// RUN: %clang_cc1 -std=c++2a -verify %s -fcxx-exceptions -triple=x86_64-linux-gnu -Wno-mismatched-new-delete
#include "Inputs/std-compare.h"
namespace std {
struct type_info;
struct destroying_delete_t {
explicit destroying_delete_t() = default;
} inline constexpr destroying_delete{};
struct nothrow_t {
explicit nothrow_t() = default;
} inline constexpr nothrow{};
using size_t = decltype(sizeof(0));
enum class align_val_t : size_t {};
};
[[nodiscard]] void *operator new(std::size_t, const std::nothrow_t&) noexcept;
[[nodiscard]] void *operator new(std::size_t, std::align_val_t, const std::nothrow_t&) noexcept;
[[nodiscard]] void *operator new[](std::size_t, const std::nothrow_t&) noexcept;
[[nodiscard]] void *operator new[](std::size_t, std::align_val_t, const std::nothrow_t&) noexcept;
[[nodiscard]] void *operator new[](std::size_t, std::align_val_t);
void operator delete(void*, const std::nothrow_t&) noexcept;
void operator delete(void*, std::align_val_t, const std::nothrow_t&) noexcept;
void operator delete[](void*, const std::nothrow_t&) noexcept;
void operator delete[](void*, std::align_val_t, const std::nothrow_t&) noexcept;
// Helper to print out values for debugging.
constexpr void not_defined();
template<typename T> constexpr void print(T) { not_defined(); }
namespace ThreeWayComparison {
struct A {
int n;
constexpr friend int operator<=>(const A &a, const A &b) {
return a.n < b.n ? -1 : a.n > b.n ? 1 : 0;
}
};
static_assert(A{1} <=> A{2} < 0);
static_assert(A{2} <=> A{1} > 0);
static_assert(A{2} <=> A{2} == 0);
static_assert(1 <=> 2 < 0);
static_assert(2 <=> 1 > 0);
static_assert(1 <=> 1 == 0);
constexpr int k = (1 <=> 1, 0);
// expected-warning@-1 {{three-way comparison result unused}}
static_assert(std::strong_ordering::equal == 0);
constexpr void f() {
void(1 <=> 1);
}
struct MemPtr {
void foo() {}
void bar() {}
int data;
int data2;
long data3;
};
struct MemPtr2 {
void foo() {}
void bar() {}
int data;
int data2;
long data3;
};
using MemPtrT = void (MemPtr::*)();
using FnPtrT = void (*)();
void FnPtr1() {}
void FnPtr2() {}
#define CHECK(...) ((__VA_ARGS__) ? void() : throw "error")
#define CHECK_TYPE(...) static_assert(__is_same(__VA_ARGS__));
constexpr bool test_constexpr_success = [] {
{
auto &EQ = std::strong_ordering::equal;
auto &LESS = std::strong_ordering::less;
auto &GREATER = std::strong_ordering::greater;
using SO = std::strong_ordering;
auto eq = (42 <=> 42);
CHECK_TYPE(decltype(eq), SO);
CHECK(eq.test_eq(EQ));
auto less = (-1 <=> 0);
CHECK_TYPE(decltype(less), SO);
CHECK(less.test_eq(LESS));
auto greater = (42l <=> 1u);
CHECK_TYPE(decltype(greater), SO);
CHECK(greater.test_eq(GREATER));
}
{
using PO = std::partial_ordering;
auto EQUIV = PO::equivalent;
auto LESS = PO::less;
auto GREATER = PO::greater;
auto eq = (42.0 <=> 42.0);
CHECK_TYPE(decltype(eq), PO);
CHECK(eq.test_eq(EQUIV));
auto less = (39.0 <=> 42.0);
CHECK_TYPE(decltype(less), PO);
CHECK(less.test_eq(LESS));
auto greater = (-10.123 <=> -101.1);
CHECK_TYPE(decltype(greater), PO);
CHECK(greater.test_eq(GREATER));
}
return true;
}();
int dummy = 42;
int dummy2 = 101;
constexpr bool tc9 = (&dummy <=> &dummy2) != 0; // expected-error {{constant expression}} expected-note {{unspecified}}
template <class T, class R, class I>
constexpr T makeComplex(R r, I i) {
T res{r, i};
return res;
};
} // namespace ThreeWayComparison
constexpr bool for_range_init() {
int k = 0;
for (int arr[3] = {1, 2, 3}; int n : arr) k += n;
return k == 6;
}
static_assert(for_range_init());
namespace Virtual {
struct NonZeroOffset { int padding = 123; };
constexpr void assert(bool b) { if (!b) throw 0; }
// Ensure that we pick the right final overrider during construction.
struct A {
virtual constexpr char f() const { return 'A'; }
char a = f();
constexpr ~A() { assert(f() == 'A'); }
};
struct NoOverrideA : A {};
struct B : NonZeroOffset, NoOverrideA {
virtual constexpr char f() const { return 'B'; }
char b = f();
constexpr ~B() { assert(f() == 'B'); }
};
struct NoOverrideB : B {};
struct C : NonZeroOffset, A {
virtual constexpr char f() const { return 'C'; }
A *pba;
char c = ((A*)this)->f();
char ba = pba->f();
constexpr C(A *pba) : pba(pba) {}
constexpr ~C() { assert(f() == 'C'); }
};
struct D : NonZeroOffset, NoOverrideB, C { // expected-warning {{inaccessible}}
virtual constexpr char f() const { return 'D'; }
char d = f();
constexpr D() : C((B*)this) {}
constexpr ~D() { assert(f() == 'D'); }
};
constexpr int n = (D(), 0);
constexpr D d;
static_assert(((B&)d).a == 'A');
static_assert(((C&)d).a == 'A');
static_assert(d.b == 'B');
static_assert(d.c == 'C');
// During the construction of C, the dynamic type of B's A is B.
static_assert(d.ba == 'B');
static_assert(d.d == 'D');
static_assert(d.f() == 'D');
constexpr const A &a = (B&)d;
constexpr const B &b = d;
static_assert(a.f() == 'D');
static_assert(b.f() == 'D');
// FIXME: It is unclear whether this should be permitted.
