serde generated code triggers new clippy::type_repetition_in_bounds warning

[imp]

Clippy has recently introduced new lint type_repetition_in_bounds and apparently serde-generated code (#[derive(Serialize, Deserialize)]) triggers this lint in some cases.

   Checking playground v0.0.1 (/playground)
warning: this type has already been used as a bound predicate
 --> src/main.rs:8:17
  |
8 | #[derive(Debug, Serialize, Deserialize)]
  |                 ^^^^^^^^^
  |
note: lint level defined here
 --> src/main.rs:1:9
  |
1 | #![warn(clippy::type_repetition_in_bounds)]
  |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  = help: consider combining the bounds: `S: Foo + _serde::Serialize`
  = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#type_repetition_in_bounds

warning: this type has already been used as a bound predicate
 --> src/main.rs:8:28
  |
8 | #[derive(Debug, Serialize, Deserialize)]
  |                            ^^^^^^^^^^^
  |
  = help: consider combining the bounds: `S: Foo + _serde::Deserialize`
  = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#type_repetition_in_bounds

    Finished dev [unoptimized + debuginfo] target(s) in 0.61s

Code example

[dtolnay]

Thanks, I reported this as a Clippy false positive in rust-lang/rust-clippy#4326.