[multiple changes]
2011-04-30 Daniel Krugler <daniel.kruegler@googlemail.com> * include/std/type_traits (__is_default_constructible_atom, __is_default_constructible_safe<, true>, __is_direct_constructible_new_safe, __is_base_to_derived_ref<,, true>, __is_lvalue_to_rvalue_ref<,, true>, __is_direct_constructible_ref_cast, __is_direct_constructible, __is_nary_constructible): Simplify; add comments throughout. 2011-04-30 Paolo Carlini <paolo.carlini@oracle.com> * testsuite/20_util/make_signed/requirements/typedefs_neg.cc: Adjust dg-error line numbers. * testsuite/20_util/make_unsigned/requirements/typedefs_neg.cc: Likewise. * testsuite/20_util/declval/requirements/1_neg.cc: Likewise. From-SVN: r173222
This commit is contained in:
Paolo Carlini
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2ad7ae18f4
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2c7a09d774
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@ -1,3 +1,20 @@
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2011-04-30 Daniel Krugler <daniel.kruegler@googlemail.com>
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* include/std/type_traits (__is_default_constructible_atom,
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__is_default_constructible_safe<, true>,
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__is_direct_constructible_new_safe,
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__is_base_to_derived_ref<,, true>, __is_lvalue_to_rvalue_ref<,, true>,
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__is_direct_constructible_ref_cast, __is_direct_constructible,
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__is_nary_constructible): Simplify; add comments throughout.
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2011-04-30 Paolo Carlini <paolo.carlini@oracle.com>
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* testsuite/20_util/make_signed/requirements/typedefs_neg.cc:
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Adjust dg-error line numbers.
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* testsuite/20_util/make_unsigned/requirements/typedefs_neg.cc:
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Likewise.
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* testsuite/20_util/declval/requirements/1_neg.cc: Likewise.
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2011-04-30 Doug Kwan <dougkwan@google.com>
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* include/Makefile.am (install-freestanding-headers): Also install
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@ -550,7 +550,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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struct __is_array_unknown_bounds
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: public __and_<is_array<_Tp>, __not_<extent<_Tp>>>::type
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{ };
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// In N3290 is_destructible does not say anything about function
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// types and abstract types, see LWG 2049. This implementation
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// describes function types as trivially nothrow destructible and
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// abstract types as destructible, iff the explicit destructor
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// call expression is wellformed.
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struct __do_is_destructible_impl_1
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{
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template<typename _Up>
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@ -571,6 +576,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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typedef decltype(__test<_Tp>(0)) type;
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};
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// Special implementation for abstract types
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struct __do_is_destructible_impl_2
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{
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template<typename _Tp, typename = decltype(declval<_Tp&>().~_Tp())>
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@ -632,23 +638,23 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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template<typename _Tp>
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struct __is_default_constructible_atom
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: public __and_<is_destructible<_Tp>,
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__is_default_constructible_impl<_Tp>>::type::type
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: public __and_<__not_<is_void<_Tp>>,
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__is_default_constructible_impl<_Tp>>::type
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{ };
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template<typename _Tp, bool = is_array<_Tp>::value>
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struct __is_default_constructible_safe;
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// The following technique is a workaround for a gcc defect, which does
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// not sfinae away attempts to default-construct arrays of unknown bounds.
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// Complete arrays can be default-constructed, if the element type is
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// default-constructible, but arrays with unknown bounds are not:
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// The following technique is a workaround for a current core language
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// restriction, which does not allow for array types to occur in
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// functional casts of the form T(). Complete arrays can be default-
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// constructed, if the element type is default-constructible, but
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// arrays with unknown bounds are not.
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template<typename _Tp>
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struct __is_default_constructible_safe<_Tp, true>
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: public __and_<__is_array_known_bounds<_Tp>,
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__is_default_constructible_atom<typename
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remove_all_extents<_Tp>::type>>::type::type
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remove_all_extents<_Tp>::type>>::type
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{ };
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template<typename _Tp>
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@ -663,6 +669,18 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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_Tp>::value)>
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{ };
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// Implementation of is_constructible.
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// The hardest part of this trait is the binary direct-initialization
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// case, because we hit into a functional cast of the form T(arg).
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// This implementation uses different strategies depending on the
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// target type to reduce the test overhead as much as possible:
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//
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// a) For a reference target type, we use a static_cast expression
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// modulo its extra cases.
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//
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// b) For a non-reference target type we use a ::new expression.
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struct __do_is_static_castable_impl
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{
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template<typename _From, typename _To, typename
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@ -682,8 +700,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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template<typename _From, typename _To>
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struct __is_static_castable_safe
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: public __and_<__or_<is_void<_To>, is_destructible<_To>>,
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__is_static_castable_impl<_From, _To>>::type::type
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: public __is_static_castable_impl<_From, _To>::type
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{ };
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// __is_static_castable
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@ -693,6 +710,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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_From, _To>::value)>
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{ };
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// Implementation for non-reference types. To meet the proper
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// variable definition semantics, we also need to test for
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// is_destructible in this case.
