free c: channel.
free m,n: bitstring.

event A.
event B.
event C.

query event(C) ==> event(A).
query event(B) ==> event(A).

process
    (
        out(c,m);
        event A;
        sync 1;
        event B;
        out(c,m)
    )|(
        phase 1;
        sync 1;
        event C;
        out(c,n)
    )

(* EXPECTPV
Error: Phase is incompatible with sync.
xtime: error in child process (status : 2)
END *)
