diff --git a/src/comp/back/upcall.rs b/src/comp/back/upcall.rs
index 3c39e889afc..40e365612d6 100644
--- a/src/comp/back/upcall.rs
+++ b/src/comp/back/upcall.rs
@@ -37,7 +37,7 @@ type upcalls =
      shared_free: ValueRef,
      mark: ValueRef,
      new_str: ValueRef,
-     vec_append: ValueRef,
+     evec_append: ValueRef,
      get_type_desc: ValueRef,
      ivec_resize: ValueRef,
      ivec_spill: ValueRef,
@@ -83,8 +83,8 @@ fn declare_upcalls(_tn: type_names, tydesc_type: TypeRef,
           shared_free: dv("shared_free", ~[T_ptr(T_i8())]),
           mark: d("mark", ~[T_ptr(T_i8())], T_int()),
           new_str: d("new_str", ~[T_ptr(T_i8()), T_size_t()], T_ptr(T_str())),
-          vec_append:
-              d("vec_append",
+          evec_append:
+              d("evec_append",
                 ~[T_ptr(tydesc_type), T_ptr(tydesc_type),
                   T_ptr(T_opaque_vec_ptr()), T_opaque_vec_ptr(), T_bool()],
                 T_void()),
diff --git a/src/comp/middle/trans.rs b/src/comp/middle/trans.rs
index 5370982c325..8814e29da75 100644
--- a/src/comp/middle/trans.rs
+++ b/src/comp/middle/trans.rs
@@ -2542,7 +2542,8 @@ fn trans_compare(cx: &@block_ctxt, op: ast::binop,
     }
 }
 
-fn trans_vec_append(cx: &@block_ctxt, t: &ty::t, lhs: ValueRef, rhs: ValueRef)
+fn trans_evec_append(cx: &@block_ctxt, t: &ty::t,
+                     lhs: ValueRef, rhs: ValueRef)
    -> result {
     let elt_ty = ty::sequence_element_type(bcx_tcx(cx), t);
     let skip_null = C_bool(false);
@@ -2563,7 +2564,7 @@ fn trans_vec_append(cx: &@block_ctxt, t: &ty::t, lhs: ValueRef, rhs: ValueRef)
     let dst = bcx.build.PointerCast(lhs, T_ptr(T_opaque_vec_ptr()));
     let src = bcx.build.PointerCast(rhs, T_opaque_vec_ptr());
     ret rslt(bcx,
-             bcx.build.Call(bcx_ccx(cx).upcalls.vec_append,
+             bcx.build.Call(bcx_ccx(cx).upcalls.evec_append,
                             ~[cx.fcx.lltaskptr, llvec_tydesc.val,
                               llelt_tydesc.val, dst, src, skip_null]));
 }
@@ -3170,12 +3171,13 @@ mod ivec {
     }
 }
 
-fn trans_vec_add(cx: &@block_ctxt, t: &ty::t, lhs: ValueRef, rhs: ValueRef) ->
+fn trans_evec_add(cx: &@block_ctxt, t: &ty::t,
+                  lhs: ValueRef, rhs: ValueRef) ->
    result {
     let r = alloc_ty(cx, t);
     let tmp = r.val;
     r = copy_val(r.bcx, INIT, tmp, lhs, t);
-    let bcx = trans_vec_append(r.bcx, t, tmp, rhs).bcx;
+    let bcx = trans_evec_append(r.bcx, t, tmp, rhs).bcx;
     tmp = load_if_immediate(bcx, tmp, t);
     add_clean_temp(cx, tmp, t);
     ret rslt(bcx, tmp);
@@ -3209,7 +3211,7 @@ fn trans_eager_binop(cx: &@block_ctxt, op: ast::binop, lhs: ValueRef,
             if ty::sequence_is_interior(bcx_tcx(cx), intype) {
                 ret ivec::trans_add(cx, intype, lhs, rhs);
             }
-            ret trans_vec_add(cx, intype, lhs, rhs);
+            ret trans_evec_add(cx, intype, lhs, rhs);
         }
         if is_float {
             ret rslt(cx, cx.build.FAdd(lhs, rhs));
@@ -5028,7 +5030,7 @@ fn trans_expr_out(cx: &@block_ctxt, e: &@ast::expr, output: out_method) ->
                     ret ivec::trans_append(rhs_res.bcx, t, lhs_res.res.val,
                                            rhs_res.val);
                 }
-                ret trans_vec_append(rhs_res.bcx, t, lhs_res.res.val,
+                ret trans_evec_append(rhs_res.bcx, t, lhs_res.res.val,
                                      rhs_res.val);
               }
               _ { }
diff --git a/src/rt/rust_upcall.cpp b/src/rt/rust_upcall.cpp
index 19f27f6fe94..82c7dd108f4 100644
--- a/src/rt/rust_upcall.cpp
+++ b/src/rt/rust_upcall.cpp
@@ -308,8 +308,8 @@ copy_elements(rust_task *task, type_desc *elem_t,
 }
 
 extern "C" CDECL void
-upcall_vec_append(rust_task *task, type_desc *t, type_desc *elem_t,
-                  rust_vec **dst_ptr, rust_vec *src, bool skip_null)
+upcall_evec_append(rust_task *task, type_desc *t, type_desc *elem_t,
+                   rust_vec **dst_ptr, rust_vec *src, bool skip_null)
 {
     LOG_UPCALL_ENTRY(task);
     rust_vec *dst = *dst_ptr;
@@ -338,6 +338,12 @@ upcall_vec_append(rust_task *task, type_desc *t, type_desc *elem_t,
     *dst_ptr = new_vec;
 }
 
+// FIXME: Transitional. Please remove.
+extern "C" CDECL void
+upcall_vec_append(rust_task *task, type_desc *t, type_desc *elem_t,
+                  rust_vec **dst_ptr, rust_vec *src, bool skip_null) {
+    upcall_evec_append(task, t, elem_t, dst_ptr, src, skip_null);
+}
 
 extern "C" CDECL type_desc *
 upcall_get_type_desc(rust_task *task,
diff --git a/src/rt/rustrt.def.in b/src/rt/rustrt.def.in
index ca0a344aa95..ec3cb60c6c2 100644
--- a/src/rt/rustrt.def.in
+++ b/src/rt/rustrt.def.in
@@ -102,5 +102,6 @@ upcall_new_str
 upcall_shared_malloc
 upcall_shared_free
 upcall_sleep
+upcall_evec_append
 upcall_vec_append
 upcall_yield