diff --git a/src/rustc/middle/trans/base.rs b/src/rustc/middle/trans/base.rs
index 21b9549cf822979a1bd835c78f44caf98da140b1..d46a47f0bd0e7d6d98eed38bedfc016f447be13b 100644
--- a/src/rustc/middle/trans/base.rs
+++ b/src/rustc/middle/trans/base.rs
@@ -706,12 +706,6 @@ fn make_free_glue(bcx: block, v: ValueRef, t: ty::t) {
         let bcx = drop_ty(bcx, body, body_mt.ty);
         trans_free(bcx, v)
       }
-
-      ty::ty_estr(ty::vstore_box) {
-        let v = PointerCast(bcx, v, type_of(ccx, t));
-        trans_free(bcx, v)
-      }
-
       ty::ty_opaque_box {
         let v = PointerCast(bcx, v, type_of(ccx, t));
         let td = Load(bcx, GEPi(bcx, v, [0u, abi::box_field_tydesc]));
@@ -725,8 +719,11 @@ fn make_free_glue(bcx: block, v: ValueRef, t: ty::t) {
         uniq::make_free_glue(bcx, v, t)
       }
       ty::ty_evec(_, ty::vstore_uniq) | ty::ty_estr(ty::vstore_uniq) |
+      ty::ty_evec(_, ty::vstore_box) | ty::ty_estr(ty::vstore_box) |
       ty::ty_vec(_) | ty::ty_str {
-        tvec::make_free_glue(bcx, PointerCast(bcx, v, type_of(ccx, t)), t)
+        make_free_glue(bcx, v,
+                       tvec::expand_boxed_vec_ty(bcx.tcx(), t));
+        ret;
       }
       ty::ty_evec(_, _) {
           bcx.sess().unimpl("trans::base::make_free_glue on other evec");
@@ -794,6 +791,9 @@ fn make_drop_glue(bcx: block, v0: ValueRef, t: ty::t) {
       ty::ty_evec(_, ty::vstore_uniq) | ty::ty_estr(ty::vstore_uniq) {
         free_ty(bcx, Load(bcx, v0), t)
       }
+      ty::ty_unboxed_vec(_) {
+        tvec::make_drop_glue_unboxed(bcx, v0, t)
+      }
       ty::ty_res(did, inner, substs) {
         trans_res_drop(bcx, v0, did, inner, substs.tps)
       }
diff --git a/src/rustc/middle/trans/shape.rs b/src/rustc/middle/trans/shape.rs
index cfd779460eb34b8a7bb35909a433236a7858828a..1d35d6548ae001fbf670c26dd05a35b88d419301 100644
--- a/src/rustc/middle/trans/shape.rs
+++ b/src/rustc/middle/trans/shape.rs
@@ -277,8 +277,7 @@ fn shape_of(ccx: @crate_ctxt, t: ty::t) -> [u8] {
       }
       ty::ty_evec(mt, ty::vstore_uniq) |
       ty::ty_vec(mt) {
-        shape_of(ccx,
-                 ty::mk_imm_uniq(ccx.tcx, ty::mk_unboxed_vec(ccx.tcx, mt)))
+        shape_of(ccx, tvec::expand_boxed_vec_ty(ccx.tcx, t))
       }
 
       ty::ty_estr(ty::vstore_fixed(n)) {
diff --git a/src/rustc/middle/trans/tvec.rs b/src/rustc/middle/trans/tvec.rs
index 1861f690f9eacbecc045a470cb546784d779829f..3a543b968b762becd3677b92dc64bdefadba0a00 100644
--- a/src/rustc/middle/trans/tvec.rs
+++ b/src/rustc/middle/trans/tvec.rs
@@ -5,13 +5,35 @@
 import base::{call_memmove,
                INIT, copy_val, load_if_immediate, get_tydesc,
                sub_block, do_spill_noroot,
-               dest, bcx_icx, non_gc_box_cast};
+               dest, bcx_icx, non_gc_box_cast,
+               heap, heap_exchange, heap_shared};
 import syntax::codemap::span;
 import shape::llsize_of;
 import build::*;
 import common::*;
 import util::ppaux::ty_to_str;
 
