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<body><span class="vcard"><a class="email" href="mailto:richard-llvm@metafoo.co.uk" title="Richard Smith <richard-llvm@metafoo.co.uk>"> <span class="fn">Richard Smith</span></a>
</span> changed
<a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED INVALID - Compilation error with boost::optional (from Boost 1.55)"
href="http://llvm.org/bugs/show_bug.cgi?id=18180">bug 18180</a>
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<tr>
<th>What</th>
<th>Removed</th>
<th>Added</th>
</tr>
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<td style="text-align:right;">Status</td>
<td>NEW
</td>
<td>RESOLVED
</td>
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<td style="text-align:right;">Resolution</td>
<td>---
</td>
<td>INVALID
</td>
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<b><a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED INVALID - Compilation error with boost::optional (from Boost 1.55)"
href="http://llvm.org/bugs/show_bug.cgi?id=18180#c4">Comment # 4</a>
on <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED INVALID - Compilation error with boost::optional (from Boost 1.55)"
href="http://llvm.org/bugs/show_bug.cgi?id=18180">bug 18180</a>
from <span class="vcard"><a class="email" href="mailto:richard-llvm@metafoo.co.uk" title="Richard Smith <richard-llvm@metafoo.co.uk>"> <span class="fn">Richard Smith</span></a>
</span></b>
<pre>OK, I see what's happening -- in Clang 3.3 and GCC 4.8, 'false' is being
treated as a null pointer constant. boost::optional implicitly converts to an
"unspecified-bool-type" that happens to be a pointer-to-member type, and thus
can be compared against a null pointer constant via the built-in
operator!=(pointer-to-member, pointer-to-member) overload.
In C++11 onwards, 'false' isn't a null pointer constant any more, so this
comparison is no longer valid. Clang 3.3 and GCC 4.8 don't implement that rule;
Clang 3.4 does.
=> INVALID</pre>
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