// RUN: %clang_cc1 -std=c++98 -triple x86_64-unknown-unknown %s -verify=expected,cxx98 -fexceptions -fcxx-exceptions -pedantic-errors
// RUN: %clang_cc1 -std=c++11 -triple x86_64-unknown-unknown %s -verify=expected,since-cxx11,cxx11 -fexceptions -fcxx-exceptions -pedantic-errors
// RUN: %clang_cc1 -std=c++14 -triple x86_64-unknown-unknown %s -verify=expected,since-cxx11,since-cxx14 -fexceptions -fcxx-exceptions -pedantic-errors
// RUN: %clang_cc1 -std=c++17 -triple x86_64-unknown-unknown %s -verify=expected,since-cxx11,since-cxx14 -fexceptions -fcxx-exceptions -pedantic-errors
// RUN: %clang_cc1 -std=c++20 -triple x86_64-unknown-unknown %s -verify=expected,since-cxx11,since-cxx14,since-cxx20 -fexceptions -fcxx-exceptions -pedantic-errors
// RUN: %clang_cc1 -std=c++23 -triple x86_64-unknown-unknown %s -verify=expected,since-cxx11,since-cxx14,since-cxx20 -fexceptions -fcxx-exceptions -pedantic-errors
// RUN: %clang_cc1 -std=c++2c -triple x86_64-unknown-unknown %s -verify=expected,since-cxx11,since-cxx14,since-cxx20 -fexceptions -fcxx-exceptions -pedantic-errors
#if __cplusplus == 199711L
#define static_assert(...) __extension__ _Static_assert(__VA_ARGS__)
// cxx98-error@-1 {{variadic macros are a C99 feature}}
#endif
namespace cwg2007 { // cwg2007: 3.4
template<typename T> struct A { typename T::error e; };
template<typename T> struct B { };
B<A<void> > b1;
B<A<void> > b2 = b1;
int a = b2[0];
// cxx98-error@-1 {{type 'B<A<void> >' does not provide a subscript operator}}
// since-cxx11-error@-2 {{type 'B<A<void>>' does not provide a subscript operator}}
int b = __builtin_addressof(b2)->foo;
// cxx98-error@-1 {{no member named 'foo' in 'cwg2007::B<cwg2007::A<void> >'}}
// since-cxx11-error@-2 {{no member named 'foo' in 'cwg2007::B<cwg2007::A<void>>'}}
}
// cwg2009: na
namespace cwg2026 { // cwg2026: 11
template<int> struct X {};
const int a = a + 1; // #cwg2026-a
// expected-warning@-1 {{variable 'a' is uninitialized when used within its own initialization}}
X<a> xa; // #cwg2026-xa
// cxx98-error@-1 {{non-type template argument of type 'int' is not an integral constant expression}}
// cxx98-note@-2 {{initializer of 'a' is not a constant expression}}
// cxx98-note@#cwg2026-a {{declared here}}
// since-cxx11-error@#cwg2026-xa {{non-type template argument is not a constant expression}}
// since-cxx11-note@#cwg2026-xa {{initializer of 'a' is not a constant expression}}
// since-cxx11-note@#cwg2026-a {{declared here}}
#if __cplusplus >= 201103L
constexpr int b = b;
// since-cxx11-error@-1 {{constexpr variable 'b' must be initialized by a constant expression}}
// since-cxx11-note@-2 {{read of object outside its lifetime is not allowed in a constant expression}}
[[clang::require_constant_initialization]] int c = c;
// since-cxx11-error@-1 {{variable does not have a constant initializer}}
// since-cxx11-note@-2 {{required by 'require_constant_initialization' attribute here}}
// cxx11-note@-3 {{read of non-const variable 'c' is not allowed in a constant expression}}
// cxx11-note@-4 {{declared here}}
// since-cxx14-note@-5 {{read of object outside its lifetime is not allowed in a constant expression}}
#endif
#if __cplusplus >= 202002L
constinit int d = d;
// since-cxx20-error@-1 {{variable does not have a constant initializer}}
// since-cxx20-note@-2 {{required by 'constinit' specifier here}}
// since-cxx20-note@-3 {{read of object outside its lifetime is not allowed in a constant expression}}
#endif
void f() {
static const int e = e + 1; // #cwg2026-e
// expected-warning@-1 {{static variable 'e' is suspiciously used within its own initialization}}
X<e> xe; // #cwg2026-xe
// cxx98-error@-1 {{non-type template argument of type 'int' is not an integral constant expression}}
// cxx98-note@-2 {{initializer of 'e' is not a constant expression}}