D d_not_constexpr;
static_assert(d_not_constexpr.f() == 'D'); // expected-error {{constant expression}} expected-note {{virtual function called on object 'd_not_constexpr' whose dynamic type is not constant}}
// Check that we apply a proper adjustment for a covariant return type.
struct Covariant1 {
D d;
virtual const A *f() const;
};
template<typename T>
struct Covariant2 : Covariant1 {
virtual const T *f() const;
};
template<typename T>
struct Covariant3 : Covariant2<T> {
constexpr virtual const D *f() const { return &this->d; }
};
constexpr Covariant3<B> cb;
constexpr Covariant3<C> cc;
constexpr const Covariant1 *cb1 = &cb;
constexpr const Covariant2<B> *cb2 = &cb;
static_assert(cb1->f()->a == 'A');
static_assert(cb1->f() == (B*)&cb.d);
static_assert(cb1->f()->f() == 'D');
static_assert(cb2->f()->b == 'B');
static_assert(cb2->f() == &cb.d);
static_assert(cb2->f()->f() == 'D');
constexpr const Covariant1 *cc1 = &cc;
constexpr const Covariant2<C> *cc2 = &cc;
static_assert(cc1->f()->a == 'A');
static_assert(cc1->f() == (C*)&cc.d);
static_assert(cc1->f()->f() == 'D');
static_assert(cc2->f()->c == 'C');
static_assert(cc2->f() == &cc.d);
static_assert(cc2->f()->f() == 'D');
static_assert(cb.f()->d == 'D');
static_assert(cc.f()->d == 'D');
struct Abstract {
constexpr virtual void f() = 0; // expected-note {{declared here}}
constexpr Abstract() { do_it(); } // expected-note {{in call to}}
constexpr void do_it() { f(); } // expected-note {{pure virtual function 'Virtual::Abstract::f' called}}
};
struct PureVirtualCall : Abstract { void f(); }; // expected-note {{in call to 'Abstract}}
constexpr PureVirtualCall pure_virtual_call; // expected-error {{constant expression}} expected-note {{in call to 'PureVirtualCall}}
}
namespace DynamicCast {
struct A2 { virtual void a2(); };
struct A : A2 { virtual void a(); };
struct B : A {};
struct C2 { virtual void c2(); };
struct C : A, C2 { A *c = dynamic_cast<A*>(static_cast<C2*>(this)); };
struct D { virtual void d(); };
struct E { virtual void e(); };
struct F : B, C, D, private E { void *f = dynamic_cast<void*>(static_cast<D*>(this)); };
struct Padding { virtual void padding(); };
struct G : Padding, F {};
constexpr G g;
// During construction of C, A is unambiguous subobject of dynamic type C.
static_assert(g.c == (C*)&g);
// ... but in the complete object, the same is not true, so the runtime fails.
static_assert(dynamic_cast<const A*>(static_cast<const C2*>(&g)) == nullptr);
// dynamic_cast<void*> produces a pointer to the object of the dynamic type.
static_assert(g.f == (void*)(F*)&g);
static_assert(dynamic_cast<const void*>(static_cast<const D*>(&g)) == &g);
// expected-note@+1 {{reference dynamic_cast failed: 'A' is an ambiguous base class of dynamic type 'DynamicCast::G' of operand}}
constexpr int d_a = (dynamic_cast<const A&>(static_cast<const D&>(g)), 0); // expected-error {{}}
// Can navigate from A2 to its A...
static_assert(&dynamic_cast<A&>((A2&)(B&)g) == &(A&)(B&)g);
// ... and from B to its A ...
static_assert(&dynamic_cast<A&>((B&)g) == &(A&)(B&)g);
// ... but not from D.
// expected-note@+1 {{reference dynamic_cast failed: 'A' is an ambiguous base class of dynamic type 'DynamicCast::G' of operand}}
static_assert(&dynamic_cast<A&>((D&)g) == &(A&)(B&)g); // expected-error {{}}
// Can cast from A2 to sibling class D.
static_assert(&dynamic_cast<D&>((A2&)(B&)g) == &(D&)g);
// Cannot cast from private base E to derived class F.
// expected-note@+1 {{reference dynamic_cast failed: static type 'DynamicCast::E' of operand is a non-public base class of dynamic type 'DynamicCast::G'}}
constexpr int e_f = (dynamic_cast<F&>((E&)g), 0); // expected-error {{}}
// Cannot cast from B to private sibling E.
// expected-note@+1 {{reference dynamic_cast failed: 'E' is a non-public base class of dynamic type 'DynamicCast::G' of operand}}
constexpr int b_e = (dynamic_cast<E&>((B&)g), 0); // expected-error {{}}
struct Unrelated { virtual void unrelated(); };
// expected-note@+1 {{reference dynamic_cast failed: dynamic type 'DynamicCast::G' of operand does not have a base class of type 'Unrelated'}}
constexpr int b_unrelated = (dynamic_cast<Unrelated&>((B&)g), 0); // expected-error {{}}
// expected-note@+1 {{reference dynamic_cast failed: dynamic type 'DynamicCast::G' of operand does not have a base class of type 'Unrelated'}}
constexpr int e_unrelated = (dynamic_cast<Unrelated&>((E&)g), 0); // expected-error {{}}
}
namespace TypeId {
struct A {
const std::type_info &ti = typeid(*this);
};
struct A2 : A {};
static_assert(&A().ti == &typeid(A));
static_assert(&typeid((A2())) == &typeid(A2));
extern A2 extern_a2;
static_assert(&typeid(extern_a2) == &typeid(A2));
constexpr A2 a2;
constexpr const A &a1 = a2;
static_assert(&typeid(a1) == &typeid(A));
struct B {
virtual void f();
const std::type_info &ti1 = typeid(*this);
};
struct B2 : B {
const std::type_info &ti2 = typeid(*this);
};
static_assert(&B2().ti1 == &typeid(B));
static_assert(&B2().ti2 == &typeid(B2));
extern B2 extern_b2;
// expected-note@+1 {{typeid applied to object 'extern_b2' whose dynamic type is not constant}}
static_assert(&typeid(extern_b2) == &typeid(B2)); // expected-error {{constant expression}}
constexpr B2 b2;
constexpr const B &b1 = b2;
static_assert(&typeid(b1) == &typeid(B2));
constexpr bool side_effects() {
// Not polymorphic nor a glvalue.
bool OK = true;
(void)typeid(OK = false, A2()); // expected-warning {{has no effect}}
if (!OK) return false;
// Not polymorphic.
