt, st: &ty::sty) {
         w.write_str(~"O[");
         for m: ty::method in methods {
             enc_proto(w, m.proto);
-            w.write_str(istr::from_estr(m.ident));
+            w.write_str(m.ident);
             enc_ty_fn(w, cx, m.inputs, m.output, m.cf, m.constrs);
         }
         w.write_char(']');
diff --git a/src/comp/middle/alias.rs b/src/comp/middle/alias.rs
index 03fcb283621..177f5f752a9 100644
--- a/src/comp/middle/alias.rs
+++ b/src/comp/middle/alias.rs
@@ -10,6 +10,7 @@ import syntax::visit;
 import visit::vt;
 import std::vec;
 import std::str;
+import std::istr;
 import std::option;
 import std::option::some;
 import std::option::none;
@@ -593,7 +594,7 @@ fn expr_root(cx: &ctx, ex: @ast::expr, autoderef: bool) ->
             alt ty::struct(cx.tcx, auto_unbox.t) {
               ty::ty_rec(fields) {
                 for fld: ty::field in fields {
-                    if str::eq(ident, fld.ident) {
+                    if istr::eq(ident, fld.ident) {
                         mut = fld.mt.mut != ast::imm;
                         break;
                     }
diff --git a/src/comp/middle/ast_map.rs b/src/comp/middle/ast_map.rs
index 356d2b46b8c..a0b1a96e3d6 100644
--- a/src/comp/middle/ast_map.rs
+++ b/src/comp/middle/ast_map.rs
@@ -131,7 +131,7 @@ mod test {
     fn test_node_span_item() {
         let expected: codemap::span = ast_util::mk_sp(20u, 30u);
         let node =
-            node_item(@{ident: "test",
+            node_item(@{ident: ~"test",
                         attrs: [],
                         id: 0,
                         node: item_mod({view_items: [], items: []}),
@@ -143,7 +143,7 @@ mod test {
     fn test_node_span_obj_ctor() {
         let expected: codemap::span = ast_util::mk_sp(20u, 30u);
         let node =
-            node_obj_ctor(@{ident: "test",
+            node_obj_ctor(@{ident: ~"test",
                             attrs: [],
                             id: 0,
                             node: item_mod({view_items: [], items: []}),
@@ -155,7 +155,7 @@ mod test {
     fn test_node_span_native_item() {
         let expected: codemap::span = ast_util::mk_sp(20u, 30u);
         let node =
-            node_native_item(@{ident: "test",
+            node_native_item(@{ident: ~"test",
                                attrs: [],
                                node: native_item_ty,
                                id: 0,
diff --git a/src/comp/middle/resolve.rs b/src/comp/middle/resolve.rs
index 9c0c5281ccc..f65449e7099 100644
--- a/src/comp/middle/resolve.rs
+++ b/src/comp/middle/resolve.rs
@@ -432,7 +432,7 @@ fn follow_import(e: &env, sc: &scopes, path: &[ident], sp: &span) ->
           ast::def_mod(_) | ast::def_native_mod(_) { ret dcur; }
           _ {
             e.sess.span_err(sp,
-                            str::connect(path, "::") +
+                            istr::to_estr(istr::connect(path, ~"::")) +
                                 " does not name a module.");
             ret none;
           }
@@ -465,7 +465,7 @@ fn resolve_import(e: &env, defid: ast::def_id, name: &ast::ident,
     let end_id = ids[n_idents - 1u];
     // Ignore the current scope if this import would shadow itself.
     let sc =
-        if str::eq(name, ids[0]) { std::list::cdr(sc_in) } else { sc_in };
+        if istr::eq(name, ids[0]) { std::list::cdr(sc_in) } else { sc_in };
     if n_idents == 1u {
         register(e, defid, sp, end_id, sc_in,
                  lookup_in_scope(e, sc, sp, end_id, ns_value),
@@ -559,9 +559,10 @@ fn unresolved_err(e: &env, sc: &scopes, sp: &span, name: &ident, kind: &str) {
     }
     let err_scope = find_fn_or_mod_scope(sc);
     for rs: {ident: str, sc: scope} in e.reported {
-        if str::eq(rs.ident, name) && err_scope == rs.sc { ret; }
+        if str::eq(rs.ident, istr::to_estr(name))
+            && err_scope == rs.sc { ret; }
     }
-    e.reported += [{ident: name, sc: err_scope}];
+    e.reported += [{ident: istr::to_estr(name), sc: err_scope}];
     e.sess.span_err(sp, mk_unresolved_msg(name, kind));
 }
 
@@ -570,7 +571,7 @@ fn unresolved_fatal(e: &env, sp: &span, id: &ident, kind: &str) -> ! {
 }
 
 fn mk_unresolved_msg(id: &ident, kind: &str) -> str {
-    ret #fmt["unresolved %s: %s", kind, id];
+    ret #fmt["unresolved %s: %s", kind, istr::to_estr(id)];
 }
 
 // Lookup helpers
@@ -734,7 +735,7 @@ fn lookup_in_ty_params(name: &ident, ty_params: &[ast::ty_param]) ->
    option::t<def> {
     let i = 0u;
     for tp: ast::ty_param in ty_params {
-        if str::eq(tp.ident, name) { ret some(ast::def_ty_arg(i, tp.kind)); }
+        if istr::eq(tp.ident, name) { ret some(ast::def_ty_arg(i, tp.kind)); }
         i += 1u;
     }
     ret none::<def>;
@@ -744,7 +745,7 @@ fn lookup_in_pat(name: &ident, pat: &@ast::pat) -> option::t<def_id> {
     let found = none;
     for each bound in ast_util::pat_bindings(pat) {
         let p_name = alt bound.node { ast::pat_bind(n) { n } };
-        if str::eq(p_name, name) { found = some(local_def(bound.id)); }
+        if istr::eq(p_name, name) { found = some(local_def(bound.id)); }
     }
     ret found;
 }
@@ -755,7 +756,7 @@ fn lookup_in_fn(name: &ident, decl: &ast::fn_decl,
     alt ns {
       ns_value. {
         for a: ast::arg in decl.inputs {
-            if str::eq(a.ident, name) {
+            if istr::eq(a.ident, name) {
                 ret some(ast::def_arg(local_def(a.id)));
             }
         }
@@ -771,7 +772,7 @@ fn lookup_in_obj(name: &ident, ob: &ast::_obj, ty_params: &[ast::ty_param],
     alt ns {
       ns_value. {
         for f: ast::obj_field in ob.fields {
-            if str::eq(f.ident, name) {
+            if istr::eq(f.ident, name) {
                 ret some(ast::def_obj_field(local_def(f.id)));
             }
         }
@@ -810,12 +811,12 @@ fn lookup_in_block(name: &ident, b: &ast::blk_, pos: uint, loc_pos: uint,
                 alt it.node {
                   ast::item_tag(variants, _) {
                     if ns == ns_type {
-                        if str::eq(it.ident, name) {
+                        if istr::eq(it.ident, name) {
                             ret some(ast::def_ty(local_def(it.id)));
                         }
                     } else if ns == ns_value {
                         for v: ast::variant in variants {
-                            if str::eq(v.node.name, name) {
+                            if istr::eq(v.node.name, name) {
                                 let i = v.node.id;
                                 ret some(ast::def_variant(local_def(it.id),
                                                           local_def(i)));
@@ -824,7 +825,7 @@ fn lookup_in_block(name: &ident, b: &ast::blk_, pos: uint, loc_pos: uint,
                     }
                   }
                   _ {
-                    if str::eq(it.ident, name) {
+                    if istr::eq(it.ident, name) {
                         let found = found_def_item(it, ns);
                         if !is_none(found) { ret found; }
                     }
@@ -898,13 +899,15 @@ fn lookup_in_mod(e: &env, m: &def, sp: &span, name: &ident, ns: namespace,
     if defid.crate != ast::local_crate {
         // examining a module in an external crate
 
-        let cached = e.ext_cache.find({did: defid, ident: name, ns: ns});
+        let cached = e.ext_cache.find({did: defid,
+                                       ident: istr::to_estr(name), ns: ns});
         if !is_none(cached) { ret cached; }
         let path = [name];
         if defid.node != -1 { path = e.ext_map.get(defid) + path; }
         let fnd = lookup_external(e, defid.crate, path, ns);
         if !is_none(fnd) {
-            e.ext_cache.insert({did: defid, ident: name, ns: ns},
+            e.ext_cache.insert({did: defid,
+                                ident: istr::to_estr(name), ns: ns},
                                option::get(fnd));
         }
         ret fnd;
@@ -955,7 +958,7 @@ fn lookup_in_local_mod(e: &env, node_id: node_id, sp: &span, id: &ident,
         ret none::<def>; // name is not visible
 
     }
-    alt info.index.find(istr::from_estr(id)) {
+    alt info.index.find(id) {
       none. { }
       some(lst_) {
         let lst = lst_;
@@ -1000,25 +1003,27 @@ fn lookup_glob_in_mod(e: &env, info: @indexed_mod, sp: &span, id: &ident,
         } else {
             for match: glob_imp_def in matches {
                 let sp = match.item.span;
-                e.sess.span_note(sp, #fmt["'%s' is imported here", id]);
+                e.sess.span_note(sp, #fmt["'%s' is imported here",
+                                          istr::to_estr(id)]);
             }
             e.sess.span_fatal(sp,
-                              "'" + id + "' is glob-imported from" +
+                              "'" + istr::to_estr(id)
+                              + "' is glob-imported from" +
                                   " multiple different modules.");
         }
     }
     // since we don't know what names we have in advance,
     // absence takes the place of todo()
 
