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<base href="https://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW " title="NEW --- - user-defined conversion function allows cast to reference" href="https://urldefense.proofpoint.com/v2/url?u=https-3A__llvm.org_bugs_show-5Fbug.cgi-3Fid-3D24131&d=AwMBaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=pF93YEPyB-J_PERP4DUZOJDzFVX5ZQ57vQk33wu0vio&m=H7B6Y6JZw7AjaaVpA9CC5aTGzft9HH6Fal6mHXDaY84&s=ZRvQmCF1VzHqK6Ggb6XYBv3Ojiem9no5B7w2bgsAIFk&e=">24131</a>
</td>
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<th>Summary</th>
<td>user-defined conversion function allows cast to reference
</td>
</tr>
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<th>Product</th>
<td>clang
</td>
</tr>
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<th>Version</th>
<td>3.6
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
</td>
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<th>Status</th>
<td>NEW
</td>
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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>C++11
</td>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
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<th>Reporter</th>
<td>barry.revzin@gmail.com
</td>
</tr>
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<th>CC</th>
<td>dgregor@apple.com, llvmbugs@cs.uiuc.edu
</td>
</tr>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Consider the following code, slightly simplified from SO question
(<a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__stackoverflow.com_q_31428980_2069064&d=AwMBaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=pF93YEPyB-J_PERP4DUZOJDzFVX5ZQ57vQk33wu0vio&m=H7B6Y6JZw7AjaaVpA9CC5aTGzft9HH6Fal6mHXDaY84&s=LoOlQPuhrmV5FcLNz21qe33LS6svR4_-NmuFhVp8i9M&e=">http://stackoverflow.com/q/31428980/2069064</a>):
#include <string>
struct S
{
std::string s;
explicit operator std::string() const { return s; }
};
int main()
{
static_cast<std::string const&>(S{"hi"});
}
According to [over.match.conv], the candidate conversion functions are those
that "yield type T or a type that can be converted to type T via a standard
conversion sequence." But S does not have a conversion function that yields
std::string const& and the conversion from std::string to std::string const& is
not a standard conversion sequence. This code should be rejected (which gcc
does).</pre>
</div>
</p>
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