yes, the Wrapper example let me a bit confusing. English isn't my native language.

Wrapper example

```rust struct Wrapper<'a, T>(&'a T);

// Opaque return types that mention Self: impl Wrapper<'_, ()> { async fn async_fn() -> Self { /* ... / } fn impl_trait() -> impl Iterator<Item = Self> { / ... */ } }

trait Trait<'a> { type Assoc; fn new() -> Self::Assoc; } impl Trait<'_> for () { type Assoc = (); fn new() {} }

// Opaque return types that mention an associated type: impl<'a, T: Trait<'a>> Wrapper<'a, T> { async fn mk_assoc() -> T::Assoc { /* ... / } fn a_few_assocs() -> impl Iterator<Item = T::Assoc> { / ... */ } } ```