“defaulted special member function - a (user-declared) special member function specified (see Section 1.1.“Defaulted Functions” on page 33) to be implemented using its default (i.e., compiler-generated) definition. Note that, in some situations (e.g., see Section 3.1.“union ’11” on page 1174), the compiler may choose to delete an implicitly or explicitly declared and defaulted function.” (EMCppSfe 2021)