[bug:trunk] regexp marshal problem from 1.9.1 to 1.9.2

e$B0J2<$N$h$&$K!"e(B 1.9.1p378 e$B$+$ie(B 1.9.2 e$B$Xe(B // e$B$re(B
marshal e$B$GAw$m$&$H$9$k$H!"e(B
ArgumentError e$B$K$J$j$^$9!#e(B

% ruby-1.9.1p378 -e ‘Marshal.dump(//, STDOUT)’ | ./ruby -e
‘Marshal.load(STDIN)’
-e:1:in load': dump format error for symbol(0x63) (ArgumentError) from -e:1:in
zsh: done ruby-1.9.1p378 -e ‘Marshal.dump(//, STDOUT)’ |
zsh: exit 1 ./ruby -e ‘Marshal.load(STDIN)’
% ruby-1.9.1p378 -v
ruby 1.9.1p378 (2010-01-10 revision 26273) [i686-linux]
% ./ruby -v
ruby 1.9.2dev (2010-02-11 trunk 26634) [i686-linux]

marshal e$B$G@8@.$5$l$kCf?H$O0J2<$N$h$&$K$J$C$F$$$^$9!#e(B

% ruby-1.9.1p378 -e ‘Marshal.dump(//, STDOUT)’ | od -c
0000000 004 \b I / \0 \0 006 : \r e n c o d i n
0000020 g " \r U S - A S C I I
0000033