Can copy constructor S(S&) be non-trivial?

Quick question about copy constructors. Is “istrivial” true in the following example? clang thinks it is not trivially-copyable but gcc seems to disagree.

#include <type_traits>
struct S {
S(S&) = default;
};
bool istrivial = std::is_trivially_copyable::value;

If I understand the following defect report correctly, gcc seems correct:

http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#2171