https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113075
Bug ID: 113075
Summary: Inconsistent/wrong diagnostic when incorrectly taking
address of single/overloaded
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: waffl3x at protonmail dot com
Target Milestone: ---
I am including all 3 bugs in a single report as they are similar and
located in the same region of code.
```
struct S {
void f() {}
void g() {}
void g(int) {}
void test() {
void (S::*fp)() = &f;
void (S::*gp)() = &g;
}
};
```
<source>: In member function 'void S::test()':
<source>:29:24: error: ISO C++ forbids taking the address of an unqualified or
parenthesized non-static member function to form a pointer to member function.
Say '&S::f' [-fpermissive]
29 | void (S::*fp)() = &f;
| ^
<source>:30:24: error: assuming pointer to member 'void S::g()' [-fpermissive]
30 | void (S::*gp)() = &g;
| ^
<source>:30:24: note: (a pointer to member can only be formed with '&S::g')
The error message between the overloaded case and the single case is
largely different. Perhaps there is a reason why it should be different
but this is kind of confusing in my opinion.
```
struct S {
void f() {}
void g() {}
void g(int) {}
};
int main()
{
S s{};
void (S::*fp)() = &s.f;
void (S::*gp)() = &s.g;
}
```
<source>: In function 'int main()':
<source>:32:24: error: ISO C++ forbids taking the address of a bound member
function to form a pointer to member function. Say '&S::f' [-fpermissive]
32 | void (S::*fp)() = &s.f;
| ~~^
<source>:33:24: error: assuming pointer to member 'void S::g()' [-fpermissive]
33 | void (S::*gp)() = &s.g;
| ^
<source>:33:24: note: (a pointer to member can only be formed with '&S::g')
The single function case has a slightly different message, while the
overloaded case has an identical message. This appears to be due to a
lack of context in resolve_address_of_overloaded_function where the
errors are emitted in the overloaded case.
```
struct B {
void f() {}
void g() {}
void g(int) {}
};
struct D : B {
void test() {
void (D::*fp)() = &f;
void (D::*gp)() = &g;
}
};
```
<source>: In member function 'void D::test()':
<source>:10:24: error: ISO C++ forbids taking the address of an unqualified or
parenthesized non-static member function to form a pointer to member function.
Say '&D::f' [-fpermissive]
10 | void (D::*fp)() = &f;
| ^
<source>:11:24: error: assuming pointer to member 'void B::g()' [-fpermissive]
11 | void (D::*gp)() = &g;
| ^
<source>:11:24: note: (a pointer to member can only be formed with '&B::g')
The single function case properly suggests &D::f but the overload case
suggests &B::g instead.
All 3 bugs are super mild, and I don't know how feasible they are to
fix, but at the very least it's worth tracking them in my opinion.
