[Bug fortran/66045] ICE on incorrect code with null

["kargl at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66045

kargl at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P4
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-05-07
                 CC|                            |kargl at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #1 from kargl at gcc dot gnu.org ---
Confirmed.

This patch (watch copy-n-paste tab corruption)

Index: expr.c
===================================================================
--- expr.c      (revision 222869)
+++ expr.c      (working copy)
@@ -3118,19 +3118,22 @@ gfc_check_assign (gfc_expr *lvalue, gfc_
        bad_proc = true;

       /* (ii) The assignment is in the main program; or  */
-      if (gfc_current_ns->proc_name->attr.is_main_program)
+      if (gfc_current_ns->proc_name
+         && gfc_current_ns->proc_name->attr.is_main_program)
        bad_proc = true;

       /* (iii) A module or internal procedure...  */
-      if ((gfc_current_ns->proc_name->attr.proc == PROC_INTERNAL
-          || gfc_current_ns->proc_name->attr.proc == PROC_MODULE)
+      if (gfc_current_ns->proc_name
+         && (gfc_current_ns->proc_name->attr.proc == PROC_INTERNAL
+             || gfc_current_ns->proc_name->attr.proc == PROC_MODULE)
          && gfc_current_ns->parent
          && (!(gfc_current_ns->parent->proc_name->attr.function
                || gfc_current_ns->parent->proc_name->attr.subroutine)
              || gfc_current_ns->parent->proc_name->attr.is_main_program))
        {
          /* ... that is not a function...  */
-         if (!gfc_current_ns->proc_name->attr.function)
+         if (gfc_current_ns->proc_name
+             && !gfc_current_ns->proc_name->attr.function)
            bad_proc = true;

          /* ... or is not an entry and has a different name.  */

yields

gfc6 -c po.f90
po.f90:3:19:

    integer :: null=null()
                   1
Error: NULL appears on right-hand side in assignment at (1)