Hi Konrad,

thanks for the precise error report.

On Mon, 30 Jul 2018 18:16:54 +0200
Konrad Hinsen <konrad.hinsen@fastmail.net> wrote:

> Dear Guix experts,
> 
> When updating my Guix installation after three weeks of absence, I
> noticed a build failure:
> 
>    $ guix pull –commit=de596e99549d7764f370ab2ed3b756f620b1f23d
>    $ guix build racket

Could it be the case that in your `guix build ...` you are not using
the guix you pulled?

What does `guix --version` say?

Where does `which guix` point to?

It should point to

~/.config/guix/current/bin/guix

I suspect you have an older version of Guix (i.e. "before the new
implementation") in your $PATH with a higher precedence (more to the
beginning of the $PATH variable). See what `echo $PATH` says. If that
is the case, adapt your path.

HTH,

Björn