1 // RUN: %clang_cc1 -fsyntax-only -fcxx-exceptions -verify -Wno-unused -Wunused-comparison %s 2 3 struct A { 4 bool operator==(const A&); 5 bool operator!=(const A&); 6 bool operator<(const A&); 7 bool operator>(const A&); 8 bool operator<=(const A&); 9 bool operator>=(const A&); 10 A operator|=(const A&); 11 operator bool(); 12 }; 13 14 void test() { 15 int x, *p; 16 A a, b; 17 18 x == 7; // expected-warning {{equality comparison result unused}} \ 19 // expected-note {{use '=' to turn this equality comparison into an assignment}} 20 x != 7; // expected-warning {{inequality comparison result unused}} \ 21 // expected-note {{use '|=' to turn this inequality comparison into an or-assignment}} 22 x < 7; // expected-warning {{relational comparison result unused}} 23 x > 7; // expected-warning {{relational comparison result unused}} 24 x <= 7; // expected-warning {{relational comparison result unused}} 25 x >= 7; // expected-warning {{relational comparison result unused}} 26 27 7 == x; // expected-warning {{equality comparison result unused}} 28 p == p; // expected-warning {{equality comparison result unused}} \ 29 // expected-note {{use '=' to turn this equality comparison into an assignment}} \ 30 // expected-warning {{self-comparison always evaluates to true}} 31 a == a; // expected-warning {{equality comparison result unused}} \ 32 // expected-note {{use '=' to turn this equality comparison into an assignment}} 33 a == b; // expected-warning {{equality comparison result unused}} \ 34 // expected-note {{use '=' to turn this equality comparison into an assignment}} 35 a != b; // expected-warning {{inequality comparison result unused}} \ 36 // expected-note {{use '|=' to turn this inequality comparison into an or-assignment}} 37 a < b; // expected-warning {{relational comparison result unused}} 38 a > b; // expected-warning {{relational comparison result unused}} 39 a <= b; // expected-warning {{relational comparison result unused}} 40 a >= b; // expected-warning {{relational comparison result unused}} 41 42 A() == b; // expected-warning {{equality comparison result unused}} 43 if (42) x == 7; // expected-warning {{equality comparison result unused}} \ 44 // expected-note {{use '=' to turn this equality comparison into an assignment}} 45 else if (42) x == 7; // expected-warning {{equality comparison result unused}} \ 46 // expected-note {{use '=' to turn this equality comparison into an assignment}} 47 else x == 7; // expected-warning {{equality comparison result unused}} \ 48 // expected-note {{use '=' to turn this equality comparison into an assignment}} 49 do x == 7; // expected-warning {{equality comparison result unused}} \ 50 // expected-note {{use '=' to turn this equality comparison into an assignment}} 51 while (false); 52 while (false) x == 7; // expected-warning {{equality comparison result unused}} \ 53 // expected-note {{use '=' to turn this equality comparison into an assignment}} 54 for (x == 7; // expected-warning {{equality comparison result unused}} \ 55 // expected-note {{use '=' to turn this equality comparison into an assignment}} 56 x == 7; // No warning -- result is used 57 x == 7) // expected-warning {{equality comparison result unused}} \ 58 // expected-note {{use '=' to turn this equality comparison into an assignment}} 59 x == 7; // expected-warning {{equality comparison result unused}} \ 60 // expected-note {{use '=' to turn this equality comparison into an assignment}} 61 switch (42) default: x == 7; // expected-warning {{equality comparison result unused}} \ 62 // expected-note {{use '=' to turn this equality comparison into an assignment}} 63 switch (42) case 42: x == 7; // expected-warning {{equality comparison result unused}} \ 64 // expected-note {{use '=' to turn this equality comparison into an assignment}} 65 switch (42) { 66 case 1: 67 case 2: 68 default: 69 case 3: 70 case 4: 71 x == 7; // expected-warning {{equality comparison result unused}} \ 72 // expected-note {{use '=' to turn this equality comparison into an assignment}} 73 } 74 75 (void)(x == 7); 76 (void)(p == p); // expected-warning {{self-comparison always evaluates to true}} 77 { bool b = x == 7; } 78 79 { bool b = ({ x == 7; // expected-warning {{equality comparison result unused}} \ 80 // expected-note {{use '=' to turn this equality comparison into an assignment}} 81 x == 7; }); } // no warning on the second, its result is used! 82 83 #define EQ(x,y) (x) == (y) 84 EQ(x, 5); 85 #undef EQ 86 } 87 88 namespace PR10291 { 89 template<typename T> 90 class X 91 { 92 public: 93 94 X() : i(0) { } 95 96 void foo() 97 { 98 throw 99 i == 0u ? 100 5 : 6; 101 } 102 103 private: 104 int i; 105 }; 106 107 X<int> x; 108 } 109 110 namespace PR19724 { 111 class stream { 112 } cout, cin; 113 114 stream &operator<(stream &s, int); 115 bool operator<(stream &s, stream &s2); 116 117 void test() { 118 cout < 5; // no warning, operator returns a reference 119 cout < cin; // expected-warning {{relational comparison result unused}} 120 } 121 } 122 123 namespace PR19791 { 124 struct S { 125 void operator!=(int); 126 int operator==(int); 127 }; 128 129 void test() { 130 S s; 131 s != 1; 132 s == 1; // expected-warning{{equality comparison result unused}} 133 // expected-note@-1{{use '=' to turn this equality comparison into an assignment}} 134 } 135 } 136