+// Boxed vector types are in some sense currently a "shorthand" for a box
+// containing an unboxed vector. This expands a boxed vector type into such an
+// expanded type. It doesn't respect mutability, but that doesn't matter at
+// this point.
+fn expand_boxed_vec_ty(tcx: ty::ctxt, t: ty::t) -> ty::t {
+    let unit_ty = ty::sequence_element_type(tcx, t);
+    let unboxed_vec_ty = ty::mk_mut_unboxed_vec(tcx, unit_ty);
+    alt ty::get(t).struct {
+      ty::ty_vec(_) | ty::ty_str |
+      ty::ty_estr(ty::vstore_uniq) | ty::ty_evec(_, ty::vstore_uniq) {
+        ty::mk_imm_uniq(tcx, unboxed_vec_ty)
+      }
+      ty::ty_estr(ty::vstore_box) | ty::ty_evec(_, ty::vstore_box) {
+        ty::mk_imm_box(tcx, unboxed_vec_ty)
+      }
+      _ { tcx.sess.bug("non boxed-vec type \
+                        in tvec::expand_boxed_vec_ty");
+      }
+    }
+}
+
 fn get_fill(bcx: block, vptr: ValueRef) -> ValueRef {
     let _icx = bcx.insn_ctxt("tvec::get_fill");
     Load(bcx, GEPi(bcx, vptr, [0u, abi::vec_elt_fill]))
@@ -40,21 +62,25 @@ fn pointer_add(bcx: block, ptr: ValueRef, bytes: ValueRef) -> ValueRef {
     ret PointerCast(bcx, InBoundsGEP(bcx, bptr, [bytes]), old_ty);
 }
 
-fn alloc_uniq_raw(bcx: block, unit_ty: ty::t,
-                  fill: ValueRef, alloc: ValueRef) -> result {
-    let _icx = bcx.insn_ctxt("tvec::alloc_uniq_raw");
+fn alloc_raw(bcx: block, unit_ty: ty::t,
+              fill: ValueRef, alloc: ValueRef, heap: heap) -> result {
+    let _icx = bcx.insn_ctxt("tvec::alloc_uniq");
     let ccx = bcx.ccx();
 
     let vecbodyty = ty::mk_mut_unboxed_vec(bcx.tcx(), unit_ty);
     let vecsize = Add(bcx, alloc, llsize_of(ccx, ccx.opaque_vec_type));
 
-    let {box, body} = base::malloc_unique_dyn(bcx, vecbodyty, vecsize);
+    let {box, body} = base::malloc_general_dyn(bcx, vecbodyty, heap, vecsize);
     Store(bcx, fill, GEPi(bcx, body, [0u, abi::vec_elt_fill]));
     Store(bcx, alloc, GEPi(bcx, body, [0u, abi::vec_elt_alloc]));
     ret {bcx: bcx, val: box};
 }
+fn alloc_uniq_raw(bcx: block, unit_ty: ty::t,
+                  fill: ValueRef, alloc: ValueRef) -> result {
+    alloc_raw(bcx, unit_ty, fill, alloc, heap_exchange)
+}
 
-fn alloc_uniq(bcx: block, unit_ty: ty::t, elts: uint) -> result {
+fn alloc_vec(bcx: block, unit_ty: ty::t, elts: uint, heap: heap) -> result {
     let _icx = bcx.insn_ctxt("tvec::alloc_uniq");
     let ccx = bcx.ccx();
     let llunitty = type_of::type_of(ccx, unit_ty);
@@ -63,7 +89,7 @@ fn alloc_uniq(bcx: block, unit_ty: ty::t, elts: uint) -> result {
     let fill = Mul(bcx, C_uint(ccx, elts), unit_sz);
     let alloc = if elts < 4u { Mul(bcx, C_int(ccx, 4), unit_sz) }
                 else { fill };
-    let {bcx: bcx, val: vptr} = alloc_uniq_raw(bcx, unit_ty, fill, alloc);
+    let {bcx: bcx, val: vptr} = alloc_raw(bcx, unit_ty, fill, alloc, heap);
     ret {bcx: bcx, val: vptr};
 }
 
