<html>
    <head>
      <base href="http://llvm.org/bugs/" />
    </head>
    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW --- - -Wunsused_variable gives false positive for template"
   href="http://llvm.org/bugs/show_bug.cgi?id=17014">17014</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>-Wunsused_variable gives false positive for template
          </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++
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>unassignedclangbugs@nondot.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>artur@ebasoft.com.pl
          </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>clang version 3.4 (trunk 189329)
Target: x86_64-unknown-linux-gnu
Thread model: posix

#include <iostream>
#include <string>

struct bar {
  int value;
};

struct foo {
  foo( bar & b, int x) 
    {
    b.value = x;
    }
};
template<typename T>
struct baz {
  void operator()(bar & b, T argc) const
  {
  foo false_positive_unsused_variable(b,argc);
  std::cout << "Result is "<< b.value << std::endl;
  }
};

int main(int argc, char **argv) {
  bar b;
  baz<int> z;
  z(b, argc);

    return 0;
}

clang++    -Wunused-variable -O3 -DNDEBUG   -o
CMakeFiles/clang_test.dir/main.cpp.o -c
/home/artur/projects/clang_test/main.cpp
/home/artur/projects/clang_test/main.cpp:18:7: warning: unused variable
'false_positive_unsused_variable'
      [-Wunused-variable]
  foo false_positive_unsused_variable(b,argc);
      ^


I've checked 
<a class="bz_bug_link 
          bz_status_RESOLVED  bz_closed"
   title="RESOLVED FIXED - False positive "unused variable '__range'" with ranged for loop in template"
   href="show_bug.cgi?id=9968">http://llvm.org/bugs/show_bug.cgi?id=9968</a>
that one is fixed.

But it colud be connected with
<a class="bz_bug_link 
          bz_status_NEW "
   title="NEW --- - False positive for -Wunused-variable in function template when calling nontrivial ctor with __func__"
   href="show_bug.cgi?id=15532">http://llvm.org/bugs/show_bug.cgi?id=15532</a></pre>
        </div>
      </p>
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