diff --git a/src/rt/rust_upcall.cpp b/src/rt/rust_upcall.cpp
index 4753850ca59..f43d819891a 100644
--- a/src/rt/rust_upcall.cpp
+++ b/src/rt/rust_upcall.cpp
@@ -290,23 +290,66 @@ upcall_shared_realloc(void *ptr, size_t size) {
 
 /**********************************************************************/
 
-struct s_str_new_args {
+struct s_str_new_uniq_args {
     const char *cstr;
     size_t len;
     rust_str *retval;
 };
 
 extern "C" CDECL void
-upcall_s_str_new(s_str_new_args *args) {
+upcall_s_str_new_uniq(s_str_new_uniq_args *args) {
     rust_task *task = rust_get_current_task();
     LOG_UPCALL_ENTRY(task);
-    args->retval = make_str(task->kernel, args->cstr, args->len, "str_new");
+    args->retval = make_str(task->kernel, args->cstr, args->len,
+                            "str_new_uniq");
 }
 
+extern "C" CDECL rust_str*
+upcall_str_new_uniq(const char *cstr, size_t len) {
+    s_str_new_uniq_args args = { cstr, len, 0 };
+    UPCALL_SWITCH_STACK(&args, upcall_s_str_new_uniq);
+    return args.retval;
+}
+
+// FIXME: this is an old compatibility-name for upcall_str_new_uniq
+// can remove after next snapshot.
 extern "C" CDECL rust_str*
 upcall_str_new(const char *cstr, size_t len) {
-    s_str_new_args args = { cstr, len, 0 };
-    UPCALL_SWITCH_STACK(&args, upcall_s_str_new);
+    s_str_new_uniq_args args = { cstr, len, 0 };
+    UPCALL_SWITCH_STACK(&args, upcall_s_str_new_uniq);
+    return args.retval;
+}
+
+
+
+struct s_str_new_shared_args {
+    const char *cstr;
+    size_t len;
+    rust_opaque_box *retval;
+};
+
+extern "C" CDECL void
+upcall_s_str_new_shared(s_str_new_shared_args *args) {
+    rust_task *task = rust_get_current_task();
+    LOG_UPCALL_ENTRY(task);
+
+    size_t str_fill = args->len + 1;
+    size_t str_alloc = str_fill;
+    args->retval = (rust_opaque_box *)
+        task->kernel->malloc(sizeof(rust_opaque_box) +
+                             vec_size<char>(str_fill),
+                             "str_new_shared");
+    rust_str *str = (rust_str *)box_body(args->retval);
+    str->fill = str_fill;
+    str->alloc = str_alloc;
+    memcpy(&str->data, args->cstr, args->len);
+    str->data[args->len] = '\0';
+}
+
+extern "C" CDECL rust_opaque_box*
+upcall_str_new_shared(const char *cstr, size_t len) {
+    s_str_new_shared_args args = { cstr, len, 0 };
+    UPCALL_SWITCH_STACK(&args, upcall_s_str_new_shared);
     return args.retval;
 }
 
diff --git a/src/rt/rustrt.def.in b/src/rt/rustrt.def.in
index 171718b64f2..aa0082a82be 100644
--- a/src/rt/rustrt.def.in
+++ b/src/rt/rustrt.def.in
@@ -76,6 +76,8 @@ upcall_shared_free
 upcall_shared_realloc
 upcall_vec_grow
 upcall_str_new
+upcall_str_new_uniq
+upcall_str_new_shared
 upcall_str_concat
 upcall_call_shim_on_c_stack
 upcall_call_shim_on_rust_stack
diff --git a/src/rustc/back/abi.rs b/src/rustc/back/abi.rs
index c02960deb00..4379a35f5f6 100644
--- a/src/rustc/back/abi.rs
+++ b/src/rustc/back/abi.rs
@@ -71,6 +71,9 @@ const vec_elt_alloc: int = 1;
 
 const vec_elt_elems: int = 2;
 
+const slice_elt_base: int = 0;
+const slice_elt_len: int = 1;
+
 const worst_case_glue_call_args: int = 7;
 
 const abi_version: uint = 1u;
diff --git a/src/rustc/back/upcall.rs b/src/rustc/back/upcall.rs
index b1b60c3b127..f43ef4a5c12 100644
--- a/src/rustc/back/upcall.rs
+++ b/src/rustc/back/upcall.rs
@@ -17,7 +17,8 @@ type upcalls =
      shared_realloc: ValueRef,
      mark: ValueRef,
      vec_grow: ValueRef,
-     str_new: ValueRef,
+     str_new_uniq: ValueRef,
+     str_new_shared: ValueRef,
      str_concat: ValueRef,
      cmp_type: ValueRef,
      log_type: ValueRef,
@@ -65,8 +66,10 @@ fn declare_upcalls(targ_cfg: @session::config,
               d("mark", [T_ptr(T_i8())], int_t),
           vec_grow:
               dv("vec_grow", [T_ptr(T_ptr(opaque_vec_t)), int_t]),
-          str_new:
-              d("str_new", [T_ptr(T_i8()), int_t], T_ptr(opaque_vec_t)),
+          str_new_uniq:
+              d("str_new_uniq", [T_ptr(T_i8()), int_t], T_ptr(opaque_vec_t)),
+          str_new_shared:
+              d("str_new_shared", [T_ptr(T_i8()), int_t], T_ptr(T_i8())),
           str_concat:
               d("str_concat", [T_ptr(opaque_vec_t), T_ptr(opaque_vec_t)],
                 T_ptr(opaque_vec_t)),
diff --git a/src/rustc/middle/trans/alt.rs b/src/rustc/middle/trans/alt.rs
index a92385268bb..3ce6d9ed62a 100644
--- a/src/rustc/middle/trans/alt.rs
+++ b/src/rustc/middle/trans/alt.rs
@@ -49,7 +49,7 @@ fn trans_opt(bcx: block, o: opt) -> opt_result {
           ast::expr_lit(@{node: ast::lit_str(s), _}) {
             let strty = ty::mk_str(bcx.tcx());
             let cell = empty_dest_cell();
-            bcx = tvec::trans_str(bcx, s, by_val(cell));
+            bcx = tvec::trans_estr(bcx, s, ast::vstore_uniq, by_val(cell));
             add_clean_temp(bcx, *cell, strty);
             ret single_result(rslt(bcx, *cell));
           }
diff --git a/src/rustc/middle/trans/base.rs b/src/rustc/middle/trans/base.rs
index 849d8af21b4..2a57766d66f 100644
--- a/src/rustc/middle/trans/base.rs
+++ b/src/rustc/middle/trans/base.rs
@@ -673,10 +673,11 @@ fn make_drop_glue(bcx: block, v0: ValueRef, t: ty::t) {
     let ccx = bcx.ccx();
     let bcx = alt ty::get(t).struct {
       ty::ty_box(_) | ty::ty_opaque_box |
-      ty::ty_estr(ty::vstore_box) {
+      ty::ty_estr(ty::vstore_box) | ty::ty_evec(_, ty::vstore_box) {
         decr_refcnt_maybe_free(bcx, Load(bcx, v0), t)
       }
-      ty::ty_uniq(_) | ty::ty_vec(_) | ty::ty_str {
+      ty::ty_uniq(_) | ty::ty_vec(_) | ty::ty_str |
+      ty::ty_evec(_, ty::vstore_uniq) | ty::ty_estr(ty::vstore_uniq) {
         free_ty(bcx, Load(bcx, v0), t)
       }
       ty::ty_res(did, inner, tps) {
@@ -1328,7 +1329,7 @@ fn trans_lit(cx: block, lit: ast::lit, dest: dest) -> block {
     let _icx = cx.insn_ctxt("trans_lit");
     if dest == ignore { ret cx; }
     alt lit.node {
-      ast::lit_str(s) { tvec::trans_str(cx, s, dest) }
+      ast::lit_str(s) { tvec::trans_estr(cx, s, ast::vstore_uniq, dest) }
       _ {
         store_in_dest(cx, trans_crate_lit(cx.ccx(), lit), dest)
       }
@@ -2294,16 +2295,18 @@ fn trans_index(cx: block, ex: @ast::expr, base: @ast::expr,
         let body = GEPi(bcx, v, [0, 0]);
         (lim, body)
       }
+
       ty::ty_estr(ty::vstore_slice(_)) |
       ty::ty_evec(_, ty::vstore_slice(_)) {
-        let body = Load(bcx, GEPi(bcx, v, [0, 0]));
-        let lim = Load(bcx, GEPi(bcx, v, [0, 1]));
+        let body = Load(bcx, GEPi(bcx, v, [0, abi::slice_elt_base]));
+        let lim = Load(bcx, GEPi(bcx, v, [0, abi::slice_elt_len]));
         (lim, body)
       }
 
