2f237670b1
A call through a function pointer has no associated FunctionDecl, but it still might have a nodiscard return type. Ensure there is a codepath to emit the nodiscard warning in this case. Fixes #142453
80 lines
2.5 KiB
C
80 lines
2.5 KiB
C
// RUN: %clang_cc1 -fsyntax-only -std=c2x -verify %s
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// This is the latest version of nodiscard that we support.
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_Static_assert(__has_c_attribute(nodiscard) == 202003L);
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struct [[nodiscard]] S1 { // ok
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int i;
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};
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struct [[nodiscard, nodiscard]] S2 { // ok
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int i;
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};
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struct [[nodiscard("Wrong")]] S3 {
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int i;
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};
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struct S3 get_s3(void);
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[[nodiscard]] int f1(void);
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enum [[nodiscard]] E1 { One };
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[[nodiscard]] int i; // expected-warning {{'nodiscard' attribute only applies to Objective-C methods, enums, structs, unions, classes, functions, function pointers, and typedefs}}
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struct [[nodiscard]] S4 {
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int i;
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};
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struct S4 get_s(void);
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enum [[nodiscard]] E2 { Two };
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enum E2 get_e(void);
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[[nodiscard]] int get_i(void);
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void f2(void) {
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get_s(); // expected-warning {{ignoring return value of type 'S4' declared with 'nodiscard' attribute}}
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get_s3(); // expected-warning {{ignoring return value of type 'S3' declared with 'nodiscard' attribute: Wrong}}
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get_i(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
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get_e(); // expected-warning {{ignoring return value of type 'E2' declared with 'nodiscard' attribute}}
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// Okay, warnings are not encouraged
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(void)get_s();
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(void)get_s3();
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(void)get_i();
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(void)get_e();
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One; // expected-warning {{expression result unused}}
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(enum E2)(0); // expected-warning {{expression result unused}}
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(struct S4){1}; // expected-warning {{expression result unused}}
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}
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struct [[nodiscard]] error_info{
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int i;
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};
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struct error_info enable_missile_safety_mode(void);
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void launch_missiles(void);
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void test_missiles(void) {
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enable_missile_safety_mode(); // expected-warning {{ignoring return value of type 'error_info' declared with 'nodiscard'}}
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launch_missiles();
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}
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[[nodiscard]] int f3();
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void GH104391() {
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#define M (unsigned int) f3()
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M; // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
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}
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[[nodiscard]] typedef int NoDInt; // expected-warning {{'[[nodiscard]]' attribute ignored when applied to a typedef}}
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typedef __attribute__((warn_unused)) int WUInt; // expected-warning {{'warn_unused' attribute only applies to structs, unions, and classes}}
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typedef __attribute__((warn_unused_result)) int WURInt;
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NoDInt get_nodint();
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WUInt get_wuint();
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WURInt get_wurint();
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void f4(void) {
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get_nodint(); // no warning because attribute is ignored
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get_wuint(); // no warning because attribute is ignored
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get_wurint(); // expected-warning {{ignoring return value of type 'WURInt' declared with 'warn_unused_result' attribute}}
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}
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