| 1 | // RUN: %clang_cc1 -verify -std=c++1z %s |
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| 2 | |
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| 3 | namespace Explicit { |
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| 4 | // Each notional constructor is explicit if the function or function template |
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| 5 | // was generated from a constructor or deduction-guide that was declared explicit. |
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| 6 | template<typename T> struct A { |
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| 7 | A(T); |
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| 8 | A(T*); |
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| 9 | A(...); |
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| 10 | }; |
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| 11 | template<typename T> A(T) -> A<T>; |
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| 12 | template<typename T> explicit A(T*) -> A<T**>; // expected-note {{explicit}} |
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| 13 | |
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| 14 | int *p; |
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| 15 | A a(p); |
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| 16 | A b = p; |
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| 17 | A c{p}; |
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| 18 | A d = {p}; // expected-error {{selected an explicit deduction guide}} |
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| 19 | |
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| 20 | using X = A<int**>; |
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| 21 | using Y = A<int>; // uses the implicit guide, being more specialized than the eligible user-defined deduction guides. |
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| 22 | |
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| 23 | using X = decltype(a); |
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| 24 | using Y = decltype(b); |
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| 25 | using X = decltype(c); |
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| 26 | } |
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| 27 | |
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| 28 | |
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| 29 | namespace std { |
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| 30 | template<typename T> struct initializer_list { |
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| 31 | const T *ptr; |
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| 32 | __SIZE_TYPE__ size; |
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| 33 | initializer_list(); |
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| 34 | }; |
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| 35 | } |
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| 36 | |
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| 37 | namespace p0702r1 { |
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| 38 | template<typename T> struct X { // expected-note {{candidate}} |
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| 39 | X(std::initializer_list<T>); // expected-note {{candidate}} |
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| 40 | }; |
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| 41 | |
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| 42 | X xi = {0}; |
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| 43 | X xxi = {xi}; |
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| 44 | extern X<int> xi; |
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| 45 | // Prior to P0702R1, this is X<X<int>>. |
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| 46 | extern X<int> xxi; |
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| 47 | |
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| 48 | struct Y : X<int> {}; |
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| 49 | Y y {{0}}; |
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| 50 | X xy {y}; |
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| 51 | extern X<int> xy; |
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| 52 | |
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| 53 | struct Z : X<int>, X<float> {}; |
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| 54 | Z z = {{0}, {0.0f}}; |
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| 55 | // This is not X<Z> even though that would work. Instead, it's ambiguous |
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| 56 | // between X<int> and X<float>. |
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| 57 | X xz = {z}; // expected-error {{no viable constructor or deduction guide}} |
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| 58 | } |
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| 59 | namespace pr34970 { |
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| 60 | //https://bugs.llvm.org/show_bug.cgi?id=34970 |
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| 61 | |
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| 62 | template <typename X, typename Y> struct IsSame { |
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| 63 | static constexpr bool value = false; |
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| 64 | }; |
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| 65 | |
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| 66 | template <typename Z> struct IsSame<Z, Z> { |
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| 67 | static constexpr bool value = true; |
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| 68 | }; |
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| 69 | |
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| 70 | template <typename T> struct Optional { |
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| 71 | template <typename U> Optional(U&&) { } |
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| 72 | }; |
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| 73 | |
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| 74 | template <typename A> Optional(A) -> Optional<A>; |
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| 75 | |
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| 76 | int main() { |
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| 77 | Optional opt(1729); |
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| 78 | Optional dupe(opt); |
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| 79 | |
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| 80 | static_assert(IsSame<decltype(opt), Optional<int>>::value); |
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| 81 | static_assert(IsSame<decltype(dupe), Optional<int>>::value); |
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| 82 | static_assert(!IsSame<decltype(dupe), Optional<Optional<int>>>::value); |
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| 83 | return 0; |
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| 84 | } |
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| 85 | |
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| 86 | |
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| 87 | } |
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