diff --git a/src/librustc/driver/driver.rs b/src/librustc/driver/driver.rs
index 44c092d86977..355bc1376664 100644
--- a/src/librustc/driver/driver.rs
+++ b/src/librustc/driver/driver.rs
@@ -898,9 +898,9 @@ mod test {
                              getopts::fail_str(f))
             };
         let sessopts = build_session_options(
-            ~"rustc", matches, diagnostic::emit);
+            @~"rustc", matches, diagnostic::emit);
         let sess = build_session(sessopts, diagnostic::emit);
-        let cfg = build_configuration(sess, ~"whatever", str_input(~""));
+        let cfg = build_configuration(sess, @~"whatever", str_input(~""));
         assert!((attr::contains_name(cfg, ~"test")));
     }
 
@@ -917,9 +917,9 @@ mod test {
               }
             };
         let sessopts = build_session_options(
-            ~"rustc", matches, diagnostic::emit);
+            @~"rustc", matches, diagnostic::emit);
         let sess = build_session(sessopts, diagnostic::emit);
-        let cfg = build_configuration(sess, ~"whatever", str_input(~""));
+        let cfg = build_configuration(sess, @~"whatever", str_input(~""));
         let test_items = attr::find_meta_items_by_name(cfg, ~"test");
         assert!((vec::len(test_items) == 1u));
     }
diff --git a/src/librustc/middle/trans/common.rs b/src/librustc/middle/trans/common.rs
index f14096443b2b..cec9a95671e4 100644
--- a/src/librustc/middle/trans/common.rs
+++ b/src/librustc/middle/trans/common.rs
@@ -184,7 +184,7 @@ pub struct CrateContext {
      monomorphized: @mut HashMap<mono_id, ValueRef>,
      monomorphizing: @mut HashMap<ast::def_id, uint>,
      // Cache computed type parameter uses (see type_use.rs)
-     type_use_cache: @mut HashMap<ast::def_id, ~[type_use::type_uses]>,
+     type_use_cache: @mut HashMap<ast::def_id, @~[type_use::type_uses]>,
      // Cache generated vtables
      vtables: @mut HashMap<mono_id, ValueRef>,
      // Cache of constant strings,
diff --git a/src/librustc/middle/trans/monomorphize.rs b/src/librustc/middle/trans/monomorphize.rs
index 7aab6367d405..c6ade350e0bb 100644
--- a/src/librustc/middle/trans/monomorphize.rs
+++ b/src/librustc/middle/trans/monomorphize.rs
@@ -342,7 +342,7 @@ pub fn make_mono_id(ccx: @CrateContext,
                     substs: &[ty::t],
                     vtables: Option<typeck::vtable_res>,
                     impl_did_opt: Option<ast::def_id>,
-                    +param_uses: Option<~[type_use::type_uses]>) -> mono_id {
+                    param_uses: Option<@~[type_use::type_uses]>) -> mono_id {
     let precise_param_ids = match vtables {
       Some(vts) => {
         let item_ty = ty::lookup_item_type(ccx.tcx, item);
@@ -353,12 +353,12 @@ pub fn make_mono_id(ccx: @CrateContext,
                 match *bound {
                   ty::bound_trait(_) => {
                     v.push(meth::vtable_id(ccx, /*bad*/copy vts[i]));
-                    i += 1u;
+                    i += 1;
                   }
                   _ => ()
                 }
             }
-            (*subst, if v.len() > 0u { Some(v) } else { None })
+            (*subst, if !v.is_empty() { Some(v) } else { None })
         })
       }
       None => {
@@ -367,7 +367,7 @@ pub fn make_mono_id(ccx: @CrateContext,
     };
     let param_ids = match param_uses {
       Some(ref uses) => {
-        vec::map2(precise_param_ids, *uses, |id, uses| {
+        vec::map2(precise_param_ids, **uses, |id, uses| {
             if ccx.sess.no_monomorphic_collapse() {
                 match copy *id {
                     (a, b) => mono_precise(a, b)
@@ -377,7 +377,7 @@ pub fn make_mono_id(ccx: @CrateContext,
                     // XXX: Bad copy.
                     (a, copy b@Some(_)) => mono_precise(a, b),
                     (subst, None) => {
-                        if *uses == 0u {
+                        if *uses == 0 {
                             mono_any
                         } else if *uses == type_use::use_repr &&
                             !ty::type_needs_drop(ccx.tcx, subst)
diff --git a/src/librustc/middle/trans/type_use.rs b/src/librustc/middle/trans/type_use.rs
index 25e3ed0f400a..4094c597bbbe 100644
--- a/src/librustc/middle/trans/type_use.rs
+++ b/src/librustc/middle/trans/type_use.rs
@@ -47,9 +47,9 @@ use syntax::ast_util;
 use syntax::visit;
 
 pub type type_uses = uint; // Bitmask
-pub static use_repr: uint = 1u;   /* Dependency on size/alignment/mode and
+pub static use_repr: uint = 1;   /* Dependency on size/alignment/mode and
                                      take/drop glue */
-pub static use_tydesc: uint = 2u; /* Takes the tydesc, or compares */
+pub static use_tydesc: uint = 2; /* Takes the tydesc, or compares */
 
 pub struct Context {
     ccx: @CrateContext,
@@ -57,9 +57,9 @@ pub struct Context {
 }
 
 pub fn type_uses_for(ccx: @CrateContext, fn_id: def_id, n_tps: uint)
-    -> ~[type_uses] {
+    -> @~[type_uses] {
     match ccx.type_use_cache.find(&fn_id) {
-      Some(uses) => return /*bad*/ copy *uses,
+      Some(uses) => return *uses,
       None => ()
     }
 
@@ -70,11 +70,11 @@ pub fn type_uses_for(ccx: @CrateContext, fn_id: def_id, n_tps: uint)
     };
 
     // Conservatively assume full use for recursive loops
-    ccx.type_use_cache.insert(fn_id, vec::from_elem(n_tps, 3u));
+    ccx.type_use_cache.insert(fn_id, @vec::from_elem(n_tps, 3u));
 
     let cx = Context {
         ccx: ccx,
-        uses: @mut vec::from_elem(n_tps, 0u)
+        uses: @mut vec::from_elem(n_tps, 0)
     };
     match ty::get(ty::lookup_item_type(cx.ccx.tcx, fn_id).ty).sty {
         ty::ty_bare_fn(ty::BareFnTy {sig: ref sig, _}) |
@@ -92,8 +92,9 @@ pub fn type_uses_for(ccx: @CrateContext, fn_id: def_id, n_tps: uint)
     }
 
     if fn_id_loc.crate != local_crate {
-        let uses = copy *cx.uses;
-        ccx.type_use_cache.insert(fn_id, copy uses);
+        let Context { uses: @uses, _ } = cx;
+        let uses = @uses; // mutability
+        ccx.type_use_cache.insert(fn_id, uses);
         return uses;
     }
     let map_node = match ccx.tcx.items.find(&fn_id_loc.node) {
@@ -179,9 +180,9 @@ pub fn type_uses_for(ccx: @CrateContext, fn_id: def_id, n_tps: uint)
                                 ccx.tcx.sess.parse_sess.interner)));
       }
     }
-    // XXX: Bad copies, use @vec instead?
-    let uses = copy *cx.uses;
-    ccx.type_use_cache.insert(fn_id, copy uses);
+    let Context { uses: @uses, _ } = cx;
+    let uses = @uses; // mutability
+    ccx.type_use_cache.insert(fn_id, uses);
     uses
 }
 
@@ -253,7 +254,7 @@ pub fn mark_for_method_call(cx: Context, e_id: node_id, callee_id: node_id) {
                 //               before stage2
                 let ts = /*bad*/ copy **ts;
                 let type_uses = type_uses_for(cx.ccx, did, ts.len());
-                for vec::each2(type_uses, ts) |uses, subst| {
+                for vec::each2(*type_uses, ts) |uses, subst| {
                     type_needs(cx, *uses, *subst)
                 }
             }
@@ -302,7 +303,7 @@ pub fn mark_for_expr(cx: Context, e: @expr) {
             let ts = copy **ts;
             let id = ast_util::def_id_of_def(*cx.ccx.tcx.def_map.get(&e.id));
             let uses_for_ts = type_uses_for(cx.ccx, id, ts.len());
-            for vec::each2(uses_for_ts, ts) |uses, subst| {
+            for vec::each2(*uses_for_ts, ts) |uses, subst| {
                 type_needs(cx, *uses, *subst)
             }
         }
diff --git a/src/librustdoc/parse.rs b/src/librustdoc/parse.rs
index d09182e87f31..6c759e935b93 100644
--- a/src/librustdoc/parse.rs
+++ b/src/librustdoc/parse.rs
@@ -39,5 +39,5 @@ pub fn from_str_sess(sess: session::Session, source: ~str) -> @ast::crate {
 }
 