-    if !info.glob_imported_names.contains_key(istr::from_estr(id)) {
-        info.glob_imported_names.insert(istr::from_estr(id), resolving(sp));
+    if !info.glob_imported_names.contains_key(id) {
+        info.glob_imported_names.insert(id, resolving(sp));
         let val = per_ns(e, info, sp, id, ns_value, dr);
         let typ = per_ns(e, info, sp, id, ns_type, dr);
         let md = per_ns(e, info, sp, id, ns_module, dr);
-        info.glob_imported_names.insert(istr::from_estr(id),
+        info.glob_imported_names.insert(id,
                                         resolved(val, typ, md));
     }
-    alt info.glob_imported_names.get(istr::from_estr(id)) {
+    alt info.glob_imported_names.get(id) {
       todo(_, _, _, _, _) { e.sess.bug("Shouldn't've put a todo in."); }
       resolving(sp) {
         ret none::<def>; //circularity is okay in import globs
@@ -1075,7 +1080,6 @@ fn lookup_in_mie(e: &env, mie: &mod_index_entry, ns: namespace) ->
 // Module indexing
 fn add_to_index(index: &hashmap<identistr, list<mod_index_entry>>,
                 id: &ident, ent: &mod_index_entry) {
-    let id = istr::from_estr(id);
     alt index.find(id) {
       none. { index.insert(id,
                            cons(ent, @nil::<mod_index_entry>)); }
@@ -1193,7 +1197,7 @@ fn check_for_collisions(e: &@env, c: &ast::crate) {
     for each m: @{key: ast::node_id, val: @indexed_mod} in e.mod_map.items() {
         for each name: @{key: identistr, val: list<mod_index_entry>} in
                  m.val.index.items() {
-            check_mod_name(*e, istr::to_estr(name.key), name.val);
+            check_mod_name(*e, name.key, name.val);
         }
     }
     // Other scopes have to be checked the hard way.
@@ -1211,7 +1215,8 @@ fn check_mod_name(e: &env, name: &ident, entries: list<mod_index_entry>) {
     let saw_type = false;
     let saw_value = false;
     fn dup(e: &env, sp: &span, word: &str, name: &ident) {
-        e.sess.span_fatal(sp, "duplicate definition of " + word + name);
+        e.sess.span_fatal(sp, "duplicate definition of " + word
+                          + istr::to_estr(name));
     }
     while true {
         alt entries {
@@ -1303,11 +1308,11 @@ fn check_arm(e: &@env, a: &ast::arm, x: &(), v: &vt<()>) {
                             "inconsistent number of bindings");
         } else {
             for name: ident in ch.seen {
-                if is_none(vec::find(bind str::eq(name, _), seen0)) {
+                if is_none(vec::find(bind istr::eq(name, _), seen0)) {
                     // Fight the alias checker
                     let name_ = name;
                     e.sess.span_err(a.pats[i].span,
-                                    "binding " + name_ +
+                                    "binding " + istr::to_estr(name_) +
                                         " does not occur in first pattern");
                 }
             }
@@ -1399,8 +1404,9 @@ fn checker(e: &env, kind: str) -> checker {
 
 fn check_name(ch: &checker, sp: &span, name: &ident) {
     for s: ident in ch.seen {
-        if str::eq(s, name) {
-            ch.sess.span_fatal(sp, "duplicate " + ch.kind + " name: " + name);
+        if istr::eq(s, name) {
+            ch.sess.span_fatal(sp, "duplicate " + ch.kind
+                               + " name: " + istr::to_estr(name));
         }
     }
 }
diff --git a/src/comp/middle/trans.rs b/src/comp/middle/trans.rs
index 0fd6762a4d1..c2391563b78 100644
--- a/src/comp/middle/trans.rs
+++ b/src/comp/middle/trans.rs
@@ -4240,7 +4240,7 @@ fn trans_rec(cx: &@block_ctxt, fields: &[ast::field],
         bcx = dst_res.bcx;
         let expr_provided = false;
         for f: ast::field in fields {
-            if str::eq(f.node.ident, tf.ident) {
+            if istr::eq(f.node.ident, tf.ident) {
                 expr_provided = true;
                 let lv = trans_lval(bcx, f.node.expr);
                 bcx = move_val_if_temp(lv.res.bcx, INIT, dst_res.val,
@@ -5060,6 +5060,7 @@ fn alloc_local(cx: &@block_ctxt, local: &@ast::local) -> result {
     alt local.node.pat.node {
       ast::pat_bind(ident) {
         if bcx_ccx(cx).sess.get_opts().debuginfo {
+            let ident = istr::to_estr(ident);
             llvm::LLVMSetValueName(r.val, str::buf(ident));
         }
       }
@@ -5523,7 +5524,7 @@ fn trans_tag_variant(cx: @local_ctxt, tag_id: ast::node_id,
         fn_args +=
             [{mode: ast::alias(false),
               ty: varg.ty,
-              ident: istr::to_estr(~"arg" + uint::to_str(i, 10u)),
+              ident: ~"arg" + uint::to_str(i, 10u),
               id: varg.id}];
     }
     assert (cx.ccx.item_ids.contains_key(variant.node.id));
@@ -5625,7 +5626,7 @@ fn trans_const(cx: &@crate_ctxt, e: @ast::expr, id: ast::node_id) {
 fn trans_item(cx: @local_ctxt, item: &ast::item) {
     alt item.node {
       ast::item_fn(f, tps) {
-        let sub_cx = extend_path(cx, item.ident);
+        let sub_cx = extend_path(cx, istr::to_estr(item.ident));
         alt cx.ccx.item_ids.find(item.id) {
           some(llfndecl) {
             trans_fn(sub_cx, item.span, f, llfndecl, none, tps, item.id);
@@ -5639,7 +5640,7 @@ fn trans_item(cx: @local_ctxt, item: &ast::item) {
       ast::item_obj(ob, tps, ctor_id) {
         let sub_cx =
             @{obj_typarams: tps, obj_fields: ob.fields
-                 with *extend_path(cx, item.ident)};
+                 with *extend_path(cx, istr::to_estr(item.ident))};
         trans_obj(sub_cx, item.span, ob, ctor_id, tps);
       }
       ast::item_res(dtor, dtor_id, tps, ctor_id) {
@@ -5657,12 +5658,13 @@ fn trans_item(cx: @local_ctxt, item: &ast::item) {
       }
       ast::item_mod(m) {
         let sub_cx =
-            @{path: cx.path + [item.ident],
-              module_path: cx.module_path + [item.ident] with *cx};
+            @{path: cx.path + [istr::to_estr(item.ident)],
+              module_path: cx.module_path
+                  + [istr::to_estr(item.ident)] with *cx};
         trans_mod(sub_cx, m);
       }
       ast::item_tag(variants, tps) {
-        let sub_cx = extend_path(cx, item.ident);
+        let sub_cx = extend_path(cx, istr::to_estr(item.ident));
         let degen = std::vec::len(variants) == 1u;
         let i = 0;
         for variant: ast::variant in variants {
@@ -5717,6 +5719,7 @@ fn decl_fn_and_pair_full(ccx: &@crate_ctxt, sp: &span, path: &[str],
     let ps: str = mangle_exported_name(ccx, path, node_type);
     register_fn_pair(ccx, ps, llfty, llfn, node_id);
 
+    let path = istr::from_estrs(path);
     let is_main: bool = is_main_name(path) && !ccx.sess.get_opts().library;
     if is_main { create_main_wrapper(ccx, sp, llfn, node_type); }
 }
@@ -6029,14 +6032,15 @@ fn decl_native_fn_and_pair(ccx: &@crate_ctxt, sp: &span, path: &[str],
     finish_fn(fcx, lltop);
 }
 
-fn item_path(item: &@ast::item) -> [str] { ret [item.ident]; }
+fn item_path(item: &@ast::item) -> [str] { ret [istr::to_estr(item.ident)]; }
 
 fn collect_native_item(ccx: @crate_ctxt, i: &@ast::native_item, pt: &[str],
                        _v: &vt<[str]>) {
     alt i.node {
       ast::native_item_fn(_, _, _) {
         if !ccx.obj_methods.contains_key(i.id) {
-            decl_native_fn_and_pair(ccx, i.span, pt, i.ident, i.id);
+            decl_native_fn_and_pair(ccx, i.span, pt,
+                                    istr::to_estr(i.ident), i.id);
         }
       }
       _ { }
@@ -6050,7 +6054,7 @@ fn collect_item_1(ccx: @crate_ctxt, i: &@ast::item, pt: &[str],
       ast::item_const(_, _) {
         let typ = node_id_type(ccx, i.id);
         let s =
-            mangle_exported_name(ccx, pt + [i.ident],
+            mangle_exported_name(ccx, pt + [istr::to_estr(i.ident)],
                                  node_id_type(ccx, i.id));
         let g =
             llvm::LLVMAddGlobal(ccx.llmod, type_of(ccx, i.span, typ),
@@ -6110,7 +6114,8 @@ fn collect_tag_ctor(ccx: @crate_ctxt, i: &@ast::item, pt: &[str],
       ast::item_tag(variants, tps) {
         for variant: ast::variant in variants {
             if std::vec::len(variant.node.args) != 0u {
-                decl_fn_and_pair(ccx, i.span, new_pt + [variant.node.name],
+                decl_fn_and_pair(ccx, i.span,
+                                 new_pt + [istr::to_estr(variant.node.name)],
                                  "tag", tps, variant.node.id);
             }
         }
@@ -6138,7 +6143,8 @@ fn trans_constant(ccx: @crate_ctxt, it: &@ast::item, pt: &[str],
         let n_variants = std::vec::len::<ast::variant>(variants);
         while i < n_variants {
             let variant = variants[i];
-            let p = new_pt + [it.ident, variant.node.name, "discrim"];
+            let p = new_pt + istr::to_estrs([it.ident,
+                                             variant.node.name, ~"discrim"]);
             let s = mangle_exported_name(ccx, p, ty::mk_int(ccx.tcx));
             let discrim_gvar =
                 llvm::LLVMAddGlobal(ccx.llmod, T_int(), str::buf(s));
diff --git a/src/comp/middle/trans_alt.rs b/src/comp/middle/trans_alt.rs
index 57539c2a3c5..fdd2446cb1b 100644
--- a/src/comp/middle/trans_alt.rs
+++ b/src/comp/middle/trans_alt.rs
@@ -60,7 +60,7 @@ fn variant_opt(ccx: &@crate_ctxt, pat_id: ast::node_id) -> opt {
 type bind_map = [{ident: ast::ident, val: ValueRef}];
 fn assoc(key: str, list: &bind_map) -> option::t<ValueRef> {
     for elt: {ident: ast::ident, val: ValueRef} in list {
-        if str::eq(elt.ident, key) { ret some(elt.val); }
+        if istr::eq(elt.ident, istr::from_estr(key)) { ret some(elt.val); }
     }
     ret none;
 }
@@ -146,7 +146,7 @@ fn enter_rec(m: &match, col: uint, fields: &[ast::ident], val: ValueRef) ->
             for fname: ast::ident in fields {
                 let pat = dummy;
                 for fpat: ast::field_pat in fpats {
-                    if str::eq(fpat.ident, fname) { pat = fpat.pat; break; }
+                    if istr::eq(fpat.ident, fname) { pat = fpat.pat; break; }
                 }
                 pats += [pat];
             }
@@ -234,7 +234,7 @@ fn collect_record_fields(m: &match, col: uint) -> [ast::ident] {
         alt br.pats[col].node {
           ast::pat_rec(fs, _) {
             for f: ast::field_pat in fs {
-                if !vec::any(bind str::eq(f.ident, _), fields) {
+                if !vec::any(bind istr::eq(f.ident, _), fields) {
                     fields += [f.ident];
                 }
             }
diff --git a/src/comp/middle/trans_objects.rs b/src/comp/middle/trans_objects.rs
index 17a600e971d..c55d32593d8 100644
--- a/src/comp/middle/trans_objects.rs
+++ b/src/comp/middle/trans_objects.rs
@@ -1,6 +1,7 @@
 // Translation of object-related things to LLVM IR.
 
 import std::str;
+import std::istr;
 import std::option;
 import std::vec;
 import option::none;
@@ -396,7 +397,7 @@ tag vtbl_mthd {
 
 // Alphabetize ast::methods by ident.  A helper for create_vtbl.
 fn ast_mthd_lteq(a: &@ast::method, b: &@ast::method) -> bool {
-    ret str::lteq(a.node.ident, b.node.ident);
+    ret istr::lteq(a.node.ident, b.node.ident);
 }
 
