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Fix PR39619 - iterator_traits isn't SFINAE-friendly enough. Thanks to Eric for the report

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git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@346738 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Marshall Clow
2018-11-13 05:33:31 +00:00
parent 94664a1ad8
commit 3870a97d86
3 changed files with 141 additions and 1 deletions
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19
include/iterator
View File

@@ -437,6 +437,23 @@ struct _LIBCPP_TEMPLATE_VIS forward_iterator_tag : public input_iterator_t
struct _LIBCPP_TEMPLATE_VIS bidirectional_iterator_tag : public forward_iterator_tag {};
struct _LIBCPP_TEMPLATE_VIS random_access_iterator_tag : public bidirectional_iterator_tag {};
template <class _Tp>
struct __has_iterator_typedefs
{
private:
struct __two {char __lx; char __lxx;};
template <class _Up> static __two __test(...);
template <class _Up> static char __test(typename std::__void_t<typename _Up::iterator_category>::type* = 0,
typename std::__void_t<typename _Up::difference_type>::type* = 0,
typename std::__void_t<typename _Up::value_type>::type* = 0,
typename std::__void_t<typename _Up::reference>::type* = 0,
typename std::__void_t<typename _Up::pointer>::type* = 0
);
public:
static const bool value = sizeof(__test<_Tp>(0,0,0,0,0)) == 1;
};
template <class _Tp>
struct __has_iterator_category
{
@@ -479,7 +496,7 @@ struct __iterator_traits<_Iter, true>
template <class _Iter>
struct _LIBCPP_TEMPLATE_VIS iterator_traits
: __iterator_traits<_Iter, __has_iterator_category<_Iter>::value> {};
: __iterator_traits<_Iter, __has_iterator_typedefs<_Iter>::value> {};
template<class _Tp>
struct _LIBCPP_TEMPLATE_VIS iterator_traits<_Tp*>

122
test/std/iterators/iterator.primitives/iterator.traits/empty.fail.cpp Normal file
View File

