Fortran: diagnostics for actual arguments to pointer dummy arguments [PR94104]

Error message improvement.  In Fortran 2008 actual procedure arguments
associated with a pointer, intent(in) attribute, dummy argument
can also have the target attribute, not just pointer.

gcc/fortran/ChangeLog:

	PR fortran/94104
	* interface.cc (gfc_compare_actual_formal): Improve error message
	dependent on Fortran standard level.

gcc/testsuite/ChangeLog:

	PR fortran/94104
	* gfortran.dg/parens_2.f90: Adjust to improved error message.
	* gfortran.dg/PR94104a.f90: New test.
	* gfortran.dg/PR94104b.f90: New test.

1 files changed, 31 insertions, 17 deletions

diff --git a/gcc/fortran/interface.cc b/gcc/fortran/interface.cc
index d3e1995..49dbd1d 100644
--- a/gcc/fortran/interface.cc
+++ b/gcc/fortran/interface.cc
@@ -3477,25 +3477,39 @@ gfc_compare_actual_formal (gfc_actual_arglist **ap, gfc_formal_arglist *formal,
 	  goto match;
 	}
 
-      if (a->expr->expr_type != EXPR_NULL
-	  && compare_pointer (f->sym, a->expr) == 0)
+      if (a->expr->expr_type != EXPR_NULL)
 	{
-	  if (where)
-	    gfc_error ("Actual argument for %qs must be a pointer at %L",
-		       f->sym->name, &a->expr->where);
-	  ok = false;
-	  goto match;
-	}
+	  int cmp = compare_pointer (f->sym, a->expr);
+	  bool pre2008 = ((gfc_option.allow_std & GFC_STD_F2008) == 0);
 
-      if (a->expr->expr_type != EXPR_NULL
-	  && (gfc_option.allow_std & GFC_STD_F2008) == 0
-	  && compare_pointer (f->sym, a->expr) == 2)
-	{
-	  if (where)
-	    gfc_error ("Fortran 2008: Non-pointer actual argument at %L to "
-		       "pointer dummy %qs", &a->expr->where,f->sym->name);
-	  ok = false;
-	  goto match;
+	  if (pre2008 && cmp == 0)
+	    {
+	      if (where)
+		gfc_error ("Actual argument for %qs at %L must be a pointer",
+			   f->sym->name, &a->expr->where);
+	      ok = false;
+	      goto match;
+	    }
+
+	  if (pre2008 && cmp == 2)
+	    {
+	      if (where)
+		gfc_error ("Fortran 2008: Non-pointer actual argument at %L to "
+			   "pointer dummy %qs", &a->expr->where, f->sym->name);
+	      ok = false;
+	      goto match;
+	    }
+
+	  if (!pre2008 && cmp == 0)
+	    {
+	      if (where)
+		gfc_error ("Actual argument for %qs at %L must be a pointer "
+			   "or a valid target for the dummy pointer in a "
+			   "pointer assignment statement",
+			   f->sym->name, &a->expr->where);
+	      ok = false;
+	      goto match;
+	    }
 	}