Error installing ppx_driver.v0.9.114.40+66

[bcc32]

I get the following error while installing ppx_driver through opam from the https://ocaml.janestreet.com/opam-repository repo.

[ERROR] The compilation of ppx_driver failed at "jbuilder build --only-packages
        ppx_driver --root . -j 4 @install".

#=== ERROR while installing ppx_driver.v0.9.114.40+66 =========================#
# opam-version 1.2.2
# os           darwin
# command      jbuilder build --only-packages ppx_driver --root . -j 4 @install
# path         /Users/rouka/.opam/4.04.1/build/ppx_driver.v0.9.114.40+66
# compiler     4.04.1
# exit-code    1
# env-file     /Users/rouka/.opam/4.04.1/build/ppx_driver.v0.9.114.40+66/ppx_driver-58256-0c525f.env
# stdout-file  /Users/rouka/.opam/4.04.1/build/ppx_driver.v0.9.114.40+66/ppx_driver-58256-0c525f.out
# stderr-file  /Users/rouka/.opam/4.04.1/build/ppx_driver.v0.9.114.40+66/ppx_driver-58256-0c525f.err
### stderr ###
# Error: This expression has type
# [...]
#            structure : Ppx_ast.Selected_ast.Ast.Parsetree.structure;
#            toplevel_phrase : Ppx_ast.Selected_ast.Ast.Parsetree.toplevel_phrase;
#            type_declaration : Ppx_ast.Selected_ast.Ast.Parsetree.type_declaration;
#            type_extension : Ppx_ast.Selected_ast.Ast.Parsetree.type_extension >
#          Migrate_parsetree_versions.get_expression =
#            Ast_403.Parsetree.expression
#        but an expression was expected of type
#          Ppx_ast__Import.Ocaml.Ast.Parsetree.expression =
#            Parsetree.expression

The files referred to in the error output are attached here:
log.tar.gz

[Deleted user]

Indeed, it was a superfluous conversion

[bcc32]

Working now, thanks.