@@ -79,20 +105,18 @@ fn duplicate_uniq(bcx: block, vptr: ValueRef, vec_ty: ty::t) -> result {
     call_memmove(bcx, new_data_ptr, data_ptr, fill);
 
     let bcx = if ty::type_needs_drop(bcx.tcx(), unit_ty) {
-        iter_vec(bcx, newptr, vec_ty, base::take_ty)
+        iter_vec_raw(bcx, new_data_ptr, vec_ty, fill, base::take_ty)
     } else { bcx };
     ret rslt(bcx, newptr);
 }
-fn make_free_glue(bcx: block, vptr: ValueRef, vec_ty: ty::t) ->
+
+fn make_drop_glue_unboxed(bcx: block, vptr: ValueRef, vec_ty: ty::t) ->
    block {
-    let _icx = bcx.insn_ctxt("tvec::make_free_glue");
+    let _icx = bcx.insn_ctxt("tvec::make_drop_glue_unboxed");
     let tcx = bcx.tcx(), unit_ty = ty::sequence_element_type(tcx, vec_ty);
-    base::with_cond(bcx, IsNotNull(bcx, vptr)) {|bcx|
-        let bcx = if ty::type_needs_drop(tcx, unit_ty) {
-            iter_vec(bcx, vptr, vec_ty, base::drop_ty)
-        } else { bcx };
-        base::trans_unique_free(bcx, vptr)
-    }
+    if ty::type_needs_drop(tcx, unit_ty) {
+        iter_vec_unboxed(bcx, vptr, vec_ty, base::drop_ty)
+    } else { bcx }
 }
 
 fn trans_evec(bcx: block, args: [@ast::expr],
@@ -141,13 +165,18 @@ fn trans_evec(bcx: block, args: [@ast::expr],
             {bcx: bcx, val: p, dataptr: vp}
           }
           ast::vstore_uniq {
-            let {bcx, val} = alloc_uniq(bcx, unit_ty, args.len());
+            let {bcx, val} = alloc_vec(bcx, unit_ty, args.len(),
+                                       heap_exchange);
             add_clean_free(bcx, val, true);
             let dataptr = get_dataptr(bcx, get_bodyptr(bcx, val));
             {bcx: bcx, val: val, dataptr: dataptr}
           }
           ast::vstore_box {
-            bcx.ccx().sess.unimpl("unhandled tvec::trans_evec");
+            let {bcx, val} = alloc_vec(bcx, unit_ty, args.len(),
+                                       heap_shared);
+            add_clean_free(bcx, val, true);
+            let dataptr = get_dataptr(bcx, get_bodyptr(bcx, val));
+            {bcx: bcx, val: val, dataptr: dataptr}
           }
         };
 
@@ -223,13 +252,11 @@ fn get_base_and_len(cx: block, v: ValueRef, e_ty: ty::t)
         let len = Load(cx, GEPi(cx, v, [0u, abi::slice_elt_len]));
         (base, len)
       }
-      ty::vstore_uniq {
+      ty::vstore_uniq | ty::vstore_box {
+        #debug["get_base_and_len: %s", val_str(ccx.tn, v)];
         let body = tvec::get_bodyptr(cx, v);
         (tvec::get_dataptr(cx, body), tvec::get_fill(cx, body))
       }
-      ty::vstore_box {
-        cx.ccx().sess.unimpl("unhandled tvec::get_base_and_len");
-      }
     }
 }
 
@@ -388,7 +415,7 @@ fn trans_add(bcx: block, vec_ty: ty::t, lhs: ValueRef,
 
 fn iter_vec_raw(bcx: block, data_ptr: ValueRef, vec_ty: ty::t,
                 fill: ValueRef, f: iter_vec_block) -> block {
-    let _icx = bcx.insn_ctxt("tvec::iter_vec_uniq");
+    let _icx = bcx.insn_ctxt("tvec::iter_vec_raw");
 
     let unit_ty = ty::sequence_element_type(bcx.tcx(), vec_ty);
 
@@ -422,11 +449,12 @@ fn iter_vec_uniq(bcx: block, vptr: ValueRef, vec_ty: ty::t,
     iter_vec_raw(bcx, data_ptr, vec_ty, fill, f)
 }
 
