Rust generic op trait pains

mul_generic.rs

use std::ops::Mul;

pub struct Foo<T>(T, T);

// Either of the following traits can be implemented individually, but both together cause an infinite recursion.
// If both traits are limited to a single type T it works fine.

impl<L, R, O> Mul<&Foo<R>> for &Foo<L>
where
	for<'l, 'r> &'l L: Mul<&'r R, Output = O>,
{
	type Output = Foo<O>;
	fn mul(self, other: &Foo<R>) -> Foo<O> {
		Foo(&self.0 * &other.0, &self.1 * &other.1)
	}
}

impl<T> Mul<&T> for &Foo<T>
where
	for<'l, 'r> &'l T: Mul<&'r T, Output = T>,
{
	type Output = Foo<T>;
	fn mul(self, other: &T) -> Foo<T> {
		Foo(&self.0 * other, &self.1 * other)
	}
}

mul_scalar.rs

use std::ops::Mul;

pub struct Foo<T>(T, T);

// ok
impl<T> Mul<&T> for &Foo<T>
where
	for<'l, 'r> &'l T: Mul<&'r T, Output = T>,
{
	type Output = Foo<T>;
	fn mul(self, other: &T) -> Foo<T> {
		Foo(&self.0 * other, &self.1 * other)
	}
}

// causes error E0210 with the somewhat misleading hint
// "type parameter `T` must be used as the type parameter for some local type"
impl<T> Mul<&Foo<T>> for &T
where
	for<'l, 'r> &'l T: Mul<&'r T, Output = T>,
{
	type Output = Foo<T>;
	fn mul(self, other: &Foo<T>) -> Foo<T> {
		Foo(self * &other.0, self * &other.1)
	}
}

// impl for a concrete foreign type causes no issues...
/*impl Mul<&Foo<f32>> for &f32 {
	type Output = Foo<f32>;
	fn mul(self, other: &Foo<f32>) -> Foo<f32> {
		Foo(self * &other.0, self * &other.1)
	}
}*/