https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108669
Bug ID: 108669
Summary: [diagnostic] std::vector of incomplete type has member
referenced
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: ldalessandro at gmail dot com
Target Milestone: ---
In the following code example, I perform a value initialization of a
std::vector of incomplete type.
-
#include <vector>
struct B;
struct A {
std::vector<B> _;
};
A a{}; // <--here
struct B {};
-
https://godbolt.org/z/ab5Erqc1n
This should run afoul of the second half of
https://eel.is/c++draft/vector#overview-4. "T shall be complete before any
member of the resulting specialization of vector is referenced."
I honestly don't know if that "shall" implies this is ill-formed or undefined
behavior. However, this test case has started to be rejected in clang-15 for
-std=C++20 code specifically, thus it would be a very helpful quality-of-life
improvement if gcc could issue a diagnostic for this problem as well.
