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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Missing result unused after macro expansion"
href="https://llvm.org/bugs/show_bug.cgi?id=24404">24404</a>
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<th>Summary</th>
<td>Missing result unused after macro expansion
</td>
</tr>
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<th>Product</th>
<td>clang
</td>
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<th>Version</th>
<td>unspecified
</td>
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<th>Hardware</th>
<td>Macintosh
</td>
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<th>OS</th>
<td>MacOS X
</td>
</tr>
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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>
</tr>
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<th>Component</th>
<td>-New Bugs
</td>
</tr>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>adkap@adkap.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>This follows from a bug in a popular Obj-C testing framework Expecta:
<a href="https://github.com/specta/expecta/issues/160">https://github.com/specta/expecta/issues/160</a>
Basically, a macro evaluates to an Objective-C object pointer, is sent a
message, and the result is unused. There is no warning produced. However if the
macro is enclosed in parens/(), the warning is produced as expected.
This isn't an academic case: I had several tests "pass" because the trailing
parentheses were accidentally omitted.
A very short example
<a href="https://gist.github.com/adamkaplan/3c69fda47bf02790a860#file-expexpectawarningdemo-m">https://gist.github.com/adamkaplan/3c69fda47bf02790a860#file-expexpectawarningdemo-m</a>
My configuration:
Apple LLVM version 6.1.0 (clang-602.0.53) (based on LLVM 3.6.0svn)
Target: x86_64-apple-darwin14.4.0</pre>
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