gawk internal error in regex

[Stepan Kasal]

Hello,
  I have noticed the following bug:

Command

        gawk 'BEGIN{"o\n" ~ /o$($|.)/}'

causes core dump, with this backtrace:

#0  0x4006c3a1 in kill () from /lib/libc.so.6
#1  0x4006bfe5 in raise () from /lib/libc.so.6
#2  0x4006d75b in abort () from /lib/libc.so.6
#3  0x080699e4 in catchsig (sig=0) at main.c:1054
#4  0x4006c278 in __libc_sigaction () from /lib/libc.so.6
#5  0x08071ee0 in proceed_next_node (mctx=0xbffff520, nregs=2, regs=0x808f020, 
pidx=0xbffff46c, node=0,
    eps_via_nodes=0xbffff480, fs=0x0) at regexec.c:1235
#6  0x08072182 in set_regs (preg=0xbffff46c, mctx=0xbffff520, nmatch=2, 
pmatch=0x808f020, fl_backtrack=0) at regexec.c:1429
#7  0x080713f8 in re_search_internal (preg=0x1, string=0x808e9b8 "o\n", 
length=2, start=0, range=2, stop=2, nmatch=2,
    pmatch=0x808f020, eflags=0) at regexec.c:855
#8  0x08070c5c in re_search_stub (bufp=0x808e9e8, string=0x808e9b8 "o\n", 
length=2, start=0, range=0, stop=2, regs=0x808ea08,
    ret_len=0) at regexec.c:444
#9  0x080709f0 in re_search (bufp=0x4, string=0x40168f8c " N\022", length=6, 
start=0, range=2, regs=0x808ea08) at regexec.c:314
#10 0x0806b48a in research (rp=0x808e9e8, str=0x808f020 "", start=0, len=2, 
flags=4) at re.c:248
#11 0x08079497 in match_op (tree=0x808e468) at eval.c:2091
#12 0x08077799 in r_tree_eval (tree=0x808e4a8, iscond=0) at eval.c:1004
#13 0x08076c42 in interpret (tree=0x808e4a8) at eval.c:877
#14 0x08075df7 in interpret (tree=0x808e428) at eval.c:456
#15 0x080685b5 in main (argc=2, argv=0xbffffa34) at main.c:588
#16 0x40059bec in __libc_start_main () from /lib/libc.so.6

(well, the backtrace is from a development version, where the same segfault
appears).

Have a nice day,
        Stepan Kasal