https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68051
Bug ID: 68051
Summary: copy constructor does not copy default initialized
union member
Product: gcc
Version: 5.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: akju at mailinator dot com
Target Milestone: ---
The assertion at the end of the following code fails erroneously:
#include <string>
#include <cassert>
struct test
{
union {int v = 0;};
std::string dummy;
};
int main ()
{
test x;
x.v = 1;
test y = x;
assert (y.v == 1);
}
According to the assembly listing, it seems that the copy construction of y
uses the default member initializer of v instead of x.v. This behaviour does
not occur if the dummy member is removed causing the struct to be trivially
copyable.