 fn cfg(sess: session::Session, input: driver::input) -> ast::crate_cfg {
-    driver::build_configuration(sess, ~"rustdoc", input)
+    driver::build_configuration(sess, @~"rustdoc", input)
 }
diff --git a/src/librusti/rusti.rc b/src/librusti/rusti.rc
index 8e4a58c766e5..e14a6e0e7409 100644
--- a/src/librusti/rusti.rc
+++ b/src/librusti/rusti.rc
@@ -127,7 +127,7 @@ fn record(repl: Repl, blk: @ast::blk, intr: @token::ident_interner) -> Repl {
 fn run(repl: Repl, input: ~str) -> Repl {
     let options = @session::options {
         crate_type: session::unknown_crate,
-        binary: repl.binary,
+        binary: @repl.binary,
         addl_lib_search_paths: repl.lib_search_paths.map(|p| Path(*p)),
         jit: true,
         .. *session::basic_options()
@@ -146,7 +146,7 @@ fn run(repl: Repl, input: ~str) -> Repl {
 
     debug!("building driver configuration");
     let cfg = driver::build_configuration(sess,
-                                          repl.binary,
+                                          @repl.binary,
                                           wrapped);
 
     let outputs = driver::build_output_filenames(wrapped, &None, &None, sess);
@@ -191,14 +191,14 @@ fn compile_crate(src_filename: ~str, binary: ~str) -> Option<bool> {
     match do task::try {
         let src_path = Path(src_filename);
         let options = @session::options {
-            binary: binary,
+            binary: @binary,
             addl_lib_search_paths: ~[os::getcwd()],
             .. *session::basic_options()
         };
         let input = driver::file_input(src_path);
         let sess = driver::build_session(options, diagnostic::emit);
         *sess.building_library = true;
-        let cfg = driver::build_configuration(sess, binary, input);
+        let cfg = driver::build_configuration(sess, @binary, input);
         let outputs = driver::build_output_filenames(
             input, &None, &None, sess);
         // If the library already exists and is newer than the source
diff --git a/src/librustpkg/rustpkg.rc b/src/librustpkg/rustpkg.rc
index f8805142769c..c28e790338db 100644
--- a/src/librustpkg/rustpkg.rc
+++ b/src/librustpkg/rustpkg.rc
@@ -76,13 +76,13 @@ impl PkgScript {
         // Build the rustc session data structures to pass
         // to the compiler
         let options = @session::options {
-            binary: binary,
+            binary: @binary,
             crate_type: session::bin_crate,
             .. *session::basic_options()
         };
         let input = driver::file_input(script);
         let sess = driver::build_session(options, diagnostic::emit);
-        let cfg = driver::build_configuration(sess, binary, input);
+        let cfg = driver::build_configuration(sess, @binary, input);
         let (crate, _) = driver::compile_upto(sess, cfg, input,
                                               driver::cu_parse, None);
         let work_dir = dest_dir(id);
diff --git a/src/librustpkg/util.rs b/src/librustpkg/util.rs
index 19938e8c5f17..c61a0025ff6d 100644
--- a/src/librustpkg/util.rs
+++ b/src/librustpkg/util.rs
@@ -467,7 +467,7 @@ pub fn compile_input(sysroot: Option<Path>,
         test: test,
         maybe_sysroot: sysroot,
         addl_lib_search_paths: ~[copy *out_dir],
-        .. *driver::build_session_options(binary, &matches, diagnostic::emit)
+        .. *driver::build_session_options(@binary, &matches, diagnostic::emit)
     };
     let mut crate_cfg = options.cfg;
 
@@ -499,7 +499,7 @@ pub fn compile_crate_from_input(input: driver::input, build_dir_opt: Option<Path
     debug!("Calling build_output_filenames with %?", build_dir_opt);
     let outputs = driver::build_output_filenames(input, &build_dir_opt, &None, sess);
     debug!("Outputs are %? and output type = %?", outputs, sess.opts.output_type);
-    let cfg = driver::build_configuration(sess, binary, input);
+    let cfg = driver::build_configuration(sess, @binary, input);
     match crate_opt {
         Some(c) => {
             debug!("Calling compile_rest, outputs = %?", outputs);