warn-unused-value-cxx11.cpp
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// RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify -Wunused-value %s
void f() __attribute__((const));
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);
}
void h() {
int i = 0;
(void)noexcept(++i); // expected-warning {{expression with side effects has no effect in an unevaluated context}}
decltype(i++) j = 0; // expected-warning {{expression with side effects has no effect in an unevaluated context}}
}
struct S {
S operator++(int);
S(int i);
S();
int& f();
S g();
};
void j() {
S s;
int i = 0;
(void)noexcept(s++); // Ok
(void)noexcept(i++); // expected-warning {{expression with side effects has no effect in an unevaluated context}}
(void)noexcept(i = 5); // expected-warning {{expression with side effects has no effect in an unevaluated context}}
(void)noexcept(s = 5); // Ok
(void)sizeof(s.f()); // Ok
(void)sizeof(s.f() = 5); // expected-warning {{expression with side effects has no effect in an unevaluated context}}
(void)noexcept(s.g() = 5); // Ok
}
}