diff --git a/src/librustc/middle/const_eval.rs b/src/librustc/middle/const_eval.rs
index 68e40c75da84..e6d1a0ca27c4 100644
--- a/src/librustc/middle/const_eval.rs
+++ b/src/librustc/middle/const_eval.rs
@@ -92,7 +92,8 @@ fn classify(e: @expr,
                       ast::expr_vstore_fixed(_) |
                       ast::expr_vstore_slice => classify(e, def_map, tcx),
                       ast::expr_vstore_uniq |
-                      ast::expr_vstore_box => non_const
+                      ast::expr_vstore_box |
+                      ast::expr_vstore_mut_box => non_const
                   }
               }
 
diff --git a/src/librustc/middle/trans/expr.rs b/src/librustc/middle/trans/expr.rs
index c6b5b9fbfe0f..2e4d95acdfbd 100644
--- a/src/librustc/middle/trans/expr.rs
+++ b/src/librustc/middle/trans/expr.rs
@@ -392,7 +392,8 @@ fn trans_rvalue_datum_unadjusted(bcx: block, expr: @ast::expr) -> DatumBlock {
     trace_span!(bcx, expr.span, shorten(bcx.expr_to_str(expr)));
 
     match expr.node {
-        ast::expr_vstore(contents, ast::expr_vstore_box) => {
+        ast::expr_vstore(contents, ast::expr_vstore_box) |
+        ast::expr_vstore(contents, ast::expr_vstore_mut_box) => {
             return tvec::trans_uniq_or_managed_vstore(bcx, heap_shared,
                                                       expr, contents);
         }
diff --git a/src/librustc/middle/ty.rs b/src/librustc/middle/ty.rs
index 5f27e8665dd4..7d6f937f82d1 100644
--- a/src/librustc/middle/ty.rs
+++ b/src/librustc/middle/ty.rs
@@ -3187,6 +3187,7 @@ fn expr_kind(tcx: ctxt,
         ast::expr_addr_of(*) |
         ast::expr_binary(*) |
         ast::expr_vstore(_, ast::expr_vstore_box) |
+        ast::expr_vstore(_, ast::expr_vstore_mut_box) |
         ast::expr_vstore(_, ast::expr_vstore_uniq) => {
             RvalueDatumExpr
         }
diff --git a/src/librustc/middle/typeck/astconv.rs b/src/librustc/middle/typeck/astconv.rs
index f80b655a860b..4d0fdcdca406 100644
--- a/src/librustc/middle/typeck/astconv.rs
+++ b/src/librustc/middle/typeck/astconv.rs
@@ -176,13 +176,14 @@ fn ast_ty_to_ty<AC: ast_conv, RS: region_scope Copy Owned>(
         let tcx = self.tcx();
 
         match a_seq_ty.ty.node {
-            // to convert to an e{vec,str}, there can't be a
-            // mutability argument
-            _ if a_seq_ty.mutbl != ast::m_imm => (),
             ast::ty_vec(mt) => {
-                return ty::mk_evec(tcx, ast_mt_to_mt(self, rscope, mt), vst);
+                let mut mt = ast_mt_to_mt(self, rscope, mt);
+                if a_seq_ty.mutbl == ast::m_mutbl {
+                    mt = { ty: mt.ty, mutbl: ast::m_mutbl };
+                }
+                return ty::mk_evec(tcx, mt, vst);
             }
-            ast::ty_path(path, id) => {
+            ast::ty_path(path, id) if a_seq_ty.mutbl == ast::m_imm => {
                 match tcx.def_map.find(id) {
                     Some(ast::def_prim_ty(ast::ty_str)) => {
                         check_path_args(tcx, path, NO_TPS | NO_REGIONS);
diff --git a/src/librustc/middle/typeck/check.rs b/src/librustc/middle/typeck/check.rs
index ee93c7fccef9..b24550f2bc64 100644
--- a/src/librustc/middle/typeck/check.rs
+++ b/src/librustc/middle/typeck/check.rs
@@ -1705,9 +1705,14 @@ fn check_expr_with_unifier(fcx: @fn_ctxt,
           }
           ast::expr_vec(args, mutbl) => {
             let tt = ast_expr_vstore_to_vstore(fcx, ev, args.len(), vst);
+            let mutability;
+            match vst {
+                ast::expr_vstore_mut_box => mutability = ast::m_mutbl,
+                _ => mutability = mutbl
+            }
             let t: ty::t = fcx.infcx().next_ty_var();
             for args.each |e| { bot |= check_expr_with(fcx, *e, t); }
-            ty::mk_evec(tcx, {ty: t, mutbl: mutbl}, tt)
+            ty::mk_evec(tcx, {ty: t, mutbl: mutability}, tt)
           }
           ast::expr_repeat(element, count_expr, mutbl) => {
             let count = ty::eval_repeat_count(tcx, count_expr, expr.span);
@@ -2721,7 +2726,7 @@ fn ast_expr_vstore_to_vstore(fcx: @fn_ctxt, e: @ast::expr, n: uint,
             ty::vstore_fixed(u)
         }
         ast::expr_vstore_uniq => ty::vstore_uniq,
-        ast::expr_vstore_box => ty::vstore_box,
+        ast::expr_vstore_box | ast::expr_vstore_mut_box => ty::vstore_box,
         ast::expr_vstore_slice => {
             let r = fcx.infcx().next_region_var(e.span, e.id);
             ty::vstore_slice(r)
diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index da28e349a563..353bb26ea9ea 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -645,6 +645,7 @@ enum expr_vstore {
     expr_vstore_fixed(Option<uint>),   // [1,2,3,4]
     expr_vstore_uniq,                  // ~[1,2,3,4]
     expr_vstore_box,                   // @[1,2,3,4]
+    expr_vstore_mut_box,               // @mut [1,2,3,4]
     expr_vstore_slice                  // &[1,2,3,4]
 }
 