A2 a2;
(void)typeid(OK = false, a2); // expected-warning {{has no effect}}
if (!OK) return false;
// Not a glvalue.
(void)typeid(OK = false, B2()); // expected-warning {{has no effect}}
if (!OK) return false;
// Polymorphic glvalue: operand evaluated.
OK = false;
B2 b2;
(void)typeid(OK = true, b2); // expected-warning {{will be evaluated}}
return OK;
}
static_assert(side_effects());
}
namespace Union {
struct Base {
int y; // expected-note 2{{here}}
};
struct A : Base {
int x;
int arr[3];
union { int p, q; };
};
union B {
A a;
int b;
};
constexpr int read_wrong_member() { // expected-error {{never produces a constant}}
B b = {.b = 1};
return b.a.x; // expected-note {{read of member 'a' of union with active member 'b'}}
}
constexpr int change_member() {
B b = {.b = 1};
b.a.x = 1;
return b.a.x;
}
static_assert(change_member() == 1);
constexpr int change_member_then_read_wrong_member() { // expected-error {{never produces a constant}}
B b = {.b = 1};
b.a.x = 1;
return b.b; // expected-note {{read of member 'b' of union with active member 'a'}}
}
constexpr int read_wrong_member_indirect() { // expected-error {{never produces a constant}}
B b = {.b = 1};
int *p = &b.a.y;
return *p; // expected-note {{read of member 'a' of union with active member 'b'}}
}
constexpr int read_uninitialized() {
B b = {.b = 1};
int *p = &b.a.y;
b.a.x = 1;
return *p; // expected-note {{read of uninitialized object}}
}
static_assert(read_uninitialized() == 0); // expected-error {{constant}} expected-note {{in call}}
constexpr void write_wrong_member_indirect() { // expected-error {{never produces a constant}}
B b = {.b = 1};
int *p = &b.a.y;
*p = 1; // expected-note {{assignment to member 'a' of union with active member 'b'}}
}
constexpr int write_uninitialized() {
B b = {.b = 1};
int *p = &b.a.y;
b.a.x = 1;
*p = 1;
return *p;
}
static_assert(write_uninitialized() == 1);
constexpr int change_member_indirectly() {
B b = {.b = 1};
b.a.arr[1] = 1;
int &r = b.a.y;
r = 123;
b.b = 2;
b.a.y = 3;
b.a.arr[2] = 4;
return b.a.arr[2];
}
static_assert(change_member_indirectly() == 4);
constexpr B return_uninit() {
B b = {.b = 1};
b.a.x = 2;
return b;
}
constexpr B uninit = return_uninit(); // expected-error {{constant expression}} expected-note {{subobject 'y' is not initialized}}
static_assert(return_uninit().a.x == 2);
constexpr A return_uninit_struct() {
B b = {.b = 1};
b.a.x = 2;
return b.a; // expected-note {{in call to 'A(b.a)'}} expected-note {{subobject 'y' is not initialized}}
}
// Note that this is rejected even though return_uninit() is accepted, and
// return_uninit() copies the same stuff wrapped in a union.
//
// Copying a B involves copying the object representation of the union, but
// copying an A invokes a copy constructor that copies the object
// elementwise, and reading from b.a.y is undefined.
static_assert(return_uninit_struct().x == 2); // expected-error {{constant expression}} expected-note {{in call}}
constexpr B return_init_all() {
B b = {.b = 1};
b.a.x = 2;
b.a.y = 3;
b.a.arr[0] = 4;
b.a.arr[1] = 5;
b.a.arr[2] = 6;
return b;
}
static_assert(return_init_all().a.x == 2);
static_assert(return_init_all().a.y == 3);
static_assert(return_init_all().a.arr[0] == 4);
static_assert(return_init_all().a.arr[1] == 5);
static_assert(return_init_all().a.arr[2] == 6);
static_assert(return_init_all().a.p == 7); // expected-error {{}} expected-note {{read of member 'p' of union with no active member}}
static_assert(return_init_all().a.q == 8); // expected-error {{}} expected-note {{read of member 'q' of union with no active member}}
constexpr B init_all = return_init_all();
constexpr bool test_no_member_change = []{
union U { char dummy = {}; };
U u1;
U u2;
u1 = u2;
return true;
}();
struct S1 {
int n;
};
struct S2 : S1 {};
struct S3 : S2 {};
void f() {
S3 s;
s.n = 0;
}
union ref_member_1 {
int a;
int b;
};
struct ref_member_2 {
ref_member_1 &&r;
};
union ref_member_3 {
ref_member_2 a, b;
};
constexpr int ref_member_test_1() {
ref_member_3 r = {.a = {.r = {.a = 1}}};
r.a.r.b = 2;
return r.a.r.b;
}
static_assert(ref_member_test_1() == 2);
constexpr int ref_member_test_2() { // expected-error {{never produces a constant}}
ref_member_3 r = {.a = {.r = {.a = 1}}};
// FIXME: This note isn't great. The 'read' here is reading the referent of the reference.
r.b.r.b = 2; // expected-note {{read of member 'b' of union with active member 'a'}}
return r.b.r.b;
}
namespace PR43762 {
struct A { int x = 1; constexpr int f() { return 1; } };
struct B : A { int y = 1; constexpr int g() { return 2; } };
struct C {
int x;
constexpr virtual int f() = 0;
};
struct D : C {
int y;
constexpr virtual int f() override { return 3; }
};
union U {
int n;
B b;
D d;
};
constexpr int test(int which) {
U u{.n = 5};
switch (which) {
case 0:
u.b.x = 10; // expected-note {{active member 'n'}}
return u.b.f();
case 1:
u.b.y = 10; // expected-note {{active member 'n'}}
return u.b.g();
case 2:
u.d.x = 10; // expected-note {{active member 'n'}}
return u.d.f();
case 3:
u.d.y = 10; // expected-note {{active member 'n'}}
return u.d.f();
}
}
static_assert(test(0)); // expected-error {{}} expected-note {{in call}}
static_assert(test(1)); // expected-error {{}} expected-note {{in call}}
static_assert(test(2)); // expected-error {{}} expected-note {{in call}}
static_assert(test(3)); // expected-error {{}} expected-note {{in call}}
}
}
namespace TwosComplementShifts {
using uint32 = __UINT32_TYPE__;
using int32 = __INT32_TYPE__;
static_assert(uint32(int32(0x1234) << 16) == 0x12340000);
static_assert(uint32(int32(0x1234) << 19) == 0x91a00000);
static_assert(uint32(int32(0x1234) << 20) == 0x23400000);
static_assert(uint32(int32(0x1234) << 24) == 0x34000000);
static_assert(uint32(int32(-1) << 31) == 0x80000000);
static_assert(-1 >> 1 == -1);
static_assert(-1 >> 31 == -1);
static_assert(-2 >> 1 == -1);
static_assert(-3 >> 1 == -2);
static_assert(-4 >> 1 == -2);
}
namespace Uninit {
constexpr int f(bool init) {
int a;
if (init)
a = 1;
return a; // expected-note {{read of uninitialized object}}
}
static_assert(f(true) == 1);
static_assert(f(false) == 1); // expected-error {{constant expression}} expected-note {{in call}}
struct X {
int n; // expected-note {{declared here}}
constexpr X(bool init) {
if (init) n = 123;
}
};
constinit X x1(true);
constinit X x2(false); // expected-error {{constant initializer}} expected-note {{constinit}} expected-note {{subobject 'n' is not initialized}}
struct Y {
struct Z { int n; }; // expected-note {{here}}
Z z1;
Z z2;
Z z3;
// OK: the lifetime of z1 (and its members) start before the initializer of
// z2 runs.
