`ark_std::error` vs `core::error`

[burdges]

`ark_std::error` vs `core::error`

[burdges]

See w3f/ring-vrf@b87e3a1#diff-b956979688cec9dec3a8d6eeb4ccd2a129e0d48803110ee9def443aec17d72d7R105

[Pratyush]

100% agree that we should switch to core::error, but as things stand this is not actionable, right? We need error_in_core to be stabilized first. I would prefer to avoid rust version detection, as that would involve a build.rs which worsens compile time.

[burdges]

I simply meant copy "more of" std::error from std into ark-std, specifically the <dyn Error>::downcast part.

I'll make @achimcc submit a PR for it if our auditors think error passing matters in ark-scale link above. We've correct error passing in the substrate host already, which maybe enough.