implementation of 'std::cmp::PartialEq' is not general enough - rust

Question

I am trying to use mockiato to mock a function that accepts an Option of my struct A but am receiving the following error.
error: implementation of `std::cmp::PartialEq` is not general enough
--> src\main.rs:45:14
|
45 | .expect_do_feature(|arg| arg.partial_eq(Some(&cfg)))
| ^^^^^^^^^^^^^^^^^ implementation of `std::cmp::PartialEq` is not general enough
|
= note: `std::cmp::PartialEq<std::option::Option<&'1 A>>` would have to be implemented for the type `std::option::Option<&A>`, for any lifetime `'1`...
= note: ...but `std::cmp::PartialEq` is actually implemented for the type `std::option::Option<&'2 A>`, for some specific lifetime `'2`
I would've thought the #[derive(PartialEq)] on the struct A would generate what was needed, but it looks like it doesn't quite do the full job. How do I implement what the compiler is telling me to do?
use std::collections::HashMap;
#[cfg(test)]
use mockiato::mockable;
#[derive(PartialEq)]
pub struct A {
pub data: HashMap<String, i32>,
}
impl A {
pub fn new() -> Self {
A {
data: HashMap::new(),
}
}
}
pub struct B;
#[cfg_attr(test, mockable)]
pub trait ProvidesFeature {
fn do_feature(&self, config: Option<&A>) -> Option<Vec<i32>>;
}
impl B {
pub fn new() -> Self {
B {}
}
pub fn do_feature(&self, config: Option<&A>) -> Option<Vec<i32>> {
Some(vec!())
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_mocking() {
let mut feature_mock = ProvidesFeatureMock::new();
feature_mock
.expect_do_feature(|arg| arg.partial_eq(None))
.times(1..)
.returns(Some(vec!()));
assert_eq!(vec![0; 0], feature_mock.do_feature(None).unwrap());
}
}
fn main() {
println!("Hello, world!");
}
In order to compile, I used mockiato = "0.9.5" in Cargo.toml. Don't forget to run this with cargo test if you attempt to reproduce.