constexpr Y() : z2{ (z1.n = 1, z1.n + 1) } { z3.n = 3; }
// Not OK: z3 is not in its lifetime when the initializer of z2 runs.
constexpr Y(int) : z2{
(z3.n = 1, // expected-note {{assignment to object outside its lifetime}}
z3.n + 1) // expected-warning {{uninitialized}}
} { z1.n = 3; }
constexpr Y(int, int) : z2{} {}
};
// FIXME: This is working around clang not implementing DR2026. With that
// fixed, we should be able to test this without the injected copy.
constexpr Y copy(Y y) { return y; } // expected-note {{in call to 'Y(y)'}} expected-note {{subobject 'n' is not initialized}}
constexpr Y y1 = copy(Y());
static_assert(y1.z1.n == 1 && y1.z2.n == 2 && y1.z3.n == 3);
constexpr Y y2 = copy(Y(0)); // expected-error {{constant expression}} expected-note {{in call}}
static_assert(Y(0,0).z2.n == 0);
static_assert(Y(0,0).z1.n == 0); // expected-error {{constant expression}} expected-note {{read of uninitialized object}}
static_assert(Y(0,0).z3.n == 0); // expected-error {{constant expression}} expected-note {{read of uninitialized object}}
static_assert(copy(Y(0,0)).z2.n == 0); // expected-error {{constant expression}} expected-note {{in call}}
constexpr unsigned char not_even_unsigned_char() {
unsigned char c;
return c; // expected-note {{read of uninitialized object}}
}
constexpr unsigned char x = not_even_unsigned_char(); // expected-error {{constant expression}} expected-note {{in call}}
constexpr int switch_var(int n) {
switch (n) {
case 1:
int a;
a = n;
return a;
case 2:
a = n;
return a;
}
}
constexpr int s1 = switch_var(1);
constexpr int s2 = switch_var(2);
static_assert(s1 == 1 && s2 == 2);
constexpr bool switch_into_init_stmt() {
switch (1) {
if (int n; false) {
for (int m; false;) {
case 1:
n = m = 1;
return n == 1 && m == 1;
}
}
}
}
static_assert(switch_into_init_stmt());
}
namespace dtor {
void lifetime_extension() {
struct X { constexpr ~X() {} };
X &&a = X();
}
template<typename T> constexpr T &&ref(T &&t) { return (T&&)t; }
struct Buf {
char buf[64];
int n = 0;
constexpr void operator+=(char c) { buf[n++] = c; }
constexpr bool operator==(const char *str) const {
return str[n] == 0 && __builtin_memcmp(str, buf, n) == 0;
}
constexpr bool operator!=(const char *str) const { return !operator==(str); }
};
struct A {
constexpr A(Buf &buf, char c) : buf(buf), c(c) { buf += c; }
constexpr ~A() { buf += c; }
constexpr operator bool() const { return true; }
Buf &buf;
char c;
};
constexpr bool dtor_calls_dtor() {
union U {
constexpr U(Buf &buf) : u(buf, 'u') { buf += 'U'; }
constexpr ~U() { u.buf += 'U'; }
A u, v;
};
struct B : A {
A c, &&d, e;
union {
A f;
};
U u;
constexpr B(Buf &buf)
: A(buf, 'a'), c(buf, 'c'), d(ref(A(buf, 'd'))), e(A(buf, 'e')), f(buf, 'f'), u(buf) {
buf += 'b';
}
constexpr ~B() {
buf += 'b';
}
};
Buf buf;
{
B b(buf);
if (buf != "acddefuUb")
return false;
}
if (buf != "acddefuUbbUeca")
return false;
return true;
}
static_assert(dtor_calls_dtor());
constexpr void abnormal_termination(Buf &buf) {
struct Indestructible {
constexpr ~Indestructible(); // not defined
};
A a(buf, 'a');
A(buf, 'b');
int n = 0;
for (A &&c = A(buf, 'c'); A d = A(buf, 'd'); A(buf, 'e')) {
switch (A f(buf, 'f'); A g = A(buf, 'g')) { // expected-warning {{boolean}}
case false: {
A x(buf, 'x');
}
case true: {
A h(buf, 'h');
switch (n++) {
case 0:
break;
case 1:
continue;
case 2:
return;
}
break;
}
default:
Indestructible indest;
}
A j = (A(buf, 'i'), A(buf, 'j'));
}
}
constexpr bool check_abnormal_termination() {
Buf buf = {};
abnormal_termination(buf);
return buf ==
"abbc"
"dfgh" /*break*/ "hgfijijeed"
"dfgh" /*continue*/ "hgfeed"
"dfgh" /*return*/ "hgfd"
"ca";
}
static_assert(check_abnormal_termination());
constexpr bool run_dtors_on_array_filler() {
struct S {
int times_destroyed = 0;
constexpr ~S() { if (++times_destroyed != 1) throw "oops"; }
};
S s[3];
return true;
}
static_assert(run_dtors_on_array_filler());
// Ensure that we can handle temporary cleanups for array temporaries.
