Clippy emits warnings when pedantic lints are enabled with derive macro

[Squitch1]

Using the derive macros, clippy emits warnings when clippy::pedantic lints are enabled for structures containing fields typed with Option<&Foo>. These errors are emitted on the latest version of Rust, both on the stable and nightly branches.

Here is a minimal reproduction code:

#[derive(bitcode::Decode, bitcode::Encode)]
pub struct Foo<'a> {
    pub bar: Option<&'a str>,
}

And here are the warnings:

error: since `&` implements the `Copy` trait, `&Option<&T>` can be simplified to `Option<&T>`
|
| #[derive(bitcode::Decode, bitcode::Encode)]
|                           ^^^^^^^^^^^^^^^
|
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ref_option_ref
...
   = note: this error originates in the derive macro `bitcode::Encode` (in Nightly builds, run with -Z macro-backtrace for more info)

error: since `&` implements the `Copy` trait, `&Option<&T>` can be simplified to `Option<&T>`
|
| #[derive(bitcode::Decode, bitcode::Encode)]
|          ^^^^^^^^^^^^^^^
|
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ref_option_ref
...
   = note: this error originates in the derive macro `bitcode::Decode` (in Nightly builds, run with -Z macro-backtrace for more info)

[finnbear]

Thanks for the report! This will be fixed in the next bitcode version.