`<concepts>` is built upon `<type_traits>`, which is implemented via magic
intrinsic macros. Proper evolution path should be to rather define those
macros in terms of `<meta>` and keep `<type_traits>` as backward
compatiblity.

how am I supposed to end the twisted road of your hair in such a dark
night??
unless the candle of your face does shed some light upon my way!!!

در تاریخ سه‌شنبه ۶ اکتبر ۲۰۲۶،‏ ۱۵:۳۰ <
std-discussion-request_at_[hidden]> نوشت:

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> 1. Should the concepts in <concepts>, <iterator>, etc. have
> their meta function counterparts in <meta> ? (Bingzhi)
>
>
>
> ---------- Forwarded message ----------
> From: Bingzhi <bingzhi2025_at_[hidden]>
> To: std-discussion_at_[hidden]
> Cc:
> Bcc:
> Date: Tue, 6 Oct 2026 00:28:37 +0800
> Subject: [std-discussion] Should the concepts in <concepts>, <iterator>,
> etc. have their meta function counterparts in <meta> ?
>
> For example, the concept `movable`, as its counterpart, should
> `meta::is_movable_type` exists in <meta> (in future C++)?
> I know meta function lacks subsumption. But at least, should C++ in the
> future add things like `std::meta::is_movable_type` ?
>
>
> ** Furthermore, should meta function be subsumable? Sounds crazy huh?
> `concept bool` might be a good type for this. But I didn't encounter any
> reasonable use cases, subsumption is only needed in template constraints,
> so I guess this is nonsense, almost ...*
>
> The reason I want `meta::is_movable_type` is that `movable` is impossible
> to implement without a `template <...>`,
> and templates are much more slower in compilation speed than concepts and
> meta functions (not function templates).
> It definitely doesn't require subsumption.
>
> I don't know if somebody has already argued things like
> `meta::is_movable_type` (a proposal, a compiler MVP, etc.).
>
> I want to hear your thoughts.
>
> Bingzhi
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