 // Alphabetize vtbl_mthds by ident.  A helper for create_vtbl.
@@ -404,14 +405,14 @@ fn vtbl_mthd_lteq(a: &vtbl_mthd, b: &vtbl_mthd) -> bool {
     alt a {
       normal_mthd(ma) {
         alt b {
-          normal_mthd(mb) { ret str::lteq(ma.node.ident, mb.node.ident); }
-          fwding_mthd(mb) { ret str::lteq(ma.node.ident, mb.ident); }
+          normal_mthd(mb) { ret istr::lteq(ma.node.ident, mb.node.ident); }
+          fwding_mthd(mb) { ret istr::lteq(ma.node.ident, mb.ident); }
         }
       }
       fwding_mthd(ma) {
         alt b {
-          normal_mthd(mb) { ret str::lteq(ma.ident, mb.node.ident); }
-          fwding_mthd(mb) { ret str::lteq(ma.ident, mb.ident); }
+          normal_mthd(mb) { ret istr::lteq(ma.ident, mb.node.ident); }
+          fwding_mthd(mb) { ret istr::lteq(ma.ident, mb.ident); }
         }
       }
     }
@@ -430,7 +431,7 @@ fn filtering_fn(cx: @local_ctxt, m: &vtbl_mthd, addtl_meths: [@ast::method])
     alt m {
       fwding_mthd(fm) {
         for am: @ast::method in addtl_meths {
-            if str::eq(am.node.ident, fm.ident) { ret none; }
+            if istr::eq(am.node.ident, fm.ident) { ret none; }
         }
         ret some(fwding_mthd(fm));
       }
@@ -598,7 +599,8 @@ fn process_bkwding_mthd(cx: @local_ctxt, sp: &span, m: @ty::method,
 
     // Create a local context that's aware of the name of the method we're
     // creating.
-    let mcx: @local_ctxt = @{path: cx.path + ["method", m.ident] with *cx};
+    let mcx: @local_ctxt = @{path: cx.path
+        + ["method", istr::to_estr(m.ident)] with *cx};
 
     // Make up a name for the backwarding function.
     let fn_name: str = "backwarding_fn";
@@ -726,7 +728,8 @@ fn process_fwding_mthd(cx: @local_ctxt, sp: &span, m: @ty::method,
 
     // Create a local context that's aware of the name of the method we're
     // creating.
-    let mcx: @local_ctxt = @{path: cx.path + ["method", m.ident] with *cx};
+    let mcx: @local_ctxt = @{path: cx.path
+        + ["method", istr::to_estr(m.ident)] with *cx};
 
     // Make up a name for the forwarding function.
     let fn_name: str = "forwarding_fn";
@@ -917,7 +920,7 @@ fn process_normal_mthd(cx: @local_ctxt, m: @ast::method, self_ty: ty::t,
       }
     }
     let mcx: @local_ctxt =
-        @{path: cx.path + ["method", m.node.ident] with *cx};
+        @{path: cx.path + ["method", istr::to_estr(m.node.ident)] with *cx};
     let s: str = mangle_internal_name_by_path(mcx.ccx, mcx.path);
     let llfn: ValueRef = decl_internal_fastcall_fn(cx.ccx.llmod, s, llfnty);
 
diff --git a/src/comp/middle/tstate/auxiliary.rs b/src/comp/middle/tstate/auxiliary.rs
index 49942eaef6b..640619301c1 100644
--- a/src/comp/middle/tstate/auxiliary.rs
+++ b/src/comp/middle/tstate/auxiliary.rs
@@ -67,7 +67,7 @@ fn comma_str(args: &[@constr_arg_use]) -> str {
         if comma { rslt += ", "; } else { comma = true; }
         alt a.node {
           carg_base. { rslt += "*"; }
-          carg_ident(i) { rslt += i.ident; }
+          carg_ident(i) { rslt += istr::to_estr(i.ident); }
           carg_lit(l) { rslt += lit_to_str(l); }
         }
     }
@@ -77,7 +77,8 @@ fn comma_str(args: &[@constr_arg_use]) -> str {
 fn constraint_to_str(tcx: &ty::ctxt, c: &sp_constr) -> str {
     alt c.node {
       ninit(_, i) {
-        ret "init(" + i + " [" + tcx.sess.span_str(c.span) + "])";
+        ret "init(" +
+            istr::to_estr(i) + " [" + tcx.sess.span_str(c.span) + "])";
       }
       npred(p, _, args) {
         ret path_to_str(p) + "(" + comma_str(args) + ")" + "[" +
@@ -169,11 +170,11 @@ fn log_states_err(pp: &pre_and_post_state) {
     log_cond_err(p2);
 }
 
-fn print_ident(i: &ident) { log " " + i + " "; }
+fn print_ident(i: &ident) { log ~" " + i + ~" "; }
 
 fn print_idents(idents: &mutable [ident]) {
     if vec::len::<ident>(idents) == 0u { ret; }
-    log "an ident: " + vec::pop::<ident>(idents);
+    log ~"an ident: " + vec::pop::<ident>(idents);
     print_idents(idents);
 }
 
@@ -592,7 +593,9 @@ fn constraints(fcx: &fn_ctxt) -> [norm_constraint] {
 fn match_args(fcx: &fn_ctxt, occs: &@mutable [pred_args],
               occ: &[@constr_arg_use]) -> uint {
     log "match_args: looking at " +
-            constr_args_to_str(fn (i: &inst) -> str { ret i.ident; }, occ);
+            constr_args_to_str(fn (i: &inst) -> str {
+                ret istr::to_estr(i.ident);
+            }, occ);
     for pd: pred_args in *occs {
         log "match_args: candidate " + pred_args_to_str(pd);
         fn eq(p: &inst, q: &inst) -> bool { ret p.node == q.node; }
@@ -684,7 +687,9 @@ fn expr_to_constr(tcx: ty::ctxt, e: &@expr) -> sp_constr {
 
 fn pred_args_to_str(p: &pred_args) -> str {
     "<" + istr::to_estr(uint::str(p.node.bit_num)) + ", " +
-        constr_args_to_str(fn (i: &inst) -> str { ret i.ident; }, p.node.args)
+        constr_args_to_str(fn (i: &inst) -> str {
+            ret istr::to_estr(i.ident);
+        }, p.node.args)
         + ">"
 }
 
@@ -790,7 +795,7 @@ fn insts_to_str(stuff: &[constr_arg_general_<inst>]) -> str {
         rslt +=
             " " +
                 alt i {
-                  carg_ident(p) { p.ident }
+                  carg_ident(p) { istr::to_estr(p.ident) }
                   carg_base. { "*" }
                   carg_lit(_) { "[lit]" }
                 } + " ";
diff --git a/src/comp/middle/tstate/ck.rs b/src/comp/middle/tstate/ck.rs
index 070417e6401..8d42e761571 100644
--- a/src/comp/middle/tstate/ck.rs
+++ b/src/comp/middle/tstate/ck.rs
@@ -37,6 +37,7 @@ import std::option;
 import std::option::t;
 import std::option::some;
 import std::option::none;
+import std::istr;
 import aux::*;
 import syntax::print::pprust::ty_to_str;
 import util::common::log_stmt_err;
@@ -54,7 +55,9 @@ fn check_unused_vars(fcx: &fn_ctxt) {
           ninit(id, v) {
             if !vec_contains(fcx.enclosing.used_vars, id) && v[0] != '_' as u8
                {
-                fcx.ccx.tcx.sess.span_warn(c.c.span, "unused variable " + v);
+                fcx.ccx.tcx.sess.span_warn(c.c.span,
+                                           "unused variable "
+                                           + istr::to_estr(v));
             }
           }
           _ {/* ignore pred constraints */ }
@@ -147,7 +150,8 @@ fn check_states_against_conditions(fcx: &fn_ctxt, f: &_fn,
            !type_is_nil(fcx.ccx.tcx, ret_ty_of_fn(fcx.ccx.tcx, id)) &&
            f.decl.cf == return {
         fcx.ccx.tcx.sess.span_err(f.body.span,
-                                  "In function " + fcx.name +
+                                  "In function " +
+                                  istr::to_estr(fcx.name) +
                                       ", not all control paths \
                                         return a value");
         fcx.ccx.tcx.sess.span_fatal(f.decl.output.span,
@@ -162,7 +166,7 @@ fn check_states_against_conditions(fcx: &fn_ctxt, f: &_fn,
         if !promises(fcx, post, fcx.enclosing.i_diverge) {
             fcx.ccx.tcx.sess.span_fatal(f.body.span,
                                         "In non-returning function " +
-                                            fcx.name +
+                                            istr::to_estr(fcx.name) +
                                             ", some control paths may \
                                            return to the caller");
         }
@@ -192,8 +196,11 @@ fn fn_states(f: &_fn, tps: &[ast::ty_param], sp: &span, i: &fn_ident,
 
     assert (ccx.fm.contains_key(id));
     let f_info = ccx.fm.get(id);
-    let name = option::from_maybe("anon", i);
-    let fcx = {enclosing: f_info, id: id, name: name, ccx: ccx};
+    let name = option::from_maybe(~"anon", i);
+    let fcx = {enclosing: f_info,
+               id: id,
+               name: name,
+               ccx: ccx};
     check_fn_states(fcx, f, tps, id, sp, i);
 }
 
diff --git a/src/comp/middle/tstate/collect_locals.rs b/src/comp/middle/tstate/collect_locals.rs
index f4729c3182e..ef7b38d452c 100644
--- a/src/comp/middle/tstate/collect_locals.rs
+++ b/src/comp/middle/tstate/collect_locals.rs
@@ -18,7 +18,7 @@ type ctxt = {cs: @mutable [sp_constr], tcx: ty::ctxt};
 fn collect_local(loc: &@local, cx: &ctxt, v: &visit::vt<ctxt>) {
     for each p: @pat in pat_bindings(loc.node.pat) {
         let ident = alt p.node { pat_bind(id) { id } };
-        log "collect_local: pushing " + ident;;
+        log ~"collect_local: pushing " + ident;;
         *cx.cs += [respan(loc.span, ninit(p.id, ident))];
     }
     visit::visit_local(loc, cx, v);
@@ -94,7 +94,7 @@ fn add_constraint(tcx: &ty::ctxt, c: sp_constr, next: uint, tbl: constr_map)
    to a bit number in the precondition/postcondition vectors */
 fn mk_fn_info(ccx: &crate_ctxt, f: &_fn, tp: &[ty_param], f_sp: &span,
               f_name: &fn_ident, id: node_id) {
-    let name = fn_ident_to_string(id, f_name);
+    let name = istr::from_estr(fn_ident_to_string(id, f_name));
     let res_map = @new_def_hash::<constraint>();
     let next: uint = 0u;
 
@@ -130,7 +130,7 @@ fn mk_fn_info(ccx: &crate_ctxt, f: &_fn, tp: &[ty_param], f_sp: &span,
     // and the name of the function, with a '!' appended to it, for the
     // "diverges" constraint
     let diverges_id = ccx.tcx.sess.next_node_id();
-    let diverges_name = name + "!";
+    let diverges_name = name + ~"!";
     add_constraint(cx.tcx, respan(f_sp, ninit(diverges_id, diverges_name)),
                    next, res_map);
 
