[Bug c++/49224] [C++0x] Scoped enumeration instantiated even if not required

["egallager at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=49224

Eric Gallager <egallager at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |egallager at gcc dot gnu.org

--- Comment #1 from Eric Gallager <egallager at gcc dot gnu.org> ---
(In reply to Johannes Schaub from comment #0)
> GCC should not instantiate the definition of the scoped enumeration:
> 
> template<typename T>
> struct A {
>   enum class B {
>     X = T::value
>   };
> };
> 
> int main() {
>   A<int> a;
> }
> 
> GCC error:
> 
> main1.cpp: In instantiation of ‘A<int>’:
> main1.cpp:9:10:   instantiated from here
> main1.cpp:3:14: error: ‘value’ is not a member of ‘int’
> 
> This code looks well-formed. Only if we look into the enumeration, as
> "A<int>::B::X", the definition of the enumeration is required to exist and
> thus implicitly instantiated. This is specified at 14.7.1p1 and p2.

Confirmed that g++ rejects it, but clang rejects it too:

$ /usr/local/bin/g++ -c -Wall -Wextra -pedantic 49224.cc
49224.cc: In instantiation of ‘struct A<int>’:
49224.cc:9:9:   required from here
49224.cc:3:13: error: ‘value’ is not a member of ‘int’
  enum class B {
             ^
49224.cc: In function ‘int main()’:
49224.cc:9:9: warning: unused variable ‘a’ [-Wunused-variable]
  A<int> a;
         ^
$ /sw/opt/llvm-3.1/bin/clang++ -c -Wall -Wextra -pedantic 49224.cc
49224.cc:3:7: error: expected identifier or '{'
        enum class B {
             ^
49224.cc:3:2: warning: declaration does not declare anything
[-Wmissing-declarations]
        enum class B {
        ^~~~
49224.cc:9:9: warning: unused variable 'a' [-Wunused-variable]
        A<int> a;
               ^
2 warnings and 1 error generated.
$

Since I'm not sure if this is intentional or not, I'm leaving it UNCONFIRMED.