| 1 | // RUN: %clang_cc1 -std=c++1z -Wno-binding-in-condition -verify %s |
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| 2 | |
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| 3 | struct X { |
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| 4 | bool flag; |
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| 5 | int data; |
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| 6 | constexpr explicit operator bool() const { |
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| 7 | return flag; |
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| 8 | } |
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| 9 | constexpr operator int() const { |
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| 10 | return data; |
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| 11 | } |
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| 12 | }; |
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| 13 | |
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| 14 | namespace CondInIf { |
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| 15 | constexpr int f(X x) { |
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| 16 | if (auto [ok, d] = x) |
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| 17 | return d + int(ok); |
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| 18 | else |
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| 19 | return d * int(ok); |
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| 20 | ok = {}; // expected-error {{use of undeclared identifier 'ok'}} |
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| 21 | d = {}; // expected-error {{use of undeclared identifier 'd'}} |
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| 22 | } |
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| 23 | |
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| 24 | static_assert(f({true, 2}) == 3); |
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| 25 | static_assert(f({false, 2}) == 0); |
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| 26 | |
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| 27 | constexpr char g(char const (&x)[2]) { |
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| 28 | if (auto &[a, b] = x) |
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| 29 | return a; |
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| 30 | else |
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| 31 | return b; |
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| 32 | |
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| 33 | if (auto [a, b] = x) // expected-error {{an array type is not allowed here}} |
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| 34 | ; |
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| 35 | } |
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| 36 | |
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| 37 | static_assert(g("x") == 'x'); |
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| 38 | } // namespace CondInIf |
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| 39 | |
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| 40 | namespace CondInSwitch { |
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| 41 | constexpr int f(int n) { |
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| 42 | switch (X s = {true, n}; auto [ok, d] = s) { |
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| 43 | s = {}; |
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| 44 | case 0: |
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| 45 | return int(ok); |
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| 46 | case 1: |
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| 47 | return d * 10; |
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| 48 | case 2: |
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| 49 | return d * 40; |
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| 50 | default: |
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| 51 | return 0; |
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| 52 | } |
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| 53 | ok = {}; // expected-error {{use of undeclared identifier 'ok'}} |
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| 54 | d = {}; // expected-error {{use of undeclared identifier 'd'}} |
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| 55 | s = {}; // expected-error {{use of undeclared identifier 's'}} |
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| 56 | } |
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| 57 | |
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| 58 | static_assert(f(0) == 1); |
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| 59 | static_assert(f(1) == 10); |
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| 60 | static_assert(f(2) == 80); |
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| 61 | } // namespace CondInSwitch |
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| 62 | |
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| 63 | namespace CondInWhile { |
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| 64 | constexpr int f(int n) { |
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| 65 | int m = 1; |
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| 66 | while (auto [ok, d] = X{n > 1, n}) { |
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| 67 | m *= d; |
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| 68 | --n; |
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| 69 | } |
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| 70 | return m; |
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| 71 | return ok; // expected-error {{use of undeclared identifier 'ok'}} |
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| 72 | } |
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| 73 | |
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| 74 | static_assert(f(0) == 1); |
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| 75 | static_assert(f(1) == 1); |
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| 76 | static_assert(f(4) == 24); |
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| 77 | } // namespace CondInWhile |
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| 78 | |
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| 79 | namespace CondInFor { |
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| 80 | constexpr int f(int n) { |
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| 81 | int a = 1, b = 1; |
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| 82 | for (X x = {true, n}; auto &[ok, d] = x; --d) { |
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| 83 | if (d < 2) |
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| 84 | ok = false; |
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| 85 | else { |
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| 86 | int x = b; |
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| 87 | b += a; |
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| 88 | a = x; |
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| 89 | } |
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| 90 | } |
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| 91 | return b; |
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| 92 | return d; // expected-error {{use of undeclared identifier 'd'}} |
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| 93 | } |
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| 94 | |
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| 95 | static_assert(f(0) == 1); |
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| 96 | static_assert(f(1) == 1); |
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| 97 | static_assert(f(2) == 2); |
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| 98 | static_assert(f(5) == 8); |
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| 99 | } // namespace CondInFor |
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| 100 | |
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