[Bug fortran/110644] Error in gfc_format_decoder

["kyle.shores44 at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110644

--- Comment #20 from Kyle Shores <kyle.shores44 at gmail dot com> ---
(In reply to Steve Kargl from comment #19)
> On Fri, Mar 08, 2024 at 05:42:05PM +0000, kyle.shores44 at gmail dot com
> wrote:
> > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110644
> > 
> > --- Comment #17 from Kyle Shores <kyle.shores44 at gmail dot com> ---
> > I was able to get tuv-x to compile by putting use statements in problematic
> > files at the top of the module. In one case, I had to match the use ordering to
> > the order that the objects were used in the module (unsure if that mattered),
> > and I also removed an object in a use only statement that wasn't used in that
> > same file and then it compiled (these last two issues were for the same file
> > test/unit/radiator/from_host.F90)
> > 
> > 
> 
> It seems your code is hitting a NULL pointer dereference when
> generating a warning.  In resolve.cc(resolve_procedure_expression),
> one finds
> 
>   /* A non-RECURSIVE procedure that is used as procedure expression within
> its
>      own body is in danger of being called recursively.  */
>   if (is_illegal_recursion (sym, gfc_current_ns))
>     gfc_warning (0, "Non-RECURSIVE procedure %qs at %L is possibly calling"
> 		 " itself recursively.  Declare it RECURSIVE or use"
> 		 " %<-frecursive%>", sym->name, &expr->where);
> 
> for whatever reason &expr->where is a NULL pointer.  If I change
> the above to remove &expr->where, then your code compiles with 
> a bunch of warningsi, e.g.,
> 
> [ 95%] Building Fortran object
> test/oldtuv/CMakeFiles/oldphotolib.dir/util/la_srb.type.F90.o
> /usr/home/sgk/tmp/tuv-x/test/oldtuv/util/la_srb.type.F90:873:28:
> 
>   873 |       end module la_srb_type
>       |                            1
> Warning: Non-RECURSIVE procedure 'get_config_array' at (1) is possibly
> calling itself recursively.  Declare it RECURSIVE or use '-frecursive'
>  
> Unfortunately, without a much smaller example code, I cannot go
> any further in debugging your problem.

Well that's odd, that function doesn't call itself recursively

For example get_config_array:
https://github.com/NCAR/tuv-x/blob/6930151e3cd89189df4ec046fdf19c02300d4380/src/util/config.F90#L715-L754


Either way, this PR fixes the issue for gcc 13 be moving use statements around
https://github.com/NCAR/tuv-x/pull/53. The bug still exists in gcc 13, but for
anyone else who encounters this issue, they can try pulling use statements up
to the top of the module