Hi Tobias, Please go ahead and commit the patch. I think that your analysis is correct about expr_null and that your patch is the best way to deal with the problem.
Best regards Paul On Tue, 23 Mar 2021 at 17:54, Tobias Burnus <tob...@codesourcery.com> wrote: > Hi Paul, > > On 23.03.21 18:34, Paul Richard Thomas wrote: > > I took something of a detour in reviewing this patch. Although short, > > understanding it is not straightforward! > > I concur – and as I wrote both in the patch email and in the PR, it is > not straight forward which message is showing with which setting. > > Actually, I think there are many straight-forward ways to fix it > "properly" but they tend to hide some nicer error messages in favour of > a more generic one. Only by taking into account all the diagnostic and > hidden/delayed diagnostic, the patch becomes complex. (-: > > > Your patch works as advertised and regtests OK (with the patch for > > PR93660 on board as well). Is NULL the only case where this can happen? > > I am not sure whether any other code would profit form getting one of > the attributes conditionally assigned in intrinsic.c. > > Otherwise, I think that's the only code which verifies like that it in > such a way whether an intrinsic function was used. I think the reason > that it does so is because 'null' is turned early during parsing into > EXPR_NULL, which is not a function and, hence, bypasses some of the > later checking code in resolve.c. > > > > Just to aid my understanding, I tried: > > diff --git a/gcc/fortran/primary.c b/gcc/fortran/primary.c > > > > --- a/gcc/fortran/primary.c > > +++ b/gcc/fortran/primary.c > > @@ -3922,6 +3922,9 @@ gfc_match_rvalue (gfc_expr **result) > > if (m == MATCH_NO) > > m = MATCH_YES; > > > > + if (!strcmp (sym->name, "NULL") || !strcmp (sym->name, "null")) > > + sym->attr.intrinsic = 1; > > + > > break; > > > > generic_function: > > > > which also works and regtests OK. (I couldn't remember whether > > sym->name is upper or lower case at this stage.) > > Should be always lowercase, I think. But I am also not sure that your > aid-understanding patch will work correctly with 'external null' or a > use-/host-associated/interface 'null' procedure or some array variable. > Inside intrinsic.c, we are at least sure that we did get an intrinsic > function after having passed all intrinsic checks. > > Tobias > > ----------------- > Mentor Graphics (Deutschland) GmbH, Arnulfstrasse 201, 80634 München > Registergericht München HRB 106955, Geschäftsführer: Thomas Heurung, Frank > Thürauf > -- "If you can't explain it simply, you don't understand it well enough" - Albert Einstein
