A pair of more or less obvious --enable-checking fixes

[Zack Weinberg <zack at wolery dot cumb dot org>]

1) c-decl.c:pushdecl does not handle an ERROR_MARK in the type slots of
   the prototype properly.  For instance:

void a(void x) {}

This causes --enable-checking failures on noncompile/921116-1.c and
920216-2.c.

2) The transparent_union_flag of TYPE trees is now overloaded to mean
   something else for array types.  The TYPE_TRANSPARENT_UNION() macro
   was changed to check that it's being called on a union type.  But
   print_node() blindly applies TYPE_TRANSPARENT_UNION to all types,
   which means you get an abort if you try to print any type tree from
   the debugger.

The appended patch fixes both issues.  It survived a bootstrap with
all --enable-checking options active, on i386-linux.  There are now no
regressions of --enable-checking versus the normal build, in the C
testsuite.  There are regressions in the C++ testsuite; I think these
are all the VOID_TYPE_P() problem Geoff Keating mentioned earlier.
Anyway, they haven't anything to do with my changes.

I'm checking this in as an obvious patch.

zw

	* c-decl.c (pushdecl): Do not call COMPLETE_TYPE_P on
	error_mark_node. 
	* print-tree.c (print_node): The transparent_union_flag means
	different things for unions and arrays.  Do not inspect it
	with TYPE_TRANSPARENT_UNION.

===================================================================
Index: c-decl.c
--- c-decl.c	2000/06/06 21:54:52	1.120
+++ c-decl.c	2000/06/07 22:36:00
@@ -2422,8 +2422,12 @@ pushdecl (x)
 	    b->shadowed = tree_cons (name, oldlocal, b->shadowed);
 	}
 
-      /* Keep count of variables in this level with incomplete type.  */
-      if (!COMPLETE_TYPE_P (TREE_TYPE (x)))
+      /* Keep count of variables in this level with incomplete type.
+	 If the input is erroneous, we can have error_mark in the type
+	 slot (e.g. "f(void a, ...)") - that doesn't count as an
+	 incomplete type.  */
+      if (TREE_TYPE (x) != error_mark_node
+	  && !COMPLETE_TYPE_P (TREE_TYPE (x)))
 	++b->n_incomplete;
     }
 
===================================================================
Index: print-tree.c
--- print-tree.c	2000/05/27 15:21:15	1.31
+++ print-tree.c	2000/06/07 22:36:02
@@ -480,8 +480,17 @@ print_node (file, prefix, node, indent)
 	fputs (" string-flag", file);
       if (TYPE_NEEDS_CONSTRUCTING (node))
 	fputs (" needs-constructing", file);
-      if (TYPE_TRANSPARENT_UNION (node))
-	fputs (" transparent-union", file);
+      /* The transparent-union flag is used for different things in
+	 different nodes.  */
+      if (TYPE_CHECK (node)->type.transparent_union_flag)
+	{
+	  if (TREE_CODE (node) == UNION_TYPE)
+	    fputs (" transparent-union", file);
+	  else if (TREE_CODE (node) == ARRAY_TYPE)
+	    fputs (" nonaliased-component", file);
+	  else
+	    fputs (" tu-flag", file);
+	}
       if (TYPE_PACKED (node))
 	fputs (" packed", file);