[Bug c++/65422] New: [C++11] Rejected valid double expansion packs.

[bugs at qult dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65422

            Bug ID: 65422
           Summary: [C++11] Rejected valid double expansion packs.
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: bugs at qult dot net

Created attachment 35031
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35031&action=edit
Failing code with double parameter pack expansion.

The attached code fails to compile with pretty much any version of GCC (up to
the head of the Git repository), with -std=c++11, complaining about the double
parameter pack expansion.  When using the brace-initialization syntax instead
(commented-out in the attached code), the code compiles fine.

Clang 3.5 compiles both versions fine.