Consider the following simplified code:
template <class T> class Foo { T t; const T* t_ptr; public: constexpr Foo(T t): t(t), t_ptr(&this->t) {} constexpr Foo(const Foo& foo): t(foo.t), t_ptr(&this->t) {} constexpr T get_t() const { return *t_ptr; } }; template <class T> constexpr Foo<T> foo(T t) { return Foo<T>(t); } constexpr auto f = foo(1); static_assert(f.get_t() == 1); It successfully compiles with Clang and MSVC but GCC 15 gives an error:
<source>:16:25: error: non-constant condition for static assertion 16 | static_assert(f.get_t() == 1); | ~~~~~~~~~~^~~~ <source>:16:22: in 'constexpr' expansion of 'f.Foo<int>::get_t()' <source>:8:17: error: the value of 'f' is not usable in a constant expression 8 | return *t_ptr; | ^~~~~ <source>:15:16: note: 'f' used in its own initializer 15 | constexpr auto f = foo(1); | ^ Compiler returned: 1 Is this code valid? Is this a bug in GCC? Is there a workaround to make constexpr structs that contain a pointer to its own member work?
