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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 - No diagnostic for no_unique_address extension on anonymous union"
href="https://bugs.llvm.org/show_bug.cgi?id=46566">46566</a>
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<th>Summary</th>
<td>No diagnostic for no_unique_address extension on anonymous union
</td>
</tr>
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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>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++2a
</td>
</tr>
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<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>blitzrakete@gmail.com, erik.pilkington@gmail.com, llvm-bugs@lists.llvm.org, richard-llvm@metafoo.co.uk
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<p>
<div>
<pre>According to the 2020 DIS for C++, subclause 11.4 [class.mem] paragraph 13, the
attribute-specifier-seq of a member-declaration shall not be present when the
member-declarator-list is omitted.
Clang accepts such an attribute-specifier-seq and applies the associated
semantics with no diagnostic even in pedantic mode.
### SOURCE (<stdin>):
struct Empty {};
struct A {
[[no_unique_address]] union {
Empty emp [[no_unique_address]];
};
char x[3];
};
extern char szA[sizeof(A)];
extern char szA[3];
### COMPILER INVOCATION:
clang -cc1 -fsyntax-only -std=c++20 -Wall -Wextra -pedantic-errors -xc++ -
### ACTUAL OUTPUT:
(rc=0)
### EXPECTED OUTPUT:
Diagnostic message; a warning that is upgraded to an error.
### COMPILER VERSION INFO (clang++ -v):
clang version 11.0.0 (<a href="https://github.com/llvm/llvm-project.git">https://github.com/llvm/llvm-project.git</a>
c5b4f03b53a48b7dc35ce6c345bb06871cd7699e)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /opt/wandbox/clang-head/bin
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.5.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6.5.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.5.0
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.5.0
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Candidate multilib: x32;@mx32
Selected multilib: .;@m64</pre>
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</p>
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