parse-tree-il rejects '(define ...)

[Matt Wette]

This is guile 2.0.11.  
I think I’m following what is in the reference manual. 
Any clue what the problem is? — Matt
scheme@(guile-user)> (define t1 '(begin (define (toplevel x) 1)))
scheme@(guile-user)> (parse-tree-il t1)
ERROR: In procedure scm-error:
ERROR: unrecognized tree-il (define (toplevel x) 1)

Entering a new prompt.  Type `,bt' for a backtrace or `,q' to continue.
scheme@(guile-user) [1]>