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struct __do_is_direct_constructible_impl
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{
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template<typename _Tp, typename _Arg, typename
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@ -713,7 +733,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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template<typename _Tp, typename _Arg>
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struct __is_direct_constructible_new_safe
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: public __and_<is_destructible<_Tp>,
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__is_direct_constructible_impl<_Tp, _Arg>>::type::type
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__is_direct_constructible_impl<_Tp, _Arg>>::type
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{ };
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template<typename, typename>
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@ -736,10 +756,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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>::type>::type __src_t;
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typedef typename remove_cv<typename remove_reference<_To
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>::type>::type __dst_t;
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typedef typename __and_<
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__not_<is_same<__src_t, __dst_t>>,
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is_base_of<__src_t, __dst_t>
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>::type type;
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typedef __and_<__not_<is_same<__src_t, __dst_t>>,
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is_base_of<__src_t, __dst_t>> type;
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static constexpr bool value = type::value;
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};
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@ -760,10 +778,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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_From>::type>::type __src_t;
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typedef typename remove_cv<typename remove_reference<
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_To>::type>::type __dst_t;
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typedef typename __or_<
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is_same<__src_t, __dst_t>,
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is_base_of<__dst_t, __src_t>
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>::type type;
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typedef __or_<is_same<__src_t, __dst_t>,
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is_base_of<__dst_t, __src_t>> type;
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static constexpr bool value = type::value;
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};
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@ -772,25 +788,20 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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: public false_type
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{ };
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// Here we handle direct-initialization to a reference type
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// as equivalent to a static_cast modulo overshooting conversions.
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// These are restricted to the following conversion:
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// a) A base class to a derived class reference
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// b) An lvalue-reference to an rvalue-reference
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// Here we handle direct-initialization to a reference type as
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// equivalent to a static_cast modulo overshooting conversions.
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// These are restricted to the following conversions:
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// a) A glvalue of a base class to a derived class reference
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// b) An lvalue to an rvalue-reference of reference-compatible
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// types
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template<typename _Tp, typename _Arg>
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struct __is_direct_constructible_ref_cast
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: public __and_<__is_static_castable<_Arg, _Tp>,
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__not_<__or_<__is_base_to_derived_ref<_Arg, _Tp>,
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__is_lvalue_to_rvalue_ref<_Arg, _Tp>
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>>>::type::type
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>>>::type
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{ };
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// Direct-initialization is tricky, because of functional
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// casts: For a conversion to reference we fall back to a
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// static_cast modulo extra cases, otherwise we use a
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// new expression:
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template<typename _Tp, typename _Arg>
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struct __is_direct_constructible_new
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: public conditional<is_reference<_Tp>::value,
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@ -802,9 +813,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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template<typename _Tp, typename _Arg>
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struct __is_direct_constructible
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: public integral_constant<bool, (__is_direct_constructible_new<
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_Tp, _Arg>::type::value)>
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_Tp, _Arg>::value)>
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{ };
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// Since default-construction and binary direct-initialization have
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// been handled separately, the implementation of the remaining
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// n-ary construction cases is rather straightforward.
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struct __do_is_nary_constructible_impl
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{
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template<typename _Tp, typename... _Args, typename
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@ -824,9 +838,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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template<typename _Tp, typename... _Args>
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struct __is_nary_constructible
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: public __and_<is_destructible<_Tp>,
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__is_nary_constructible_impl<_Tp, _Args...>
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>::type::type
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: public __is_nary_constructible_impl<_Tp, _Args...>::type
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{
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static_assert(sizeof...(_Args) > 1,
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"Only useful for > 1 arguments");
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@ -19,7 +19,7 @@
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// with this library; see the file COPYING3. If not see
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// <http://www.gnu.org/licenses/>.
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// { dg-error "static assertion failed" "" { target *-*-* } 1603 }
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// { dg-error "static assertion failed" "" { target *-*-* } 1615 }
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#include <utility>
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@ -48,5 +48,5 @@ void test01()
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// { dg-error "instantiated from here" "" { target *-*-* } 40 }
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// { dg-error "instantiated from here" "" { target *-*-* } 42 }
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// { dg-error "invalid use of incomplete type" "" { target *-*-* } 1389 }
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// { dg-error "declaration of" "" { target *-*-* } 1353 }
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// { dg-error "invalid use of incomplete type" "" { target *-*-* } 1401 }
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// { dg-error "declaration of" "" { target *-*-* } 1365 }
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@ -48,5 +48,5 @@ void test01()
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// { dg-error "instantiated from here" "" { target *-*-* } 40 }
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// { dg-error "instantiated from here" "" { target *-*-* } 42 }
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// { dg-error "invalid use of incomplete type" "" { target *-*-* } 1313 }
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// { dg-error "declaration of" "" { target *-*-* } 1277 }
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// { dg-error "invalid use of incomplete type" "" { target *-*-* } 1325 }
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// { dg-error "declaration of" "" { target *-*-* } 1289 }
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