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<base href="http://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Deduction for reference conversion template discards cv-qualifiers"
href="http://llvm.org/bugs/show_bug.cgi?id=20783">20783</a>
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<th>Summary</th>
<td>Deduction for reference conversion template discards cv-qualifiers
</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>All
</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>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>C++11
</td>
</tr>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>hstong@ca.ibm.com
</td>
</tr>
<tr>
<th>CC</th>
<td>dgregor@apple.com, llvmbugs@cs.uiuc.edu
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Template argument deduction for reference conversions do not deduce the correct
type with respect to cv-qualifiers of the deduced A.
See N3290 subclause 14.8.2.3 [temp.deduct.conv]; the P/A pair used for type
deduction in the case below would be T/const int.
Deduction should succeed with T = const int.
As the error message shows, the deduction produced "int" instead of "const
int".
### SOURCE:
$ cat deduceTemplateConv.cc
struct A {
template <typename T> operator T&() { static_assert(sizeof(T) == 0, ""); }
};
template <> A::operator const int &(void);
const int &x = A();
### COMPILER INVOCATION AND OUTPUT:
$ clang -x c++ -std=c++11 deduceTemplateConv.cc
deduceTemplateConv.cc:2:41: error: static_assert failed ""
template <typename T> operator T&() { static_assert(sizeof(T) == 0, ""); }
^ ~~~~~~~~~~~~~~
deduceTemplateConv.cc:6:16: note: in instantiation of function template
specialization 'A::operator int &<int>' requested here
const int &x = A();
^
1 error generated.
### EXPECTED OUTPUT:
Successful compile.
### COMPILER VERSION INFO:
$ clang++ -v
clang version 3.6.0 (trunk 215824)
Target: x86_64-unknown-linux-gnu
Thread model: posix
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8.2
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9.0
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8
Candidate multilib: .;@m64
Selected multilib: .;@m64</pre>
</div>
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