On Tue, Dec 22, 2020 at 03:57:56PM +0800, jim x via Gcc-patches wrote:
> struct A{
> A(){}
> };
> union C{
> A a;
> int b = 0;
> };
> int main(){
> C c;
> }
>
> GCC reports the default constructor for union `C` is defined as
> deleted. However, the relevant rule in the current c++ standard says
> that:
> > A defaulted default constructor for class X is defined as deleted if:
> >> X is a union that has a variant member with a non-trivial default
> >> constructor and no variant member of X has a default member initializer,
> >> X is a non-union class that has a variant member M with a non-trivial
> >> default constructor and no variant member of the anonymous union
> >> containing M has a default member initializer
That would mean GCC (but neither clang++ nor ICC too) doesn't implement
CWG2084 properly.
Why are you mailing gcc-patches though when you don't have a patch?
TThis should be filed into https://gcc.gnu.org/bugzilla/
Jakub
