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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Move from destroyed object in tuple_cat of nested tuples"
href="http://llvm.org/bugs/show_bug.cgi?id=22806">22806</a>
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<th>Summary</th>
<td>Move from destroyed object in tuple_cat of nested tuples
</td>
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<th>Product</th>
<td>libc++
</td>
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<th>Version</th>
<td>3.6
</td>
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<th>Hardware</th>
<td>Macintosh
</td>
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<th>OS</th>
<td>MacOS X
</td>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>normal
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>All Bugs
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>ldionne.2@gmail.com
</td>
</tr>
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<th>CC</th>
<td>llvmbugs@cs.uiuc.edu, mclow.lists@gmail.com
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<th>Classification</th>
<td>Unclassified
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<p>
<div>
<pre>This bug concerns libc++ trunk (git-svn ID 230867).
In the following code, `Tracked{}` is destroyed and is then moved-from.
std::tuple_cat(std::make_tuple(std::make_tuple(Tracked{})));
Here's a self-contained test program:
#include <cassert>
#include <tuple>
struct Tracked {
enum class State { CONSTRUCTED, MOVED_FROM, DESTROYED };
State state;
Tracked() : state{State::CONSTRUCTED} { }
Tracked(Tracked const& t) : state{State::CONSTRUCTED} {
assert(t.state != State::MOVED_FROM && "copying a moved-from
object");
assert(t.state != State::DESTROYED && "copying a destroyed
object");
}
Tracked(Tracked&& t) : state{State::CONSTRUCTED} {
assert(t.state != State::MOVED_FROM && "double moving from an
object");
assert(t.state != State::DESTROYED && "moving from a destroyed
object");
t.state = State::MOVED_FROM;
}
~Tracked() {
assert(state != State::DESTROYED && "double-destroying an object");
state = State::DESTROYED;
}
};
int main() {
std::tuple_cat(std::make_tuple(std::make_tuple(Tracked{})));
}
Compiling and then running this will produce:
Assertion failed: (t.state != State::DESTROYED && "moving from a destroyed
object")
I don't have the time to investigate this further right now, unfortunately.</pre>
</div>
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