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PR c++/81933 * typeck2.c (split_nonconstant_init_1): Return false if we didn't split out anything. * g++.dg/cpp1y/constexpr-empty4.C: New test. From-SVN: r256951
52 lines
1.9 KiB
C
52 lines
1.9 KiB
C
// PR c++/81933
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// { dg-do compile { target c++14 } }
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namespace std {
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template <typename _Tp> struct __decay_and_strip { typedef _Tp __type; };
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template <int> struct enable_if { typedef int type; };
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template <typename _Head> struct _Head_base {
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constexpr _Head_base(_Head) {}
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};
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template <unsigned long, typename...> struct _Tuple_impl;
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template <unsigned long _Idx, typename _Head, typename... _Tail>
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struct _Tuple_impl<_Idx, _Head, _Tail...> : _Tuple_impl<1, _Tail...>, // { dg-warning "direct base" }
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_Head_base<_Head> {
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typedef _Tuple_impl<1, _Tail...> _Inherited;
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typedef _Head_base<_Head> _Base;
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constexpr _Tuple_impl(_Head __head, _Tail... __tail)
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: _Inherited(__tail...), _Base(__head) {}
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_Tuple_impl(const _Tuple_impl &) = default;
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_Tuple_impl(_Tuple_impl &&);
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};
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template <unsigned long _Idx, typename _Head>
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struct _Tuple_impl<_Idx, _Head> : _Head_base<_Head> {
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typedef _Head_base<_Head> _Base;
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constexpr _Tuple_impl(_Head __head) : _Base(__head) {}
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};
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template <int> struct _TC {
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static constexpr bool _NotSameTuple() { return true; }
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};
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template <typename... _Elements> class tuple : _Tuple_impl<0, _Elements...> {
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typedef _Tuple_impl<0, _Elements...> _Inherited;
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public:
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template <typename... _UElements,
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enable_if<_TC<1>::_NotSameTuple()>::type = false>
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constexpr tuple(_UElements... __elements) : _Inherited(__elements...) {}
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tuple(const tuple &) = default;
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};
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template <typename... _Elements>
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constexpr tuple<typename __decay_and_strip<_Elements>::__type...>
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make_tuple(_Elements... __args) {
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typedef tuple<typename __decay_and_strip<_Elements>::__type...> __result_type;
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return __result_type(__args...);
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}
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}
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struct any_udt {};
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template <typename... Tuples> constexpr auto flatten(Tuples... tuples) {
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auto all = std::make_tuple(tuples...);
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auto flat(all);
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return flat;
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}
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constexpr auto fail = flatten(any_udt{}, any_udt{});
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