Problem with guile-2.9.1-prerelease

[Thomas Morley]

Hi,

according to this post:
https://lists.gnu.org/archive/html/guile-devel/2018-10/msg00000.html
guile prepares to release 3.0 soon.

I tried to test LilyPond with the guile-2.9.1-prelease.
Checking out our dev/guile-v2-work-branch, rebasing, applying several
patches (working with guile-2.2.4) as well as editing configure.ac and
aclocal.m4 to accept this guile-version I've got a successful 'make'

Though, 'make doc' fails soon with 'input/regression/rest-positioning.ly'
I boiled it down to this minimal:

\version "2.21.0"
$@(make-list 2 #{ r1 #})

I get:

$ lilypond-git-guile-3.0 atest-80.ly
GNU LilyPond 2.21.0
Processing `atest-80.ly'
Parsing...Backtrace:
           6 (apply-smob/1 #<catch-closure 560bc9932720>)
In ice-9/eval.scm:
   293:34  5 (_ #(#(#<directory (lily) 560bc9a165a0>) #<variable 5…>))
    619:8  4 (_ #(#(#(#(#(#(#(#<directory (lily) …>) …) …) …) …) …) …))
In srfi/srfi-1.scm:
    640:9  3 (for-each #<procedure 560bcae4a5e0 at ice-9/eval.scm:3…> …)
In ice-9/eval.scm:
    619:8  2 (_ #(#(#(#(#(#<directory (lily) 560bc9a1…> …) …) …) …) …))
In ice-9/boot-9.scm:
    826:9  1 (catch _ _ #<procedure 560bcb002540 at ice-9/eval.scm:…> …)
In unknown file:
           0 (ly:parse-file "atest-80.ly")

ERROR: In procedure ly:parse-file:
In procedure struct-ref: Wrong type argument in position 1 (expecting
struct): #<Prob: Music C++: Music((duration . #<Duration 1 >) (origin
. #<location atest-80.ly:629:2>))((display-methods #<procedure method
(a)>) (name . RestEvent) (iterator-ctor . #<procedure
ly:rhythmic-music-iterator::constructor ()>) (types event
rhythmic-event rest-event)) >

I'm not able to get meaningful info out of this.
Any insight?

Thanks,
  Harm