rolling boulder crash

Core was generated by `/games/slex-2.6.1/slexdir/slex -d /games/slex-2.6.1/slexdir -u potato44'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x0000000000e26595 in ohitmon (mon=<optimized out>, mtmp=<optimized out>,
    otmp=0x80178c680, range=-1, verbose=0) at mthrowu.c:895
895                                     if (is_dwarf(mon->data)) shieldblockrate += 5;
(gdb) backtrace
#0  0x0000000000e26595 in ohitmon (mon=<optimized out>, mtmp=<optimized out>,
    otmp=0x80178c680, range=-1, verbose=0) at mthrowu.c:895
#1  0x00000000010fff5f in launch_obj (otyp=<optimized out>,
    x1=<optimized out>, y1=<optimized out>, x2=1, y2=0, style=0)
    at trap.c:14492
#2  0x00000000010f96e2 in mintrap (mtmp=0x801779000) at trap.c:16270
#3  0x0000000000e1704b in m_move (mtmp=<optimized out>, after=<optimized out>)
    at monmove.c:2694
#4  0x0000000000e1014f in dochug (mtmp=0x801779000) at monmove.c:1757
#5  0x0000000000df691c in dochugw (mtmp=0x801779000) at monmove.c:109
#6  0x0000000000dca04b in movemon () at mon.c:2067
#7  0x00000000007d5555 in moveloop () at allmain.c:210
#8  0x00000000012c3ec0 in main (argc=<optimized out>, argv=<optimized out>)
    at ../sys/unix/unixmain.c:299
(gdb) p mtmp
$1 = <optimized out>
(gdb) p mon
$2 = <optimized out>
(gdb) print mtmp->data
value has been optimized out