1 // RUN: %clang_cc1 -fsyntax-only -verify %s
2 // RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify %s
3 // RUN: %clang_cc1 -std=c++14 -fsyntax-only -verify %s
4 int g(int);
5 
6 void f() {
7   int i;
8   int &r = i;
9   r = 1;
10   int *p = &r;
11   int &rr = r;
12   int (&rg)(int) = g;
13   rg(i);
14   int a[3];
15   int (&ra)[3] = a;
16   ra[1] = i;
17   int *Q;
18   int *& P = Q;
19   P[1] = 1;
20 }
21 
22 typedef int t[1];
23 void test2() {
24     t a;
25     t& b = a;
26 
27 
28     int c[3];
29     int (&rc)[3] = c;
30 }
31 
32 // C++ [dcl.init.ref]p5b1
33 struct A { };
34 struct B : A { } b;
35 
36 void test3() {
37   double d = 2.0;
38   double& rd = d; // rd refers to d
39   const double& rcd = d; // rcd refers to d
40 
41   A& ra = b; // ra refers to A subobject in b
42   const A& rca = b; // rca refers to A subobject in b
43 }
44 
45 B fB();
46 
47 // C++ [dcl.init.ref]p5b2
48 void test4() {
49   double& rd2 = 2.0; // expected-error{{non-const lvalue reference to type 'double' cannot bind to a temporary of type 'double'}}
50   int i = 2;
51   double& rd3 = i; // expected-error{{non-const lvalue reference to type 'double' cannot bind to a value of unrelated type 'int'}}
52 
53   const A& rca = fB();
54 }
55 
56 void test5() {
57   //  const double& rcd2 = 2; // rcd2 refers to temporary with value 2.0
58   const volatile int cvi = 1;
59   const int& r = cvi; // expected-error{{binding reference of type 'const int' to value of type 'const volatile int' drops 'volatile' qualifier}}
60 
61 #if __cplusplus >= 201103L
62   const int& r2{cvi}; // expected-error{{binding reference of type 'const int' to value of type 'const volatile int' drops 'volatile' qualifier}}
63 
64   const int a = 2;
65   int& r3{a}; // expected-error{{binding reference of type 'int' to value of type 'const int' drops 'const' qualifier}}
66 
67   const int&& r4{a}; // expected-error{{rvalue reference to type 'const int' cannot bind to lvalue of type 'const int'}}
68 
69   void func();
70   void func(int);
71   int &ptr1 = {func}; // expected-error{{address of overloaded function 'func' does not match required type 'int'}}
72   int &&ptr2{func}; // expected-error{{address of overloaded function 'func' does not match required type 'int'}}
73   // expected-note@-4{{candidate function}}
74   // expected-note@-4{{candidate function}}
75   // expected-note@-6{{candidate function}}
76   // expected-note@-6{{candidate function}}
77 #endif
78 }
79 
80 // C++ [dcl.init.ref]p3
81 int& test6(int& x) {
82   int& yo; // expected-error{{declaration of reference variable 'yo' requires an initializer}}
83 
84   return x;
85 }
86 int& not_initialized_error; // expected-error{{declaration of reference variable 'not_initialized_error' requires an initializer}}
87 extern int& not_initialized_okay;
88 
89 class Test6 { // expected-warning{{class 'Test6' does not declare any constructor to initialize its non-modifiable members}}
90   int& okay; // expected-note{{reference member 'okay' will never be initialized}}
91 };
92 
93 struct C : B, A { }; // expected-warning {{direct base 'A' is inaccessible due to ambiguity:\n    struct C -> struct B -> struct A\nstruct C -> struct A}}
94 
95 void test7(C& c) {
96   A& a1 = c; // expected-error {{ambiguous conversion from derived class 'C' to base class 'A':}}
97 }
98 
99 // C++ [dcl.ref]p1, C++ [dcl.ref]p4
100 void test8(int& const,// expected-error{{'const' qualifier may not be applied to a reference}}
101 
102            void&,     // expected-error{{cannot form a reference to 'void'}}
103            int& &)    // expected-error{{type name declared as a reference to a reference}}
104 {
105   typedef int& intref;
106   typedef intref& intrefref; // C++ DR 106: reference collapsing
107 
108   typedef intref const intref_c; // expected-warning {{'const' qualifier on reference type 'intref' (aka 'int &') has no effect}}
109   typedef intref_c intref; // ok, same type
110 
