https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96533
Bug ID: 96533
Summary: ICE with -Wunused-parameter when using three-way
comparison
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: natattak at gmail dot com
Target Milestone: ---
Minimal example:
#include <compare>
#include <functional>
struct S {
// making it a member fixes the issue
friend auto operator<=>(S, S) = default;
};
// removing 'rhs' fixes the issue
template <typename Lhs, typename Rhs>
auto operator<(Lhs&&, Rhs&& rhs) {
return true;
}
int main() {
// using operator< directly fixes the issue
//return S{} < S{};
return std::less{}(S{}, S{});
}
Compiled with `g++ -std=c++20 -Wunused-parameter`. Output:
'
Internal compiler error: Error reporting routines re-entered.
Please submit a full bug report,
with preprocessed source if appropriate.
See <https://gcc.gnu.org/bugs/> for instructions.
First noticed on g++ 10.1, tested on compiler explorer with current trunk:
https://godbolt.org/z/85j8TW
