and
has lower precedence than &&
.
But for an unassuming user, problems might occur if it is used along with other operators whose precedence are in between, for example, the assignment operator:
def happy?() true; end
def know_it?() true; end
todo = happy? && know_it? ? "Clap your hands" : "Do Nothing"
todo
# => "Clap your hands"
todo = happy? and know_it? ? "Clap your hands" : "Do Nothing"
todo
# => true