- Title
- Questionable type-dependency of concept-ids
- Status
- c++20
- Section
- 13.8.3.3 [temp.dep.expr]
- Submitter
- Hubert Tong
Created on 2019-02-03.00:00:00 last changed 59 months ago
Messages
Date: 2020-02-15.00:00:00
Proposed resolution (February, 2020):
Change 13.8.3.3 [temp.dep.expr] paragraph 3 as follows:
...
Change 13.8.3.4 [temp.dep.constexpr] paragraph 3 as follows:
it is a concept-id and any of its arguments are dependent,
it is type-dependent,
...
An id-expression is type-dependent if it is not a concept-id and it contains
An id-expression is value-dependent if:
Date: 2020-02-15.00:00:00
[Accepted at the February, 2020 (Prague) meeting.]
The rules for type-dependency do not appear to take the bool type associated with concept-ids into account. For example:
template <typename T> concept C = true;
template <typename T> struct A;
template <> struct A<bool> { using type = bool; };
template <typename T>
void f(A<decltype(C<T>)>::type); // error: needs typename to avoid vexing parse
| History | |||
|---|---|---|---|
| Date | User | Action | Args |
| 2020-12-15 00:00:00 | admin | set | messages: + msg6478 |
| 2019-02-03 00:00:00 | admin | create | |