I'm using command line Maxima. OK:
(%i1) facsum(x,x);
(%o1) x
Not OK:
(%i2) facsum(x + x^2,x);
Maxima encountered a Lisp error:
Error in PROGN [or a callee]: Caught fatal error [memory may be damaged]
(%i3) build_info();
Maxima version: 5.13.99rc1
Maxima build date: 21:32 12/4/2007
host type: i686-pc-mingw32
lisp-implementation-type: GNU Common Lisp (GCL)
lisp-implementation-version: GCL 2.6.8
Our testsuite doesn't have any checks on facsum and friends ;(
Barton