It's an optimization hack. By nature, they aren't that nice to look at.
`sym_equal` only makes 2 appearances in the whole codebase (to be bound to `Symbol#==` and `Symbol#===` in string.c), so there's not a whole lot of room for confusion.
Also, this is Ruby core! Smart people do what works and makes sense to them and don't spend a lot of time worrying about how clear it is to us unwashed masses.
`sym_equal` only makes 2 appearances in the whole codebase (to be bound to `Symbol#==` and `Symbol#===` in string.c), so there's not a whole lot of room for confusion.
Also, this is Ruby core! Smart people do what works and makes sense to them and don't spend a lot of time worrying about how clear it is to us unwashed masses.