https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112590
Bug ID: 112590
Summary: structural constexpr class fails to instantiate
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: janezz55 at gmail dot com
Target Milestone: ---
Compiling:
#include <cstddef>
template <auto C> void test() {}
template <std::size_t N>
struct S
{
int a_[N];
int* f_;
constexpr S(): a_{}, f_{a_} {}
};
int main()
{
test<S<10>{}>();
return 0;
}
fails with:
prog.cc: In function 'int main()':
prog.cc:18:16: error: no matching function for call to 'test<S<10>()>()'
18 | test<S<10>{}>();
| ~~~~~~~~~~~~~^~
prog.cc:4:6: note: candidate: 'template<auto C> void test()'
4 | void test()
| ^~~~
prog.cc:4:6: note: template argument deduction/substitution failed:
prog.cc:18:16: error: 'S<10>{int [10](), ((int*)(&<anonymous>.S<10>::a_))}' is
not a constant expression
18 | test<S<10>{}>();
| ~~~~~~~~~~~~~^~
prog.cc:18:16: error: 'S<10>()' is not a constant expression because it refers
to an incompletely initialized variable
But everything is initialized. I believe a workaround exists, but I didn't
experiment.
https://wandbox.org/permlink/xA81TIzI5XsXdh57