@@ -147,9 +147,9 @@ fn mk_fn_info(ccx: &crate_ctxt, f: &_fn, tp: &[ty_param], f_sp: &span,
          i_diverge: ninit(diverges_id, diverges_name),
          used_vars: v};
     ccx.fm.insert(id, rslt);
-    log name + istr::to_estr(~" has "
-                             + std::uint::str(num_constraints(rslt))
-                             + ~" constraints");
+    log istr::to_estr(name + ~" has "
+                      + std::uint::str(num_constraints(rslt))
+                      + ~" constraints");
 }
 
 
diff --git a/src/comp/middle/tstate/pre_post_conditions.rs b/src/comp/middle/tstate/pre_post_conditions.rs
index c1d81d4d277..d9d88b04533 100644
--- a/src/comp/middle/tstate/pre_post_conditions.rs
+++ b/src/comp/middle/tstate/pre_post_conditions.rs
@@ -1,5 +1,6 @@
 
 import std::vec;
+import std::istr;
 import std::option;
 import std::option::none;
 import std::option::some;
@@ -68,11 +69,11 @@ fn find_pre_post_item(ccx: &crate_ctxt, i: &item) {
                  {constrs: @new_def_hash::<constraint>(),
                   num_constraints: 0u,
                   cf: return,
-                  i_return: ninit(0, ""),
-                  i_diverge: ninit(0, ""),
+                  i_return: ninit(0, ~""),
+                  i_diverge: ninit(0, ~""),
                   used_vars: v},
              id: 0,
-             name: "",
+             name: ~"",
              ccx: ccx};
         find_pre_post_expr(fake_fcx, e);
       }
@@ -369,7 +370,7 @@ fn find_pre_post_expr(fcx: &fn_ctxt, e: @expr) {
         let rslt = expr_pp(fcx.ccx, e);
         clear_pp(rslt);
         let upvars = freevars::get_freevars(fcx.ccx.tcx, e.id);
-        for id: node_id in *upvars { handle_var(fcx, rslt, id, "upvar"); }
+        for id: node_id in *upvars { handle_var(fcx, rslt, id, ~"upvar"); }
       }
       expr_block(b) {
         find_pre_post_block(fcx, b);
@@ -750,7 +751,7 @@ fn fn_pre_post(f: &_fn, tps: &[ty_param], sp: &span, i: &fn_ident,
     let fcx =
         {enclosing: ccx.fm.get(id),
          id: id,
-         name: fn_ident_to_string(id, i),
+         name: istr::from_estr(fn_ident_to_string(id, i)),
          ccx: ccx};
     find_pre_post_fn(fcx, f);
 }
diff --git a/src/comp/middle/ty.rs b/src/comp/middle/ty.rs
index b6ce008b0c7..02ec4573901 100644
--- a/src/comp/middle/ty.rs
+++ b/src/comp/middle/ty.rs
@@ -1513,7 +1513,7 @@ fn hash_type_structure(st: &sty) -> uint {
       ty_native_fn(_, args, rty) { ret hash_fn(28u, args, rty); }
       ty_obj(methods) {
         let h = 29u;
-        for m: method in methods { h += h << 5u + str::hash(m.ident); }
+        for m: method in methods { h += h << 5u + istr::hash(m.ident); }
         ret h;
       }
       ty_var(v) { ret hash_uint(30u, v as uint); }
@@ -1801,20 +1801,21 @@ fn stmt_node_id(s: &@ast::stmt) -> ast::node_id {
 fn field_idx(sess: &session::session, sp: &span, id: &ast::ident,
              fields: &[field]) -> uint {
     let i: uint = 0u;
-    for f: field in fields { if str::eq(f.ident, id) { ret i; } i += 1u; }
-    sess.span_fatal(sp, "unknown field '" + id + "' of record");
+    for f: field in fields { if istr::eq(f.ident, id) { ret i; } i += 1u; }
+    sess.span_fatal(sp, "unknown field '" +
+                    istr::to_estr(id) + "' of record");
 }
 
 fn method_idx(sess: &session::session, sp: &span, id: &ast::ident,
               meths: &[method]) -> uint {
     let i: uint = 0u;
-    for m: method in meths { if str::eq(m.ident, id) { ret i; } i += 1u; }
-    sess.span_fatal(sp, "unknown method '" + id + "' of obj");
+    for m: method in meths { if istr::eq(m.ident, id) { ret i; } i += 1u; }
+    sess.span_fatal(sp, "unknown method '" + istr::to_estr(id) + "' of obj");
 }
 
 fn sort_methods(meths: &[method]) -> [method] {
     fn method_lteq(a: &method, b: &method) -> bool {
-        ret str::lteq(a.ident, b.ident);
+        ret istr::lteq(a.ident, b.ident);
     }
     ret std::sort::merge_sort::<method>(bind method_lteq(_, _), meths);
 }
@@ -2135,7 +2136,7 @@ mod unify {
         while i < expected_len {
             let e_meth = expected_meths[i];
             let a_meth = actual_meths[i];
-            if !str::eq(e_meth.ident, a_meth.ident) {
+            if !istr::eq(e_meth.ident, a_meth.ident) {
                 ret ures_err(terr_obj_meths(e_meth.ident, a_meth.ident));
             }
             let r =
@@ -2412,7 +2413,7 @@ mod unify {
                       none. { ret ures_err(terr_record_mutability); }
                       some(m) { mut = m; }
                     }
-                    if !str::eq(expected_field.ident, actual_field.ident) {
+                    if !istr::eq(expected_field.ident, actual_field.ident) {
                         let err =
                             terr_record_fields(expected_field.ident,
                                                actual_field.ident);
@@ -2622,14 +2623,14 @@ fn type_err_to_str(err: &ty::type_err) -> str {
       }
       terr_record_mutability. { ret "record elements differ in mutability"; }
       terr_record_fields(e_fld, a_fld) {
-        ret "expected a record with field '" + e_fld +
-                "' but found one with field '" + a_fld + "'";
+        ret "expected a record with field '" + istr::to_estr(e_fld) +
+                "' but found one with field '" + istr::to_estr(a_fld) + "'";
       }
       terr_arg_count. { ret "incorrect number of function parameters"; }
       terr_meth_count. { ret "incorrect number of object methods"; }
       terr_obj_meths(e_meth, a_meth) {
-        ret "expected an obj with method '" + e_meth +
-                "' but found one with method '" + a_meth + "'";
+        ret "expected an obj with method '" + istr::to_estr(e_meth) +
+                "' but found one with method '" + istr::to_estr(a_meth) + "'";
       }
       terr_mode_mismatch(e_mode, a_mode) {
         ret "expected argument mode " + mode_str_1(e_mode) + " but found " +
diff --git a/src/comp/middle/typeck.rs b/src/comp/middle/typeck.rs
index 5a71c99cec2..4ae6ecd003f 100644
--- a/src/comp/middle/typeck.rs
+++ b/src/comp/middle/typeck.rs
@@ -107,7 +107,7 @@ fn lookup_def(fcx: &@fn_ctxt, sp: &span, id: ast::node_id) -> ast::def {
 fn ident_for_local(loc: &@ast::local) -> ast::ident {
     ret alt loc.node.pat.node {
           ast::pat_bind(name) { name }
-          _ { "local" }
+          _ { ~"local" }
         }; // FIXME DESTR
 }
 
@@ -626,7 +626,7 @@ mod collect {
                  ty_params: &[ast::ty_param]) -> ty::ty_param_kinds_and_ty {
         let methods = get_obj_method_types(cx, ob);
         let t_obj = ty::mk_obj(cx.tcx, ty::sort_methods(methods));
-        t_obj = ty::rename(cx.tcx, t_obj, id);
+        t_obj = ty::rename(cx.tcx, t_obj, istr::to_estr(id));
         ret {kinds: ty_param_kinds(ty_params), ty: t_obj};
     }
     fn ty_of_obj_ctor(cx: @ctxt, id: &ast::ident, ob: &ast::_obj,
@@ -1322,7 +1322,7 @@ fn check_pat(fcx: &@fn_ctxt, map: &ast_util::pat_id_map, pat: &@ast::pat,
         let vid = lookup_local(fcx, pat.span, pat.id);
         let typ = ty::mk_var(fcx.ccx.tcx, vid);
         typ = demand::simple(fcx, pat.span, expected, typ);
-        let canon_id = map.get(istr::from_estr(name));
+        let canon_id = map.get(name);
         if canon_id != pat.id {
             let ct =
                 ty::mk_var(fcx.ccx.tcx,
@@ -1429,8 +1429,8 @@ fn check_pat(fcx: &@fn_ctxt, map: &ast_util::pat_id_map, pat: &@ast::pat,
                       fields",
                      ex_f_count, f_count]);
         }
-        fn matches(name: &str, f: &ty::field) -> bool {
-            ret str::eq(name, f.ident);
+        fn matches(name: &istr, f: &ty::field) -> bool {
+            ret istr::eq(name, f.ident);
         }
         for f: ast::field_pat in fields {
             alt vec::find(bind matches(f.ident, _), ex_fields) {
@@ -1439,7 +1439,7 @@ fn check_pat(fcx: &@fn_ctxt, map: &ast_util::pat_id_map, pat: &@ast::pat,
                 fcx.ccx.tcx.sess.span_fatal(pat.span,
                                             #fmt["mismatched types: did not \
                                              expect a record with a field %s",
-                                                 f.ident]);
+                                                 istr::to_estr(f.ident)]);
               }
             }
         }
@@ -2255,7 +2255,7 @@ fn check_expr_with_unifier(fcx: &@fn_ctxt, expr: &@ast::expr, unify: &unifier,
             for f: spanned<ty::field> in fields_t {
                 let found = false;
                 for bf: ty::field in base_fields {
-                    if str::eq(f.node.ident, bf.ident) {
+                    if istr::eq(f.node.ident, bf.ident) {
                         demand::simple(fcx, f.span, bf.mt.ty, f.node.mt.ty);
                         found = true;
                     }
@@ -2263,7 +2263,7 @@ fn check_expr_with_unifier(fcx: &@fn_ctxt, expr: &@ast::expr, unify: &unifier,
                 if !found {
                     tcx.sess.span_fatal(f.span,
                                         "unknown field in record update: " +
-                                            f.node.ident);
+                                        istr::to_estr(f.node.ident));
                 }
             }
           }
@@ -2419,7 +2419,7 @@ fn check_expr_with_unifier(fcx: &@fn_ctxt, expr: &@ast::expr, unify: &unifier,
                option::t<ty::method> {
 
                 for om: @ast::method in outer_obj_methods {
-                    if str::eq(om.node.ident, m.ident) {
+                    if istr::eq(om.node.ident, m.ident) {
                         // We'd better be overriding with one of the same
                         // type.  Check to make sure.
                         let new_type = ty_of_method(ccx, om);
@@ -2427,7 +2427,7 @@ fn check_expr_with_unifier(fcx: &@fn_ctxt, expr: &@ast::expr, unify: &unifier,
                             ccx.tcx.sess.span_fatal(
                                 om.span,
                                 "Attempted to override method "
-                                + m.ident +
+                                + istr::to_estr(m.ident) +
                                 " with one of a different type");
                         }
                         ret none;
@@ -2504,7 +2504,7 @@ fn check_decl_local(fcx: &@fn_ctxt, local: &@ast::local) -> bool {
     alt fcx.locals.find(local.node.id) {
       none. {
         fcx.ccx.tcx.sess.bug("check_decl_local: local id not found " +
-                                 ident_for_local(local));
+                             istr::to_estr(ident_for_local(local)));
       }
       some(i) {
         let t = ty::mk_var(fcx.ccx.tcx, i);
diff --git a/src/comp/syntax/ast.rs b/src/comp/syntax/ast.rs
index d380fbecdb4..4009ff2bd4e 100644
--- a/src/comp/syntax/ast.rs
+++ b/src/comp/syntax/ast.rs
@@ -7,7 +7,7 @@ import codemap::filename;
 
 type spanned<T> = {node: T, span: span};
 
