- Sad goodbye to insert_before_element_under_condition
 - ~label instead of ~pre
 - No superfluous Env.Varname.get
 - Gmp only allowed
 - Dataflow analysis allowed
 - Using exception for term_has_lv_from_vi
 - Fix incorrect assert false from effective_lscope_from_pred_or_term
 - fold_left for index_from_sizes_and_shifts