[Bug c++/68387] New: [c++1z] gcc hangs forever on this code

[ryan.burn at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68387

            Bug ID: 68387
           Summary: [c++1z] gcc hangs forever on this code
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ryan.burn at gmail dot com
  Target Milestone: ---

Created attachment 36740
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36740&action=edit
preprocessed code

The attached code causes gcc to hang forever.