$ cd ~/src/coreutils
 $ grep -I -r --exclude-dir=.git '\berror_\b' .
 ./tests/shell-or-perl:error_ ()
 ./tests/shell-or-perl:  test $# -gt 1 || error_ "option '\''$1'\'' requires an argument"
 ./tests/shell-or-perl:    -*) error_ "unknown option '$1'";;
 ./tests/shell-or-perl:  0) error_ "missing argument";;
 ./tests/shell-or-perl:  || error_ "test script '$test_script' does not exist, or isn't readable"
 ./tests/shell-or-perl:  || error_ "cannot read from the test script '$test_script'"
 ./tests/shell-or-perl:error_ "dead code reached"
 ./tests/init.cfg:# FIXME: eventually s/error_/fail_/ and remove the definition of error_ below.
 ./tests/init.cfg:    error_ "Error running getlimits"
 ./tests/init.cfg:error_() { echo "$0: $@" 1>&2; Exit 1; }
 ./tests/init.cfg:framework_failure() { error_ 'failure in testing framework'; }

So, time to remove dead code, right? :-)

What about the attached patch?

Regards,
  Stefano