https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102748
Bug ID: 102748
Summary: static_assert on concept leads to undefined reference
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: raffael at casagrande dot ch
Target Milestone: ---
Try to compile and link the following simple program with `-std=c++20`:
-----------------------------------
template <class RANGE, class CALLABLE>
auto ForEachGuided(RANGE&& range, CALLABLE&& c) {
range.begin();
}
struct RandomAccessRangeAT {
void begin() const noexcept;
};
template <class FE_SPACE_FACTORY>
concept FESpaceFactory = requires(const FE_SPACE_FACTORY& fe_space_factory,
const RandomAccessRangeAT& range) {
{fe_space_factory(range)};
};
int main() {
auto fes_provider = [](auto&& range) {
ForEachGuided(range, []() {});
};
static_assert(FESpaceFactory<decltype(fes_provider)>);
}
--------------------------------------
Compilation will work, but during linking we get the error message:
"undefined reference to `RandomAccessRangeAT::begin() const'"
As soon as we apply some optimization flags, the linking error vanishes.
Also clang doesn't have this problem...
