54 lines
1.5 KiB
C
54 lines
1.5 KiB
C
|
// RUN: %clang_cc1 -fsyntax-only -std=c2x -verify %s
|
||
|
|
|
||
|
|
struct [[nodiscard]] S1 { // ok
|
||
|
|
int i;
|
||
|
|
};
|
||
|
|
struct [[nodiscard nodiscard]] S2 { // expected-error {{attribute 'nodiscard' cannot appear multiple times in an attribute specifier}}
|
||
|
|
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, and function pointers}}
|
||
|
|
|
||
|
|
struct [[nodiscard]] S4 {
|
||
|
|
int i;
|
||
|
|
};
|
||
|
|
struct S4 get_s(void);
|
||
|
|
|
||
|
|
enum [[nodiscard]] E2 { Two };
|
||
|
|
enum E2 get_e(void);
|
||
|
|
|
||
|
|
[[nodiscard]] int get_i();
|
||
|
|
|
||
|
|
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();
|
||
|
|
}
|
||
|
|
|