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This would only work for concrete types (not i= nside >>>> generic functions). >>>> >>>> As an example, convert `as_char_ptr_in_const_context`, so instead of >>>> >>>> kernel::str::as_char_ptr_in_const_context(c_str) >>>> >>>> one may write >>>> >>>> const_call!(c_str.as_char_ptr()) >>>> >>>> instead. >>>> >>>> Signed-off-by: Gary Guo >>> >>> Thanks for resending this! >>> >>> So I definitely like having `#[const_eval_only]`, because we do want >>> to limit those calls sometimes and it is nice to have C++'s equivalent >>> to `consteval` (perhaps this could be called just `#[consteval]` to >>> match?); i.e. what we talked about in the call. I'm okay with either. I put in `_only` because I think it makes it very cle= ar that this is not just const-evalutable (that's provided by `const`) and is *always* const evaled. >>> >>> On `Const` and `const_call!`, i.e. the other two patches: I am not >>> sure if we care that much to introduce a macro for it, but it doesn't >>> look bad either. I guess perhaps it helps to have a consistent way to >>> do it and to easily remove it later when the actual feature lands in >>> Rust. I would like to hear some thoughts on it from others. >> >> I think it's good to have such macro compared to our current approach; i= t can be >> made into a identity macro once we have const trait impl. >> >> FWIW, I even considered an extra macro that allow you to write >> >> #[const_trait_impl] // #[const_trait_impl(foreign)] for core types >> impl MyTrait for MyType {} >> >> and generate the `impl Const` part too (and also add a line to the docum= entation >> that the method is const-callable with `const_call!()`). >> >> Best, >> Gary > > I agree with the consteval macro, that sounds very nice. > > On the const_call! I have similar thoughts to Miguel. I reckon if we > have a bunch of prospective users of this right now, and some thoughts > on what would use this in the future then it's good. If it's just one > use case right now, then not so sure. Some other candidates include `Alignable` (we currently have a "const_align= _up") and maybe `IntoSafeCast`. Best, Gary