error[E0599]: `bool` is not an iterator
  --> ui_tests/export_fn_raw_return.rs:10:33
   |
9  | #[export_fn(return_raw)]
   | ------------------------ in this procedural macro expansion
10 | pub fn test_fn(input: Point) -> bool {
   |                                 ^^^^ `bool` is not an iterator
   |
   = note: the following trait bounds were not satisfied:
           `bool: std::iter::Iterator`
           which is required by `&mut bool: std::iter::Iterator`
   = note: this error originates in the attribute macro `export_fn` (in Nightly builds, run with -Z macro-backtrace for more info)