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      <base href="https://llvm.org/bugs/" />
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    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW --- - list::remove should not require allocator to have default constructor"
   href="https://llvm.org/bugs/show_bug.cgi?id=31378">31378</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>list::remove should not require allocator to have default constructor
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>libc++
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>unspecified
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>All
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>All
          </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>All Bugs
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>lukasl@ca.ibm.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org, mclow.lists@gmail.com
          </td>
        </tr>

        <tr>
          <th>Classification</th>
          <td>Unclassified
          </td>
        </tr></table>
      <p>
        <div>
        <pre>The current libc++ implementation of `std::list::remove` uses the default
constructor of `std::list`:

<span class="quote">> list<_Tp, _Alloc> __deleted_nodes; // collect the nodes we're removing</span >

This subsequently calls the default constructor of `_Alloc`. However, reading
through section 17.6.3.5 ("Allocator requirements") of the C++11 standard
draft, it appears allocators are not required to be DefaultConstructable.

I believe the constructor of `__deleted_nodes` should simply be given the
allocator instance of the existing list:

<span class="quote">> list<_Tp, _Alloc> __deleted_nodes(get_allocator()); // collect the nodes we're removing</span ></pre>
        </div>
      </p>
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