guix pull fails for a 4 days at least with the same error:

fish: Unknown command: nix
fish:
nix show-derivation
"/home/shegeley/.cache/.fr-sqOEpp/273vsd5gv1ch73ayih504s5wcxvysq-module-import-compiled.drv"

I had nix-service-type enabled and I had this problem. Then I disabled it
(with remove-service...), reconfigured the system. Same error message and
problem. Cleaned the thrash (guix gc) and tried to pull without
substitutes. Same result each time.

shegeley@zone51 ~ (master) [127]> guix pull
Updating channel 'nonguix' from Git repository at '
https://gitlab.com/nonguix/nonguix'...
Updating channel 'guix' from Git repository at '
https://git.savannah.gnu.org/git/guix.git'...
Authenticating channel 'guix', commits 9edb3f6 to 5e59153 (4 new commits)...
Building from these channels:
  guix      https://git.savannah.gnu.org/git/guix.git 5e59153
  nonguix   https://gitlab.com/nonguix/nonguix 21d41c8
substitute: updating substitutes from 'https://ci.guix.gnu.org'... 100.0%
... [author comment]
building
/gnu/store/6r273vsd5gv1ch73ayih504s5wcxvysq-module-import-compiled.drv...
|builder for
`/gnu/store/6r273vsd5gv1ch73ayih504s5wcxvysq-module-import-compiled.drv'
failed with exit code 1
build of
/gnu/store/6r273vsd5gv1ch73ayih504s5wcxvysq-module-import-compiled.drv
failed
View build log at
'/var/log/guix/drvs/6r/273vsd5gv1ch73ayih504s5wcxvysq-module-import-compiled.drv.bz2'.
cannot build derivation
`/gnu/store/nrhi4j1vrhjfibv6i1wvwa6zq4lnilpg-compute-guix-derivation.drv':
1 dependencies couldn't be built
guix pull: error: build of
`/gnu/store/nrhi4j1vrhjfibv6i1wvwa6zq4lnilpg-compute-guix-derivation.drv'
failed

(first time using mail-based issues system, tried to find issue-opening
rules on https://issues.guix.gnu.org/)