`derive(derive_more::From)` doesn't foward properly

[CGMossa]

My case is that I want something equivalent to this:

#[derive(Debug, Clone, Copy)]
pub struct ReplacementParameter(Probability);

impl From<ReplacementParameter> for f64 {
    fn from(value: ReplacementParameter) -> Self {
        value.0.into()
    }
}

Since Probability implements TryFrom<f64>. But derive_more is failing on that, even if I use #[from(forward)].

What am I missing and maybe what is derive_more missing here?

[JelteF]

You're mixing From and TryFrom in this issue, which are different traits.

Can you share the a full code sample that you tried? (I don't see the definition of Probability) What do you want to be able to do/what exact implementation do you expect to be generated?

On Fri, 18 Jun 2021, 00:27 CGMossa, @.***> wrote:

My case is that I want something equivalent to this:

#[derive(Debug, Clone, Copy)]pub struct ReplacementParameter(Probability); impl From<ReplacementParameter> for f64 { fn from(value: ReplacementParameter) -> Self { value.0.into() } }

Since Probability implements TryFrom. But derive_more is failing on that, even if I use #[from(forward)].

What am I missing and maybe what is derive_more missing here?

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[JelteF]

Also what's the compile error that you are getting?

On Fri, 18 Jun 2021, 00:27 CGMossa, @.***> wrote:

My case is that I want something equivalent to this:

#[derive(Debug, Clone, Copy)]pub struct ReplacementParameter(Probability); impl From<ReplacementParameter> for f64 { fn from(value: ReplacementParameter) -> Self { value.0.into() } }

Since Probability implements TryFrom. But derive_more is failing on that, even if I use #[from(forward)].

What am I missing and maybe what is derive_more missing here?

— You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub https://github.com/JelteF/derive_more/issues/166, or unsubscribe https://github.com/notifications/unsubscribe-auth/AAI3YJTZBZUJF4SM3JT3DLDTTJZD5ANCNFSM464RHMEQ .

[tyranron]

@CGMossa forwarding is possible if f64 implements From<Probability>. The current syntax on master and 1.0.0-beta.* releases would be:

#[derive(Clone, Copy, Debug, Into)]
#[into(f64)]
pub struct ReplacementParameter(Probability);

However, if f64 implements only TryFrom<Probability>, you should use TryInto instead, which, at the moment, doesn't support granular types, though (tracked by https://github.com/JelteF/derive_more/issues/98).

I'm closing this for now. Feel free to reopen or ping, if we haven't understood your use case and the desired feature correctly.

[CGMossa]

Err sorry for not following this or closing it. It has been too long since this, and I've recently recreated this example, without running into this hiccup.