message: Fixing null pointer sanitization issue.
diff: @@ -474,7 +474,9 @@ inline SparseTensor SparseTensor::Concat(
  const int st_num_entries = st.num_entries();
  // Fill in indices & values.
  + if (st_num_entries > 0) {
  std::copy_n(&st.vals_.vec<T>()(0), st_num_entries, &vals_t(offset));
  + }
  const auto* st_ix = &st.ix_.matrix<int64>()(0, 0);
  auto* ix_out = &ix_t(offset, 0);
  