[Bug c++/58109] alignas() fails to compile with constant expression

[rs2740 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58109

TC <rs2740 at gmail dot com> changed:

           What    |Removed                     |Added
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                 CC|                            |rs2740 at gmail dot com

--- Comment #5 from TC <rs2740 at gmail dot com> ---
The test cases in this bug appear to work with GCC 4.9.0 or later; however a
somewhat similar example from http://stackoverflow.com/q/34376921/2756719 fails
to compile:

template <typename T>
struct Base {
  constexpr static int Align_ = alignof(T);
};

template <typename T>
struct Derived : Base<T> {
  using Base_ = Base<T>;
  using Base_::Align_;
  alignas(Align_) char buf[1];
};