The construct wouldn't be valid as written for the reasons you mention. The blog post for this discussion glosses over the details by writing `impl Future<Item = Bool>` instead of the concrete type a future would have to have in Rust today.
I'm not an expert but one of the ongoing dicussions in the impl Trait RFC is where the construct can show up. The preliminary version can only appear as a return type from a function where the compiler can always determine the exact details at compile time depending on the chain of calls. I believe typing out the entire type of the future in the struct would work but, again, I only somewhat know my way around the language.
I'm not an expert but one of the ongoing dicussions in the impl Trait RFC is where the construct can show up. The preliminary version can only appear as a return type from a function where the compiler can always determine the exact details at compile time depending on the chain of calls. I believe typing out the entire type of the future in the struct would work but, again, I only somewhat know my way around the language.