Seeing a core dump with latest mutt

[Will Fiveash <will.fiveash@xxxxxxxxxx>]

Trying to run Mutt 1.5.20 (2010-03-02) I'm seeing it core dump with this
stack:

core 'mutt.28601.core' of 28601:        /home/willf/bin/i386/mutt willf
 fe529982 process_free (deadbeef, 1, 0, fea6c8fa) + 22
 fe529a7a free     (deadbeef, feae2000, 8044bf8, fea6e34a) + 1a
 fea6e383 __regfree_std (fe341f90, 820c3a0, 0, fea63950) + 43
 fea6396e regfree  (820c3a0, 820c3a0, 8046450, 100) + 2a
 080bb1ac eat_regexp (820c3d0, 8044c60, 8046430, 66) + 1c4
 080bc64b mutt_pattern_comp (814da90, 1, 8046430, 0) + 5d0
 0809dbc9 mutt_parse_hook (80462a0, 8046240, 10, 8046430) + 47e
 080925ec mutt_parse_rc_line (81f0648, 80462a0, 8046430, feea923e) + 138
 08092286 source_rc (81717b8, 8046430, 8046b88, 8094770) + 166
 08094785 mutt_init (0, 0, 80473c8, 80a1336) + c24
 080a134e main     (2, 80473f8, 8047404, feffb804, 80473ec, 806788a) + 751
 080678eb _start   (2, 80475b8, 80475d2, 0, 80475d8, 80475fa) + 83

I think the cause is this line in my .muttrc:

save-hook '~f foo\.bar@(something|other)\.com' =foo

If I change this to:

save-hook '~f "foo\.bar@(something|other)\.com"' =foo

then no core.

-- 
Will Fiveash