https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121368
Bug ID: 121368
Summary: [[nodiscard]] warning not triggered when discarding
return value from function pointer call
Product: gcc
Version: 15.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: 2023091106 at cauc dot edu.cn
Target Milestone: ---
g++ -std=c++17 -Wall -Wextra -Wunused -O0
====code====
#include <functional>
struct [[nodiscard]] S {};
S (*test_fun())();
int main(){
test_fun()(); // No warning
std::bind(test_fun())(); // Emits warning: discarding nodiscard return
return 0;
}
====output====
warning: ignoring return value of type 'S' declared with 'nodiscard' attribute
[-Wunused-value]
Only for the std::bind(test_fun())() line.
No warning is emitted for test_fun()();, even though S is [[nodiscard]].
