Shared via Rust Playground

playground.rs

macro_rules! as_item {
    ($i:item) => {$i};
}

macro_rules! impl_partial_eq {
    ([$($lt:tt)*] $lhs:ty, $rhs:ty) => {
        as_item! {
            impl<$($lt)*> PartialEq<$rhs> for $lhs {
                fn eq(&self, other: &$rhs) -> bool {
                    // common implementation of PartialEq goes here
                    panic!()
                }
            }
        }
    };
}

struct Foo<'a> { x: &'a i32 }

impl_partial_eq!(['a] Foo<'a>, Foo<'a>);
fn main() {}