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index 925934d165f6..f340a52a4e7d 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -38,7 +38,8 @@ use ast::{_mod, add, arg, arm, attribute,
              expr_lit, expr_log, expr_loop, expr_loop_body, expr_mac,
              expr_paren, expr_path, expr_rec, expr_repeat, expr_ret,
              expr_swap, expr_struct, expr_tup, expr_unary, expr_unary_move,
-             expr_vec, expr_vstore, expr_while, extern_fn, field, fn_decl,
+             expr_vec, expr_vstore, expr_vstore_mut_box, expr_while,
+             extern_fn, field, fn_decl,
              foreign_item, foreign_item_const, foreign_item_fn, foreign_mod,
              ident, impure_fn, infer, inherited,
              item, item_, item_class, item_const, item_enum, item_fn,
@@ -1450,8 +1451,11 @@ impl Parser {
             hi = e.span.hi;
             // HACK: turn @[...] into a @-evec
             ex = match e.node {
-              expr_vec(*) | expr_lit(@{node: lit_str(_), span: _})
-              if m == m_imm => expr_vstore(e, expr_vstore_box),
+              expr_vec(*) if m == m_mutbl =>
+                expr_vstore(e, expr_vstore_mut_box),
+              expr_vec(*) if m == m_imm => expr_vstore(e, expr_vstore_box),
+              expr_lit(@{node: lit_str(_), span: _}) if m == m_imm =>
+                expr_vstore(e, expr_vstore_box),
               _ => expr_unary(box(m), e)
             };
           }
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index b4a5407c0024..e0523613ee66 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -1027,6 +1027,10 @@ fn print_expr_vstore(s: ps, t: ast::expr_vstore) {
       ast::expr_vstore_fixed(None) => word(s.s, ~"_"),
       ast::expr_vstore_uniq => word(s.s, ~"~"),
       ast::expr_vstore_box => word(s.s, ~"@"),
+      ast::expr_vstore_mut_box => {
+        word(s.s, ~"@");
+        word(s.s, ~"mut");
+      }
       ast::expr_vstore_slice => word(s.s, ~"&"),
     }
 }
diff --git a/src/test/compile-fail/borrowck-mut-boxed-vec.rs b/src/test/compile-fail/borrowck-mut-boxed-vec.rs
new file mode 100644
index 000000000000..cd36bedfa241
--- /dev/null
+++ b/src/test/compile-fail/borrowck-mut-boxed-vec.rs
@@ -0,0 +1,7 @@
+fn main() {
+    let v = @mut [ 1, 2, 3 ];
+    for v.each |_x| {   //~ ERROR illegal borrow
+        v[1] = 4;
+    }
+}
+
diff --git a/src/test/run-pass/new-vstore-mut-box-syntax.rs b/src/test/run-pass/new-vstore-mut-box-syntax.rs
new file mode 100644
index 000000000000..6b77d778eb95
--- /dev/null
+++ b/src/test/run-pass/new-vstore-mut-box-syntax.rs
@@ -0,0 +1,5 @@
+fn main() {
+    let x: @mut [int] = @mut [ 1, 2, 3 ];
+
+}
+