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// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 %s
int f() __attribute__((warn_unused_result));
struct S {
void t() const;
};
S g1() __attribute__((warn_unused_result));
S *g2() __attribute__((warn_unused_result));
S &g3() __attribute__((warn_unused_result));
void test() {
f(); // expected-warning {{ignoring return value}}
g1(); // expected-warning {{ignoring return value}}
g2(); // expected-warning {{ignoring return value}}
g3(); // expected-warning {{ignoring return value}}
(void)f();
(void)g1();
(void)g2();
(void)g3();
if (f() == 0) return;
g1().t();
g2()->t();
g3().t();
int i = f();
S s1 = g1();
S *s2 = g2();
S &s3 = g3();
const S &s4 = g1();
}
struct X {
int foo() __attribute__((warn_unused_result));
};
void bah() {
X x, *x2;
x.foo(); // expected-warning {{ignoring return value}}
x2->foo(); // expected-warning {{ignoring return value}}
}
namespace warn_unused_CXX11 {
class Status;
class Foo {
public:
Status doStuff();
};
struct [[clang::warn_unused_result]] Status {
bool ok() const;
Status& operator=(const Status& x);
inline void Update(const Status& new_status) {
if (ok()) {
*this = new_status; //no-warning
}
}
};
Status DoSomething();
Status& DoSomethingElse();
Status* DoAnotherThing();
Status** DoYetAnotherThing();
void lazy() {
Status s = DoSomething();
if (!s.ok()) return;
Status &rs = DoSomethingElse();
if (!rs.ok()) return;
Status *ps = DoAnotherThing();
if (!ps->ok()) return;
Status **pps = DoYetAnotherThing();
if (!(*pps)->ok()) return;
(void)DoSomething();
(void)DoSomethingElse();
(void)DoAnotherThing();
(void)DoYetAnotherThing();
DoSomething(); // expected-warning {{ignoring return value}}
DoSomethingElse();
DoAnotherThing();
DoYetAnotherThing();
}
template <typename T>
class [[clang::warn_unused_result]] StatusOr {
};
StatusOr<int> doit();
void test() {
Foo f;
f.doStuff(); // expected-warning {{ignoring return value}}
doit(); // expected-warning {{ignoring return value}}
auto func = []() { return Status(); };
func(); // expected-warning {{ignoring return value}}
}
}
namespace PR17587 {
struct [[clang::warn_unused_result]] Status;
struct Foo {
Status Bar();
};
struct Status {};
void Bar() {
Foo f;
f.Bar(); // expected-warning {{ignoring return value}}
};
}
namespace PR18571 {
// Unevaluated contexts should not trigger unused result warnings.
template <typename T>
auto foo(T) -> decltype(f(), bool()) { // Should not warn.
return true;
}
void g() {
foo(1);
}
}
namespace std {
class type_info { };
}
namespace {
// The typeid expression operand is evaluated only when the expression type is
// a glvalue of polymorphic class type.
struct B {
virtual void f() {}
};
struct D : B {
void f() override {}
};
struct C {};
void g() {
// The typeid expression operand is evaluated only when the expression type is
// a glvalue of polymorphic class type; otherwise the expression operand is not
// evaluated and should not trigger a diagnostic.
D d;
C c;
(void)typeid(f(), c); // Should not warn.
(void)typeid(f(), d); // expected-warning {{ignoring return value}} expected-warning {{expression with side effects will be evaluated despite being used as an operand to 'typeid'}}
// The sizeof expression operand is never evaluated.
(void)sizeof(f(), c); // Should not warn.
// The noexcept expression operand is never evaluated.
(void)noexcept(f(), false); // Should not warn.
}
}
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