| 1 | // RUN: %clang_cc1 -fsyntax-only -verify -Wunused-value %s |
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| 2 | // RUN: %clang_cc1 -fsyntax-only -verify -Wunused-value -std=c++98 %s |
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| 3 | // RUN: %clang_cc1 -fsyntax-only -verify -Wunused-value -std=c++11 %s |
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| 4 | |
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| 5 | // PR4806 |
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| 6 | namespace test0 { |
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| 7 | class Box { |
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| 8 | public: |
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| 9 | int i; |
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| 10 | volatile int j; |
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| 11 | }; |
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| 12 | |
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| 13 | void doit() { |
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| 14 | // pointer to volatile has side effect (thus no warning) |
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| 15 | Box* box = new Box; |
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| 16 | box->i; // expected-warning {{expression result unused}} |
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| 17 | box->j; |
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| 18 | #if __cplusplus <= 199711L |
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| 19 | // expected-warning@-2 {{expression result unused}} |
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| 20 | #endif |
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| 21 | } |
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| 22 | } |
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| 23 | |
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| 24 | namespace test1 { |
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| 25 | struct Foo { |
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| 26 | int i; |
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| 27 | bool operator==(const Foo& rhs) { |
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| 28 | return i == rhs.i; |
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| 29 | } |
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| 30 | }; |
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| 31 | |
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| 32 | #define NOP(x) (x) |
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| 33 | void b(Foo f1, Foo f2) { |
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| 34 | NOP(f1 == f2); // expected-warning {{expression result unused}} |
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| 35 | } |
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| 36 | #undef NOP |
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| 37 | } |
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| 38 | |
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| 39 | namespace test2 { |
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| 40 | extern "C++" { |
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| 41 | namespace std { |
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| 42 | template<typename T> struct basic_string { |
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| 43 | struct X {}; |
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| 44 | void method() const { |
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| 45 | X* x; |
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| 46 | &x[0]; // expected-warning {{expression result unused}} |
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| 47 | } |
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| 48 | }; |
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| 49 | typedef basic_string<char> string; |
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| 50 | void func(const std::string& str) { |
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| 51 | str.method(); // expected-note {{in instantiation of member function}} |
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| 52 | } |
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| 53 | } |
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| 54 | } |
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| 55 | } |
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| 56 | |
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| 57 | namespace test3 { |
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| 58 | struct Used { |
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| 59 | Used(); |
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| 60 | Used(int); |
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| 61 | Used(int, int); |
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| 62 | ~Used() {} |
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| 63 | }; |
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| 64 | struct __attribute__((warn_unused)) Unused { |
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| 65 | Unused(); |
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| 66 | Unused(int); |
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| 67 | Unused(int, int); |
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| 68 | ~Unused() {} |
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| 69 | }; |
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| 70 | void f() { |
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| 71 | Used(); |
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| 72 | Used(1); |
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| 73 | Used(1, 1); |
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| 74 | Unused(); // expected-warning {{expression result unused}} |
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| 75 | Unused(1); // expected-warning {{expression result unused}} |
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| 76 | Unused(1, 1); // expected-warning {{expression result unused}} |
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| 77 | #if __cplusplus >= 201103L // C++11 or later |
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| 78 | Used({}); |
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| 79 | Unused({}); // expected-warning {{expression result unused}} |
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| 80 | #endif |
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| 81 | } |
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| 82 | } |
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| 83 | |
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| 84 | namespace std { |
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| 85 | struct type_info {}; |
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| 86 | } |
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| 87 | |
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| 88 | namespace test4 { |
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| 89 | struct Good { Good &f(); }; |
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| 90 | struct Bad { virtual Bad& f(); }; |
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| 91 | |
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| 92 | void f() { |
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| 93 | int i = 0; |
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| 94 | (void)typeid(++i); // expected-warning {{expression with side effects has no effect in an unevaluated context}} |
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| 95 | |
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| 96 | Good g; |
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| 97 | (void)typeid(g.f()); // Ok; not a polymorphic use of a glvalue. |
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| 98 | |
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| 99 | // This is a polymorphic use of a glvalue, which results in the typeid being |
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| 100 | // evaluated instead of unevaluated. |
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| 101 | Bad b; |
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| 102 | (void)typeid(b.f()); // expected-warning {{expression with side effects will be evaluated despite being used as an operand to 'typeid'}} |
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| 103 | |
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| 104 | // A dereference of a volatile pointer is a side effecting operation, however |
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| 105 | // since it is idiomatic code, and the alternatives induce higher maintenance |
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| 106 | // costs, it is allowed. |
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| 107 | int * volatile x; |
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| 108 | (void)sizeof(*x); // Ok |
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| 109 | } |
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| 110 | } |
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| 111 | |
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