error: #[graphql_subscription] attribute is applicable to non-trait `impl` blocks only
  --> fail/subscription/wrong_syntax.rs:12:1
   |
12 | #[graphql_subscription]
   | ^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: this error originates in the attribute macro `graphql_subscription` (in Nightly builds, run with -Z macro-backtrace for more info)

error[E0609]: no field `self` on type `&ObjA`
  --> fail/subscription/wrong_syntax.rs:15:50
   |
15 |         Box::pin(stream::once(future::ready(self.self.field)))
   |                                                  ^^^^ unknown field
   |
   = note: available field is: `field`