https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115229
Bug ID: 115229
Summary: inconsistent `error: possibly dangling reference to a
temporary`
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: pobrn at protonmail dot com
Target Milestone: ---
Consider the following piece of C++ code:
```
struct A {
int q;
int *p;
};
struct B {
A value_or() {
return A {};
}
};
B f();
void test() {
const auto& x = f().value_or();
}
```
gcc 15, 14 show the following diagnostic:
```
<source>: In function 'void test()':
<source>:15:21: error: possibly dangling reference to a temporary
[-Werror=dangling-reference]
15 | const auto& x = f().value_or();
| ^
<source>:15:37: note: the temporary was destroyed at the end of the full
expression 'f().B::value_or()'
15 | const auto& x = f().value_or();
| ~~~~~~~~~~~~^~
```
while gcc 13 does not.
Could someone help me understand why this warning is even shown? I would assume
lifetime extension should extend the lifetime of the returned value as needed.
Note that removing `int *p` from `A` makes the warning go away, so I am not
sure if this warning has anything to do with the lifetime of the returned
value, but then I am confused why the error points to `x`.
