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<base href="http://llvm.org/bugs/" />
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<body><table border="1" cellspacing="0" cellpadding="8">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Unrecognized indirect pack expansion when accessing value member"
href="http://llvm.org/bugs/show_bug.cgi?id=21289">21289</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Unrecognized indirect pack expansion when accessing value member
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>3.4
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>C++11
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>juchem@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>dgregor@apple.com, llvmbugs@cs.uiuc.edu
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>The parameter packs in the code below are not recognized as unexpanded:
constant<size_type, 0>::type<Args>::value...
zero<Args>::value...
Tested in clang 3.4.1 from <a href="http://gcc.godbolt.org/">http://gcc.godbolt.org/</a> using -std=c++11:
<a href="http://goo.gl/R1soR4">http://goo.gl/R1soR4</a>
It works in gcc 4.7 and up with -std=c++0x/-std=c++11.
-----------
#include <iostream>
#include <tuple>
#include <type_traits>
#include <utility>
template <typename T>
struct fixed {
template <typename> using type = T;
};
template <typename T>
struct fixed2 {
template <typename>
struct with {
using type = T;
};
};
template<typename T, T Value>
struct constant {
template <typename>
using type = std::integral_constant<T, Value>;
};
using size_type = std::size_t;
template <typename>
using zero = std::integral_constant<size_type, 0>;
template <typename... Args>
bool foo() {
using tuple = std::tuple<fixed<size_type>::type<Args>..., size_type>;
tuple t(constant<size_type, 0>::type<Args>::value..., 0);
return (&t == (tuple*)1);
}
template <typename... Args>
bool bar() {
using tuple = std::tuple<fixed<size_type>::type<Args>..., size_type>;
tuple t(zero<Args>::value..., 0);
return (&t == (tuple*)1);
}
template <typename... Args>
bool baz() {
using tuple = std::tuple<typename fixed2<size_type>::template
with<Args>::type..., size_type>;
tuple t(constant<size_type, 0>::type<Args>::value..., 0);
return (&t == (tuple*)1);
}
int main() {
std::cout << foo() << std::endl;
std::cout << foo<int, bool, double>() << std::endl;
std::cout << bar() << std::endl;
std::cout << bar<int, bool, double>() << std::endl;
std::cout << baz() << std::endl;
std::cout << baz<int, bool, double>() << std::endl;
};</pre>
</div>
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