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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 - function attribute "diagnose_if" doesn't show error if the argument uses statements and declarations in expressions"
href="https://bugs.llvm.org/show_bug.cgi?id=38111">38111</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>function attribute "diagnose_if" doesn't show error if the argument uses statements and declarations in expressions
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>6.0
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>Frontend
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>naruse@airemix.jp
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>If the target function of "diagnose_if" attribute receives an argument which
uses GCC extension, statements and declarations in expressions, clang doesn't
show error.
If there're only statements, it works.
But if there're also declarations, it doesn't show any errors.
```
% cat b.c
int scan_args(char *fmt)
__attribute__((diagnose_if(fmt[0]!=2,"invalid format string","error")))
{
return 0;
}
int
main(int argc, char **argv) {
return scan_args(__extension__({"20";}));
}
% clang b.c
b.c:10:44: error: invalid format string
return scan_args(__extension__({"20";}));
^
b.c:2:20: note: from 'diagnose_if' attribute on 'scan_args':
__attribute__((diagnose_if(fmt[0]!=2,"invalid format string","error")))
^ ~~~~~~~~~
1 error generated.
```
```
% cat b.c
int scan_args(char *fmt)
__attribute__((diagnose_if(fmt[0]!=2,"invalid format string","error")))
{
return 0;
}
int
main(int argc, char **argv) {
return scan_args(__extension__({char *s="20";s;}));
}
% clang b.c
```</pre>
</div>
</p>
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