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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Clang++ selects wrong constructor in return statement (lvalue instead of rvalue)"
href="https://llvm.org/bugs/show_bug.cgi?id=28096">28096</a>
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<th>Summary</th>
<td>Clang++ selects wrong constructor in return statement (lvalue instead of rvalue)
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
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<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>All
</td>
</tr>
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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>
</tr>
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<th>Component</th>
<td>C++
</td>
</tr>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>stefan.walk+llvm@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>dgregor@apple.com, llvm-bugs@lists.llvm.org
</td>
</tr>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Repro case below - if I read <a href="http://eel.is/c++draft/class.copy#32">http://eel.is/c++draft/class.copy#32</a> correctly the
rvalue overload should be selected, but clang++ selects the lvalue one and
errors out. This is for example annoying when trying to return a local
unique_ptr to a derived class as a unique_ptr to the base class. G++ accepts
the code.
struct A {};
struct B {};
template <typename T>
struct X
{
X() = default;
template <typename bar>
X(X<bar> const&) = delete;
template <typename bar>
X(X<bar>&&) {}
};
X<A> f()
{
X<B> x;
return x;
}</pre>
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