method vpredicate = function
| Papp (lf, _, targs) -> collect_apps lf targs ; SkipChildren
| Pvalid t | Pvalid_index(t,_) | Pvalid_range(t,_,_)
| Pinitialized t | Pfresh t ->
debug "[Calls_collection] predicate app on %a" !Ast_printer.d_term t;
collect_apps_builtin [t] ; SkipChildren
| Pseparated lt -> collect_apps_builtin lt ; SkipChildren
| _ -> DoChildren