[Bug fortran/96038] New: Confirming implicitly type parameter causes an invalid error

[kargl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96038

            Bug ID: 96038
           Summary: Confirming implicitly type parameter causes an invalid
                    error
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: kargl at gcc dot gnu.org
  Target Milestone: ---

Consider the following fixed-form source code:

      function ifoo()
      parameter (n = 50)
      integer n
      ifoo = n
      end

Everything is implicitly type.  Gfortran gives

      function ifoo()
      parameter (n = 50)
      integer n
      ifoo = n
      end

% gfortran -c a.f
a.f:3:15:

    3 |       integer n
      |               1
Error: PARAMETER at (1) is missing an initializer

which is wrong.  The code should compile as an implicitly type
entity can appear in a declaration statement if that declaration
statement confirms the implicit type.

The patch is straight forward.  This is against svn revision 280156.
The patch has not been regression tested.

Index: gcc/fortran/decl.c
===================================================================
--- gcc/fortran/decl.c  (revision 280157)
+++ gcc/fortran/decl.c  (working copy)
@@ -1864,13 +1864,16 @@ add_init_expr_to_sym (const char *name, gfc_expr **ini

   /* If this symbol is confirming an implicit parameter type,
      then an initialization expression is not allowed.  */
-  if (attr.flavor == FL_PARAMETER
-      && sym->value != NULL
-      && *initp != NULL)
+  if (attr.flavor == FL_PARAMETER && sym->value != NULL)
     {
-      gfc_error ("Initializer not allowed for PARAMETER %qs at %C",
-                sym->name);
-      return false;
+      if (*initp != NULL)
+       {
+         gfc_error ("Initializer not allowed for PARAMETER %qs at %C",
+                    sym->name);
+         return false;
+       }
+      else
+       return true;
     }

   if (init == NULL)