We made stack effects mandatory for most definitions as it appeared an area of frustration with new Factor programmers. However, we have a stack checker that s

We made stack effects mandatory for most definitions as it appeared an area of frustration with new Factor programmers. However, we have a stack checker that still supports optional stack effects if you yearn for the good ol' days: https://github.com/slavapestov/factor/issues/887 https://github.com/slavapestov/factor/issues/887