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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - fatal error: base class '...' has a flexible array member"
href="https://bugs.llvm.org/show_bug.cgi?id=50005">50005</a>
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<th>Summary</th>
<td>fatal error: base class '...' has a flexible array member
</td>
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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>PC
</td>
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<th>OS</th>
<td>All
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>enhancement
</td>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>C++
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>llvm@behdad.org
</td>
</tr>
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<th>CC</th>
<td>blitzrakete@gmail.com, dgregor@apple.com, erik.pilkington@gmail.com, llvm-bugs@lists.llvm.org, richard-llvm@metafoo.co.uk
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<pre>In HarfBuzz we extensively use the Struct Hack [0]. Up until now we've used
"array[1]" for that. This upsets ubsan [1]. So I'm looking to replace it with
flexible arrays on compilers that support it.
However, trying to do that I get the "base class '...' has a flexible array
member" error. The derived class only has one base class and no members. So I
like to ask that this special-case be allowed.
Test case, based on actual code:
```
struct UnsignedArray {
unsigned count;
int array[];
};
struct SortedUnsignedArray : UnsignedArray {
};
```
I've tested this with Apple clang 12.
[0] <a href="http://c-faq.com/struct/structhack.html">http://c-faq.com/struct/structhack.html</a>
[1] <a href="https://github.com/harfbuzz/harfbuzz/issues/2953">https://github.com/harfbuzz/harfbuzz/issues/2953</a></pre>
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