The attached reproducer script requires Emacs and Guile. When running it, the REPL prints out many lines, the last ones being: $1884 = #f $1885 = #f $1886 = #f $1887 = #f $1888 = #f $1889 = #f $1890 = #f $1891 = #f $1892 = #f Too many root sets ./repro.sh: line 11: 2014 Aborted (core dumped) guile --language=elisp < elisp-spec.el This happens both for Guile 2.2.6 on Arch and Guile 3.0.2 on Debian Sid, launched with `docker run --rm -i -t debian:sid bash`.