2005-07-07  Javier Miranda  <miranda@adacore.com>

	* freeze.adb (Freeze_Entity): Check wrong uses of tag incomplete types.

	* par-ch3.adb (P_Type_Declaration): Give support to tagged incomplete
	types:
	--
	  type DEFINING_IDENTIFIER [DISCRIMINANT_PART] [IS TAGGED];
	--

	* sem_attr.adb (Check_Not_Incomplete_Type): Additional checks for wrong
	use of tag incomplete types.

	* sem_ch3.adb (Analyze_Incomplete_Type): Add mininum decoration to
	give support to tagged incomplete types.

	* sem_ch5.adb (Analyze_Case_Statement): In generated code, if the
	expression is a discriminant reference and its type is private, as can
	happen within a stream operation for a mutable record, use the full
	view of the type to resolve the case alternatives.
	(Analyze_Assignment): Check wrong dereference of incomplete types.

	* sem_ch6.adb (Process_Formals): Allow the use of tagged incomplete
	types.

	* sem_res.adb (Resolve_Explicit_Dereference): Allow the use of tagged
	incomplete types.

	* sinfo.adb (Taggged_Present/Set_Taggged_Present): Applicable to
	N_Incomplete_Type_Declaration nodes.

	* sinfo.ads (N_Incomplete_Type_Declaration): Addition of attribute
	Tag_Present to give support to tagged incomplete types:
	--
	  type DEFINING_IDENTIFIER [DISCRIMINANT_PART] [IS TAGGED];
	--

From-SVN: r101695