Found a bug by asan.

arbor/util/piecewise.hpp

@@ -429,16 +429,18 @@ struct pw_elements {
  auto ei = begin(values);
  auto ee = end(values);
 
- if (ei == ee) { // empty case
+ // clean-up
+ clear();
+
+ // empty case
+ if (ei == ee) {
  if (vi != ve) throw std::runtime_error{"Vertices and values need to have same length; values too long."};
- clear();
  return;
  }
- clear();
  if (vi == ve) throw std::runtime_error{"Vertices and values need to have same length; values too short."};
-
  reserve(vertices.size());
  double left = *vi++;
+ if (vi == ve) throw std::runtime_error{"Vertices and values need to have same length; values too short."};
  double right = *vi++;
  push_back(left, right, *ei++);