Crash in ode2 and solve



ode2() crashes on the trivial ode dy/dx=0

I tracked this down to the routine solve1() in ode2.{lisp,mac), 
and can reproduce the problem from the command line as
solve('diff(y,x),'diff(y,x))

Output from CVS maxima / clisp-2.31 below.

######################################################################
(C1) ode2('diff(y,x),y,x);

*** - CAR: #:G7885 is not a LIST
The following restarts are available:
MACSYMA-QUIT   :R1      Macsyma top-level

1. Break [1]> :R1
Maxima restarted.
;; Loading file /usr/share/maxima/5.9.0.1cvs/share/maxima-init.lisp ...
;; Loaded file /usr/share/maxima/5.9.0.1cvs/share/maxima-init.lisp
(C2) solve('diff(y,x),'diff(y,x));

*** - CAR: #:G7921 is not a LIST
The following restarts are available:
MACSYMA-QUIT   :R1      Macsyma top-level

1. Break [2]> :R1
Maxima restarted.
;; Loading file /usr/share/maxima/5.9.0.1cvs/share/maxima-init.lisp ...
;; Loaded file /usr/share/maxima/5.9.0.1cvs/share/maxima-init.lisp