-fn iter_vec(bcx: block, vptr: ValueRef, vec_ty: ty::t,
-            f: iter_vec_block) -> block {
-    let _icx = bcx.insn_ctxt("tvec::iter_vec");
-    let fill = get_fill(bcx, get_bodyptr(bcx, vptr));
-    ret iter_vec_uniq(bcx, vptr, vec_ty, fill, f);
+fn iter_vec_unboxed(bcx: block, body_ptr: ValueRef, vec_ty: ty::t,
+                    f: iter_vec_block) -> block {
+    let _icx = bcx.insn_ctxt("tvec::iter_vec_unboxed");
+    let fill = get_fill(bcx, body_ptr);
+    let dataptr = get_dataptr(bcx, body_ptr);
+    ret iter_vec_raw(bcx, dataptr, vec_ty, fill, f);
 }
 
 //
diff --git a/src/rustc/middle/trans/type_of.rs b/src/rustc/middle/trans/type_of.rs
index fb9112fc751ff88c0209d5d585f5db8e60444b4d..760b2b4ee0afb105cc33788ad248cfb009152fe7 100644
--- a/src/rustc/middle/trans/type_of.rs
+++ b/src/rustc/middle/trans/type_of.rs
@@ -91,7 +91,9 @@ fn type_of(cx: @crate_ctxt, t: ty::t) -> TypeRef {
           }
           ty::ty_enum(did, _) { type_of_enum(cx, did, t) }
           ty::ty_estr(ty::vstore_box) { T_box_ptr(T_box(cx, T_i8())) }
-          ty::ty_evec(mt, ty::vstore_box) |
+          ty::ty_evec(mt, ty::vstore_box) { 
+            T_box_ptr(T_box(cx, T_vec(cx, type_of(cx, mt.ty))))
+          }
           ty::ty_box(mt) { T_box_ptr(T_box(cx, type_of(cx, mt.ty))) }
           ty::ty_opaque_box { T_box_ptr(T_box(cx, T_i8())) }
           ty::ty_uniq(mt) { T_unique_ptr(T_unique(cx, type_of(cx, mt.ty))) }
diff --git a/src/rustc/middle/ty.rs b/src/rustc/middle/ty.rs
index a76a8143a89e3f9f8f5bdd02bed3cfc5ec673df0..0d4cc92b1ef85dca94db83bb7704a6fe41f8b270 100644
--- a/src/rustc/middle/ty.rs
+++ b/src/rustc/middle/ty.rs
@@ -1112,7 +1112,7 @@ fn type_is_str(ty: t) -> bool {
 fn sequence_element_type(cx: ctxt, ty: t) -> t {
     alt get(ty).struct {
       ty_str | ty_estr(_) { ret mk_mach_uint(cx, ast::ty_u8); }
-      ty_vec(mt) | ty_evec(mt, _) { ret mt.ty; }
+      ty_vec(mt) | ty_evec(mt, _) | ty_unboxed_vec(mt) { ret mt.ty; }
       _ { cx.sess.bug("sequence_element_type called on non-sequence value"); }
     }
 }
@@ -1134,7 +1134,8 @@ fn get_element_type(ty: t, i: uint) -> t {
 
 pure fn type_is_boxed(ty: t) -> bool {
     alt get(ty).struct {
-      ty_box(_) | ty_opaque_box { true }
+      ty_box(_) | ty_opaque_box |
+      ty_evec(_, vstore_box) | ty_estr(vstore_box) { true }
       _ { false }
     }
 }
@@ -1212,6 +1213,7 @@ fn type_needs_drop(cx: ctxt, ty: t) -> bool {
       ty_estr(vstore_fixed(_)) | ty_estr(vstore_slice(_)) |
       ty_evec(_, vstore_slice(_)) { false }
       ty_evec(mt, vstore_fixed(_)) { type_needs_drop(cx, mt.ty) }
+      ty_unboxed_vec(mt) { type_needs_drop(cx, mt.ty) }
       ty_rec(flds) {
         for flds.each {|f| if type_needs_drop(cx, f.mt.ty) { accum = true; } }
         accum