Is there an RFC for this?

[sffc]

The ConstDefault trait is great, and it should belong in the standard library. Are you aware of (or proposing yourself) an RFC to add this to the Rust standard library?

[AerialX]

Well the hope is that const_trait_impl will cover this by simply allowing std::default::Default to be usable in const contexts, and then this trait could be superseded by a ~const Default bound! It even looks like unstable rust has gained some const Default impls semi-recently.