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// RUN: %clang_cc1 -fsyntax-only -std=c2x -verify %s
struct [[nodiscard]] S1 { // ok
int i;
};
struct [[nodiscard, nodiscard]] S2 { // ok
int i;
};
struct [[nodiscard("Wrong")]] S3 { // FIXME: may need an extension warning.
int i;
};
struct S3 get_s3(void);
[[nodiscard]] int f1(void);
enum [[nodiscard]] E1 { One };
[[nodiscard]] int i; // expected-warning {{'nodiscard' attribute only applies to Objective-C methods, enums, structs, unions, classes, functions, function pointers, and typedefs}}
struct [[nodiscard]] S4 {
int i;
};
struct S4 get_s(void);
enum [[nodiscard]] E2 { Two };
enum E2 get_e(void);
[[nodiscard]] int get_i(void);
void f2(void) {
get_s(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
get_s3(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute: Wrong}}
get_i(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
get_e(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
// Okay, warnings are not encouraged
(void)get_s();
(void)get_s3();
(void)get_i();
(void)get_e();
}
struct [[nodiscard]] error_info{
int i;
};
struct error_info enable_missile_safety_mode(void);
void launch_missiles(void);
void test_missiles(void) {
enable_missile_safety_mode(); // expected-warning {{ignoring return value of function declared with 'nodiscard'}}
launch_missiles();
}
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