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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Improper symbol redefinition diagnostic for names in different declarative regions"
href="https://bugs.llvm.org/show_bug.cgi?id=37556">37556</a>
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</tr>
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<th>Summary</th>
<td>Improper symbol redefinition diagnostic for names in different declarative regions
</td>
</tr>
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<th>Product</th>
<td>clang
</td>
</tr>
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<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>Windows NT
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>C++
</td>
</tr>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>Casey@Carter.net
</td>
</tr>
<tr>
<th>CC</th>
<td>dgregor@apple.com, llvm-bugs@lists.llvm.org
</td>
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<p>
<div>
<pre>Compiling this well-formed program with -std=c++2a:
namespace X {
inline namespace Y { int swap; }
template<class>
struct S {
friend void swap(S&, S&) {}
};
}
int main() {
X::S<int> s1, s2;
swap(s1, s2);
}
produces diagnostics (<a href="https://godbolt.org/g/ceWLxY">https://godbolt.org/g/ceWLxY</a>):
<source>:6:21: error: redefinition of 'swap' as different kind of symbol
friend void swap(S&, S&) {}
^
<source>:11:15: note: in instantiation of template class 'X::S<int>'
requested here
X::S<int> s1, s2;
^
<source>:2:30: note: previous definition is here
inline namespace Y { int swap; }
^
1 error generated.
Note that the program compiles successfully if S is replaced by a non-template
class. Discussion on the CWG reflector verified that this program is
well-formed, including Richard's statement "Oops, Clang's redeclaration check
in the template instantiation case is incorrectly performing a redeclaration
lookup as if for a qualified name here, rather than a redeclaration lookup for
an unqualified name."</pre>
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</p>
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