89 lines · cpp
1// RUN: %clang_cc1 -verify=expected,pre20 %s -std=c++112// RUN: %clang_cc1 -verify=expected,pre20 %s -std=c++173// RUN: %clang_cc1 -verify=expected %s -std=c++204 5// A function that is explicitly defaulted shall6struct A {7 // -- be a special member function [C++20: or a comparison operator function],8 A(int) = default;9#if __cplusplus <= 201703L10 // expected-error@-2 {{only special member functions may be defaulted}}11#else12 // expected-error@-4 {{only special member functions and comparison operators may be defaulted}}13#endif14 A(A) = default; // expected-error {{must pass its first argument by reference}}15 void f(A) = default; // expected-error-re {{only special member functions{{( and comparison operators)?}} may be defaulted}}16 17 bool operator==(const A&) const = default; // pre20-warning {{defaulted comparison operators are a C++20 extension}}18 bool operator!=(const A&) const = default; // pre20-warning {{defaulted comparison operators are a C++20 extension}}19 bool operator<(const A&) const = default; // pre20-error {{only special member functions may be defaulted}}20 bool operator>(const A&) const = default; // pre20-error {{only special member functions may be defaulted}}21 bool operator<=(const A&) const = default; // pre20-error {{only special member functions may be defaulted}}22 bool operator>=(const A&) const = default; // pre20-error {{only special member functions may be defaulted}}23 bool operator<=>(const A&) const = default; // pre20-error 1+{{}} pre20-warning {{'<=>' is a single token in C++20}}24 25 A operator+(const A&) const = default; // expected-error-re {{only special member functions{{( and comparison operators)?}} may be defaulted}}26 27 // -- have the same declared function type as if it had been implicitly28 // declared29 void operator=(const A &) = default; // expected-error {{must return 'A &'}}30 A(...) = default;31 A(const A &, ...) = default;32 A &operator=(const A&) const = default;33 A &operator=(A) const = default; // expected-error {{must be an lvalue refe}}34#if __cplusplus <= 201703L35 // expected-error@-5 {{cannot be variadic}}36 // expected-error@-5 {{cannot be variadic}}37 // expected-error@-5 {{may not have 'const'}}38 // expected-error@-5 {{may not have 'const'}}39#else40 // expected-warning@-10 {{implicitly deleted}} expected-note@-10 {{declared type does not match the type of an implicit default constructor}}41 // expected-warning@-10 {{implicitly deleted}} expected-note@-10 {{declared type does not match the type of an implicit copy constructor}}42 // expected-warning@-10 {{implicitly deleted}} expected-note@-10 {{declared type does not match the type of an implicit copy assignment}}43#endif44 45 // (except for possibly differing ref-qualifiers46 A &operator=(A &&) & = default;47 48 // and except that in the case of a copy constructor or copy assignment49 // operator, the parameter type may be "reference to non-const T")50 A(A &) = default;51 A &operator=(A &) = default;52 53 // -- not have default arguments54 A(double = 0.0) = default; // expected-error {{cannot have default arguments}}55 A(const A & = 0) = default; // expected-error {{cannot have default arguments}}56};57 58struct A2 {59 A2(...);60 A2(const A2 &, ...);61 A2 &operator=(const A2&) const;62};63A2::A2(...) = default; // expected-error {{cannot be variadic}}64A2::A2(const A2&, ...) = default; // expected-error {{cannot be variadic}}65A2 &A2::operator=(const A2&) const = default; // expected-error {{may not have 'const'}}66 67struct B {68 B(B&);69 B &operator=(B&);70};71struct C : B {72 C(const C&) = default;73 C &operator=(const C&) = default;74#if __cplusplus <= 201703L75 // expected-error@-3 {{is const, but a member or base requires it to be non-const}}76 // expected-error@-3 {{is const, but a member or base requires it to be non-const}}77#else78 // expected-warning@-6 {{implicitly deleted}} expected-note@-6 {{type does not match}}79 // expected-warning@-6 {{implicitly deleted}} expected-note@-6 {{type does not match}}80#endif81};82 83struct D : B { // expected-note 2{{base class}}84 D(const D&);85 D &operator=(const D&);86};87D::D(const D&) = default; // expected-error {{would delete}} expected-error {{is const, but}}88D &D::operator=(const D&) = default; // expected-error {{would delete}} expected-error {{is const, but}}89