1 // RUN: %clang_cc1 -fsyntax-only -verify %s
2 // RUN: %clang_cc1 -fsyntax-only -verify -Wtautological-undefined-compare %s
3 // RUN: %clang_cc1 -fsyntax-only -verify -Wno-tautological-compare -Wtautological-undefined-compare %s
4 // RUN: %clang_cc1 -fsyntax-only -verify -Wtautological-compare %s
5 
test1(int & x)6 void test1(int &x) {
7   if (x == 1) { }
8   if (&x == 0) { }
9   // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to false}}
10   if (&x != 0) { }
11   // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to true}}
12 }
13 
14 class test2 {
test2()15   test2() : x(y) {}
16 
foo()17   void foo() {
18     if (this == 0) { }
19     // expected-warning@-1{{'this' pointer cannot be null in well-defined C++ code; comparison may be assumed to always evaluate to false}}
20     if (this != 0) { }
21     // expected-warning@-1{{'this' pointer cannot be null in well-defined C++ code; comparison may be assumed to always evaluate to true}}
22   }
23 
bar()24   void bar() {
25     if (x == 1) { }
26     if (&x == 0) { }
27     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to false}}
28     if (&x != 0) { }
29     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to true}}
30   }
31 
32   int &x;
33   int y;
34 };
35 
36 namespace function_return_reference {
37   int& get_int();
38   // expected-note@-1 4{{'get_int' returns a reference}}
39   class B {
40   public:
41     static int &stat();
42     // expected-note@-1 4{{'stat' returns a reference}}
43     int &get();
44     // expected-note@-1 8{{'get' returns a reference}}
45   };
46 
test()47   void test() {
48     if (&get_int() == 0) {}
49     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to false}}
50     if (&(get_int()) == 0) {}
51     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to false}}
52 
53     if (&get_int() != 0) {}
54     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to true}}
55     if (&(get_int()) != 0) {}
56     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to true}}
57 
58     if (&B::stat() == 0) {}
59     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to false}}
60     if (&(B::stat()) == 0) {}
61     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to false}}
62 
63     if (&B::stat() != 0) {}
64     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to true}}
65     if (&(B::stat()) != 0) {}
66     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to true}}
67 
68     B b;
69     if (&b.get() == 0) {}
70     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to false}}
71     if (&(b.get()) == 0) {}
72     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to false}}
73 
74     if (&b.get() != 0) {}
75     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to true}}
76     if (&(b.get()) != 0) {}
77     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to true}}
78 
79     B* b_ptr = &b;
80     if (&b_ptr->get() == 0) {}
81     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to false}}
82     if (&(b_ptr->get()) == 0) {}
83     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to false}}
84 
85     if (&b_ptr->get() != 0) {}
86     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to true}}
87     if (&(b_ptr->get()) != 0) {}
88     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to true}}
89 
90     int& (B::*m_ptr)() = &B::get;
91     if (&(b.*m_ptr)() == 0) {}
92     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to false}}
93     if (&((b.*m_ptr)()) == 0) {}
94     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to false}}
95 
96     if (&(b.*m_ptr)() != 0) {}
97     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to true}}
98     if (&((b.*m_ptr)()) != 0) {}
99     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to true}}
100 
101     int& (*f_ptr)() = &get_int;
102     if (&(*f_ptr)() == 0) {}
103     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to false}}
104     if (&((*f_ptr)()) == 0) {}
105     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to false}}
106 
107     if (&(*f_ptr)() != 0) {}
108     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to true}}
109     if (&((*f_ptr)()) != 0) {}
110     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to true}}
111   }
112 }
113 
114 namespace macros {
115   #define assert(x) if (x) {}
116 
test(int & x)117   void test(int &x) {
118     assert(&x != 0);
119     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to true}}
120     assert(&x == 0);
121     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to false}}
122     assert(&x != 0 && "Expecting valid reference");
123     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to true}}
124     assert(&x == 0 && "Expecting invalid reference");
125     // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to false}}
126   }
127 
128   class S {
test()129     void test() {
130       assert(this != 0);
131       // expected-warning@-1{{'this' pointer cannot be null in well-defined C++ code; comparison may be assumed to always evaluate to true}}
132       assert(this == 0);
133       // expected-warning@-1{{'this' pointer cannot be null in well-defined C++ code; comparison may be assumed to always evaluate to false}}
134       assert(this != 0 && "Expecting valid reference");
135       // expected-warning@-1{{'this' pointer cannot be null in well-defined C++ code; comparison may be assumed to always evaluate to true}}
136       assert(this == 0 && "Expecting invalid reference");
137       // expected-warning@-1{{'this' pointer cannot be null in well-defined C++ code; comparison may be assumed to always evaluate to false}}
138     }
139   };
140 }
141