@@ -0,0 +1,122 @@
//===----------------------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// <iterator>
// struct iterator_traits
// {
// };
#include <iterator>
#include "test_macros.h"
struct A {};
struct NotAnIteratorEmpty {};
struct NotAnIteratorNoDifference
{
// typedef int difference_type;
typedef A value_type;
typedef A* pointer;
typedef A& reference;
typedef std::forward_iterator_tag iterator_category;
};
struct NotAnIteratorNoValue
{
typedef int difference_type;
// typedef A value_type;
typedef A* pointer;
typedef A& reference;
typedef std::forward_iterator_tag iterator_category;
};
struct NotAnIteratorNoPointer
{
typedef int difference_type;
typedef A value_type;
// typedef A* pointer;
typedef A& reference;
typedef std::forward_iterator_tag iterator_category;
};
struct NotAnIteratorNoReference
{
typedef int difference_type;
typedef A value_type;
typedef A* pointer;
// typedef A& reference;
typedef std::forward_iterator_tag iterator_category;
};
struct NotAnIteratorNoCategory
{
typedef int difference_type;
typedef A value_type;
typedef A* pointer;
typedef A& reference;
// typedef std::forward_iterator_tag iterator_category;
};
int main()
{
{
typedef std::iterator_traits<NotAnIteratorEmpty> T;
typedef T::difference_type DT; // expected-error-re {{no type named 'difference_type' in 'std::__1::iterator_traits<{{.+}}>}}
typedef T::value_type VT; // expected-error-re {{no type named 'value_type' in 'std::__1::iterator_traits<{{.+}}>}}
typedef T::pointer PT; // expected-error-re {{no type named 'pointer' in 'std::__1::iterator_traits<{{.+}}>}}
typedef T::reference RT; // expected-error-re {{no type named 'reference' in 'std::__1::iterator_traits<{{.+}}>}}
typedef T::iterator_category CT; // expected-error-re {{no type named 'iterator_category' in 'std::__1::iterator_traits<{{.+}}>}}
}
{
typedef std::iterator_traits<NotAnIteratorNoDifference> T;
typedef T::difference_type DT; // expected-error-re {{no type named 'difference_type' in 'std::__1::iterator_traits<{{.+}}>}}
typedef T::value_type VT; // expected-error-re {{no type named 'value_type' in 'std::__1::iterator_traits<{{.+}}>}}
typedef T::pointer PT; // expected-error-re {{no type named 'pointer' in 'std::__1::iterator_traits<{{.+}}>}}
typedef T::reference RT; // expected-error-re {{no type named 'reference' in 'std::__1::iterator_traits<{{.+}}>}}
typedef T::iterator_category CT; // expected-error-re {{no type named 'iterator_category' in 'std::__1::iterator_traits<{{.+}}>}}
}
{
typedef std::iterator_traits<NotAnIteratorNoValue> T;
typedef T::difference_type DT; // expected-error-re {{no type named 'difference_type' in 'std::__1::iterator_traits<{{.+}}>}}
typedef T::value_type VT; // expected-error-re {{no type named 'value_type' in 'std::__1::iterator_traits<{{.+}}>}}
typedef T::pointer PT; // expected-error-re {{no type named 'pointer' in 'std::__1::iterator_traits<{{.+}}>}}
typedef T::reference RT; // expected-error-re {{no type named 'reference' in 'std::__1::iterator_traits<{{.+}}>}}
typedef T::iterator_category CT; // expected-error-re {{no type named 'iterator_category' in 'std::__1::iterator_traits<{{.+}}>}}
}
{
typedef std::iterator_traits<NotAnIteratorNoPointer> T;
typedef T::difference_type DT; // expected-error-re {{no type named 'difference_type' in 'std::__1::iterator_traits<{{.+}}>}}
typedef T::value_type VT; // expected-error-re {{no type named 'value_type' in 'std::__1::iterator_traits<{{.+}}>}}
typedef T::pointer PT; // expected-error-re {{no type named 'pointer' in 'std::__1::iterator_traits<{{.+}}>}}
typedef T::reference RT; // expected-error-re {{no type named 'reference' in 'std::__1::iterator_traits<{{.+}}>}}
typedef T::iterator_category CT; // expected-error-re {{no type named 'iterator_category' in 'std::__1::iterator_traits<{{.+}}>}}
}
{
typedef std::iterator_traits<NotAnIteratorNoReference> T;
typedef T::difference_type DT; // expected-error-re {{no type named 'difference_type' in 'std::__1::iterator_traits<{{.+}}>}}
typedef T::value_type VT; // expected-error-re {{no type named 'value_type' in 'std::__1::iterator_traits<{{.+}}>}}
typedef T::pointer PT; // expected-error-re {{no type named 'pointer' in 'std::__1::iterator_traits<{{.+}}>}}
typedef T::reference RT; // expected-error-re {{no type named 'reference' in 'std::__1::iterator_traits<{{.+}}>}}
typedef T::iterator_category CT; // expected-error-re {{no type named 'iterator_category' in 'std::__1::iterator_traits<{{.+}}>}}
}
{
typedef std::iterator_traits<NotAnIteratorNoCategory> T;
typedef T::difference_type DT; // expected-error-re {{no type named 'difference_type' in 'std::__1::iterator_traits<{{.+}}>}}
typedef T::value_type VT; // expected-error-re {{no type named 'value_type' in 'std::__1::iterator_traits<{{.+}}>}}
typedef T::pointer PT; // expected-error-re {{no type named 'pointer' in 'std::__1::iterator_traits<{{.+}}>}}
typedef T::reference RT; // expected-error-re {{no type named 'reference' in 'std::__1::iterator_traits<{{.+}}>}}
typedef T::iterator_category CT; // expected-error-re {{no type named 'iterator_category' in 'std::__1::iterator_traits<{{.+}}>}}
}
}

1
test/std/iterators/iterator.primitives/iterator.traits/iterator.pass.cpp
View File

@@ -39,5 +39,6 @@ int main()
static_assert((std::is_same<It::difference_type, int>::value), "");
static_assert((std::is_same<It::value_type, A>::value), "");
static_assert((std::is_same<It::pointer, A*>::value), "");
static_assert((std::is_same<It::reference, A&>::value), "");
static_assert((std::is_same<It::iterator_category, std::forward_iterator_tag>::value), "");
}