struct ArrElem { constexpr ~ArrElem() {} };
using Arr = ArrElem[3];
static_assert(((void)Arr{}, true));
}
namespace dynamic_alloc {
constexpr int *p = // expected-error {{constant}} expected-note {{pointer to heap-allocated object is not a constant expression}}
new int; // expected-note {{heap allocation performed here}}
constexpr int f(int n) {
int *p = new int[n];
for (int i = 0; i != n; ++i) {
p[i] = i;
}
int k = 0;
for (int i = 0; i != n; ++i) {
k += p[i];
}
delete[] p;
return k;
}
static_assert(f(123) == 123 * 122 / 2);
constexpr bool nvdtor() { // expected-error {{never produces a constant expression}}
struct S {
constexpr ~S() {}
};
struct T : S {};
delete (S*)new T; // expected-note {{delete of object with dynamic type 'T' through pointer to base class type 'S' with non-virtual destructor}}
return true;
}
constexpr int vdtor_1() {
int a;
struct S {
constexpr S(int *p) : p(p) {}
constexpr virtual ~S() { *p = 1; }
int *p;
};
struct T : S {
// implicit destructor defined eagerly because it is constexpr and virtual
using S::S;
};
delete (S*)new T(&a);
return a;
}
static_assert(vdtor_1() == 1);
constexpr int vdtor_2() {
int a = 0;
struct S { constexpr virtual ~S() {} };
struct T : S {
constexpr T(int *p) : p(p) {}
constexpr ~T() { ++*p; }
int *p;
};
S *p = new T{&a};
delete p;
return a;
}
static_assert(vdtor_2() == 1);
constexpr int vdtor_3(int mode) {
int a = 0;
struct S { constexpr virtual ~S() {} };
struct T : S {
constexpr T(int *p) : p(p) {}
constexpr ~T() { ++*p; }
int *p;
};
S *p = new T[3]{&a, &a, &a}; // expected-note 2{{heap allocation}}
switch (mode) {
case 0:
delete p; // expected-note {{non-array delete used to delete pointer to array object of type 'T[3]'}}
break;
case 1:
// FIXME: This diagnosic isn't great; we should mention the cast to S*
// somewhere in here.
delete[] p; // expected-note {{delete of pointer to subobject '&{*new T[3]#0}[0]'}}
break;
case 2:
delete (T*)p; // expected-note {{non-array delete used to delete pointer to array object of type 'T[3]'}}
break;
case 3:
delete[] (T*)p;
break;
}
return a;
}
static_assert(vdtor_3(0) == 3); // expected-error {{}} expected-note {{in call}}
static_assert(vdtor_3(1) == 3); // expected-error {{}} expected-note {{in call}}
static_assert(vdtor_3(2) == 3); // expected-error {{}} expected-note {{in call}}
static_assert(vdtor_3(3) == 3);
constexpr void delete_mismatch() { // expected-error {{never produces a constant expression}}
delete[] // expected-note {{array delete used to delete pointer to non-array object of type 'int'}}
new int; // expected-note {{allocation}}
}
template<typename T>
constexpr T dynarray(int elems, int i) {
T *p;
if constexpr (sizeof(T) == 1)
p = new T[elems]{"fox"}; // expected-note {{evaluated array bound 3 is too small to hold 4 explicitly initialized elements}}
else
p = new T[elems]{1, 2, 3}; // expected-note {{evaluated array bound 2 is too small to hold 3 explicitly initialized elements}}
T n = p[i]; // expected-note 4{{past-the-end}}
delete [] p;
return n;
}
static_assert(dynarray<int>(4, 0) == 1);
static_assert(dynarray<int>(4, 1) == 2);
static_assert(dynarray<int>(4, 2) == 3);
static_assert(dynarray<int>(4, 3) == 0);
static_assert(dynarray<int>(4, 4) == 0); // expected-error {{constant expression}} expected-note {{in call}}
static_assert(dynarray<int>(3, 2) == 3);
static_assert(dynarray<int>(3, 3) == 0); // expected-error {{constant expression}} expected-note {{in call}}
static_assert(dynarray<int>(2, 1) == 0); // expected-error {{constant expression}} expected-note {{in call}}
static_assert(dynarray<char>(5, 0) == 'f');
static_assert(dynarray<char>(5, 1) == 'o');
static_assert(dynarray<char>(5, 2) == 'x');
static_assert(dynarray<char>(5, 3) == 0); // (from string)
static_assert(dynarray<char>(5, 4) == 0); // (from filler)
static_assert(dynarray<char>(5, 5) == 0); // expected-error {{constant expression}} expected-note {{in call}}
static_assert(dynarray<char>(4, 0) == 'f');
static_assert(dynarray<char>(4, 1) == 'o');
static_assert(dynarray<char>(4, 2) == 'x');
static_assert(dynarray<char>(4, 3) == 0);
static_assert(dynarray<char>(4, 4) == 0); // expected-error {{constant expression}} expected-note {{in call}}
static_assert(dynarray<char>(3, 2) == 'x'); // expected-error {{constant expression}} expected-note {{in call}}
constexpr bool run_dtors_on_array_filler() {
struct S {
int times_destroyed = 0;
constexpr ~S() { if (++times_destroyed != 1) throw "oops"; }
};
delete[] new S[3];
return true;
}
static_assert(run_dtors_on_array_filler());
constexpr bool erroneous_array_bound(long long n) {
delete[] new int[n]; // expected-note {{array bound -1 is negative}} expected-note {{array bound 4611686018427387904 is too large}}
return true;
}
static_assert(erroneous_array_bound(3));
static_assert(erroneous_array_bound(0));
static_assert(erroneous_array_bound(-1)); // expected-error {{constant expression}} expected-note {{in call}}
static_assert(erroneous_array_bound(1LL << 62)); // expected-error {{constant expression}} expected-note {{in call}}
constexpr bool erroneous_array_bound_nothrow(long long n) {
int *p = new (std::nothrow) int[n];
bool result = p != 0;
delete[] p;
return result;
}
static_assert(erroneous_array_bound_nothrow(3));
static_assert(erroneous_array_bound_nothrow(0));
static_assert(!erroneous_array_bound_nothrow(-1));
static_assert(!erroneous_array_bound_nothrow(1LL << 62));
constexpr bool evaluate_nothrow_arg() {
bool ok = false;
delete new ((ok = true, std::nothrow)) int;
return ok;
}
static_assert(evaluate_nothrow_arg());
constexpr void double_delete() { // expected-error {{never produces a constant expression}}
int *p = new int;
delete p;
delete p; // expected-note {{delete of pointer that has already been deleted}}
}
constexpr bool super_secret_double_delete() {
struct A {
constexpr ~A() { delete this; } // expected-note {{destruction of object that is already being destroyed}} expected-note {{in call}}
};
delete new A; // expected-note {{in call}}
return true;
}
static_assert(super_secret_double_delete()); // expected-error {{constant expression}} expected-note {{in call}}
constexpr void use_after_free() { // expected-error {{never produces a constant expression}}
int *p = new int;
delete p;
*p = 1; // expected-note {{assignment to heap allocated object that has been deleted}}
}
constexpr void use_after_free_2() { // expected-error {{never produces a constant expression}}
struct X { constexpr void f() {} };
X *p = new X;
delete p;
p->f(); // expected-note {{member call on heap allocated object that has been deleted}}
}
template<typename T> struct X {
std::size_t n;
char *p;
void dependent();
};
template<typename T> void X<T>::dependent() {
char *p;
// Ensure that we don't try to evaluate these for overflow and crash. These
// are all value-dependent expressions.
