We have discovered a regression within OCaml 4.13.0 that make the compiler
crash on classes named
module M = struct class row = object end end
due to a collision between two families of internal identifiers.
To restore your freedom to name classes however you want, we have
released OCaml 4.13.1 as an early bug-fix release.
This new version is available as a set of OPAM switches with
opam update opam switch create 4.13.1
and as a source download here: