error[E0277]: the trait bound `CustomContext: FromContext<SubContext>` is not satisfied
 --> fail/union/trait_fail_infer_context.rs:3:1
  |
3 | #[graphql_union]
  | ^^^^^^^^^^^^^^^^ the trait `FromContext<SubContext>` is not implemented for `CustomContext`
  |
  = help: the following other types implement trait `FromContext<T>`:
            <() as FromContext<T>>
            <SubContext as FromContext<CustomContext>>
  = note: this error originates in the attribute macro `graphql_union` (in Nightly builds, run with -Z macro-backtrace for more info)

error[E0308]: mismatched types
   --> fail/union/trait_fail_infer_context.rs:3:1
    |
3   | #[graphql_union]
    | ^^^^^^^^^^^^^^^^
    | |
    | expected struct `CustomContext`, found struct `SubContext`
    | arguments to this function are incorrect
    |
    = note: expected reference `&CustomContext`
               found reference `&SubContext`
note: associated function defined here
   --> $WORKSPACE/juniper/src/executor/mod.rs
    |
    |     fn into(self, ctx: &'a C) -> FieldResult<Option<(&'a T::Context, T)>, S>;
    |        ^^^^
    = note: this error originates in the attribute macro `graphql_union` (in Nightly builds, run with -Z macro-backtrace for more info)