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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - -Wunused-lambda-capture too strict with variadic usage"
href="https://bugs.llvm.org/show_bug.cgi?id=41211">41211</a>
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<th>Summary</th>
<td>-Wunused-lambda-capture too strict with variadic usage
</td>
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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
</td>
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<th>OS</th>
<td>Windows NT
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>enhancement
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>-New Bugs
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>jvapen@gmail.com
</td>
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<th>CC</th>
<td>htmldeveloper@gmail.com, llvm-bugs@lists.llvm.org, neeilans@live.com, richard-llvm@metafoo.co.uk
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<p>
<div>
<pre>Reproduction on compiler explorer: <a href="https://godbolt.org/z/hJHQui">https://godbolt.org/z/hJHQui</a>
error: lambda capture 'i' is not used [-Werror,-Wunused-lambda-capture]
In the example below, we get a compiler warning on 'unused' lambda capture 'i'.
when changing the call to f from 'f<>' to 'f<int>', the warning goes away.
When removing the capture, as suggested, we get: error: variable 'i' cannot be
implicitly captured in a lambda with no capture-default specified
t.cpp
-----
template <typename ...T>
int h(T &&...t);
template <typename T>
int g(int i);
template<typename ...T>
auto f(int i)
{
return [i](){ return h(g<T>(i)...); };
}
int main()
{
return f<>(42)();
}
run.sh
------
clang++ -std=c++17 -O3 -Wunused-lambda-capture -Werror t.cpp</pre>
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