1 @safe unittest 2 { 3 struct CustomString 4 { 5 @safe: 6 string _impl; emptyCustomString7 @property bool empty() const { return !_impl.length; } 8 } 9 find(CustomString a,CustomString b)10 CustomString find(CustomString a, CustomString b) 11 { 12 return CustomString.init; 13 } 14 15 auto r = find(CustomString("a"), CustomString("b")); 16 assert(r.empty); 17 } 18