| 1 | // RUN: %clang_cc1 -std=c++1z -verify %s |
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| 2 | |
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| 3 | template<typename T, bool B> using Fn = T () noexcept(B); |
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| 4 | |
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| 5 | // - If the original A is a function pointer type, A can be "pointer to |
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| 6 | // function" even if the deduced A is "pointer to noexcept function". |
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| 7 | struct A { |
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| 8 | template<typename T> operator Fn<T, false>*(); // expected-note {{candidate}} |
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| 9 | }; |
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| 10 | struct B { |
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| 11 | template<typename T> operator Fn<T, true>*(); |
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| 12 | }; |
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| 13 | void (*p1)() = A(); |
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| 14 | void (*p2)() = B(); |
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| 15 | void (*p3)() noexcept = A(); // expected-error {{no viable conversion}} |
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| 16 | void (*p4)() noexcept = B(); |
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| 17 | |
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| 18 | // - If the original A is a pointer to member function type, A can be "pointer |
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| 19 | // to member of type function" even if the deduced A is "pointer to member of |
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| 20 | // type noexcept function". |
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| 21 | struct C { |
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| 22 | template<typename T> operator Fn<T, false> A::*(); // expected-note {{candidate}} |
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| 23 | }; |
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| 24 | struct D { |
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| 25 | template<typename T> operator Fn<T, true> A::*(); |
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| 26 | }; |
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| 27 | void (A::*q1)() = C(); |
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| 28 | void (A::*q2)() = D(); |
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| 29 | void (A::*q3)() noexcept = C(); // expected-error {{no viable conversion}} |
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| 30 | void (A::*q4)() noexcept = D(); |
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| 31 | |
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| 32 | // There is no corresponding rule for references. |
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| 33 | // FIXME: This seems like a defect. |
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| 34 | // FIXME: We don't actually implement the final check for equal types at all! |
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| 35 | // Instead, we handle the matching via [over.ics.user]p3: |
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| 36 | // "If the user-defined conversion is specified by a specialization of a |
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| 37 | // conversion function template, the second standard conversion sequence |
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| 38 | // shall have exact match rank." |
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| 39 | // Note that this *does* allow discarding noexcept, since that conversion has |
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| 40 | // Exact Match rank. |
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| 41 | struct E { |
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| 42 | template<typename T> operator Fn<T, false>&(); // expected-note {{candidate}} |
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| 43 | }; |
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| 44 | struct F { |
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| 45 | template<typename T> operator Fn<T, true>&(); |
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| 46 | }; |
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| 47 | void (&r1)() = E(); |
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| 48 | void (&r2)() = F(); |
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| 49 | void (&r3)() noexcept = E(); // expected-error {{no viable conversion}} |
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| 50 | void (&r4)() noexcept = F(); |
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| 51 | |
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| 52 | // FIXME: We reject this for entirely the wrong reason. We incorrectly succeed |
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| 53 | // in deducing T = void, U = G::B, and only fail due to [over.ics.user]p3. |
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| 54 | struct G { |
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| 55 | template<typename, typename> struct A {}; |
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| 56 | template<typename U> struct A<U, int> : A<U, void> {}; |
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| 57 | struct B { typedef int type; }; |
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| 58 | |
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| 59 | template<typename T, typename U = B> operator A<T, typename U::type> *(); // expected-note {{candidate function [with T = void, U = G::B]}} |
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| 60 | }; |
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| 61 | G::A<void, void> *g = G(); // expected-error {{no viable conversion}} |
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| 62 | |
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