// cxx98-note@#cwg2026-e {{declared here}}
// since-cxx11-error@#cwg2026-xe {{non-type template argument is not a constant expression}}
// since-cxx11-note@#cwg2026-xe {{initializer of 'e' is not a constant expression}}
// since-cxx11-note@#cwg2026-e {{declared here}}
#if __cplusplus >= 201103L
static constexpr int f = f;
// since-cxx11-error@-1 {{constexpr variable 'f' must be initialized by a constant expression}}
// since-cxx11-note@-2 {{read of object outside its lifetime is not allowed in a constant expression}}
[[clang::require_constant_initialization]] static int g = g;
// since-cxx11-error@-1 {{variable does not have a constant initializer}}
// since-cxx11-note@-2 {{required by 'require_constant_initialization' attribute here}}
// cxx11-note@-3 {{read of non-const variable 'g' is not allowed in a constant expression}}
// cxx11-note@-4 {{declared here}}
// since-cxx14-note@-5 {{read of object outside its lifetime is not allowed in a constant expression}}
#endif
#if __cplusplus >= 202002L
static constinit int h = h;
// since-cxx20-error@-1 {{variable does not have a constant initializer}}
// since-cxx20-note@-2 {{required by 'constinit' specifier here}}
// since-cxx20-note@-3 {{read of object outside its lifetime is not allowed in a constant expression}}
#endif
}
}
namespace cwg2049 { // cwg2049: 18
#if __cplusplus >= 202302L
template <int* x = {}> struct X {};
X<> a;
X<nullptr> b;
static_assert(__is_same(decltype(a), decltype(b)));
#endif
}
namespace cwg2061 { // cwg2061: yes
#if __cplusplus >= 201103L
namespace A {
inline namespace b {
namespace C {
// 'f' is the example from the DR. 'S' is an example where if we didn't
// properly handle the two being the same, we would get an incomplete
// type error during attempted instantiation.
template<typename T> void f();
template<typename T> struct S;
}
}
}
namespace A {
namespace C {
template<> void f<int>() { }
template<> struct S<int> { };
}
}
void use() {
A::C::f<int>();
A::C::S<int> s;
}
#endif // C++11
}
namespace cwg2076 { // cwg2076: 13
#if __cplusplus >= 201103L
namespace std_example {
struct A { A(int); };
struct B { B(A); };
B b{{0}};
struct Params { int a; int b; };
struct Foo {
Foo(Params);
};
Foo foo{{1, 2}};
}
struct string_view {
string_view(int); // not an aggregate
};
struct string {
string(int); // not an aggregate
operator string_view() const;
};
void foo(const string &); // #cwg2076-foo
void bar(string_view); // #cwg2076-bar
void func(const string &arg) {
// An argument in one set of braces is subject to user-defined conversions;
// an argument in two sets of braces is not, but an identity conversion is
// still OK.
foo(arg);
foo({arg});
foo({{arg}});
foo({{{arg}}});
// since-cxx11-error@-1 {{no matching function}}
// since-cxx11-note@#cwg2076-foo {{cannot convert initializer list}}
bar(arg);
bar({arg});
bar({{arg}});
// since-cxx11-error@-1 {{no matching function}}
// since-cxx11-note@#cwg2076-bar {{cannot convert initializer list}}
bar({{{arg}}});
// since-cxx11-error@-1 {{no matching function}}
// since-cxx11-note@#cwg2076-bar {{cannot convert initializer list}}
}
#endif
}
namespace cwg2082 { // cwg2082: 11
void test1(int x, int = sizeof(x)); // ok
#if __cplusplus >= 201103L
void test2(int x, int = decltype(x){}); // ok
#endif
}
namespace cwg2083 { // cwg2083: partial
#if __cplusplus >= 201103L
void non_const_mem_ptr() {
struct A {
int x;
int y;
};
constexpr A a = {1, 2};
struct B {
int A::*p;
constexpr int g() const {
// OK, not an odr-use of 'a'.
return a.*p;
};
};
static_assert(B{&A::x}.g() == 1, "");
static_assert(B{&A::y}.g() == 2, "");
}
#endif
const int a = 1;
int b;
// Note, references only get special odr-use / constant initializxer
// treatment in C++11 onwards. We continue to apply that even after CWG2083.
