assert like expression <expr> || { do; }

[fentas]

Should we always enforce if instead, as it can lead to unreadable expressions?
Right now, it should be always <true statement to proceed> || <consequence>
Which is nice for return, continue or break. + for return you can control the the output channel more.
E.g.

false || {
  echo "some is wrong"
  exec-with-print-somthing
  return 0
} >&2

Not 100% sure about it.