| Issue |
126558
|
| Summary |
[Clang] Cannot use a static constexpr/consteval member function to initialize a static constexpr member
|
| Labels |
|
| Assignees |
|
| Reporter |
YexuanXiao
|
I've noticed that consteval member functions exhibit very strange behavior—they can initialize static non-constexpr members but fail to work for static constexpr members.
Example ([Godbolt](https://godbolt.org/z/Ynn5xf78s)):
```cpp
struct A
{
static inline constexpr bool test_constexpr() noexcept
{
return true;
}
static inline constexpr bool t_expr = test_constexpr(); // can't compile
static inline constexpr bool test_consteval() noexcept
{
return true;
}
static inline constexpr bool t_eval = test_consteval(); // can't compile
static inline bool t_non_const = test_constexpr();
};
inline constexpr bool t_expr = A::test_constexpr();
inline constexpr bool t_eval = A::test_consteval();
```
Output:
```cpp
<source>:8:34: error: constexpr variable 't_expr' must be initialized by a constant _expression_
8 | static inline constexpr bool t_expr = test_constexpr();
| ^ ~~~~~~~~~~~~~~~~
<source>:8:43: note: undefined function 'test_constexpr' cannot be used in a constant _expression_
8 | static inline constexpr bool t_expr = test_constexpr();
| ^
<source>:3:34: note: declared here
3 | static inline constexpr bool test_constexpr() noexcept
| ^
<source>:15:34: error: constexpr variable 't_eval' must be initialized by a constant _expression_
15 | static inline constexpr bool t_eval = test_consteval();
| ^ ~~~~~~~~~~~~~~~~
<source>:15:43: note: undefined function 'test_consteval' cannot be used in a constant _expression_
15 | static inline constexpr bool t_eval = test_consteval();
| ^
<source>:10:34: note: declared here
10 | static inline constexpr bool test_consteval() noexcept
| ^
2 errors generated.
Compiler returned: 1
```
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