[LLVMdev] Clang bug?

[Howard Hinnant]

That is one evil bug!

I just tested it against tip-of-trunk clang and it appears to be fixed there (just fyi for everyone).

Howard

On Sep 27, 2012, at 7:17 PM, Adam Peterson <alpha.eta.pi at gmail.com> wrote:

> Is this a relevant location to provide information about what I
> believe is a compiler bug in clang?  If not, please forgive me for
> posting it here.  (Perhaps you can redirect me to some place more
> appropriate.)  If so, here are the details:
> 
> I have a short 15-line C++ program using only one standard header that
> clang fails to compile properly under C++11 with the new standard
> library (although the code itself doesn't use any C++11-specific
> syntax), but G++ (4.6-Ubuntu and 4.2-Darwin) compiles it fine:
> 
>    #include <map>
>    using std::map;
> 
>    template<typename K>
>    struct Templ8 {
>        struct Member {
>            typename map<K,Member*>::iterator it;
>        };
>        typedef typename map<K,Member*>::iterator iterator_type;
>    };
> 
>    int main() {
>        Templ8<int> test;
>    }
> 
> 
> 
> This is the command-line:
>    clang++ -stdlib=libc++ -std=c++11 main_bug.cpp
> If either of the flags are removed (to compile in C++03 mode, or to
> use the non-clang standard library), the code compiles.  If the
> typedef is removed or commented out, clang++ compiles the code fine.
> If the typedef is moved inside the "Member" inner class, the code
> compiles fine (even if a second typedef pulls the symbol back into the
> main template scope).
> 
> My clang version information:
>    Apple clang version 4.1 (tags/Apple/clang-421.11.65) (based on LLVM 3.1svn)
>    Target: x86_64-apple-darwin12.2.0
>    Thread model: posix
> 
> The error output:
> 
> main_bug.cpp:7:34: error: no type named 'iterator' in
> 'std::__1::map<int, Templ8<int>::Member *, std::__1::less<int>,
> std::__1::allocator<std::__1::pair<const int, Templ8<int>::Member
> *>>>'
>        typename map<K,Member*>::iterator it;
>        ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~
> /usr/bin/../lib/c++/v1/type_traits:1184:57: note: in instantiation of
> member class 'Templ8<int>::Member' requested here
> decltype((_VSTD::declval<_Tp>() = _VSTD::declval<_Arg>(), true_type()))
>                                                        ^
> /usr/bin/../lib/c++/v1/type_traits:1186:1: note: while substituting
> deduced template arguments into function template
> '__is_assignable_test' [with _Tp = Templ8<int>::Member *&, _Arg = <no
> value>]
> __is_assignable_test(_Tp&&, _Arg&&);
> ^
> /usr/bin/../lib/c++/v1/type_traits:1214:14: note: in instantiation of
> template class 'std::__1::__is_assignable_imp<Templ8<int>::Member *&,
> Templ8<int>::Member *&, false>' requested here
>    : public __is_assignable_imp<_Tp, _Arg> {};
>             ^
> /usr/bin/../lib/c++/v1/type_traits:2616:38: note: in instantiation of
> template class 'std::__1::is_assignable<Templ8<int>::Member *&,
> Templ8<int>::Member *&>' requested here
>    : public __is_nothrow_assignable<is_assignable<_Tp, _Arg>::value,
> _Tp, _Arg>
>                                     ^
> /usr/bin/../lib/c++/v1/type_traits:2667:14: note: in instantiation of
> template class 'std::__1::is_nothrow_assignable<Templ8<int>::Member
> *&, Templ8<int>::Member *&>' requested here
>    : public is_nothrow_assignable<typename add_lvalue_reference<_Tp>::type,
>             ^
> /usr/bin/../lib/c++/v1/utility:250:20: note: (skipping 9 contexts in
> backtrace; use -ftemplate-backtrace-limit=0 to see all)
>                   is_nothrow_copy_assignable<second_type>::value)
>                   ^
> /usr/bin/../lib/c++/v1/__config:253:34: note: expanded from macro '_NOEXCEPT_'
> #  define _NOEXCEPT_(x) noexcept(x)
>                                 ^
> /usr/bin/../lib/c++/v1/memory:2386:15: note: in instantiation of
> template class 'std::__1::__libcpp_compressed_pair_imp<std::__1::__tree_end_node<std::__1::__tree_node_base<void
> *> *>,
>      std::__1::allocator<std::__1::__tree_node<std::__1::pair<int,
> Templ8<int>::Member *>, void *>>, 2>' requested here
>    : private __libcpp_compressed_pair_imp<_T1, _T2>
>              ^
> /usr/bin/../lib/c++/v1/__tree:813:56: note: in instantiation of
> template class 'std::__1::__compressed_pair<std::__1::__tree_end_node<std::__1::__tree_node_base<void
> *> *>,
>      std::__1::allocator<std::__1::__tree_node<std::__1::pair<int,
> Templ8<int>::Member *>, void *>>>' requested here
>    __compressed_pair<__end_node_t, __node_allocator>  __pair1_;
>                                                       ^
> /usr/bin/../lib/c++/v1/map:711:22: note: in instantiation of template
> class 'std::__1::__tree<std::__1::pair<int, Templ8<int>::Member *>,
> std::__1::__map_value_compare<int, Templ8<int>::Member *,
>      std::__1::less<int>, true>,
> std::__1::allocator<std::__1::pair<int, Templ8<int>::Member *>>>'
> requested here
>    typedef typename __base::__node_traits                 __node_traits;
>                     ^
> main_bug.cpp:9:22: note: in instantiation of template class
> 'std::__1::map<int, Templ8<int>::Member *, std::__1::less<int>,
> std::__1::allocator<std::__1::pair<const int, Templ8<int>::Member
> *>>>'
>      requested here
>    typedef typename map<K,Member*>::iterator iterator_type;
>                     ^
> main_bug.cpp:13:17: note: in instantiation of template class
> 'Templ8<int>' requested here
>    Templ8<int> test;
>                ^
> 1 error generated.
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev