[Ada] Error on use of 'Class applied to limited view of tagged type

[Arnaud Charlet <charlet at adacore dot com>]

When the Class attribute is applied in one package that has a limited view of
a tagged type with an untagged incomplete type in its own package, then when
another unit with a nonlimited with clause for the type's package is compiled,
the compiler issues an error complaining that the prefix must be tagged. The
Available_View of the type must be tested as a condition for issuing this error.

The following test must compile quietly:

gcc -c -gnat05 ltd_with_class_attr_bug.ads

--
package Pkg1 is

   type Typ;

   type Ref is access all Typ'Class;

   type Typ is tagged null record;

end Pkg1;

package Pkg2 is

   type Typ;

   type Ref is access all Typ'Class;

   type Typ is tagged null record;

end Pkg2;

limited with Pkg1;
limited with Pkg2;

package Pkg_Ltd_With is

   procedure Proc1 (X : access Pkg1.Typ'Class);

   procedure Proc2 (Y : Pkg1.Typ'Class);

   procedure Proc3 (X : access Pkg2.Typ'Class);

   procedure Proc4 (Y : Pkg2.Typ'Class);

end Pkg_Ltd_With;

with Pkg1;
with Pkg_Ltd_With;

package Ltd_With_Class_Attr_Bug is 
end Ltd_With_Class_Attr_Bug;
--

Tested on x86_64-pc-linux-gnu, committed on trunk

2011-12-20  Gary Dismukes  <dismukes@adacore.com>

	* sem_ch8.adb (Find_Type): Test taggedness
	of the Available_Type when checking for an illegal use of an
	incomplete type, when the incomplete view is a limited view of
	a type. Remove redundant Is_Tagged test.

Attachment: difs
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