Example from #1458 no longer parses

[catamorphism]

The example from a comment in #1458, which compiled but didn't pretty-print correctly, no longer compiles:

fn plus_one(f: fn() -> int) -> int {
  return f() + 1;
}

fn ret_plus_one() -> fn(fn() -> int) -> int {
  return plus_one;
}

fn main() {
    let z = do ret_plus_one() || { 2 };
    assert z == 3;
}

issue-1458.rs:10:15: 10:32 error: this function takes 0 parameters but 1 parameter was supplied
issue-1458.rs:10     let z = do ret_plus_one() || { 2 };
                                                                          ^~~~~~~~~~~~~~~~~
issue-1458.rs:10:28: 10:38 error: Non-function passed to a `do` function as its last argument, or wrong number of arguments passed to a `do` function
issue-1458.rs:10     let z = do ret_plus_one() || { 2 };

[catamorphism]

Fixed in 4e5865