void ref_to_non_const() {
int c;
const int &ra = a; // #cwg2083-ra
int &rb = b; // #cwg2083-rb
int &rc = c; // #cwg2083-rc
struct A {
int f() {
int a = ra;
// cxx98-error@-1 {{reference to local variable 'ra' declared in enclosing function 'cwg2083::ref_to_non_const'}}
// cxx98-note@#cwg2083-ra {{'ra' declared here}}
int b = rb;
// cxx98-error@-1 {{reference to local variable 'rb' declared in enclosing function 'cwg2083::ref_to_non_const'}}
// cxx98-note@#cwg2083-rb {{'rb' declared here}}
int c = rc;
// expected-error@-1 {{reference to local variable 'rc' declared in enclosing function 'cwg2083::ref_to_non_const'}}
// expected-note@#cwg2083-rc {{'rc' declared here}}
return a + b + c;
}
};
}
#if __cplusplus >= 201103L
struct NoMut1 { int a, b; };
struct NoMut2 { NoMut1 m; };
struct NoMut3 : NoMut1 {
constexpr NoMut3(int a, int b) : NoMut1{a, b} {}
};
struct Mut1 {
int a;
mutable int b;
};
struct Mut2 { Mut1 m; };
struct Mut3 : Mut1 {
constexpr Mut3(int a, int b) : Mut1{a, b} {}
};
void mutable_subobjects() {
constexpr NoMut1 nm1 = {1, 2};
constexpr NoMut2 nm2 = {1, 2};
constexpr NoMut3 nm3 = {1, 2};
constexpr Mut1 m1 = {1, 2}; // #cwg2083-m1
constexpr Mut2 m2 = {1, 2}; // #cwg2083-m2
constexpr Mut3 m3 = {1, 2}; // #cwg2083-m3
struct A {
void f() {
static_assert(nm1.a == 1, "");
static_assert(nm2.m.a == 1, "");
static_assert(nm3.a == 1, "");
// Can't even access a non-mutable member of a variable containing mutable fields.
static_assert(m1.a == 1, "");
// since-cxx11-error@-1 {{reference to local variable 'm1' declared in enclosing function 'cwg2083::mutable_subobjects'}}
// since-cxx11-note@#cwg2083-m1 {{'m1' declared here}}
static_assert(m2.m.a == 1, "");
// since-cxx11-error@-1 {{reference to local variable 'm2' declared in enclosing function 'cwg2083::mutable_subobjects'}}
// since-cxx11-note@#cwg2083-m2 {{'m2' declared here}}
static_assert(m3.a == 1, "");
// since-cxx11-error@-1 {{reference to local variable 'm3' declared in enclosing function 'cwg2083::mutable_subobjects'}}
// since-cxx11-note@#cwg2083-m3 {{'m3' declared here}}
}
};
}
#endif
void ellipsis() {
void ellipsis(...);
struct A {};
const int n = 0;
#if __cplusplus >= 201103L
constexpr
#endif
A a = {}; // #cwg2083-a
struct B {
void f() {
ellipsis(n);
// Even though this is technically modelled as an lvalue-to-rvalue
// conversion, it calls a constructor and binds 'a' to a reference, so
// it results in an odr-use.
ellipsis(a);
// expected-error@-1 {{reference to local variable 'a' declared in enclosing function 'cwg2083::ellipsis'}}
// expected-note@#cwg2083-a {{'a' declared here}}
}
};
}
#if __cplusplus >= 201103L
void volatile_lval() {
struct A { int n; };
constexpr A a = {0}; // #cwg2083-a2
struct B {
void f() {
// An lvalue-to-rvalue conversion of a volatile lvalue always results
// in odr-use.
int A::*p = &A::n;
int x = a.*p;
volatile int A::*q = p;
int y = a.*q;
// since-cxx11-error@-1 {{reference to local variable 'a' declared in enclosing function 'cwg2083::volatile_lval'}}
// since-cxx11-note@#cwg2083-a2 {{'a' declared here}}
}
};
}
#endif
void discarded_lval() {
struct A { int x; mutable int y; volatile int z; };
A a; // #cwg2083-a-3
int &r = a.x; // #cwg2083-r
struct B {
void f() {
// FIXME: We emit more errors than we should be. They are explicitly
// marked below.
