[Bug fortran/99651] Cannot change attributes of USE-associated intrinsic

[burnus at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99651

Tobias Burnus <burnus at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2021-03-18
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1

--- Comment #2 from Tobias Burnus <burnus at gcc dot gnu.org> ---
That's for matching 'NULL()' in:
  CHAR_STAR_NULL = CHAR_STAR(NULL())
The problem is that during matching we end up
in  gfc_match_rvalue  for:
      /* Give up, assume we have a function.  */
      e->expr_type = EXPR_FUNCTION;

      if (!sym->attr.function
          && !gfc_add_function (&sym->attr, sym->name, NULL))
which then also set:
  if (attr->flavor != FL_PROCEDURE
      && !gfc_add_flavor (attr, FL_PROCEDURE, name, where))
    return false;
 attr->function = 1


And later then:
  resolve_function → resolve_unknown_f → gfc_intrinsic_func_interface
the latter than has:
  if (sym->attr.flavor == FL_UNKNOWN)
    {
      sym->attr.function = 1;
      sym->attr.intrinsic = 1;
      sym->attr.flavor = FL_PROCEDURE;
    }

Thus, at the end intrinsic is not set in the module.
For the next use, we run into the following in gfc_match_null:

  if (sym->attr.proc != PROC_INTRINSIC
      && !(sym->attr.use_assoc && sym->attr.intrinsic)
      && (!gfc_add_procedure(&sym->attr, PROC_INTRINSIC, sym->name, NULL)
          || !gfc_add_function (&sym->attr, sym->name, NULL)))
    return MATCH_ERROR;

Here, we have:
- PROC_UNKNOWN
- sym->attr.intrinsic == 0
- gfc_add_procedure
  → this calls 'check_used' → which fails due to attr->use_assoc != 0.