diff --git a/src/libsyntax/ext/build.rs b/src/libsyntax/ext/build.rs
index 69f7f2b69cd..4e0c6889092 100644
--- a/src/libsyntax/ext/build.rs
+++ b/src/libsyntax/ext/build.rs
@@ -61,6 +61,16 @@ fn mk_vec_e(cx: ext_ctxt, sp: span, exprs: [@ast::expr]) ->
     let vecexpr = ast::expr_vec(exprs, ast::m_imm);
     ret @{id: cx.next_id(), node: vecexpr, span: sp};
 }
+fn mk_vstore_e(cx: ext_ctxt, sp: span, expr: @ast::expr, vst: ast::vstore) ->
+   @ast::expr {
+    let vstoreexpr = ast::expr_vstore(expr, vst);
+    ret @{id: cx.next_id(), node: vstoreexpr, span: sp};
+}
+fn mk_uniq_vec_e(cx: ext_ctxt, sp: span, exprs: [@ast::expr]/~) ->
+   @ast::expr {
+    mk_vstore_e(cx, sp, mk_vec_e(cx, sp, exprs), ast::vstore_uniq)
+}
+
 fn mk_rec_e(cx: ext_ctxt, sp: span,
             fields: [{ident: ast::ident, ex: @ast::expr}]) ->
     @ast::expr {
diff --git a/src/libsyntax/ext/fmt.rs b/src/libsyntax/ext/fmt.rs
index 0cc4ba0a570..24a5aed7d28 100644
--- a/src/libsyntax/ext/fmt.rs
+++ b/src/libsyntax/ext/fmt.rs
@@ -61,7 +61,7 @@ fn pieces_to_expr(cx: ext_ctxt, sp: span, pieces: [piece], args: [@ast::expr])
                 }
                 flagexprs += [make_rt_path_expr(cx, sp, @fstr)];
             }
-            ret mk_vec_e(cx, sp, flagexprs);
+            ret mk_uniq_vec_e(cx, sp, flagexprs);
         }
         fn make_count(cx: ext_ctxt, sp: span, cnt: count) -> @ast::expr {
             alt cnt {
diff --git a/src/libsyntax/ext/qquote.rs b/src/libsyntax/ext/qquote.rs
index 3f3eb001250..caef1841faf 100644
--- a/src/libsyntax/ext/qquote.rs
+++ b/src/libsyntax/ext/qquote.rs
@@ -258,7 +258,7 @@ fn finish<T: qq_helper>
         rcall = mk_call(cx,sp,
                         [@"syntax", @"ext", @"qquote", @"replace"],
                         [pcall,
-                         mk_vec_e(cx,sp, qcx.gather.map_to_vec {|g|
+                         mk_uniq_vec_e(cx,sp, qcx.gather.map_to_vec {|g|
                              mk_call(cx,sp,
                                      [@"syntax", @"ext",
                                       @"qquote", @g.constr],
diff --git a/src/rustc/front/test.rs b/src/rustc/front/test.rs
index 2c40db16a45..3f5fca12e2a 100644
--- a/src/rustc/front/test.rs
+++ b/src/rustc/front/test.rs
@@ -265,8 +265,11 @@ fn mk_test_desc_vec_ty(cx: test_ctxt) -> @ast::ty {
 
     let vec_mt: ast::mt = {ty: @test_desc_ty, mutbl: ast::m_imm};
 
+    let inner_ty = @{id: cx.sess.next_node_id(),
+                     node: ast::ty_vec(vec_mt),
+                     span: dummy_sp()};
     ret @{id: cx.sess.next_node_id(),
-          node: ast::ty_vec(vec_mt),
+          node: ast::ty_vstore(inner_ty, ast::vstore_uniq),
           span: dummy_sp()};
 }
 
@@ -277,8 +280,11 @@ fn mk_test_desc_vec(cx: test_ctxt) -> @ast::expr {
         descs += [mk_test_desc_rec(cx, test)];
     }
 
+    let inner_expr = @{id: cx.sess.next_node_id(),
+                       node: ast::expr_vec(descs, ast::m_imm),
+                       span: dummy_sp()};
     ret @{id: cx.sess.next_node_id(),
-          node: ast::expr_vec(descs, ast::m_imm),
+          node: ast::expr_vstore(inner_expr, ast::vstore_uniq),
           span: dummy_sp()};
 }
 
@@ -384,10 +390,14 @@ fn mk_main(cx: test_ctxt) -> @ast::item {
     let str_ty = @{id: cx.sess.next_node_id(),
                    node: ast::ty_path(str_pt, cx.sess.next_node_id()),
                    span: dummy_sp()};
-    let args_mt: ast::mt = {ty: str_ty, mutbl: ast::m_imm};
-    let args_ty: ast::ty = {id: cx.sess.next_node_id(),
-                            node: ast::ty_vec(args_mt),
-                            span: dummy_sp()};
+    let args_mt = {ty: str_ty, mutbl: ast::m_imm};
+    let args_ty_inner = @{id: cx.sess.next_node_id(),
+                          node: ast::ty_vec(args_mt),
+                          span: dummy_sp()};
+    let args_ty = {id: cx.sess.next_node_id(),
+                   node: ast::ty_vstore(args_ty_inner, ast::vstore_uniq),
+                   span: dummy_sp()};
+
 
     let args_arg: ast::arg =
         {mode: ast::expl(ast::by_val),