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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 --- - "type name does not allow constexpr specifier to be specified" using constexpr in condition"
href="http://llvm.org/bugs/show_bug.cgi?id=22491">22491</a>
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<th>Summary</th>
<td>"type name does not allow constexpr specifier to be specified" using constexpr in condition
</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>
<tr>
<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>
<tr>
<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
</td>
</tr>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>According to N3290 subclause 6.4 [stmt.select]/6, constexpr is explicitly
allowed in the decl-specifier-seq of a condition.
This applies to "if", "switch", "for" and "while" statements.
For the source below, Clang produces an error; GCC compiles it fine.
### SOURCE (<stdin>):
class Countdown {
public:
constexpr Countdown(int bias) : bias(bias) { }
operator int();
private:
static int countdown;
int bias;
};
int main() {
if (constexpr Countdown c = 200) { }
switch (constexpr Countdown c = 100) { }
for (; constexpr Countdown c = 50; ) { }
while (constexpr Countdown c = 25) { }
}
### COMPILER INVOCATION:
clang -cc1 -std=c++11 -x c++ -
### ACTUAL OUTPUT:
<stdin>:11:8: error: type name does not allow constexpr specifier to be
specified
if (constexpr Countdown c = 200) { }
^
<stdin>:12:12: error: type name does not allow constexpr specifier to be
specified
switch (constexpr Countdown c = 100) { }
^
<stdin>:13:11: error: type name does not allow constexpr specifier to be
specified
for (; constexpr Countdown c = 50; ) { }
^
<stdin>:14:11: error: type name does not allow constexpr specifier to be
specified
while (constexpr Countdown c = 25) { }
^
4 errors generated.
### EXPECTED OUTPUT:
Clean compile.
### COMPILER VERSION INFO:
clang version 3.7.0 (trunk 228401)
Target: x86_64-unknown-linux-gnu
Thread model: posix
Found candidate GCC installation:
/usr/local/gcc-4.8.2/lib/gcc/x86_64-unknown-linux-gnu/4.8.2
Selected GCC installation:
/usr/local/gcc-4.8.2/lib/gcc/x86_64-unknown-linux-gnu/4.8.2
Candidate multilib: .;@m64
Selected multilib: .;@m64</pre>
</div>
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