p = new char[n];
p = new ((std::align_val_t)n) char[n];
p = new char(n);
}
namespace PR47143 {
constexpr char *f(int n) {
return new char[n]();
}
const char *p = f(3);
constexpr bool test() {
char *p = f(3);
bool result = !p[0] && !p[1] && !p[2];
delete [] p;
return result;
}
static_assert(test());
}
}
struct placement_new_arg {};
void *operator new(std::size_t, placement_new_arg);
void operator delete(void*, placement_new_arg);
namespace placement_new_delete {
struct ClassSpecificNew {
void *operator new(std::size_t);
};
struct ClassSpecificDelete {
void operator delete(void*);
};
struct DestroyingDelete {
void operator delete(DestroyingDelete*, std::destroying_delete_t);
};
struct alignas(64) Overaligned {};
constexpr bool ok() {
delete new Overaligned;
delete ::new ClassSpecificNew;
::delete new ClassSpecificDelete;
::delete new DestroyingDelete;
return true;
}
static_assert(ok());
constexpr bool bad(int which) {
switch (which) {
case 0:
delete new (placement_new_arg{}) int; // expected-note {{this placement new expression is not supported in constant expressions}}
break;
case 1:
delete new ClassSpecificNew; // expected-note {{call to class-specific 'operator new'}}
break;
case 2:
delete new ClassSpecificDelete; // expected-note {{call to class-specific 'operator delete'}}
break;
case 3:
delete new DestroyingDelete; // expected-note {{call to class-specific 'operator delete'}}
break;
case 4:
// FIXME: This technically follows the standard's rules, but it seems
// unreasonable to expect implementations to support this.
delete new (std::align_val_t{64}) Overaligned; // expected-note {{this placement new expression is not supported in constant expressions}}
break;
}
return true;
}
static_assert(bad(0)); // expected-error {{constant expression}} expected-note {{in call}}
static_assert(bad(1)); // expected-error {{constant expression}} expected-note {{in call}}
static_assert(bad(2)); // expected-error {{constant expression}} expected-note {{in call}}
static_assert(bad(3)); // expected-error {{constant expression}} expected-note {{in call}}
static_assert(bad(4)); // expected-error {{constant expression}} expected-note {{in call}}
}
namespace delete_random_things {
static_assert((delete new int, true));
static_assert((delete (int*)0, true));
int n; // expected-note {{declared here}}
static_assert((delete &n, true)); // expected-error {{}} expected-note {{delete of pointer '&n' that does not point to a heap-allocated object}}
struct A { int n; };
static_assert((delete &(new A)->n, true)); // expected-error {{}} expected-note {{delete of pointer to subobject '&{*new A#0}.n'}}
static_assert((delete (new int + 1), true)); // expected-error {{}} expected-note {{delete of pointer '&{*new int#0} + 1' that does not point to complete object}}
static_assert((delete[] (new int[3] + 1), true)); // expected-error {{}} expected-note {{delete of pointer to subobject '&{*new int[3]#0}[1]'}}
static_assert((delete &(int&)(int&&)0, true)); // expected-error {{}} expected-note {{delete of pointer '&0' that does not point to a heap-allocated object}} expected-note {{temporary created here}}
}
namespace value_dependent_delete {
template<typename T> void f(T *p) {
int arr[(delete p, 0)];
}
}
namespace memory_leaks {
static_assert(*new bool(true)); // expected-error {{}} expected-note {{allocation performed here was not deallocated}}
constexpr bool *f() { return new bool(true); } // expected-note {{allocation performed here was not deallocated}}
static_assert(*f()); // expected-error {{}}
struct UP {
bool *p;
constexpr ~UP() { delete p; }
constexpr bool &operator*() { return *p; }
};
constexpr UP g() { return {new bool(true)}; }
static_assert(*g()); // ok
constexpr bool h(UP p) { return *p; }
static_assert(h({new bool(true)})); // ok
}
constexpr void *operator new(std::size_t, void *p) { return p; }
namespace std {
template<typename T> constexpr T *construct(T *p) { return new (p) T; }
template<typename T> constexpr void destroy(T *p) { p->~T(); }
}
namespace dtor_call {
struct A { int n; };
constexpr void f() { // expected-error {{never produces a constant expression}}
A a; // expected-note {{destroying object 'a' whose lifetime has already ended}}
a.~A();
}
union U { A a; };
constexpr void g() {
U u;
u.a.n = 3;
u.a.~A();
// There's now effectively no active union member, but we model it as if
// 'a' is still the active union member (but its lifetime has ended).
u.a.n = 4; // Start lifetime of 'a' again.
u.a.~A();
}
static_assert((g(), true));
constexpr bool pseudo(bool read, bool recreate) {
using T = bool;
bool b = false; // expected-note {{lifetime has already ended}}
// This evaluates the store to 'b'...
