---

yaml
---
r: 3371
b: refs/heads/master
c: 8ad7f3b
h: refs/heads/master
i:
  3369: 63a8ab3
  3367: fda2127
v: v3

Author: msullivan

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 36fb7544761aed081c0dc5b5cf3f9d0267752e53
+refs/heads/master: 8ad7f3b56b79b13029384e51a201f495e0eb2a15

trunk/src/rt/rust_upcall.cpp

@@ -478,6 +478,12 @@ upcall_vec_append(rust_task *task, type_desc *t, type_desc *elem_t,
     size_t n_dst_bytes = skip_null ? dst->fill - 1 : dst->fill;
     rust_vec *new_vec = vec_grow(task, dst, n_src_bytes, &need_copy, t);
 
+    // If src and dst are the same (due to "v += v"), then dst getting
+    // resized causes src to move as well.
+    if (dst == src) {
+        src = new_vec;
+    }
+
     if (need_copy) {
         // Copy any dst elements in, omitting null if doing str.
         copy_elements(task, elem_t, &new_vec->data, &dst->data, n_dst_bytes);