https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92869
--- Comment #5 from Igor Chorazewicz <igor.chorazewicz at intel dot com> --- Ok, but P1816R0 talks about argument deduction - in my example I specify all template arguments for A, so should this fail? Moreover, for g++ 10 and g++ 9.2 even the following, non-template code fails for -std=c++2a struct A { A() = default; A(const A &) = default; A(A &&) = default; int arr[3]; }; int main() { A a = {{1,2,3}}; }