1 // PR c++/44625 2 // { dg-do compile } 3 // { dg-options "" } 4 // { dg-additional-options "-Wno-return-type" } 5 6 template<typename FP_> struct Vec { // { dg-message "note" "" { target c++17_down } } 7 Vec& operator^=(Vec& rhs) { 8 union { 9 struct {FP_ x,y,z;}; // { dg-error "20:anonymous struct" } 10 }; 11 X = y*rhs.z() - z*rhs.y(); // { dg-error "not declared|no member" } 12 } 13 Vec& operator^(Vec& rhs) { 14 return Vec(*this)^=rhs; // { dg-message "required" } 15 } 16 }; 17 Vec<double> v(3,4,12); // { dg-error "no matching|too many initializers" } 18 Vec<double> V(12,4,3); // { dg-error "no matching|too many initializers" } 19 Vec<double> c = v^V; // { dg-message "required" } 20