https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92426
Bug ID: 92426
Summary: ICE on spaceship declaration plus other P1185R2
interaction issue
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: dacamara.cameron at gmail dot com
Target Milestone: ---
I was playing around with the spaceship operator using gcc10 on godbolt and
discovered an issue trying to compile the following program:
struct Basics {
int i;
char c;
float f;
double d;
auto operator<=>(const Basics&) const = default;
};
struct Arrays {
int ai[1];
char ac[2];
float af[3];
double ad[2][2];
auto operator<=>(const Arrays&) const = default;
};
struct Bases : Basics, Arrays {
auto operator<=>(const Bases&) const = default;
};
int main() {
constexpr Bases a = { { 0, 'c', 1.f, 1. },
{ { 1 }, { 'a', 'b' }, { 1.f, 2.f, 3.f }, { { 1., 2. },
{ 3., 4. } } } };
constexpr Bases b = { { 0, 'c', 1.f, 1. },
{ { 1 }, { 'a', 'b' }, { 1.f, 2.f, 3.f }, { { 1., 2. },
{ 3., 4. } } } };
static_assert(a == b);
static_assert(!(a != b));
static_assert(!(a < b));
static_assert(a <= b);
static_assert(!(a > b));
static_assert(a >= b);
}
The program ultimately ICEs gcc10 but working with a reduced repro shows some
other gaps:
struct Arrays {
int a[2];
#ifdef MEMBERS
auto operator<=>(const Arrays&) const = default;
#endif
#ifdef FRIENDS
friend auto operator<=>(const Arrays&, const Arrays&) = default;
// friend bool operator==(const Arrays&, const Arrays&) = default; //
should be implicitly declared
#endif
};
int main() {
constexpr Arrays a1 { 1, 2 };
constexpr Arrays a2 { 3, 4 };
static_assert(a1 == a1); // OK
static_assert(a1 != a2); // OK
static_assert(a1 < a2); // ICE
}
When MEMBERS is defined it only ICEs at the final static assert, but with
FRIENDS it both leaves the implicitly declared operator== undeclared _and_
ICEs. Additionally, replacing `auto` with `std::strong_ordering` produces an
ICE in finish_expr_stmt so I assume arrays just aren't handled yet?