-type ident = str;
+type ident = istr;
 type identistr = istr;
 
 // Functions may or may not have names.
@@ -429,7 +429,7 @@ type native_mod =
 
 type variant_arg = {ty: @ty, id: node_id};
 
-type variant_ = {name: str, args: [variant_arg], id: node_id};
+type variant_ = {name: ident, args: [variant_arg], id: node_id};
 
 type variant = spanned<variant_>;
 
diff --git a/src/comp/syntax/ast_util.rs b/src/comp/syntax/ast_util.rs
index 687070da24f..72a633da928 100644
--- a/src/comp/syntax/ast_util.rs
+++ b/src/comp/syntax/ast_util.rs
@@ -16,7 +16,9 @@ fn dummy_sp() -> span { ret mk_sp(0u, 0u); }
 
 fn path_name(p: &path) -> str { path_name_i(p.node.idents) }
 
-fn path_name_i(idents: &[ident]) -> str { str::connect(idents, "::") }
+fn path_name_i(idents: &[ident]) -> str {
+    istr::to_estr(istr::connect(idents, ~"::"))
+}
 
 fn local_def(id: node_id) -> def_id { ret {crate: local_crate, node: id}; }
 
@@ -52,7 +54,7 @@ fn pat_id_map(pat: &@pat) -> pat_id_map {
     let map = std::map::new_str_hash::<node_id>();
     for each bound in pat_bindings(pat) {
         let name = alt bound.node { pat_bind(n) { n } };
-        map.insert(istr::from_estr(name), bound.id);
+        map.insert(name, bound.id);
     }
     ret map;
 }
@@ -156,7 +158,7 @@ fn is_exported(i: ident, m: _mod) -> bool {
     for vi: @ast::view_item in m.view_items {
         alt vi.node {
           ast::view_item_export(ids, _) {
-            for id in ids { if str::eq(i, id) { ret true; } }
+            for id in ids { if istr::eq(i, id) { ret true; } }
             count += 1u;
           }
           _ {/* fall through */ }
diff --git a/src/comp/syntax/ext/concat_idents.rs b/src/comp/syntax/ext/concat_idents.rs
index 466f55e60e6..0b88d09ec4d 100644
--- a/src/comp/syntax/ext/concat_idents.rs
+++ b/src/comp/syntax/ext/concat_idents.rs
@@ -11,7 +11,7 @@ fn expand_syntax_ext(cx: &ext_ctxt, sp: codemap::span, arg: @ast::expr,
             cx.span_fatal(sp, "#concat_idents requires a vector argument .")
           }
         };
-    let res: ast::ident = "";
+    let res: ast::ident = ~"";
     for e: @ast::expr in args {
         res += expr_to_ident(cx, e, "expected an ident");
     }
diff --git a/src/comp/syntax/ext/expand.rs b/src/comp/syntax/ext/expand.rs
index 542b2805402..6a80b0b6cb2 100644
--- a/src/comp/syntax/ext/expand.rs
+++ b/src/comp/syntax/ext/expand.rs
@@ -24,10 +24,11 @@ fn expand_expr(exts: &hashmap<istr, syntax_extension>, cx: &ext_ctxt,
               mac_invoc(pth, args, body) {
                 assert (vec::len(pth.node.idents) > 0u);
                 let extname = pth.node.idents[0];
-                alt exts.find(istr::from_estr(extname)) {
+                alt exts.find(extname) {
                   none. {
                     cx.span_fatal(pth.span,
-                                  #fmt["macro undefined: '%s'", extname])
+                                  #fmt["macro undefined: '%s'",
+                                       istr::to_estr(extname)])
                   }
                   some(normal(ext)) {
                     let expanded = ext(cx, pth.span, args, body);
diff --git a/src/comp/syntax/ext/fmt.rs b/src/comp/syntax/ext/fmt.rs
index c70ea3234c4..093799714a7 100644
--- a/src/comp/syntax/ext/fmt.rs
+++ b/src/comp/syntax/ext/fmt.rs
@@ -100,16 +100,16 @@ fn pieces_to_expr(cx: &ext_ctxt, sp: span, pieces: &[piece],
         let recexpr = ast::expr_rec(astfields, option::none::<@ast::expr>);
         ret @{id: cx.next_id(), node: recexpr, span: sp};
     }
-    fn make_path_vec(cx: &ext_ctxt, ident: str) -> [str] {
+    fn make_path_vec(cx: &ext_ctxt, ident: &ast::ident) -> [ast::ident] {
         fn compiling_std(cx: &ext_ctxt) -> bool {
             ret str::find(cx.crate_file_name(), "std.rc") >= 0;
         }
         if compiling_std(cx) {
-            ret ["extfmt", "rt", ident];
-        } else { ret ["std", "extfmt", "rt", ident]; }
+            ret [~"extfmt", ~"rt", ident];
+        } else { ret [~"std", ~"extfmt", ~"rt", ident]; }
     }
     fn make_rt_path_expr(cx: &ext_ctxt, sp: span, ident: str) -> @ast::expr {
-        let path = make_path_vec(cx, ident);
+        let path = make_path_vec(cx, istr::from_estr(ident));
         ret make_path_expr(cx, sp, path);
     }
     // Produces an AST expression that represents a RT::conv record,
@@ -145,7 +145,7 @@ fn pieces_to_expr(cx: &ext_ctxt, sp: span, pieces: &[piece],
               }
               count_is(c) {
                 let count_lit = make_new_int(cx, sp, c);
-                let count_is_path = make_path_vec(cx, "count_is");
+                let count_is_path = make_path_vec(cx, ~"count_is");
                 let count_is_args = [count_lit];
                 ret make_call(cx, sp, count_is_path, count_is_args);
               }
@@ -171,10 +171,10 @@ fn pieces_to_expr(cx: &ext_ctxt, sp: span, pieces: &[piece],
                          width_expr: @ast::expr, precision_expr: @ast::expr,
                          ty_expr: @ast::expr) -> @ast::expr {
             ret make_rec_expr(cx, sp,
-                              [{ident: "flags", ex: flags_expr},
-                               {ident: "width", ex: width_expr},
-                               {ident: "precision", ex: precision_expr},
-                               {ident: "ty", ex: ty_expr}]);
+                              [{ident: ~"flags", ex: flags_expr},
+                               {ident: ~"width", ex: width_expr},
+                               {ident: ~"precision", ex: precision_expr},
+                               {ident: ~"ty", ex: ty_expr}]);
         }
         let rt_conv_flags = make_flags(cx, sp, cnv.flags);
         let rt_conv_width = make_count(cx, sp, cnv.width);
@@ -185,7 +185,7 @@ fn pieces_to_expr(cx: &ext_ctxt, sp: span, pieces: &[piece],
     }
     fn make_conv_call(cx: &ext_ctxt, sp: span, conv_type: str, cnv: &conv,
                       arg: @ast::expr) -> @ast::expr {
-        let fname = "conv_" + conv_type;
+        let fname = ~"conv_" + istr::from_estr(conv_type);
         let path = make_path_vec(cx, fname);
         let cnv_expr = make_rt_conv_expr(cx, sp, cnv);
         let args = [cnv_expr, arg];
diff --git a/src/comp/syntax/ext/ident_to_str.rs b/src/comp/syntax/ext/ident_to_str.rs
index 4eb381762fe..0664987e530 100644
--- a/src/comp/syntax/ext/ident_to_str.rs
+++ b/src/comp/syntax/ext/ident_to_str.rs
@@ -1,4 +1,5 @@
 import std::vec;
+import std::istr;
 import std::option;
 import base::*;
 import syntax::ast;
@@ -17,8 +18,8 @@ fn expand_syntax_ext(cx: &ext_ctxt, sp: codemap::span, arg: @ast::expr,
     }
 
     ret make_new_lit(cx, sp,
-                     ast::lit_str(expr_to_ident(cx, args[0u],
-                                                "expected an ident"),
+                     ast::lit_str(istr::to_estr(expr_to_ident(cx, args[0u],
+                                                "expected an ident")),
                                   ast::sk_rc));
 
 }
diff --git a/src/comp/syntax/ext/simplext.rs b/src/comp/syntax/ext/simplext.rs
index b0d7cd26020..94d814ae9c8 100644
--- a/src/comp/syntax/ext/simplext.rs
+++ b/src/comp/syntax/ext/simplext.rs
@@ -268,8 +268,8 @@ iter free_vars(b: &bindings, e: @expr) -> ident {
     let idents: hashmap<identistr, ()> = new_str_hash::<()>();
     fn mark_ident(i: &ident, _fld: ast_fold, b: &bindings,
                   idents: &hashmap<identistr, ()>) -> ident {
-        if b.contains_key(istr::from_estr(i)) {
-            idents.insert(istr::from_estr(i), ());
+        if b.contains_key(i) {
+            idents.insert(i, ());
         }
         ret i;
     }
@@ -281,7 +281,7 @@ iter free_vars(b: &bindings, e: @expr) -> ident {
     let f = make_fold(f_pre);
     f.fold_expr(e); // ignore result
     dummy_out(f);
-    for each id: identistr in idents.keys() { put istr::to_estr(id); }
+    for each id: identistr in idents.keys() { put id; }
 }
 
