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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 --- - incorrect warning about uninitialized variable in lamba function argument"
href="http://llvm.org/bugs/show_bug.cgi?id=15906">15906</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>incorrect warning about uninitialized variable in lamba function argument
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>C++11
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>andreas.boerner@w84u.org
</td>
</tr>
<tr>
<th>CC</th>
<td>dgregor@apple.com, llvmbugs@cs.uiuc.edu
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=10464" name="attach_10464" title="cc file that contains the bug">attachment 10464</a> <a href="attachment.cgi?id=10464&action=edit" title="cc file that contains the bug">[details]</a></span>
cc file that contains the bug
the following program generates an invalid warning:
#include <iostream>
#include <functional>
struct A {
A(std::function< void (void)> lf) : m_f(lf) {};
void exec() { m_f(); };
std::function<void(void)> m_f;
bool m_b = false;
};
namespace {
A x([](){ x.m_b = true; std::cout << "x.m_b: " << x.m_b << std::endl; });
}
int main()
{
x.exec();
return 0;
}
the warning is:
clang++ -std=gnu++11 -Wall -Weffc++ -D__STRICT_ANSI__ -I . -O0 -ggdb -o t_clang
main.cc
main.cc:13:54: warning: variable 'x' is uninitialized when used within its own
initialization [-Wuninitialized]
A x([](){ x.m_b = true; std::cout << "x.m_b: " << x.m_b << std::endl; });
~ ^
1 warning generated.
The warning in invalid, because the lambda is not executed inside the A c'tor,
but outside, at x.exec()! It can never be otherwise!
$ clang++ --version
clang version 3.3 (trunk 178622)
Target: x86_64-unknown-linux-gnu
Thread model: posix
Makefile:
all: gcc clang
gcc:
g++ -std=gnu++11 -Wall -Weffc++ -I . -O0 -ggdb -o t_gcc main.cc
@ls -sh t_gcc
clang:
clang++ -std=gnu++11 -Wall -Weffc++ -D__STRICT_ANSI__ -I . -O0 -ggdb -o
t_clang main.cc
@ls -sh t_clang
clean:
@rm -f t_gcc
@rm -f t_clang</pre>
</div>
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