(b = true).~T();
// ... and ends the lifetime of the object.
return (read
? b // expected-note {{read of object outside its lifetime}}
: true) +
(recreate
? (std::construct(&b), true)
: true);
}
static_assert(pseudo(false, false)); // expected-error {{constant expression}} expected-note {{in call}}
static_assert(pseudo(true, false)); // expected-error {{constant expression}} expected-note {{in call}}
static_assert(pseudo(false, true));
constexpr void use_after_destroy() {
A a;
a.~A();
A b = a; // expected-note {{in call}} expected-note {{read of object outside its lifetime}}
}
static_assert((use_after_destroy(), true)); // expected-error {{}} expected-note {{in call}}
constexpr void double_destroy() {
A a;
a.~A();
a.~A(); // expected-note {{destruction of object outside its lifetime}}
}
static_assert((double_destroy(), true)); // expected-error {{}} expected-note {{in call}}
struct X { char *p; constexpr ~X() { *p++ = 'X'; } };
struct Y : X { int y; virtual constexpr ~Y() { *p++ = 'Y'; } };
struct Z : Y { int z; constexpr ~Z() override { *p++ = 'Z'; } };
union VU {
constexpr VU() : z() {}
constexpr ~VU() {}
Z z;
};
constexpr bool virt_dtor(int mode, const char *expected) {
char buff[4] = {};
VU vu;
vu.z.p = buff;
switch (mode) {
case 0:
vu.z.~Z();
break;
case 1:
((Y&)vu.z).~Y();
break;
case 2:
((X&)vu.z).~X();
break;
case 3:
((Y&)vu.z).Y::~Y();
vu.z.z = 1; // ok, still have a Z (with no Y base class!)
break;
case 4:
((X&)vu.z).X::~X();
vu.z.y = 1; // ok, still have a Z and a Y (with no X base class!)
break;
}
return __builtin_strcmp(expected, buff) == 0;
}
static_assert(virt_dtor(0, "ZYX"));
static_assert(virt_dtor(1, "ZYX"));
static_assert(virt_dtor(2, "X"));
static_assert(virt_dtor(3, "YX"));
static_assert(virt_dtor(4, "X"));
constexpr bool virt_delete(bool global) {
struct A {
virtual constexpr ~A() {}
};
struct B : A {
void operator delete(void *);
constexpr ~B() {}
};
A *p = new B;
if (global)
::delete p;
else
delete p; // expected-note {{call to class-specific 'operator delete'}}
return true;
}
static_assert(virt_delete(true));
static_assert(virt_delete(false)); // expected-error {{}} expected-note {{in call}}
constexpr void use_after_virt_destroy() {
char buff[4] = {};
VU vu;
vu.z.p = buff;
((Y&)vu.z).~Y();
((Z&)vu.z).z = 1; // expected-note {{assignment to object outside its lifetime}}
}
static_assert((use_after_virt_destroy(), true)); // expected-error {{}} expected-note {{in call}}
constexpr void destroy_after_lifetime() {
A *p;
{
A a;
p = &a;
}
p->~A(); // expected-note {{destruction of object outside its lifetime}}
}
static_assert((destroy_after_lifetime(), true)); // expected-error {{}} expected-note {{in call}}
constexpr void destroy_after_lifetime2() {
A *p = []{ A a; return &a; }(); // expected-warning {{}} expected-note {{declared here}}
p->~A(); // expected-note {{destruction of variable whose lifetime has ended}}
}
static_assert((destroy_after_lifetime2(), true)); // expected-error {{}} expected-note {{in call}}
constexpr void destroy_after_lifetime3() {
A *p = []{ return &(A&)(A&&)A(); }(); // expected-warning {{}} expected-note {{temporary created here}}
p->~A(); // expected-note {{destruction of temporary whose lifetime has ended}}
}
static_assert((destroy_after_lifetime3(), true)); // expected-error {{}} expected-note {{in call}}
constexpr void destroy_after_lifetime4() { // expected-error {{never produces a constant expression}}
A *p = new A;
delete p;
p->~A(); // expected-note {{destruction of heap allocated object that has been deleted}}
}
struct Extern { constexpr ~Extern() {} } extern e;
constexpr void destroy_extern() { // expected-error {{never produces a constant expression}}
e.~Extern(); // expected-note {{cannot modify an object that is visible outside}}
}
constexpr A &&a_ref = A(); // expected-note {{temporary created here}}
constexpr void destroy_extern_2() { // expected-error {{never produces a constant expression}}
a_ref.~A(); // expected-note {{destruction of temporary is not allowed in a constant expression outside the expression that created the temporary}}
}
struct S {
constexpr S() { n = 1; }
constexpr ~S() { n = 0; }
int n;
};
constexpr void destroy_volatile() {
volatile S s;
}
static_assert((destroy_volatile(), true)); // ok, not volatile during construction and destruction
constexpr void destroy_null() { // expected-error {{never produces a constant expression}}
((A*)nullptr)->~A(); // expected-note {{destruction of dereferenced null pointer}}
}
constexpr void destroy_past_end() { // expected-error {{never produces a constant expression}}
A a;
(&a+1)->~A(); // expected-note {{destruction of dereferenced one-past-the-end pointer}}
}
constexpr void destroy_past_end_array() { // expected-error {{never produces a constant expression}}
A a[2];
a[2].~A(); // expected-note {{destruction of dereferenced one-past-the-end pointer}}
}
union As {
A a, b;
};
constexpr void destroy_no_active() { // expected-error {{never produces a constant expression}}
As as;
as.b.~A(); // expected-note {{destruction of member 'b' of union with no active member}}
}
constexpr void destroy_inactive() { // expected-error {{never produces a constant expression}}
As as;
as.a.n = 1;
as.b.~A(); // expected-note {{destruction of member 'b' of union with active member 'a'}}
}
constexpr void destroy_no_active_2() { // expected-error {{never produces a constant expression}}
As as;
as.a.n = 1;
as.a.~A();
// FIXME: This diagnostic is wrong; the union has no active member now.
as.b.~A(); // expected-note {{destruction of member 'b' of union with active member 'a'}}
}
constexpr void destroy_pointer() {
using T = int*;
T p;
// We used to think this was an -> member access because its left-hand side
// is a pointer. Ensure we don't crash.
p.~T();
// Put a T back so we can destroy it again.
std::construct(&p);
}
static_assert((destroy_pointer(), true));
}
namespace temp_dtor {
void f();
struct A {
bool b;
constexpr ~A() { if (b) f(); }
};
// We can't accept either of these unless we start actually registering the
// destructors of the A temporaries to run on shutdown. It's unclear what the
// intended standard behavior is so we reject this for now.