 
@@ -298,7 +298,7 @@ fn transcribe_exprs(cx: &ext_ctxt, b: &bindings, idx_path: @mutable [uint],
             /* we need to walk over all the free vars in lockstep, except for
             the leaves, which are just duplicated */
             for each fv: ident in free_vars(b, repeat_me) {
-                let cur_pos = follow(b.get(istr::from_estr(fv)), idx_path);
+                let cur_pos = follow(b.get(fv), idx_path);
                 alt cur_pos {
                   leaf(_) { }
                   seq(ms, _) {
@@ -310,8 +310,10 @@ fn transcribe_exprs(cx: &ext_ctxt, b: &bindings, idx_path: @mutable [uint],
                         let len = vec::len(*ms);
                         if old_len != len {
                             let msg =
-                                #fmt["'%s' occurs %u times, but ", fv, len] +
-                                    #fmt["'%s' occurs %u times", old_name,
+                                #fmt["'%s' occurs %u times, but ",
+                                     istr::to_estr(fv), len] +
+                                    #fmt["'%s' occurs %u times",
+                                         istr::to_estr(old_name),
                                          old_len];
                             cx.span_fatal(repeat_me.span, msg);
                         }
@@ -350,7 +352,7 @@ fn transcribe_exprs(cx: &ext_ctxt, b: &bindings, idx_path: @mutable [uint],
 // substitute, in a position that's required to be an ident
 fn transcribe_ident(cx: &ext_ctxt, b: &bindings, idx_path: @mutable [uint],
                     i: &ident, _fld: ast_fold) -> ident {
-    ret alt follow_for_trans(cx, b.find(istr::from_estr(i)), idx_path) {
+    ret alt follow_for_trans(cx, b.find(i), idx_path) {
           some(match_ident(a_id)) { a_id.node }
           some(m) { match_error(cx, m, "an identifier") }
           none. { i }
@@ -362,8 +364,7 @@ fn transcribe_path(cx: &ext_ctxt, b: &bindings, idx_path: @mutable [uint],
                    p: &path_, _fld: ast_fold) -> path_ {
     // Don't substitute into qualified names.
     if vec::len(p.types) > 0u || vec::len(p.idents) != 1u { ret p; }
-    ret alt follow_for_trans(cx, b.find(
-        istr::from_estr(p.idents[0])), idx_path) {
+    ret alt follow_for_trans(cx, b.find(p.idents[0]), idx_path) {
           some(match_ident(id)) {
             {global: false, idents: [id.node], types: []}
           }
@@ -384,8 +385,7 @@ fn transcribe_expr(cx: &ext_ctxt, b: &bindings, idx_path: @mutable [uint],
             if vec::len(p.node.types) > 0u || vec::len(p.node.idents) != 1u {
                 e
             }
-            alt follow_for_trans(cx, b.find(
-                istr::from_estr(p.node.idents[0])), idx_path) {
+            alt follow_for_trans(cx, b.find(p.node.idents[0]), idx_path) {
               some(match_ident(id)) {
                 expr_path(respan(id.span,
                                  {global: false,
@@ -409,8 +409,7 @@ fn transcribe_type(cx: &ext_ctxt, b: &bindings, idx_path: @mutable [uint],
           ast::ty_path(pth, _) {
             alt path_to_ident(pth) {
               some(id) {
-                alt follow_for_trans(cx, b.find(
-                    istr::from_estr(id)), idx_path) {
+                alt follow_for_trans(cx, b.find(id), idx_path) {
                   some(match_ty(ty)) { ty.node }
                   some(m) { match_error(cx, m, "a type") }
                   none. { orig(t, fld) }
@@ -433,7 +432,7 @@ fn transcribe_block(cx: &ext_ctxt, b: &bindings, idx_path: @mutable [uint],
     ret alt block_to_ident(blk) {
           some(id) {
             alt follow_for_trans(cx, b.find(
-                istr::from_estr(id)), idx_path) {
+                id), idx_path) {
               some(match_block(new_blk)) { new_blk.node }
 
 
@@ -534,10 +533,10 @@ fn p_t_s_r_path(cx: &ext_ctxt, p: &path, s: &selector, b: &binders) {
                   _ { cx.bug("broken traversal in p_t_s_r") }
                 }
         }
-        if b.real_binders.contains_key(istr::from_estr(p_id)) {
+        if b.real_binders.contains_key(p_id) {
             cx.span_fatal(p.span, "duplicate binding identifier");
         }
-        b.real_binders.insert(istr::from_estr(p_id),
+        b.real_binders.insert(p_id,
                               compose_sels(s, bind select(cx, _)));
       }
       none. { }
@@ -584,7 +583,7 @@ fn p_t_s_r_mac(cx: &ext_ctxt, mac: &ast::mac, s: &selector, b: &binders) {
                 }
                 let final_step = bind select_pt_1(cx, _, select_pt_2);
                 b.real_binders.insert(
-                    istr::from_estr(id), compose_sels(s, final_step));
+                    id, compose_sels(s, final_step));
               }
               none. { no_des(cx, pth.span, "under `#<>`"); }
             }
@@ -604,7 +603,7 @@ fn p_t_s_r_mac(cx: &ext_ctxt, mac: &ast::mac, s: &selector, b: &binders) {
                     }
             }
             let final_step = bind select_pt_1(cx, _, select_pt_2);
-            b.real_binders.insert(istr::from_estr(id),
+            b.real_binders.insert(id,
                                   compose_sels(s, final_step));
           }
           none. { no_des(cx, blk.span, "under `#{}`"); }
@@ -700,7 +699,7 @@ fn add_new_extension(cx: &ext_ctxt, sp: span, arg: @expr,
           }
         };
 
-    let macro_name: option::t<str> = none;
+    let macro_name: option::t<istr> = none;
     let clauses: [@clause] = [];
     for arg: @expr in args {
         alt arg.node {
@@ -760,7 +759,7 @@ fn add_new_extension(cx: &ext_ctxt, sp: span, arg: @expr,
 
     ret {ident:
              alt macro_name {
-               some(id) { id }
+               some(id) { istr::to_estr(id) }
                none. {
                  cx.span_fatal(sp,
                                "macro definition must have " +
diff --git a/src/comp/syntax/parse/eval.rs b/src/comp/syntax/parse/eval.rs
index 18d9a04ebbf..ccb7f0cfde2 100644
--- a/src/comp/syntax/parse/eval.rs
+++ b/src/comp/syntax/parse/eval.rs
@@ -47,13 +47,18 @@ fn eval_crate_directive(cx: ctx, cdir: @ast::crate_directive, prefix: str,
                         items: &mutable [@ast::item]) {
     alt cdir.node {
       ast::cdir_src_mod(id, file_opt, attrs) {
-        let file_path = id + ".rs";
-        alt file_opt { some(f) { file_path = f; } none. { } }
+        let file_path = id + ~".rs";
+        alt file_opt {
+          some(f) {
+            file_path = istr::from_estr(f);
+          }
+          none. { }
+        }
         let full_path = if std::fs::path_is_absolute(
-            istr::from_estr(file_path)) {
-            file_path
+            file_path) {
+            istr::to_estr(file_path)
         } else {
-            prefix + istr::to_estr(std::fs::path_sep()) + file_path
+            prefix + istr::to_estr(std::fs::path_sep() + file_path)
         };
         if cx.mode == mode_depend { cx.deps += [full_path]; ret; }
         let p0 =
@@ -74,11 +79,18 @@ fn eval_crate_directive(cx: ctx, cdir: @ast::crate_directive, prefix: str,
       }
       ast::cdir_dir_mod(id, dir_opt, cdirs, attrs) {
         let path = id;
-        alt dir_opt { some(d) { path = d; } none. { } }
+        alt dir_opt {
+          some(d) {
+            path = istr::from_estr(d);
+          }
+          none. { }
+        }
         let full_path =
-            if std::fs::path_is_absolute(istr::from_estr(path)) {
-                path
-            } else { prefix + istr::to_estr(std::fs::path_sep()) + path };
+            if std::fs::path_is_absolute(path) {
+                istr::to_estr(path)
+            } else {
+            prefix + istr::to_estr(std::fs::path_sep() + path)
+        };
         let m0 = eval_crate_directives_to_mod(cx, cdirs, full_path);
         let i =
             @{ident: id,
diff --git a/src/comp/syntax/parse/parser.rs b/src/comp/syntax/parse/parser.rs
index c0beb8a32c3..85f809ef965 100644
--- a/src/comp/syntax/parse/parser.rs
+++ b/src/comp/syntax/parse/parser.rs
@@ -229,7 +229,10 @@ fn spanned<@T>(lo: uint, hi: uint, node: &T) -> spanned<T> {
 
 fn parse_ident(p: &parser) -> ast::ident {
     alt p.peek() {
-      token::IDENT(i, _) { p.bump(); ret p.get_str(i); }
+      token::IDENT(i, _) {
+        p.bump();
+        ret istr::from_estr(p.get_str(i));
+      }
       _ { p.fatal("expecting ident"); }
     }
 }
@@ -375,7 +378,8 @@ fn parse_ty_field(p: &parser) -> ast::ty_field {
 fn ident_index(p: &parser, args: &[ast::arg], i: &ast::ident) -> uint {
     let j = 0u;
     for a: ast::arg in args { if a.ident == i { ret j; } j += 1u; }
-    p.fatal("Unbound variable " + i + " in constraint arg");
+    p.fatal("Unbound variable " +
+            istr::to_estr(i) + " in constraint arg");
 }
 
 fn parse_type_constr_arg(p: &parser) -> @ast::ty_constr_arg {
@@ -742,7 +746,7 @@ fn parse_path(p: &parser) -> ast::path {
         alt p.peek() {
           token::IDENT(i, _) {
             hi = p.get_hi_pos();
-            ids += [p.get_str(i)];
+            ids += [istr::from_estr(p.get_str(i))];
             hi = p.get_hi_pos();
             p.bump();
             if p.peek() == token::MOD_SEP && p.look_ahead(1u) != token::LT {
@@ -1102,7 +1106,9 @@ fn parse_dot_or_call_expr_with(p: &parser, e: @ast::expr) -> @ast::expr {
               token::IDENT(i, _) {
                 hi = p.get_hi_pos();
                 p.bump();
-                e = mk_expr(p, lo, hi, ast::expr_field(e, p.get_str(i)));
+                e = mk_expr(p, lo, hi,
+                            ast::expr_field(
+                                e, istr::from_estr(p.get_str(i))));
               }
               t { unexpected(p, t); }
             }
@@ -1455,9 +1461,9 @@ fn parse_pat(p: &parser) -> @ast::pat {
                 p.bump();
                 subpat = parse_pat(p);
             } else {
-                if p.get_bad_expr_words()
-                    .contains_key(istr::from_estr(fieldname)) {
-                    p.fatal("found " + fieldname + " in binding position");
+                if p.get_bad_expr_words().contains_key(fieldname) {
+                    p.fatal("found " + istr::to_estr(fieldname)
+                            + " in binding position");
                 }
                 subpat =
                     @{id: p.get_id(),
@@ -1984,7 +1990,8 @@ fn parse_native_item(p: &parser, attrs: &[ast::attribute]) ->
     } else { unexpected(p, p.peek()); }
 }
 
-fn parse_native_mod_items(p: &parser, native_name: &str, abi: ast::native_abi,
+fn parse_native_mod_items(p: &parser, native_name: &str,
+                          abi: ast::native_abi,
                           first_item_attrs: &[ast::attribute]) ->
    ast::native_mod {
     // Shouldn't be any view items since we've already parsed an item attr
@@ -2027,7 +2034,7 @@ fn parse_item_native_mod(p: &parser, attrs: &[ast::attribute]) -> @ast::item {
     if p.peek() == token::EQ {
         expect(p, token::EQ);
         native_name = parse_str(p);
-    } else { native_name = id; }
+    } else { native_name = istr::to_estr(id); }
     expect(p, token::LBRACE);
     let more_attrs = parse_inner_attrs_and_next(p);
     let inner_attrs = more_attrs.inner;
@@ -2062,8 +2069,9 @@ fn parse_item_tag(p: &parser, attrs: &[ast::attribute]) -> @ast::item {
     let variants: [ast::variant] = [];
     // Newtype syntax
     if p.peek() == token::EQ {
-        if p.get_bad_expr_words().contains_key(istr::from_estr(id)) {
-            p.fatal("found " + id + " in tag constructor position");
+        if p.get_bad_expr_words().contains_key(id) {
+            p.fatal("found " + istr::to_estr(id)
+                    + " in tag constructor position");
         }
         p.bump();
         let ty = parse_ty(p, false);
@@ -2100,7 +2108,8 @@ fn parse_item_tag(p: &parser, attrs: &[ast::attribute]) -> @ast::item {
             }
             expect(p, token::SEMI);
             p.get_id();
-            let vr = {name: p.get_str(name), args: args, id: p.get_id()};
+            let vr = {name: istr::from_estr(p.get_str(name)),
+                      args: args, id: p.get_id()};
             variants += [spanned(vlo, vhi, vr)];
           }
           token::RBRACE. {/* empty */ }
@@ -2261,7 +2270,7 @@ fn parse_use(p: &parser) -> ast::view_item_ {
     ret ast::view_item_use(ident, metadata, p.get_id());
 }
 
