RFD: improved diagnostics when reading module files

[Harald Anlauf]

Steve,

I've tried to incorporate your suggestions.

On 04/06/18 21:58, Steve Kargl wrote:
> I would remove the "While reading module files:" and simply
> start the error message with "Mismatch".  I haven't looked at
> module.c, but if the module name or derived type is available
> you might considering added that to the message.   If you
> try to reference a locus with "at %C", do you get a caret
> pointing at a "USE XXXX" statement?  This might also be helpful.
>> +               }
>> +             /* gcc_assert (comp_name == c->name); */
> 
> Delete the above line.

With

Index: gcc/fortran/module.c
===================================================================
--- gcc/fortran/module.c        (revision 259189)
+++ gcc/fortran/module.c        (working copy)
@@ -5161,7 +5161,12 @@
              if (p->u.pointer == NULL)
                associate_integer_pointer (p, c);
              mio_pool_string (&comp_name);
-             gcc_assert (comp_name == c->name);
+             if (comp_name != c->name)
+               {
+                 gfc_error_now ("Mismatch in derived type components of "
+                                "%qs from %qs at %C: %qs != %qs",
+                                sym->name, sym->module, c->name,
comp_name);
+               }
              skip_list (1); /* component end.  */
            }
          mio_rparen (); /* component list closing.  */


I get some improved output.  I'm not really overwhelmed, but it is
definitely better from my point of view.  OTOH, removing the %C
makes the error message definitely less useful.

I haven't been able to produce a simple but sufficiently contorted
testcase.  But for the case I was debugging, where there was some
outdated module file holding the outdated layout of a derived type,
I was able to zgrep back to the culprit.

With the change above, I now get:

../../../../analysis/mo_ir_emis.f90:61:6:

   use mo_dec_matrix,  only: t_vector       ! decomposed vector
      1
Error: Mismatch in derived type components of 't_par_grib2' from
'mo_grib12_dwd' at (1): 'modnum' != 'shortname'
../../../../analysis/mo_ir_emis.f90:61:6: Error: Mismatch in derived
type components of 't_par_grib2' from 'mo_grib12_dwd' at (1):
'shortname' != 'longname'
f951: Fatal Error: Reading module 'mo_dec_matrix' at line 3072 column
53: Expected left parenthesis
compilation terminated.


That was useful enough for me, and I will continue using it.
If you think others may profit, please consider applying it.

Thanks,
Harald