Yeah, we use a fixed-E alias of folly::Expected<> in our codebase which is similar to absl::StatusOr. Something like:

  namespace our_project {
    class Status { ... };
  
    template <class T>
    using Expected = folly::Expected<T, Status>;
  }

absl::StatusOr<T> looks a lot like our_project::Expected<T>. This pattern of providing your own error type and aliasing Result is also somewhat common in Rust, I believe.