-fn parse_rest_import_name(p: &parser, first: ast::ident,
+fn parse_rest_import_name(p: &parser, first: &ast::ident,
                           def_ident: option::t<ast::ident>) ->
    ast::view_item_ {
     let identifiers: [ast::ident] = [first];
@@ -2336,12 +2345,13 @@ fn parse_rest_import_name(p: &parser, first: ast::ident,
     }
 }
 
-fn parse_full_import_name(p: &parser, def_ident: ast::ident) ->
+fn parse_full_import_name(p: &parser, def_ident: &ast::ident) ->
    ast::view_item_ {
     alt p.peek() {
       token::IDENT(i, _) {
         p.bump();
-        ret parse_rest_import_name(p, p.get_str(i), some(def_ident));
+        ret parse_rest_import_name(
+            p, istr::from_estr(p.get_str(i)), some(def_ident));
       }
       _ { p.fatal("expecting an identifier"); }
     }
@@ -2354,9 +2364,12 @@ fn parse_import(p: &parser) -> ast::view_item_ {
         alt p.peek() {
           token::EQ. {
             p.bump();
-            ret parse_full_import_name(p, p.get_str(i));
+            ret parse_full_import_name(p, istr::from_estr(p.get_str(i)));
+          }
+          _ {
+            ret parse_rest_import_name(
+                p, istr::from_estr(p.get_str(i)), none);
           }
-          _ { ret parse_rest_import_name(p, p.get_str(i), none); }
         }
       }
       _ { p.fatal("expecting an identifier"); }
@@ -2436,7 +2449,7 @@ fn parse_crate_mod(p: &parser, _cfg: &ast::crate_cfg) -> @ast::crate {
                   config: p.get_cfg()});
 }
 
-fn parse_str(p: &parser) -> ast::ident {
+fn parse_str(p: &parser) -> str {
     alt p.peek() {
       token::LIT_STR(s) { p.bump(); ret p.get_str(s); }
       _ { fail; }
diff --git a/src/comp/syntax/print/pprust.rs b/src/comp/syntax/print/pprust.rs
index 9dcd56407f7..530b16a2037 100644
--- a/src/comp/syntax/print/pprust.rs
+++ b/src/comp/syntax/print/pprust.rs
@@ -107,7 +107,8 @@ fn path_to_str(p: &ast::path) -> str {
     be to_str(p, bind print_path(_, _, false));
 }
 
-fn fun_to_str(f: &ast::_fn, name: str, params: &[ast::ty_param]) -> str {
+fn fun_to_str(f: &ast::_fn, name: &ast::ident,
+              params: &[ast::ty_param]) -> str {
     let writer = io::string_writer();
     let s = rust_printer(writer.get_writer());
     print_fn(s, f.decl, f.proto, name, params, f.decl.constraints);
@@ -305,7 +306,7 @@ fn print_type(s: &ps, ty: &@ast::ty) {
         fn print_field(s: &ps, f: &ast::ty_field) {
             cbox(s, indent_unit);
             print_mutability(s, f.node.mt.mut);
-            word(s.s, f.node.ident);
+            word(s.s, istr::to_estr(f.node.ident));
             word_space(s, ":");
             print_type(s, f.node.mt.ty);
             end(s);
@@ -320,7 +321,7 @@ fn print_type(s: &ps, ty: &@ast::ty) {
         pclose(s);
       }
       ast::ty_fn(proto, inputs, output, cf, constrs) {
-        print_ty_fn(s, proto, none::<str>, inputs, output, cf, constrs);
+        print_ty_fn(s, proto, none::<istr>, inputs, output, cf, constrs);
       }
       ast::ty_obj(methods) {
         head(s, "obj");
@@ -356,7 +357,7 @@ fn print_native_item(s: &ps, item: &@ast::native_item) {
         ibox(s, indent_unit);
         ibox(s, 0u);
         word_nbsp(s, "type");
-        word(s.s, item.ident);
+        word(s.s, istr::to_estr(item.ident));
         end(s); // end the inner ibox
         word(s.s, ";");
         end(s); // end the outer ibox
@@ -388,7 +389,7 @@ fn print_item(s: &ps, item: &@ast::item) {
     alt item.node {
       ast::item_const(ty, expr) {
         head(s, "const");
-        word_space(s, item.ident + ":");
+        word_space(s, istr::to_estr(item.ident) + ":");
         print_type(s, ty);
         space(s.s);
         end(s); // end the head-ibox
@@ -407,7 +408,7 @@ fn print_item(s: &ps, item: &@ast::item) {
       }
       ast::item_mod(_mod) {
         head(s, "mod");
-        word_nbsp(s, item.ident);
+        word_nbsp(s, istr::to_estr(item.ident));
         bopen(s);
         print_mod(s, _mod, item.attrs);
         bclose(s, item.span);
@@ -424,8 +425,8 @@ fn print_item(s: &ps, item: &@ast::item) {
           ast::native_abi_x86stdcall. { word_nbsp(s, "\"x86stdcall\""); }
         }
         word_nbsp(s, "mod");
-        word_nbsp(s, item.ident);
-        if !str::eq(nmod.native_name, item.ident) {
+        word_nbsp(s, istr::to_estr(item.ident));
+        if !str::eq(nmod.native_name, istr::to_estr(item.ident)) {
             word_space(s, "=");
             print_string(s, nmod.native_name);
             nbsp(s);
@@ -438,7 +439,7 @@ fn print_item(s: &ps, item: &@ast::item) {
         ibox(s, indent_unit);
         ibox(s, 0u);
         word_nbsp(s, "type");
-        word(s.s, item.ident);
+        word(s.s, istr::to_estr(item.ident));
         print_type_params(s, params);
         end(s); // end the inner ibox
 
@@ -451,13 +452,13 @@ fn print_item(s: &ps, item: &@ast::item) {
       ast::item_tag(variants, params) {
         let newtype =
             vec::len(variants) == 1u &&
-                str::eq(item.ident, variants[0].node.name) &&
+                istr::eq(item.ident, variants[0].node.name) &&
                 vec::len(variants[0].node.args) == 1u;
         if newtype {
             ibox(s, indent_unit);
             word_space(s, "tag");
         } else { head(s, "tag"); }
-        word(s.s, item.ident);
+        word(s.s, istr::to_estr(item.ident));
         print_type_params(s, params);
         space(s.s);
         if newtype {
@@ -470,7 +471,7 @@ fn print_item(s: &ps, item: &@ast::item) {
             for v: ast::variant in variants {
                 space_if_not_bol(s);
                 maybe_print_comment(s, v.span.lo);
-                word(s.s, v.node.name);
+                word(s.s, istr::to_estr(v.node.name));
                 if vec::len(v.node.args) > 0u {
                     popen(s);
                     fn print_variant_arg(s: &ps, arg: &ast::variant_arg) {
@@ -487,13 +488,13 @@ fn print_item(s: &ps, item: &@ast::item) {
       }
       ast::item_obj(_obj, params, _) {
         head(s, "obj");
-        word(s.s, item.ident);
+        word(s.s, istr::to_estr(item.ident));
         print_type_params(s, params);
         popen(s);
         fn print_field(s: &ps, field: &ast::obj_field) {
             ibox(s, indent_unit);
             print_mutability(s, field.mut);
-            word_space(s, field.ident + ":");
+            word_space(s, istr::to_estr(field.ident) + ":");
             print_type(s, field.ty);
             end(s);
         }
@@ -515,10 +516,10 @@ fn print_item(s: &ps, item: &@ast::item) {
       }
       ast::item_res(dt, dt_id, tps, ct_id) {
         head(s, "resource");
-        word(s.s, item.ident);
+        word(s.s, istr::to_estr(item.ident));
         print_type_params(s, tps);
         popen(s);
-        word_space(s, dt.decl.inputs[0].ident + ":");
+        word_space(s, istr::to_estr(dt.decl.inputs[0].ident) + ":");
         print_type(s, dt.decl.inputs[0].ty);
         pclose(s);
         space(s.s);
@@ -786,7 +787,7 @@ fn print_expr(s: &ps, expr: &@ast::expr) {
         fn print_field(s: &ps, field: &ast::field) {
             ibox(s, indent_unit);
             if field.node.mut == ast::mut { word_nbsp(s, "mutable"); }
-            word(s.s, field.node.ident);
+            word(s.s, istr::to_estr(field.node.ident));
             word_space(s, ":");
             print_expr(s, field.node.expr);
             end(s);
@@ -981,7 +982,7 @@ fn print_expr(s: &ps, expr: &@ast::expr) {
       ast::expr_field(expr, id) {
         print_expr_parens_if_unary(s, expr);
         word(s.s, ".");
-        word(s.s, id);
+        word(s.s, istr::to_estr(id));
       }
       ast::expr_index(expr, index) {
         print_expr_parens_if_unary(s, expr);
@@ -1042,7 +1043,7 @@ fn print_expr(s: &ps, expr: &@ast::expr) {
         fn print_field(s: &ps, field: &ast::anon_obj_field) {
             ibox(s, indent_unit);
             print_mutability(s, field.mut);
-            word_space(s, field.ident + ":");
+            word_space(s, istr::to_estr(field.ident) + ":");
             print_type(s, field.ty);
             space(s.s);
             word_space(s, "=");
@@ -1131,7 +1132,9 @@ fn print_decl(s: &ps, decl: &@ast::decl) {
     }
 }
 
