llvm-project/clang/test/SemaCXX/default-assignment-operator.cpp

// RUN: %clang_cc1 -fsyntax-only -verify %s

class Base { // expected-error {{cannot define the implicit default assignment operator for 'Base', because non-static reference member 'ref' can't use default assignment operator}} \
  // expected-warning{{class 'Base' does not declare any constructor to initialize its non-modifiable members}}
  int &ref;  // expected-note {{declared here}} \
  // expected-note{{reference member 'ref' will never be initialized}}
};

class X  : Base {  // // expected-error {{cannot define the implicit default assignment operator for 'X', because non-static const member 'cint' can't use default assignment operator}} \
// expected-note{{assignment operator for 'Base' first required here}}
public: 
  X();
  const int cint;  // expected-note {{declared here}}
}; 

struct Y  : X { 
  Y();
  Y& operator=(const Y&);
  Y& operator=(volatile Y&);
  Y& operator=(const volatile Y&);
  Y& operator=(Y&);
}; 

class Z : Y {};

Z z1;
Z z2;

// Test1
void f(X x, const X cx) {
  x = cx; // expected-note{{assignment operator for 'X' first required here}}
  x = cx;
  z1 = z2;
}

// Test2
class T {};
T t1;
T t2;

void g() {
  t1 = t2;
}

// Test3
class V {
public:
  V();
  V &operator = (V &b);
};

class W : V {};
W w1, w2;

void h() {
  w1 = w2;
}

// Test4

class B1 {
public:
  B1();
  B1 &operator = (B1 b);
};

class D1 : B1 {};
D1 d1, d2;

void i() {
  d1 = d2;
}

// Test5

class E1 { // expected-error{{cannot define the implicit default assignment operator for 'E1', because non-static const member 'a' can't use default assignment operator}}

public:
  const int a; // expected-note{{declared here}}
  E1() : a(0) {}  

};

E1 e1, e2;

void j() {
  e1 = e2; // expected-note{{assignment operator for 'E1' first required here}}
}

namespace ProtectedCheck {
  struct X {
  protected:
    X &operator=(const X&); // expected-note{{declared protected here}}
  };

  struct Y : public X { };

  void f(Y y) { y = y; }

  struct Z { // expected-error{{'operator=' is a protected member of 'ProtectedCheck::X'}}
    X x;
  };

  void f(Z z) { z = z; }  // expected-note{{implicit default copy assignment operator}}

}

namespace MultiplePaths {
  struct X0 { 
    X0 &operator=(const X0&);
  };

  struct X1 : public virtual X0 { };

  struct X2 : X0, X1 { };

  void f(X2 x2) { x2 = x2; }
}