opaque type `structurally_resolve_type` breakage

[lcnr]

use std::ops::{Deref, Index};
fn deref_no_target() -> impl Deref {
    if false {
        let _ = *deref_no_target();
    }
    &()
}

fn deref_with_target() -> impl Deref<Target = ()> {
    if false {
        let () = *deref_with_target();
    }
    &()
}

fn field_autoderef() -> impl Deref<Target = ((),)> {
    if false {
        let () = field_autoderef().0;
    }
    &((),)
}

fn index() -> impl Index<usize, Output = u32> {
    if false {
        assert_eq!(index()[0], 1);
    }
    [1]
}

fn index_autoderef() -> impl Deref<Target = [u8; 3]> {
    if false {
        assert_eq!(index_autoderef()[1], 1);
    }
    &[0, 1, 2]
}

[lcnr]

🤷 whether to fix these