| 1 | // RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify %s |
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| 2 | // expected-no-diagnostics |
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| 3 | |
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| 4 | // Metafunction to extract the Nth type from a set of types. |
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| 5 | template<unsigned N, typename ...Types> struct get_nth_type; |
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| 6 | |
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| 7 | template<unsigned N, typename Head, typename ...Tail> |
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| 8 | struct get_nth_type<N, Head, Tail...> : get_nth_type<N-1, Tail...> { }; |
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| 9 | |
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| 10 | template<typename Head, typename ...Tail> |
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| 11 | struct get_nth_type<0, Head, Tail...> { |
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| 12 | typedef Head type; |
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| 13 | }; |
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| 14 | |
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| 15 | // Placeholder type when get_nth_type fails. |
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| 16 | struct no_type {}; |
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| 17 | |
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| 18 | template<unsigned N> |
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| 19 | struct get_nth_type<N> { |
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| 20 | typedef no_type type; |
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| 21 | }; |
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| 22 | |
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| 23 | template<typename ...Args> |
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| 24 | typename get_nth_type<0, Args...>::type first_arg(Args...); |
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| 25 | |
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| 26 | template<typename ...Args> |
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| 27 | typename get_nth_type<1, Args...>::type second_arg(Args...); |
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| 28 | |
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| 29 | // Test explicit specification of function template arguments. |
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| 30 | void test_explicit_spec_simple() { |
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| 31 | int *ip1 = first_arg<int *>(0); |
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| 32 | int *ip2 = first_arg<int *, float*>(0, 0); |
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| 33 | float *fp1 = first_arg<float *, double*, int*>(0, 0, 0); |
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| 34 | } |
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| 35 | |
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| 36 | // Template argument deduction can extend the sequence of template |
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| 37 | // arguments corresponding to a template parameter pack, even when the |
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| 38 | // sequence contains explicitly specified template arguments. |
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| 39 | void test_explicit_spec_extension(double *dp) { |
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| 40 | int *ip1 = first_arg<int *>(0, 0); |
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| 41 | int *ip2 = first_arg<int *, float*>(0, 0, 0, 0); |
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| 42 | float *fp1 = first_arg<float *, double*, int*>(0, 0, 0); |
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| 43 | int *i1 = second_arg<float *>(0, (int*)0, 0); |
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| 44 | double *dp1 = first_arg<>(dp); |
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| 45 | } |
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| 46 | |
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| 47 | template<typename ...Types> |
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| 48 | struct tuple { }; |
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| 49 | |
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| 50 | template<typename ...Types> |
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| 51 | void accept_tuple(tuple<Types...>); |
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| 52 | |
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| 53 | void test_explicit_spec_extension_targs(tuple<int, float, double> t3) { |
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| 54 | accept_tuple(t3); |
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| 55 | accept_tuple<int, float, double>(t3); |
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| 56 | accept_tuple<int>(t3); |
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| 57 | accept_tuple<int, float>(t3); |
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| 58 | } |
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| 59 | |
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| 60 | template<typename R, typename ...ParmTypes> |
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| 61 | void accept_function_ptr(R(*)(ParmTypes...)); |
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| 62 | |
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| 63 | void test_explicit_spec_extension_funcparms(int (*f3)(int, float, double)) { |
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| 64 | accept_function_ptr(f3); |
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| 65 | accept_function_ptr<int>(f3); |
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| 66 | accept_function_ptr<int, int>(f3); |
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| 67 | accept_function_ptr<int, int, float>(f3); |
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| 68 | accept_function_ptr<int, int, float, double>(f3); |
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| 69 | } |
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| 70 | |
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