[Bug c++/62661] New: digit separator warning in if'ed out code

[olegendo at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62661

            Bug ID: 62661
           Summary: digit separator warning in if'ed out code
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: olegendo at gcc dot gnu.org

Compiling the following snippet as C or C++ < C++14:

#if 0
unsigned int test (void)
{
  return 0b0101'0101'0101'0101'0101'0101'0101'0101;
}
#endif

results in the following warning:

warning: missing terminating ' character
   return 0b0101'0101'0101'0101'0101'0101'0101'0101;
                                              ^

Putting the code in a block comment makes the warning go away.
I'm not sure how to categorize this or whether this is intended.  It looks
strange though.