https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113063
Bug ID: 113063
Summary: Strange linker error in special case involving local
class with defaulted spaceship operator and static
assert
Product: gcc
Version: 13.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: kristian.spangsege at gmail dot com
Target Milestone: ---
With the latest GCC (13.2) and also with GCC 11.4, the following C++ code
triggers a strange linker error:
#include <compare>
int main()
{
struct X {
auto operator<=>(const X&) const = default;
};
X x;
static_assert(noexcept(x < x));
static_cast<void>(x < x);
}
Godbolt: https://godbolt.org/z/PfPfznT6Y
The linker error is this:
/usr/bin/ld: /tmp/ccsnSU59.o: in function `main::X::operator<=>(X const&)
const':
t.cpp:(.text+0x31): undefined reference to
`std::strong_ordering::strong_ordering(std::strong_ordering const&)'
It seems to be a bug that is triggered by the presence of the static assertion,
but only when the it occurs before the actual invocation of the less-than
comparison operation. Also, if the local class (`X`) is moved out of `main()`,
the problem goes away.
