http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56319
Bug #: 56319
Summary: call to implicitly-deleted copy constructor accepted
Classification: Unclassified
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: major
Priority: P3
Component: c++
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: wlodzimierz.lip...@gmail.com
Hi,
GCC compiles following code. Copying of tuple of rvalues returned by:
std::forward_as_tuple, should not be allowed because it is ill formed.
(clang++ properly detects the problem and report an error.)
/*----------------------------------------------------------------------------*/
template <unsigned int ...>
struct TupleIndices
{};
template<
unsigned int I,
typename IndexTuple,
typename... Types>
struct MakeTupleIndices_;
template<
unsigned int I,
unsigned int... Indices,
typename T,
typename... Types>
struct MakeTupleIndices_<I, TupleIndices<Indices...>, T, Types...>
{
typedef typename MakeTupleIndices_<I + 1, TupleIndices<Indices..., I>,
Types...>::type type;
};
template<
unsigned int I,
unsigned int... Indices>
struct MakeTupleIndices_<I, TupleIndices<Indices...> >
{
typedef TupleIndices<Indices...> type;
};
template<typename... Types>
struct MakeTupleIndices : public MakeTupleIndices_<0, TupleIndices<>, Types...>
{};
/*----------------------------------------------------------------------------*/
void bar(int)
{
}
template <typename... Args, unsigned int... ArgsIndices>
void fooImpl(std::tuple<Args...> args, TupleIndices<ArgsIndices...>)
{
bar(std::forward<Args>(std::get<ArgsIndices>(args))...);
}
template <typename... Args>
void foo(std::tuple<Args...> args)
{
fooImpl(args, typename MakeTupleIndices<Args...>::type());
}
/*----------------------------------------------------------------------------*/
enum
{
id = 1
};
int main()
{
foo(std::forward_as_tuple(id));
return 0;
}
/*----------------------------------------------------------------------------*/
Wlodzimierz.
