I believe you missed a semicolon after `exit 1` and before `}`. `}` closes the opening `{` only at the start of a command (POSIX rules; don't remember now if bash recognizes it when it's just a command argument).
I'm just too used to how parsing works in Zsh. For bash and sh, there is indeed should be a semicolon.
In this specific case, echo can't fail to there's no need for any of that:
[ -z "$1" ] && echo "fail" >&2 && exit 1loading story #49056931