error.rs

fn convert_to_complex<'a, I>(polygons: I) -> Vec<ComplexPolygon>
    where I: Iterator<Item = &'a [(i32, i32)]>,
          I: Clone
{
  ...
}

...

static TEST_VERTS: &'static [&'static [(i32, i32)]] =
            &[&[(0, 0), (40, 0), (40, 40), (0, 40)],
              &[(10, 10), (30, 10), (30, 30), (10, 30)],
              &[(5, 5), (5, 35), (35, 35), (35, 5)],
              &[(15, 15), (15, 25), (25, 25), (25, 15)]];
        let result = convert_to_complex(TEST_VERTS.into_iter());
        
...
        
error[E0271]: type mismatch resolving `<std::slice::Iter<'_, &[(i32, i32)]> as std::iter::Iterator>::Item == &[(i32, i32)]`
   --> src/format.rs:100:22
    |
100 |         let result = convert_to_complex(TEST_VERTS.into_iter());
    |                      ^^^^^^^^^^^^^^^^^^ expected reference, found slice
    |
    = note: expected type `&&[(i32, i32)]`
    = note:    found type `&[(i32, i32)]`
    = note: required by `format::convert_to_complex`