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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Cannot use alias template in friend declaration"
href="https://bugs.llvm.org/show_bug.cgi?id=42125">42125</a>
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<th>Summary</th>
<td>Cannot use alias template in friend declaration
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<th>Product</th>
<td>clang
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<th>Version</th>
<td>8.0
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<th>Hardware</th>
<td>PC
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<th>OS</th>
<td>Linux
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<th>Status</th>
<td>NEW
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>P
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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>marco.clemencic@cern.ch
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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>Hi,
trying to use an alias template in a friend declaration fails with "error:
redefinition of 'XYZ' as different kind of symbol".
This piece of code fails to compile on clang-8:
~~~
template<typename T>
class ActualStuff {};
template <typename B>
class Other {
public:
template<typename T>
using Stuff = ActualStuff<T>;
#if 1
// this fails with:
// error: redefinition of 'Stuff' as different kind of symbol
template<typename>
friend class Stuff;
#else
// this works
template<typename>
friend class ActualStuff;
#endif
};
~~~
And the only way I found to make it work (as shown in the example) is to bypass
the alias.
As a side note, gcc accepts the code in the example.
Cheers
Marco</pre>
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