Just now on IRC I got a question on has_index() and multisets. It turns out (in various pike versions) that
Pike v7.4 release 11 running Hilfe v3.5 (Incremental Pike Frontend)
mixed m= (<"foo","bar">); m["foo"];
(1) Result: 1
has_index(m,"foo");
(2) Result: 0
search(indices(m),"foo");
(3) Result: 1
wich is not consistent with the documentation, right?