[Bug fortran/70409] New: Silent truncation of character parameters with len=huge()

[anlauf at gmx dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70409

            Bug ID: 70409
           Summary: Silent truncation of character parameters with
                    len=huge()
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: anlauf at gmx dot de
  Target Milestone: ---

Related to/derived from pr68441.

The following code demonstrates a strange behavior of character parameter
declarations if the len argument involves huge().

  integer, parameter :: huge_1 = huge(0_1)
  character(    huge_1      ), parameter :: x = 'abc'
  character(    huge(0_1)   ), parameter :: y = 'abc'
  character(    huge(0_1)+0 ), parameter :: z = 'abcdef'
  character(    huge(0_1)   )            :: a = 'abc'
  integer, parameter :: huge_2 = huge(0_2)
  character(    huge_2      ), parameter :: u = 'abc'
  character(    huge(0_2)   ), parameter :: v = 'abc'
  character(int(huge(0_2),4)), parameter :: w = 'abcdef'
  character(    huge(0_2)   )            :: b = 'abc'
  print*, huge_1, len(x), len(y), len(z), len (a)
  print*, huge_2, len(u), len(v), len(w), len (b)
end

Output for 4.6 .. 6.0 trunk:

         127         127           3           6         127
       32767       32767           3           6       32767

Expected: all numbers should be 127 in the first line, 32767 in the second.