a.x;
// expected-warning@-1 {{expression result unused}}
// expected-error@-2 {{reference to local variable 'a' declared in enclosing function 'cwg2083::discarded_lval'}} FIXME
// expected-note@#cwg2083-a-3 {{'a' declared here}}
a.*&A::x;
// expected-warning@-1 {{expression result unused}}
// expected-error@-2 {{reference to local variable 'a' declared in enclosing function 'cwg2083::discarded_lval'}} FIXME
// expected-note@#cwg2083-a-3 {{'a' declared here}}
true ? a.x : a.y; // #cwg2083-ternary
// expected-warning@-1 {{expression result unused}}
// expected-error@#cwg2083-ternary {{reference to local variable 'a' declared in enclosing function 'cwg2083::discarded_lval'}} FIXME
// expected-note@#cwg2083-a-3 {{'a' declared here}}
// expected-error@#cwg2083-ternary {{reference to local variable 'a' declared in enclosing function 'cwg2083::discarded_lval'}} FIXME
// expected-note@#cwg2083-a-3 {{'a' declared here}}
(void)a.x;
// expected-error@-1 {{reference to local variable 'a' declared in enclosing function 'cwg2083::discarded_lval'}} FIXME
// expected-note@#cwg2083-a-3 {{'a' declared here}}
a.x, discarded_lval();
// expected-warning@-1 {{left operand of comma operator has no effect}}
// expected-error@-2 {{reference to local variable 'a' declared in enclosing function 'cwg2083::discarded_lval'}} FIXME
// expected-note@#cwg2083-a-3 {{'a' declared here}}
// 'volatile' qualifier triggers an lvalue-to-rvalue conversion.
a.z;
// cxx98-warning@-1 {{expression result unused; assign into a variable to force a volatile load}}
// expected-error@-2 {{reference to local variable 'a' declared in enclosing function 'cwg2083::discarded_lval'}}
// expected-note@#cwg2083-a-3 {{'a' declared here}}
// References always get "loaded" to determine what they reference,
// even if the result is discarded.
r;
// expected-warning@-1 {{expression result unused}}
// expected-error@-2 {{reference to local variable 'r' declared in enclosing function 'cwg2083::discarded_lval'}}
// expected-note@#cwg2083-r {{'r' declared here}}
}
};
}
namespace dr_example_1 {
extern int globx;
int main() {
const int &x = globx; // #cwg2083-x
struct A {
const int *foo() { return &x; }
// cxx98-error@-1 {{reference to local variable 'x' declared in enclosing function 'cwg2083::dr_example_1::main'}}
// cxx98-note@#cwg2083-x {{'x' declared here}}
} a;
return *a.foo();
}
}
#if __cplusplus >= 201103L
namespace dr_example_2 {
struct A {
int q;
constexpr A(int q) : q(q) {}
constexpr A(const A &a) : q(a.q * 2) {} // (note, not called)
};
int main(void) {
constexpr A a(42);
constexpr int aq = a.q;
struct Q {
int foo() { return a.q; }
} q;
return q.foo();
}
// Checking odr-use does not invent an lvalue-to-rvalue conversion (and
// hence copy construction) on the potential result variable.
struct B {
int b = 42;
constexpr B() {}
constexpr B(const B&) = delete;
};
void f() {
constexpr B b;
struct Q {
constexpr int foo() const { return b.b; }
};
static_assert(Q().foo() == 42, "");
}
}
#endif
}
namespace cwg2091 { // cwg2091: 10
template<int &> struct X;
template<int &N> void f(X<N>&);
int n;
void g(X<n> &x) { f(x); }
namespace GH42233 {
enum E { I };
class AA { };
E EV[1] = {I};
template<class ENUM, const ENUM* const VALUES>
struct S
{
template< class E, const E* const V>
friend AA& operator<<( AA& os, const S<E,V>& e );
};
int f()
{
S< E, EV > x;
AA a;
a << x;
return 0;
}
} // namespace GH42233
} // namespace cwg2091
namespace cwg2094 { // cwg2094: 5
struct A { int n; };
struct B { volatile int n; };
static_assert(__is_trivially_copyable(volatile int), "");
static_assert(__is_trivially_copyable(const volatile int), "");
static_assert(__is_trivially_copyable(const volatile int[]), "");
static_assert(__is_trivially_copyable(A), "");
static_assert(__is_trivially_copyable(volatile A), "");
static_assert(__is_trivially_copyable(const volatile A), "");
static_assert(__is_trivially_copyable(const volatile A[]), "");
static_assert(__is_trivially_copyable(B), "");
static_assert(__is_trivially_constructible(A, A const&), "");
static_assert(__is_trivially_constructible(B, B const&), "");
static_assert(__is_trivially_assignable(A, const A&), "");
static_assert(__is_trivially_assignable(B, const B&), "");
}
// cwg2096: dup 2598