111   typedef intref volatile intref; // expected-warning {{'volatile' qualifier on reference type 'intref' (aka 'int &') has no effect}}
112   typedef intref _Atomic intref; // expected-warning {{'_Atomic' qualifier on reference type 'intref' (aka 'int &') has no effect}}
113 
114   void restrict_ref(__restrict intref); // ok
115   void restrict_ref(int &__restrict); // ok
116 }
117 
118 namespace var_template {
119 #if __cplusplus >= 201402L
120 int i;
121 template <typename> int &ref = i; // ok
122 template <> int &ref<float>;      // expected-error {{declaration of reference variable 'ref<float>' requires an initializer}}
123 #endif
124 } // namespace var_template
125 
126 template<typename T> int const_param(const T) {}
127 int const_ref_param = const_param<int&>(const_ref_param); // no-warning
128 
129 
130 class string {
131   char *Data;
132   unsigned Length;
133 public:
134   string();
135   ~string();
136 };
137 
138 string getInput();
139 
140 void test9() {
141   string &s = getInput(); // expected-error{{lvalue reference}}
142 }
143 
144 void test10() {
145   __attribute((vector_size(16))) typedef int vec4;
146   typedef __attribute__(( ext_vector_type(4) )) int ext_vec4;
147 
148   vec4 v;
149   int &a = v[0]; // expected-error{{non-const reference cannot bind to vector element}}
150   const int &b = v[0];
151 
152   ext_vec4 ev;
153   int &c = ev.x; // expected-error{{non-const reference cannot bind to vector element}}
154   const int &d = ev.x;
155 }
156 
157 namespace PR7149 {
158   template<typename T> struct X0
159   {
160     T& first;
161     X0(T& p1) : first(p1) { }
162   };
163 
164 
165   void f()
166   {
167     int p1[1];
168     X0< const int[1]> c(p1);
169   }
170 }
171 
172 namespace PR8608 {
173   bool& f(unsigned char& c) { return (bool&)c; }
174 }
175 
176 // The following crashed trying to recursively evaluate the LValue.
177 const int &do_not_crash = do_not_crash; // expected-warning{{reference 'do_not_crash' is not yet bound to a value when used within its own initialization}}
178 
179 namespace ExplicitRefInit {
180   // This is invalid: we can't copy-initialize an 'A' temporary using an
181   // explicit constructor.
182   struct A { explicit A(int); };
183   const A &a(0); // expected-error {{reference to type 'const ExplicitRefInit::A' could not bind to an rvalue of type 'int'}}
184 }
185 
186 namespace RefCollapseTypePrinting {
187   template<typename T> void add_lref() {
188     using X = int(T); // expected-note 4{{previous}}
189     using X = const volatile T&;
190     // expected-error@-1 {{'int &' vs 'int (int &)'}}
191     // expected-error@-2 {{'int &' vs 'int (int &&)'}}
192     // expected-error@-3 {{'const int &' vs 'int (const int &)'}}
193     // expected-error@-4 {{'const int &' vs 'int (const int &&)'}}
194   }
195   template void add_lref<int&>(); // expected-note {{instantiation of}}
196   template void add_lref<int&&>(); // expected-note {{instantiation of}}
197   template void add_lref<const int&>(); // expected-note {{instantiation of}}
198   template void add_lref<const int&&>(); // expected-note {{instantiation of}}
199 
200   template<typename T> void add_rref() {
201     using X = int(T); // expected-note 4{{previous}}
202     using X = const volatile T&&;
203     // expected-error@-1 {{'int &' vs 'int (int &)'}}
204     // expected-error@-2 {{'int &&' vs 'int (int &&)'}}
205     // expected-error@-3 {{'const int &' vs 'int (const int &)'}}
206     // expected-error@-4 {{'const int &&' vs 'int (const int &&)'}}
207   }
208   template void add_rref<int&>(); // expected-note {{instantiation of}}
209   template void add_rref<int&&>(); // expected-note {{instantiation of}}
210   template void add_rref<const int&>(); // expected-note {{instantiation of}}
211   template void add_rref<const int&&>(); // expected-note {{instantiation of}}
212 }
213 
214 namespace PR45521 {
215   struct a { template<class b> a(const b * const&); };
216   int *d;
217   const a &r = d;
218 }
219