constexpr A &&a = A{false}; // expected-error {{constant}} expected-note {{non-trivial destruction of lifetime-extended temporary}}
void f() { a.b = true; }
constexpr A &&b = A{true}; // expected-error {{constant}} expected-note {{non-trivial destruction of lifetime-extended temporary}}
// FIXME: We could in prinicple accept this.
constexpr const A &c = A{false}; // expected-error {{constant}} expected-note {{non-trivial destruction of lifetime-extended temporary}}
}
namespace value_dependent_init {
struct A {
constexpr ~A() {}
};
template<typename T> void f() {
A a = T();
}
}
namespace mutable_subobjects {
struct A {
int m;
mutable int n; // expected-note 2{{here}}
constexpr int f() const { return m; }
constexpr int g() const { return n; } // expected-note {{mutable}}
};
constexpr A a = {1, 2};
static_assert(a.f() == 1); // OK (PR44958)
static_assert(a.g() == 2); // expected-error {{constant}} expected-note {{in call}}
constexpr A b = a; // expected-error {{constant}} expected-note {{read of mutable member 'n'}} expected-note {{in call}}
auto &ti1 = typeid(a);
auto &ti2 = typeid(a.m);
auto &ti3 = typeid(a.n);
constexpr void destroy1() { // expected-error {{constexpr}}
a.~A(); // expected-note {{cannot modify an object that is visible outside}}
}
using T = int;
constexpr void destroy2() { // expected-error {{constexpr}}
a.m.~T(); // expected-note {{cannot modify an object that is visible outside}}
}
constexpr void destroy3() { // expected-error {{constexpr}}
a.n.~T(); // expected-note {{cannot modify an object that is visible outside}}
}
struct X {
mutable int n = 0;
virtual constexpr ~X() {}
};
struct Y : X {
};
constexpr Y y;
constexpr const X *p = &y;
constexpr const Y *q = dynamic_cast<const Y*>(p);
// FIXME: It's unclear whether this should be accepted. The dynamic_cast is
// undefined after 'z.y.~Y()`, for example. We essentially assume that all
// objects that the evaluator can reach have unbounded lifetimes. (We make
// the same assumption when evaluating member function calls.)
struct Z {
mutable Y y;
};
constexpr Z z;
constexpr const X *pz = &z.y;
constexpr const Y *qz = dynamic_cast<const Y*>(pz);
auto &zti = typeid(z.y);
static_assert(&zti == &typeid(Y));
}
namespace PR45133 {
struct A { long x; };
union U;
constexpr A foo(U *up);
union U {
A a = foo(this); // expected-note {{in call to 'foo(&u)'}}
int y;
};
constexpr A foo(U *up) {
up->y = 11; // expected-note {{assignment would change active union member during the initialization of a different member}}
return {42};
}
constinit U u = {}; // expected-error {{constant init}} expected-note {{constinit}}
template<int> struct X {};
union V {
int a, b;
constexpr V(X<0>) : a(a = 1) {} // ok
constexpr V(X<1>) : a(b = 1) {} // expected-note {{assignment would change active union member during the initialization of a different member}}
constexpr V(X<2>) : a() { b = 1; } // ok
// This case (changing the active member then changing it back) is debatable,
// but it seems appropriate to reject.
constexpr V(X<3>) : a((b = 1, a = 1)) {} // expected-note {{assignment would change active union member during the initialization of a different member}}
};
constinit V v0 = X<0>();
constinit V v1 = X<1>(); // expected-error {{constant init}} expected-note {{constinit}} expected-note {{in call}}
constinit V v2 = X<2>();
constinit V v3 = X<3>(); // expected-error {{constant init}} expected-note {{constinit}} expected-note {{in call}}
}
namespace PR45350 {
int q;
struct V { int n; int *p = &n; constexpr ~V() { *p = *p * 10 + n; }};
constexpr int f(int n) {
int k = 0;
V *p = new V[n];
for (int i = 0; i != n; ++i) {
if (p[i].p != &p[i].n) return -1;
p[i].n = i;
p[i].p = &k;
}
delete[] p;
return k;
}
// [expr.delete]p6:
// In the case of an array, the elements will be destroyed in order of
// decreasing address
static_assert(f(6) == 543210);
}
namespace PR47805 {
struct A {
bool bad = true;
constexpr ~A() { if (bad) throw; }
};
constexpr bool f(A a) { a.bad = false; return true; }
constexpr bool b = f(A());
struct B { B *p = this; };
constexpr bool g(B b) { return &b == b.p; }
static_assert(g({}));
}
constexpr bool destroy_at_test() {
int n = 0;
std::destroy(&n);
std::construct(&n);
return true;
}
static_assert(destroy_at_test());
namespace PR48582 {
struct S {
void *p = this;
constexpr S() {}
constexpr S(const S&) {}
};
constexpr bool b = [a = S(), b = S()] { return a.p == b.p; }();
static_assert(!b);
}
namespace PR45879 {
struct A { int n; };
struct B { A a; };
constexpr A a = (A() = B().a);
union C {
int n;
A a;
};
constexpr bool f() {
C c = {.n = 1};
c.a = B{2}.a;
return c.a.n == 2;
}
static_assert(f());
// Only syntactic assignments change the active union member.
constexpr bool g() { // expected-error {{never produces a constant expression}}
C c = {.n = 1};
c.a.operator=(B{2}.a); // expected-note 2{{member call on member 'a' of union with active member 'n' is not allowed in a constant expression}}
return c.a.n == 2;
}
static_assert(g()); // expected-error {{constant expression}} expected-note {{in call}}
}
namespace GH57431 {
class B {
virtual int constexpr f() = 0;
};
class D : B {
virtual int constexpr f() = default; // expected-error {{only special member functions and comparison operators may be defaulted}}
};
}
namespace GH57516 {
class B{
virtual constexpr ~B() = 0; // expected-note {{overridden virtual function is here}}
};
class D : B{}; // expected-error {{deleted function '~D' cannot override a non-deleted function}}
// expected-note@-1 {{destructor of 'D' is implicitly deleted because base class 'B' has an inaccessible destructor}}
}
namespace GH67317 {
constexpr unsigned char a = // expected-error {{constexpr variable 'a' must be initialized by a constant expression}} \
// expected-note {{subobject of type 'const unsigned char' is not initialized}}
__builtin_bit_cast(unsigned char, *new char[3][1]);
};
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