tree.c (walk_type_fields): Do not handle TYPE_MIN_VALUE and TYPE_MAX_VALUE for scalar types here but...

	* tree.c (walk_type_fields): Do not handle TYPE_MIN_VALUE and
	TYPE_MAX_VALUE for scalar types here but...
	(walk_tree): ...there instead.  Return NULL_TREE if the TYPE_DECL
	is attached an error mark, and the return value of the callback
	if it is not NULL_TREE.

cp/
	* pt.c (for_each_template_parm_r) <INTEGER_TYPE>: New case.
	Call for_each_template_parm on TYPE_MIN_VALUE and TYPE_MAX_VALUE.

testsuite/
	* gnat.dg/pointer_variable_bounds.adb: New test.
	* gnat.dg/pointer_variable_bounds.ads: Likewise.
	* gnat.dg/pointer_variable_bounds_q.ads: Likewise.

From-SVN: r119481