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<p class="MsoNormal">Hi,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Consider below test case:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"> 1 #include <unordered_map><o:p></o:p></p>
<p class="MsoNormal"> 2<o:p></o:p></p>
<p class="MsoNormal"> 3 using key=const int;<o:p></o:p></p>
<p class="MsoNormal"> 4 struct Myhash {<o:p></o:p></p>
<p class="MsoNormal"> 5 Myhash() = default;<o:p></o:p></p>
<p class="MsoNormal"> 6 std::hash<int> hash_int_t;<o:p></o:p></p>
<p class="MsoNormal"> 7 inline size_t operator()(const key& x) const throw() {<o:p></o:p></p>
<p class="MsoNormal"> 8 return hash_int_t(x);<o:p></o:p></p>
<p class="MsoNormal"> 9 }<o:p></o:p></p>
<p class="MsoNormal"> 10 };<o:p></o:p></p>
<p class="MsoNormal"> 11 std::unordered_map<key,int, Myhash> mm;<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">It compile with gcc (version 4.8.4) whereas I’m unable to compile same with clang.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Clang fails with below errors:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">$ clang++ fail.cpp -std=c++11 -O0 –c<o:p></o:p></p>
<p class="MsoNormal"><i>In file included from fail.cpp:1:<o:p></o:p></i></p>
<p class="MsoNormal"><i>In file included from /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/unordered_map:47:<o:p></o:p></i></p>
<p class="MsoNormal"><i>/usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/bits/hashtable.h:268:7:
<b>error</b>: static_assert failed "Cache the hash code or make functors involved in hash code and bucket index computation default constructible"<o:p></o:p></i></p>
<p class="MsoNormal"><i> static_assert(__if_hash_not_cached<<o:p></o:p></i></p>
<p class="MsoNormal"><i> ^ ~~~~~~~~~~~~~~~~~~~~~<o:p></o:p></i></p>
<p class="MsoNormal"><i>/usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/bits/unordered_map.h:120:36:
<b>error</b>: member 'iterator' found in multiple base classes of different types<o:p></o:p></i></p>
<p class="MsoNormal"><i> typedef typename _Hashtable::iterator iterator;<o:p></o:p></i></p>
<p class="MsoNormal"><i> ^<o:p></o:p></i></p>
<p class="MsoNormal"><i>In file included from fail.cpp:1:<o:p></o:p></i></p>
<p class="MsoNormal"><i>In file included from /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/unordered_map:48:<o:p></o:p></i></p>
<p class="MsoNormal"><i>/usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/bits/unordered_map.h:121:36:
<b>error</b>: member 'const_iterator' found in multiple base classes of different types<o:p></o:p></i></p>
<p class="MsoNormal"><i> typedef typename _Hashtable::const_iterator const_iterator;<o:p></o:p></i></p>
<p class="MsoNormal"><i><o:p> </o:p></i></p>
<p class="MsoNormal"><i>In file included from fail.cpp:1:<o:p></o:p></i></p>
<p class="MsoNormal"><i>In file included from /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/unordered_map:48:<o:p></o:p></i></p>
<p class="MsoNormal"><i>/usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/bits/unordered_map.h:124:36:
<b>error</b>: member 'size_type' found in multiple base classes of different types<o:p></o:p></i></p>
<p class="MsoNormal"><i> typedef typename _Hashtable::size_type size_type;<o:p></o:p></i></p>
<p class="MsoNormal"><i> ^<o:p></o:p></i></p>
<p class="MsoNormal"><i><o:p> </o:p></i></p>
<p class="MsoNormal"><i>In file included from fail.cpp:1:<o:p></o:p></i></p>
<p class="MsoNormal"><i>In file included from /usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/unordered_map:48:<o:p></o:p></i></p>
<p class="MsoNormal"><i>/usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/bits/unordered_map.h:452:7:
<b>error</b>: multiple overloads of 'erase' instantiate to the same signature 'iterator (iterator)' (aka 'int (int)')<o:p></o:p></i></p>
<p class="MsoNormal"><i> erase(iterator __it)<o:p></o:p></i></p>
<p class="MsoNormal"><i> ^<o:p></o:p></i></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Is this a known issue, or something I missed here ?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Regards,<o:p></o:p></p>
<p class="MsoNormal">Ashutosh<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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