fix: bundle Eligibility as bool

[julio4]

PartialEq impl for Eligibility do not coerce to bool, only allows to compare against bool values.
It might be better to explicitly convert to bool when necessary.

[karim-agha]

The current PartialEq<bool> allows us to use the following syntax:

if bundle.is_eligible() {
  // code
}

// or

let bundles = stream.filter(|b| bundle.is_eligible());

What downsides do you see to having this syntactic sugar? The alternative with this pr would be

if bundle.is_eligible().as_bool() {
  // code
}

// or

let bundles = stream.filter(|b| !(!bundle.is_eligible()));

[julio4]

The current PartialEq<bool> allows us to use the following syntax:

if bundle.is_eligible() {
  // code
}

I agree that this is the best syntax we could have, however condition operands only accept boolean expressions and will not implicitly call cmp impls such as PartialEq. So this will fails:

         if bundle.is_eligible(block) {
            ^^^^^^^^^^^^^^^^^^^^^^^^^ expected `bool`, found `Eligibility`

The PartialEq allows to do that:

if bundle.is_eligible() == true {
  // code
}

But I think as_bool is a more idiomatic and explicit way of doing it.

[karim-agha]

Maybe we can implement as_bool in terms of From/Into?

[julio4]

Maybe we can implement as_bool in terms of From/Into?

We can as well, but there's still the need to call .into() in condition.
as_bool is a bit more explicit, and Into a bit more straigthforward, imo both are fine.

[julio4]

Changed to Into