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<base href="http://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - generic lambda capture fails with undefined reference to custom copy ctor"
href="http://llvm.org/bugs/show_bug.cgi?id=22354">22354</a>
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<th>Summary</th>
<td>generic lambda capture fails with undefined reference to custom copy ctor
</td>
</tr>
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<th>Product</th>
<td>clang
</td>
</tr>
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<th>Version</th>
<td>3.5
</td>
</tr>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>normal
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>C++14
</td>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
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<th>Reporter</th>
<td>attugithub@gmail.com
</td>
</tr>
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<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
</td>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>When passing an object with custom copy ctor to generaic lambda capture
code compiles but fails to link with undefined reference to copy ctor.
template <typename> struct custom_copy_ctor {
custom_copy_ctor() = default;
custom_copy_ctor(custom_copy_ctor const &) {}
// custom_copy_ctor(custom_copy_ctor const&) = default; // works fine
};
int main() {
custom_copy_ctor<void> cc;
[cc](auto) {}(1);
//[cc](int){}(1); // works fine
return 0;
}
$ clang++-3.5 -std=c++14 main.cc
/tmp/main-d01cbf.o: In function `main':
main.cc:(.text+0x21): undefined reference to
`custom_copy_ctor<void>::custom_copy_ctor(custom_copy_ctor<void> const&)'
clang: error: linker command failed with exit code 1 (use -v to see
invocation)
$ clang++-3.5 --version
Debian clang version 3.5.0-9 (tags/RELEASE_350/final) (based on LLVM 3.5.0)
Target: x86_64-pc-linux-gnu
Thread model: posix
Declaring copy ctor =default prevents the issue.
Problem does not occure also when "non-generic" lambda is used
(without template function call operator)
example with online compiler
<a href="http://coliru.stacked-crooked.com/a/cc96ebfb7fbc2fca">http://coliru.stacked-crooked.com/a/cc96ebfb7fbc2fca</a></pre>
</div>
</p>
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