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<base href="https://bugs.llvm.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Clang's diagnostic suppression pragma fails in a particular macro expansion case"
href="https://bugs.llvm.org/show_bug.cgi?id=35154">35154</a>
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<th>Summary</th>
<td>Clang's diagnostic suppression pragma fails in a particular macro expansion case
</td>
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<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>
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<th>Component</th>
<td>Frontend
</td>
</tr>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>arphaman@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Clang fails to silence the -Wunused-value warning in the following test-case:
```
@class Test;
#define nil2 0
#define SOMETHING(macro) macro
#define Expected(invocation) \
({ \
SilenceWarning( \
Test *recorder = nil2; \
recorder; \
); \
})
#define SilenceWarning(macro) \
({ \
_Pragma("clang diagnostic push") \
_Pragma("clang diagnostic ignored \"-Wunused-value\"") \
macro \
_Pragma("clang diagnostic pop") \
})
int test1() {
return 5;
}
void foo(Test *other) {
SOMETHING(
Expected(test1());
)
}
```
Interestingly enough, if the use of `nil2` is replaced by `0` then the warning
is suppressed correctly.</pre>
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