<html>
    <head>
      <base href="https://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 --- - Unexpected compile time error with vector<bool>"
   href="https://llvm.org/bugs/show_bug.cgi?id=30357">30357</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Unexpected compile time error with vector<bool>
          </td>
        </tr>

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

        <tr>
          <th>Version</th>
          <td>3.8
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>PC
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>Windows NT
          </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>billy.jasiniecki@hpe.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>An test case (that is an excerpt from a standard validation test) gets an error
when compiled with both g++ and clang, but only with headers from libc++.  When
the same test case is compiled using gnu headers, the test compiles cleanly.

The test case:

#include <vector>
struct alloc : std::allocator<bool> {};
int main(void)
{
        std::vector<bool> v1;
        std::vector<bool, alloc>::reference r01 = v1[0];
}


With clang:

$ clang -c t.cpp -std=c++11 -Ic:/downloads/libcxx-3.8.1.src/include
t265.cpp:6:45: error: no viable conversion from '__bit_reference<vector<[...],
      std::__1::allocator<bool>>>' to
      '__bit_reference<vector<[...], alloc>>'
        std::vector<bool, alloc>::reference r01 = v1[0];
                                            ^     ~~~~~
c:/downloads/libcxx-3.8.1.src/include/__bit_reference:35:7: note: candidate
      constructor (the implicit copy constructor) not viable: no known
      conversion from 'reference' (aka '__bit_reference<std::__1::vector<bool,
      std::__1::allocator<bool> > >') to 'const
      std::__1::__bit_reference<std::__1::vector<bool, alloc>, true> &' for 1st
      argument
class __bit_reference
      ^
c:/downloads/libcxx-3.8.1.src/include/__bit_reference:51:31: note: candidate
      function
    _LIBCPP_INLINE_VISIBILITY operator bool() const _NOEXCEPT
                              ^
1 error generated.

With g++:

$ g++ -c t.cpp -std=c++11 -Ic:/downloads/libcxx-3.8.1.src/include
t265.cpp: In function ‘int main()’:
t265.cpp:6:55: error: conversion from ‘std::__1::vector<bool>::reference {aka
std::__1::__bit_reference<std::__1::vector<bool>, true>}’ to non-scalar type
‘std::__1::vector<bool, alloc>::reference {aka
std::__1::__bit_reference<std::__1::vector<bool, alloc>, true>}’ requested
         std::vector<bool, alloc>::reference r01 = v1[0];


The test case also compiles cleanly when headers from Dinkumware are used.</pre>
        </div>
      </p>
      <hr>
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      <ul>
          <li>You are on the CC list for the bug.</li>
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