gistfile1.txt

trait TypeFn {type Output<A>;}

struct Fix<F: TypeFn>(<F as TypeFn>::Output<Fix<F>>);

struct FnRes;
impl TypeFn for FnRes { type Output<A> = fn() -> A;}

fn return_me() -> Fix<FnRes> {
    Fix(return_me as fn() -> Fix<FnRes>)
}

fn name_of<T>(a: T) -> &'static str {
    core::any::type_name::<T>()
}

// Program returned: 0
// [/app/example.rs:17:5] name_of(return_me()) = "example::Fix<example::FnRes>"
// [/app/example.rs:18:5] name_of(return_me().0()) = "example::Fix<example::FnRes>"
// [/app/example.rs:19:5] return_me().0 = 0x0000559a4d157e50
// [/app/example.rs:19:5] return_me().0().0 = 0x0000559a4d157e50
// [/app/example.rs:19:5] return_me().0().0().0 = 0x0000559a4d157e50

fn main() {
    dbg!(name_of(return_me()));
    dbg!(name_of(return_me().0()));
    dbg!(return_me().0,
    return_me().0().0,
    return_me().0().0().0,
    );
}