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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - False positive from clang-analyzer-deadcode.DeadStores with reference and thread"
href="https://bugs.llvm.org/show_bug.cgi?id=51674">51674</a>
</td>
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<th>Summary</th>
<td>False positive from clang-analyzer-deadcode.DeadStores with reference and thread
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</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>
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<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>Static Analyzer
</td>
</tr>
<tr>
<th>Assignee</th>
<td>dcoughlin@apple.com
</td>
</tr>
<tr>
<th>Reporter</th>
<td>samuelmkearney@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>dcoughlin@apple.com, llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>To reproduce: Install LLVM 14.0, add this minimal example as main.cpp:
```
#include <chrono>
#include <thread>
#include <iostream>
using namespace std::chrono_literals;
int main()
{
bool keep_running_thread = true;
std::thread thrd(
[](const bool& keep_running) {
while (keep_running)
{
std::cout << "Still running!\n";
std::this_thread::sleep_for(200ms);
}
},
std::ref(keep_running_thread));
std::this_thread::sleep_for(1s);
keep_running_thread = false;
thrd.join();
return 0;
}
```
Run clang-tidy --checks=clang-analyzer-* main.cpp. It reports:
main.cpp:22:3: warning: Value stored to 'keep_running_thread' is never read
[clang-analyzer-deadcode.DeadStores]
keep_running_thread = false;
^ ~~~~~
main.cpp:22:3: note: Value stored to 'keep_running_thread' is never read
keep_running_thread = false;
^ ~~~~~
I would expect no warning here since a reference to keep_running_thread is
passed to the thread.
Note: You can work around this by using a capturing lambda that captures
keep_running_thread by reference; but I would expect this to work using the
method shown as well.</pre>
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