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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 - Throwing exception uses incorrect copy constructor"
href="https://bugs.llvm.org/show_bug.cgi?id=38801">38801</a>
</td>
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<tr>
<th>Summary</th>
<td>Throwing exception uses incorrect copy constructor
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
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<th>Version</th>
<td>7.0
</td>
</tr>
<tr>
<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>
<tr>
<th>Component</th>
<td>-New Bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>jvapen@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Hello all,
The following code seems to have problems being executed.
It looks like when throwing an exception, Clang tries to use a copy constructor
for the exception, however, instead of using the const& variant, it searches
for a variant without the const.
So instead of using the Copy constructor, it uses the variadic Ctor, which is
not as expected.
test.cpp
--------
struct A
{
template<typename ... T>
A(T &&...t)
{
static_assert(sizeof...(T) == 2);
}
A(const A &) = default;
//A(A &) = default;
A(A &&) = default;
A &operator=(const A &) = default;
A &operator=(A &&) = default;
};
int main(int, char **)
{
throw A{size_t{}, size_t{}};
return 0;
}
run.bat
-------
clang-cl.exe -fms-compatibility-version=19.11 /DBOOST_USE_WINDOWS_H -w
-Wno-unused-command-line-argument /Zc:inline /nologo /c /GR /EHsc /fp:precise
/FS /std:c++17 /diagnostics:caret /O2 /I. /MDd /Zc:forScope /bigobj /Zc:wchar_t
test.cpp
error
-----
test.cpp(7,7): error: static_assert failed
static_assert(sizeof...(T) == 2);
^ ~~~~~~~~~~~~~~~~~
test.cpp(20,10): note: in instantiation of function template specialization
'A::A<A &>' requested here
throw A{size_t{}, size_t{}};
^
1 error generated.</pre>
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