[Bug fortran/82243] -fcheck=bounds not checking, and behaving differently with different real kinds

[harper at msor dot vuw.ac.nz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82243

--- Comment #2 from harper at msor dot vuw.ac.nz ---
Since reporting the bug yesterday I have found that the bug requires the 
integer n to be a subprogram argument. If instead n is a constant, the
bad array assignment is correctly diagnosed at compile time
even without -fcheck=bounds. Evidence:

cayley[~/Jfh] % cat gfbug7.f90
! array section assigned to wrong-shape array constructor in subroutine.

module globals
   implicit none
   integer,parameter:: n = 40, mp = kind(1d0)
contains
   subroutine finds(       s)
     real(mp),intent(out)::s(0:)
     real(mp),dimension(0:n/2+1):: even
     integer:: i
     even = 1.0_mp
     s(0) = even(1)
     s(2:n-1:2) = [(even(i),i=1,n/2)]
     print *,'Sizes: LHS',size(s(2:n-1:2)),'RHS',size(even(1:n/2))
   end subroutine finds
end module globals

program gfbug7
   use globals, only: mp,n,finds
   implicit none
   real(mp),allocatable:: s(:)
   allocate(s(0:n))
   print *,merge('Single','Double',mp==kind(1.0))//' precision'
   call finds(n,s)
   print "(20F3.0)",s(0::2)
end program gfbug7
cayley[~/Jfh] % gf gfbug7.f90
gfbug7.f90:13:4:

      s(2:n-1:2) = [(even(i),i=1,n/2)]
     1
Error: Different shape for array assignment at (1) on dimension 1 (19 and 
20)
gfbug7.f90:19:6:

    use globals, only: mp,n,finds
       1
Fatal Error: Can't open module file ‘globals.mod’ for reading at (1): No 
such file or directory
compilation terminated.
cayley[~/Jfh] %

-- John Harper, School of Mathematics and Statistics
Victoria University, PO Box 600, Wellington 6140, New Zealand
e-mail john.harper@vuw.ac.nz phone (+64)(4)463 5276 fax (+64)(4)463 5045

---------- Forwarded message ----------
Date: Tue, 19 Sep 2017 22:47:42 +0000
From: dominiq at lps dot ens.fr <gcc-bugzilla@gcc.gnu.org>
To: John Harper <John.Harper@vuw.ac.nz>
Subject: [Bug fortran/82243] -fcheck=bounds not checking,
     and behaving differently with different real kinds
Resent-Date: Wed, 20 Sep 2017 10:48:09 +1200 (NZST)
Resent-From: <john.harper@vuw.ac.nz>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82243

Dominique d'Humieres <dominiq at lps dot ens.fr> changed:

            What    |Removed                     |Added
----------------------------------------------------------------------------
              Status|UNCONFIRMED                 |NEW
    Last reconfirmed|                            |2017-09-19
      Ever confirmed|0                           |1

--- Comment #1 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
Confirmed. Related to/duplicate of pr31059?