error: use of deprecated constant `_::DEPRECATED_SYNTAX`:
       The form `tarpc::service(derive_serde = true)` is deprecated.
       Use `tarpc::service(derive = [Serialize, Deserialize])`.
 --> tests/compile_fail/serde1/deprecated.rs:3:1
  |
3 | #[tarpc::service(derive_serde = true)]
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
note: the lint level is defined here
 --> tests/compile_fail/serde1/deprecated.rs:1:9
  |
1 | #![deny(warnings)]
  |         ^^^^^^^^
  = note: `#[deny(deprecated)]` implied by `#[deny(warnings)]`
  = note: this error originates in the attribute macro `tarpc::service` (in Nightly builds, run with -Z macro-backtrace for more info)