Derived type error when assigning function to an Option

[huonw]

fn main() {
    let mut rec_f = None;
    let f: &fn(uint) -> bool = |n| { n == 0 || (*rec_f.get_ref())(n - 1) };
    rec_f = Some(f);
}

derived-type.rs:3:47: 3:66 error: the type of this value must be known in this context
derived-type.rs:3     let f: &fn(uint) -> bool = |n| { n == 0 || (*rec_f.get_ref())(n - 1) };
                                                                 ^~~~~~~~~~~~~~~~~~~
derived-type.rs:4:12: 4:20 error: mismatched types: expected `std::option::Option<[type error]>` but found `std::option::Option<&fn<no-bounds>(uint) -> bool>` (expected type error but found fn)
derived-type.rs:4     rec_f = Some(f);
                              ^~~~~~~~
error: aborting due to 2 previous errors

[jdm]

Paging @catamorphism.

[pzol]

Updated syntax

fn main() {
    let mut rec_f = None;
    let f: &proc(uint) -> bool = |n: uint| { n == 0 || (*rec_f.get_ref())(n - 1) };
    rec_f = Some(f);
}

[steveklabnik]

I don't remember what get_ref() did, is that as_ref() now?

fn main() {
    let mut rec_f = None;
    let f = |n: usize| { n == 0 || (*rec_f.as_ref())(n - 1) };
    rec_f = Some(f);
}

errors

hello.rs:3:37: 3:52 error: type `core::option::Option<&_>` cannot be dereferenced
hello.rs:3     let f = |n: usize| { n == 0 || (*rec_f.as_ref())(n - 1) };
                                               ^~~~~~~~~~~~~~~
hello.rs:3:13: 3:62 error: mismatched types:
 expected `&core::option::Option<[closure@hello.rs:3:13: 3:62 rec_f:_]>`,
    found `_`
(cyclic type of infinite size) [E0308]
hello.rs:3     let f = |n: usize| { n == 0 || (*rec_f.as_ref())(n - 1) };
                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
hello.rs:3:13: 3:62 help: run `rustc --explain E0308` to see a detailed explanation
error: aborting due to 2 previous errors

Given how much has changed here, and no comments in a year, I'm going to just close this one.