This is thrown for an illegal operation on an
AltingBarrier
.
Description
Currently, there are the following causes:
-
different threads trying to operate on the same front-end;
-
attempt to use as a
Guard
whilst resigned;
-
attempt to
sync
whilst resigned;
-
attempt to
resign
whilst resigned;
-
attempt to
enroll
whilst enrolled;
-
attempt to
expand
whilst resigned;
-
attempt to
contract
whilst resigned;
-
attempt to
contract
with an array
of front-ends not supplied by expand
;
-
attempt to
mark
whilst resigned (caused
by a process transfering a front-end in that state).