How can I require that a reference to a generic type can be compared for equality against the generic type?

Question

I\'m trying to implement an algorithm which relies on modular exponentiation. I couldn\'t find any modular exponentiation construct for native types like u64 (only

Answer 1

You can either ignore the problem and compare a reference to a reference or non-reference to a non-reference:

if modulus == &T::one() {
// Or
if *modulus == T::one() {

Or you can use higher-ranked trait bounds:

impl PowM for T
where
    T: Num + Two + ShrAssign + Rem + PartialOrd,
    for <'a> &'a T: PartialEq,
{
    // ...
}

In either case, you need to require that T implements Copy or that it implements Clone and then add appropriate calls to .clone().

See also:

• How does for<> syntax differ from a regular lifetime bound?