-fn print_ident(s: &ps, ident: &ast::ident) { word(s.s, ident); }
+fn print_ident(s: &ps, ident: &ast::ident) {
+    word(s.s, istr::to_estr(ident));
+}
 
 fn print_for_decl(s: &ps, loc: &@ast::local, coll: &@ast::expr) {
     print_local_decl(s, loc);
@@ -1144,9 +1147,9 @@ fn print_path(s: &ps, path: &ast::path, colons_before_params: bool) {
     maybe_print_comment(s, path.span.lo);
     if path.node.global { word(s.s, "::"); }
     let first = true;
-    for id: str in path.node.idents {
+    for id: ast::ident in path.node.idents {
         if first { first = false; } else { word(s.s, "::"); }
-        word(s.s, id);
+        word(s.s, istr::to_estr(id));
     }
     if vec::len(path.node.types) > 0u {
         if colons_before_params { word(s.s, "::"); }
@@ -1162,7 +1165,7 @@ fn print_pat(s: &ps, pat: &@ast::pat) {
     s.ann.pre(ann_node);
     alt pat.node {
       ast::pat_wild. { word(s.s, "_"); }
-      ast::pat_bind(id) { word(s.s, id); }
+      ast::pat_bind(id) { word(s.s, istr::to_estr(id)); }
       ast::pat_lit(lit) { print_literal(s, lit); }
       ast::pat_tag(path, args) {
         print_path(s, path, true);
@@ -1176,7 +1179,7 @@ fn print_pat(s: &ps, pat: &@ast::pat) {
         word(s.s, "{");
         fn print_field(s: &ps, f: &ast::field_pat) {
             cbox(s, indent_unit);
-            word(s.s, f.ident);
+            word(s.s, istr::to_estr(f.ident));
             word_space(s, ":");
             print_pat(s, f.pat);
             end(s);
@@ -1199,13 +1202,13 @@ fn print_pat(s: &ps, pat: &@ast::pat) {
     s.ann.post(ann_node);
 }
 
-fn print_fn(s: &ps, decl: ast::fn_decl, proto: ast::proto, name: str,
+fn print_fn(s: &ps, decl: ast::fn_decl, proto: ast::proto, name: &ast::ident,
             typarams: &[ast::ty_param], constrs: [@ast::constr]) {
     alt decl.purity {
       ast::impure_fn. { head(s, proto_to_str(proto)); }
       _ { head(s, "pure fn"); }
     }
-    word(s.s, name);
+    word(s.s, istr::to_estr(name));
     print_type_params(s, typarams);
     print_fn_args_and_ret(s, decl, constrs);
 }
@@ -1215,7 +1218,7 @@ fn print_fn_args_and_ret(s: &ps, decl: &ast::fn_decl,
     popen(s);
     fn print_arg(s: &ps, x: &ast::arg) {
         ibox(s, indent_unit);
-        word_space(s, x.ident + ":");
+        word_space(s, istr::to_estr(x.ident) + ":");
         print_alias(s, x.mode);
         print_type(s, x.ty);
         end(s);
@@ -1236,7 +1239,7 @@ fn print_fn_block_args(s: &ps, decl: &ast::fn_decl) {
     fn print_arg(s: &ps, x: &ast::arg) {
         ibox(s, indent_unit);
         print_alias(s, x.mode);
-        word(s.s, x.ident);
+        word(s.s, istr::to_estr(x.ident));
         end(s);
     }
     commasep(s, inconsistent, decl.inputs, print_arg);
@@ -1266,7 +1269,7 @@ fn print_type_params(s: &ps, params: &[ast::ty_param]) {
         word(s.s, "<");
         fn printParam(s: &ps, param: &ast::ty_param) {
             print_kind(s, param.kind);
-            word(s.s, param.ident);
+            word(s.s, istr::to_estr(param.ident));
         }
         commasep(s, inconsistent, params, printParam);
         word(s.s, ">");
@@ -1276,14 +1279,14 @@ fn print_type_params(s: &ps, params: &[ast::ty_param]) {
 fn print_meta_item(s: &ps, item: &@ast::meta_item) {
     ibox(s, indent_unit);
     alt item.node {
-      ast::meta_word(name) { word(s.s, name); }
+      ast::meta_word(name) { word(s.s, istr::to_estr(name)); }
       ast::meta_name_value(name, value) {
-        word_space(s, name);
+        word_space(s, istr::to_estr(name));
         word_space(s, "=");
         print_literal(s, @value);
       }
       ast::meta_list(name, items) {
-        word(s.s, name);
+        word(s.s, istr::to_estr(name));
         popen(s);
         commasep(s, consistent, items, print_meta_item);
         pclose(s);
@@ -1298,7 +1301,7 @@ fn print_view_item(s: &ps, item: &@ast::view_item) {
     alt item.node {
       ast::view_item_use(id, mta, _) {
         head(s, "use");
-        word(s.s, id);
+        word(s.s, istr::to_estr(id));
         if vec::len(mta) > 0u {
             popen(s);
             commasep(s, consistent, mta, print_meta_item);
@@ -1307,38 +1310,43 @@ fn print_view_item(s: &ps, item: &@ast::view_item) {
       }
       ast::view_item_import(id, ids, _) {
         head(s, "import");
-        if !str::eq(id, ids[vec::len(ids) - 1u]) {
-            word_space(s, id);
+        if !istr::eq(id, ids[vec::len(ids) - 1u]) {
+            word_space(s, istr::to_estr(id));
             word_space(s, "=");
         }
         let first = true;
-        for elt: str in ids {
+        for elt: ast::ident in ids {
             if first { first = false; } else { word(s.s, "::"); }
-            word(s.s, elt);
+            word(s.s, istr::to_estr(elt));
         }
       }
       ast::view_item_import_from(mod_path, idents, _) {
         head(s, "import");
-        for elt: str in mod_path { word(s.s, elt); word(s.s, "::"); }
+        for elt: ast::ident in mod_path {
+            word(s.s, istr::to_estr(elt)); word(s.s, "::");
+        }
         word(s.s, "{");
         commasep(s, inconsistent, idents,
                  fn (s: &ps, w: &ast::import_ident) {
-                     word(s.s, w.node.name)
+                     word(s.s, istr::to_estr(w.node.name))
                  });
         word(s.s, "}");
       }
       ast::view_item_import_glob(ids, _) {
         head(s, "import");
         let first = true;
-        for elt: str in ids {
+        for elt: ast::ident in ids {
             if first { first = false; } else { word(s.s, "::"); }
-            word(s.s, elt);
+            word(s.s, istr::to_estr(elt));
         }
         word(s.s, "::*");
       }
       ast::view_item_export(ids, _) {
         head(s, "export");
-        commasep(s, inconsistent, ids, fn (s: &ps, w: &str) { word(s.s, w) });
+        commasep(s, inconsistent, ids,
+                 fn (s: &ps, w: &ast::ident) {
+                     word(s.s, istr::to_estr(w))
+                 });
       }
     }
     word(s.s, ";");
@@ -1402,12 +1410,18 @@ fn print_mt(s: &ps, mt: &ast::mt) {
     print_type(s, mt.ty);
 }
 
-fn print_ty_fn(s: &ps, proto: &ast::proto, id: &option::t<str>,
+fn print_ty_fn(s: &ps, proto: &ast::proto, id: &option::t<ast::ident>,
                inputs: &[ast::ty_arg], output: &@ast::ty,
                cf: &ast::controlflow, constrs: &[@ast::constr]) {
     ibox(s, indent_unit);
     word(s.s, proto_to_str(proto));
-    alt id { some(id) { word(s.s, " "); word(s.s, id); } _ { } }
+    alt id {
+      some(id) {
+        word(s.s, " ");
+        word(s.s, istr::to_estr(id));
+      }
+      _ { }
+    }
     zerobreak(s.s);
     popen(s);
     fn print_arg(s: &ps, input: &ast::ty_arg) {
@@ -1680,7 +1694,7 @@ fn ast_ty_fn_constrs_str(constrs: &[@ast::constr]) -> str {
 }
 
 fn fn_arg_idx_to_str(decl: &ast::fn_decl, idx: &uint) -> str {
-    decl.inputs[idx].ident
+    istr::to_estr(decl.inputs[idx].ident)
 }
 
 fn ast_fn_constr_to_str(decl: &ast::fn_decl, c: &@ast::constr) -> str {
diff --git a/src/comp/util/common.rs b/src/comp/util/common.rs
index f531f4c1e0c..7afad61064d 100644
--- a/src/comp/util/common.rs
+++ b/src/comp/util/common.rs
@@ -70,11 +70,11 @@ fn log_block_err(b: &ast::blk) { log_err print::pprust::block_to_str(b); }
 
 fn log_item_err(i: &@ast::item) { log_err print::pprust::item_to_str(i); }
 
-fn log_fn(f: &ast::_fn, name: str, params: &[ast::ty_param]) {
+fn log_fn(f: &ast::_fn, name: &ast::ident, params: &[ast::ty_param]) {
     log print::pprust::fun_to_str(f, name, params);
 }
 
-fn log_fn_err(f: &ast::_fn, name: str, params: &[ast::ty_param]) {
+fn log_fn_err(f: &ast::_fn, name: &ast::ident, params: &[ast::ty_param]) {
     log_err print::pprust::fun_to_str(f, name, params);
 }
 
@@ -154,8 +154,8 @@ fn call_kind_str(c: call_kind) -> str {
     }
 }
 
-fn is_main_name(path: &[str]) -> bool {
-    str::eq(option::get(std::vec::last(path)), "main")
+fn is_main_name(path: &[ast::ident]) -> bool {
+    istr::eq(option::get(std::vec::last(path)), ~"main")
 }
 
 // FIXME mode this to std::float when editing the stdlib no longer
diff --git a/src/comp/util/ppaux.rs b/src/comp/util/ppaux.rs
index 259482bc9b3..88d419ae0ce 100644
--- a/src/comp/util/ppaux.rs
+++ b/src/comp/util/ppaux.rs
@@ -38,16 +38,16 @@ fn mode_str_1(m: &ty::mode) -> str {
 fn fn_ident_to_string(id: ast::node_id, i: &ast::fn_ident) -> str {
     ret alt i {
       none. { istr::to_estr(~"anon" + int::str(id)) }
-      some(s) { s }
+      some(s) { istr::to_estr(s) }
     };
 }
 
 fn get_id_ident(cx: &ctxt, id: ast::def_id) -> str {
     if id.crate != ast::local_crate {
-        str::connect(cx.ext_map.get(id), "::")
+        str::connect(istr::to_estrs(cx.ext_map.get(id)), "::")
     } else {
         alt cx.items.find(id.node) {
-          some(ast_map::node_item(it)) { it.ident }
+          some(ast_map::node_item(it)) { istr::to_estr(it.ident) }
           _ { fail "get_id_ident: can't find item in ast_map" }
         }
     }
@@ -63,7 +63,13 @@ fn ty_to_str(cx: &ctxt, typ: &t) -> str {
                  inputs: &[arg], output: t, cf: ast::controlflow,
                  constrs: &[@constr]) -> str {
         let s = proto_to_str(proto);
-        alt ident { some(i) { s += " "; s += i; } _ { } }
+        alt ident {
+          some(i) {
+            s += " ";
+            s += istr::to_estr(i);
+          }
+          _ { }
+        }
         s += "(";
         let strs = [];
         for a: arg in inputs { strs += [fn_input_to_str(cx, a)]; }
@@ -83,7 +89,7 @@ fn ty_to_str(cx: &ctxt, typ: &t) -> str {
                       m.output, m.cf, m.constrs) + ";";
     }
     fn field_to_str(cx: &ctxt, f: &field) -> str {
-        ret f.ident + ": " + mt_to_str(cx, f.mt);
+        ret istr::to_estr(f.ident) + ": " + mt_to_str(cx, f.mt);
     }
     fn mt_to_str(cx: &ctxt, m: &mt) -> str {
         let mstr;