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From: "herring at lanl dot gov" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/97340] New: Spurious rejection of member variable template
 of reference type
Date: Thu, 08 Oct 2020 16:36:22 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D97340

            Bug ID: 97340
           Summary: Spurious rejection of member variable template of
                    reference type
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: herring at lanl dot gov
  Target Milestone: ---

In many recent versions of GCC, the following valid code

  struct A {
    template<class>
    static constexpr const int &x=3D0;
  };
  template<class T=3Dvoid>
  struct B {
    static constexpr int y=3DA::template x<int>;
  };
  template struct B<>;

produces

error: ''indirect_ref' not supported by dump_decl<declaration error>' is no=
t a
template [-fpermissive]
    7 |   static constexpr int y=3DA::template x<int>;
      |                          ~~~~~~~~~~~~^~~~~~

The 'template' after '::' here is unnecessary; removing it avoids the error,
but the error also appears if A is a class template (so that it's necessary=
 to
write "A<T>::template x<int>").  Making A::x not be a reference also avoids=
 the
error, as does referring to it from a non-templated context.=