Calling .tail() on a slice does no check at all (see https://github.com/rust-lang/rust/blob/master/src/libcore/slice.rs#L210 ), and will panic if called on a empty slice.

Nothing suggests it in the documentation, I personally expected that calling .tail() on an empty slice would return an empty slice, as .first() returns an Option.