Rust compiler output missing conditional

/*I've commented where the error is. I think the compiler output was weird for this kind of error.*/

/***** Code ******/

use std::io::println;

fn is_three(num: int) -> bool {
    num % 3 == 0
}

fn is_five(num: int) -> bool {
    num % 5 == 0
}

fn is_fftn(num: int) -> bool {
    num % 15 == 0
}

#[test]
fn test_is_three_with_not_three() {
  if is_three(1) {
    fail!("One is not three");
  }
}

#[test]
fn test_is_three() {
    if is_three(1) {
        fail!("One is not three");
    }
}

fn main() {
  for num in range(1,101) {
    let answer =
      if is_fftn(num) {
        "FizzBuzz"
      }
      else if is_three(num) {
        "Fizz"
      }
      else if { //missing conditional
        "Buzz"
      }
      else {
        ""
      };
    println(answer);
  }
}

/***** Compiler output *****/

~/Dropbox/rust$ rustc fizzbuzz.rs
fizzbuzz.rs:41:7: 41:11 error: expected `{` but found `else`
fizzbuzz.rs:41       else {
                     ^~~~

***

I would have expected something like "error: missing/expected conditional at line 38, but found '{'"