-      ty::ty_estr(_) | ty::ty_evec(_, _) {
+      ty::ty_estr(ty::vstore_box) | ty::ty_evec(_, ty::vstore_box) {
         bcx.sess().unimpl(#fmt("unsupported evec/estr type trans_index"));
       }
+
       _ {
         let lim = tvec::get_fill(bcx, v);
         let body = tvec::get_dataptr(bcx, v, type_of(ccx, unit_ty));
diff --git a/src/rustc/middle/trans/tvec.rs b/src/rustc/middle/trans/tvec.rs
index 1008d9ed8c6..50224c0d413 100644
--- a/src/rustc/middle/trans/tvec.rs
+++ b/src/rustc/middle/trans/tvec.rs
@@ -134,7 +134,7 @@ fn trans_vstore(bcx: block, e: @ast::expr,
                 v: ast::vstore, dest: dest) -> block {
     alt e.node {
       ast::expr_lit(@{node: ast::lit_str(s), span: _}) {
-        ret trans_estr(bcx, s, v, e.span, dest);
+        ret trans_estr(bcx, s, v, dest);
       }
       ast::expr_vec(es, mutbl) {
         bcx.ccx().sess.span_unimpl(e.span, "unhandled tvec::trans_vstore");
@@ -146,7 +146,7 @@ fn trans_vstore(bcx: block, e: @ast::expr,
 }
 
 fn trans_estr(bcx: block, s: str, vstore: ast::vstore,
-              sp: span, dest: dest) -> block {
+              dest: dest) -> block {
     let _icx = bcx.insn_ctxt("tvec::trans_estr");
     let ccx = bcx.ccx();
 
@@ -165,8 +165,16 @@ fn trans_estr(bcx: block, s: str, vstore: ast::vstore,
         C_struct([cs, C_uint(ccx, str::len(s))])
       }
 
-      _ {
-        bcx.ccx().sess.span_unimpl(sp, "unhandled tvec::trans_estr");
+      ast::vstore_uniq {
+        let cs = PointerCast(bcx, C_cstr(ccx, s), T_ptr(T_i8()));
+        let len = C_uint(ccx, str::len(s));
+        Call(bcx, ccx.upcalls.str_new_uniq, [cs, len])
+      }
+
+      ast::vstore_box {
+        let cs = PointerCast(bcx, C_cstr(ccx, s), T_ptr(T_i8()));
+        let len = C_uint(ccx, str::len(s));
+        Call(bcx, ccx.upcalls.str_new_shared, [cs, len])
       }
     };
 
@@ -174,15 +182,6 @@ fn trans_estr(bcx: block, s: str, vstore: ast::vstore,
     base::store_in_dest(bcx, c, dest)
 }
 
-fn trans_str(bcx: block, s: str, dest: dest) -> block {
-    let _icx = bcx.insn_ctxt("tvec::trans_str");
-    let ccx = bcx.ccx();
-    let cs = PointerCast(bcx, C_cstr(ccx, s), T_ptr(T_i8()));
-    let len = C_uint(ccx, str::len(s));
-    let n = Call(bcx, ccx.upcalls.str_new, [cs, len]);
-    ret base::store_in_dest(bcx, n, dest);
-}
-
 fn trans_append(bcx: block, vec_ty: ty::t, lhsptr: ValueRef,
                 rhs: ValueRef) -> block {
     let _icx = bcx.insn_ctxt("tvec::trans_append");
diff --git a/src/test/run-pass/estr-uniq.rs b/src/test/run-pass/estr-uniq.rs
index 178f1c8c26b..07b7fcf58d6 100644
--- a/src/test/run-pass/estr-uniq.rs
+++ b/src/test/run-pass/estr-uniq.rs
@@ -1,4 +1,8 @@
-// xfail-test
 fn main() {
     let x : str/~ = "hello"/~;
+    let _y : str/~ = "there"/~;
+    let mut z = "thing"/~;
+    z = x;
+    assert z[0] == ('h' as u8);
+    assert z[4] == ('o' as u8);
 }