Re: [Patch, Fortran] PR 92996 – fix rank resolution EXPR_ARRAY

[Tobias Burnus]

Hi Steve,

On 12/20/19 1:26 AM, Steve Kargl wrote:
> On Thu, Dec 19, 2019 at 09:30:49PM +0100, Tobias Burnus wrote:
>> The latter could be "solved" by using %C instead of %L after
>> gfc_simplify_expr in gfc_match_stopcode.
>> [The "ref" has its own address (e->ref->u.ar->where); hence,
>> the a(1,1) error would be still fine.]
>> (Though, this potentially effects more.)
> See patch in comment #2 of PR.  It regression tests cleanly,
> so it seems your parenthetical statement is not a issue.

One has the choice between
(a) Using the location where the expression was defined (in the
     scoping unit) – currently done
     (i.e. replacing expr->where by expr->symtree->n.sym->where)
(b) using the location where the parameter is used, i.e. keeping
     expr->where despite simplification.

What I meant is that there are more locations one to change from
%L to %C if one wants to get good diagnostic and keep using the
location of the declaration (as done currently) – instead of moving
to keeping the location of the expression used (as proposed).

In my opinion (b) is the most robust version while (a) can give in
_some_ cases a better diagnostic – as mentioned in the last email
and as shown by the dg-error changed I had to do in two test cases.

I played around and found two examples where the currently shown
location is not helpful.

The current compiler shows such errors:

     5 | use m
       |    1
Error: ‘dim’ argument of ‘size’ intrinsic at (1) is not a valid dimension index

     1 | complex, parameter :: x(1) = 1
       |                            1
Error: STOP code at (1) must be either INTEGER or CHARACTER type


Using approach (b), one gets for those:

     3 | stop x(1)
       |    1
Error: STOP code at (1) must be either INTEGER or CHARACTER type

     6 | print size([1,2],dim=d(1))
       |                     1
Error: ‘dim’ argument of ‘size’ intrinsic at (1) is not a valid dimension index


I think the latter diagnostic is much more helpful! I have to admit that I had to
move the "e->where = p->where" further down – after the gfc_simplify_expr call
as that one again changed the location. — I also added the two examples.

OK for the trunk?

Tobias

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