%------------------------------------------------------------------------------%

:- module bug387.

:- interface.

:- import_module io.

:- pred test(io::di, io::uo) is cc_multi.

:- implementation.

:- import_module maybe.
:- import_module require.

test(!IO) :-
    (
        MaybeBDD = ok(1)
    ;
        ExpPrime = err,
        MaybeBDD = error(ExpPrime)
    ),
    ( MaybeBDD = ok(BDD)
    ; MaybeBDD = error(Err),
        write_line(Err, !IO),
        sorry($pred, "Error")
    ),

    io.write(BDD, !IO).

:- some [T] func err = T.

% This version works:
% :- func err = int.

err = 42.