[Bug fortran/83149] [8 Regression] ICE on SELECT CASE: crash_signal in toplev.c:325

["sgk at troutmask dot apl.washington.edu" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83149

--- Comment #8 from Steve Kargl <sgk at troutmask dot apl.washington.edu> ---
On Tue, Dec 26, 2017 at 09:42:54PM +0000, neil.n.carlson at gmail dot com
wrote:
>
> Perhaps this modification of comment 2 code is clearer.

ncell is never set.

> Put this in one file:
> 
> module mod1
>   integer :: ncells
> end module
> 
> module mod2
> contains
>   function get() result(array)
>     use mod1
>     real array(ncells)

The reference to ncells is to an undefined entity. 

>     array = 1.0
>   end function
> end module
> 
> And this in another (this is different):
> 
> subroutine sub
> use mod2

You need to have 

  ncells = 1  ! or some other value here.

> s = sum(get())
> end
> 
> This gives an ICE when compiled with 8.0.0 (20171222).

The code with ncells properly defined defined still
hits an ICE.  This probably a result of not walking
mod2's namespace, but I haven't tried to debug the
problem beyond this.