| 1 | // RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify -Wunused-value %s |
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| 2 | |
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| 3 | void f() __attribute__((const)); |
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| 4 | |
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| 5 | namespace PR18571 { |
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| 6 | // Unevaluated contexts should not trigger unused result warnings. |
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| 7 | template <typename T> |
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| 8 | auto foo(T) -> decltype(f(), bool()) { // Should not warn. |
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| 9 | return true; |
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| 10 | } |
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| 11 | |
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| 12 | void g() { |
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| 13 | foo(1); |
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| 14 | } |
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| 15 | |
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| 16 | void h() { |
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| 17 | int i = 0; |
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| 18 | (void)noexcept(++i); // expected-warning {{expression with side effects has no effect in an unevaluated context}} |
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| 19 | decltype(i++) j = 0; // expected-warning {{expression with side effects has no effect in an unevaluated context}} |
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| 20 | } |
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| 21 | |
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| 22 | struct S { |
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| 23 | S operator++(int); |
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| 24 | S(int i); |
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| 25 | S(); |
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| 26 | |
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| 27 | int& f(); |
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| 28 | S g(); |
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| 29 | }; |
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| 30 | |
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| 31 | void j() { |
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| 32 | S s; |
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| 33 | int i = 0; |
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| 34 | (void)noexcept(s++); // Ok |
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| 35 | (void)noexcept(i++); // expected-warning {{expression with side effects has no effect in an unevaluated context}} |
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| 36 | (void)noexcept(i = 5); // expected-warning {{expression with side effects has no effect in an unevaluated context}} |
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| 37 | (void)noexcept(s = 5); // Ok |
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| 38 | |
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| 39 | (void)sizeof(s.f()); // Ok |
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| 40 | (void)sizeof(s.f() = 5); // expected-warning {{expression with side effects has no effect in an unevaluated context}} |
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| 41 | (void)noexcept(s.g() = 5); // Ok |
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| 42 | } |
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| 43 | |
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| 44 | } |
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