# Pre-increment and pre-decrement in arithmetic expansion are not in POSIX.
# Require either an error or a correct implementation.

! (eval 'x=4; [ $((++x)) != 5 ] || [ $x != 5 ]') 2>/dev/null &&
! (eval 'x=2; [ $((--x)) != 1 ] || [ $x != 1 ]') 2>/dev/null