https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108966
Bug ID: 108966
Summary: Inheriting consteval constructor makes it constexpr in
the derived class
Product: gcc
Version: 12.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: g...@arne-mertz.de
Target Milestone: ---
Consider the following code:
```
struct X
{
consteval X(int) {};
};
struct T : X
{
using X::X;
};
constexpr T t(22);
```
The using directive (1) should lead to a `consteval T::T(int)`. However, the
compiler errors with message
```
<source>: In constructor 'constexpr T::T(double&&) [inherited from X]':
<source>:8:14: error: 'this' is not a constant expression
8 | using X::X;
```
This indicates that the inherited constructor is considered `constexpr` instead
of `consteval` and is therefore unable to call the `consteval` base class
constructor.
See it in action: https://godbolt.org/z/K6T6f1691
Note:
- this does not happen when the constructor is replaced with `X::X() = default`
and no initializer is given to `t`, but a similar error appears with `X::X()
{}`
