// Hazard with function argument
void arg_haz(Value v) {
  gc();
  v.isUndefined();
}
// Check: why chain should cover whole function

// Hazard with local
void local_haz() {
  Value v = NullValue();
  gc();
  v.isUndefined();
}
// Check: why chain should go from body line 1-3

// Hazard with retparam
void retparam_haz() {
  Value v;
  f(&v);
  gc();
  v.isUndefined();
}
// Check: why chain should go from body line 2-4

// class hierarchy: only in uncle, or not in uncle
 -> perhaps just look at callgraph to find virtual instantiations?