[Bug c++/64626] New: C++14 single quote should not always be a digit separator

["b.r.longbons at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64626

            Bug ID: 64626
           Summary: C++14 single quote should not always be a digit
                    separator
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: b.r.longbons at gmail dot com

Created attachment 34459
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=34459&action=edit
informative testcase

During preprocessing, single quote (') should only be considered a digit
separator if it is followed by a digit or nondigit.

If it is followed by any other character, it should be considered as the start
of a new character-literal, not part of the current pp-number.

I am aware of exactly 2 other cases where a preprocessing-token needs to
consume 2 characters or none at all (. -> ... and %: -> %:%:), and gcc seems to
handle them correctly. (There is also the <:: case which looks ahead two
characters to *not* consume a character).


Unimplemented: gcc 4.8
Bad: Debian gcc 4.9.1-19
Bad: gcc 5.0.0 snapshot from 20141228
Good: Debian clang 3.4, 3.5, and svn snapshot of 3.6