Fish 3.1.0 (released February 12, 2020)
github.com4 pointsby faho0 comments
foo='PWD[$(echo hahaha >&2)0]+42'
[[ "$foo" -eq 5 ]]
In bash, this would also print "hahaha" with "a" (or any other possible variable name) instead of "PWD", that's why many think it doesn't work at all in zsh.