sem_prag.ads (Build_Classwide_Expression): new procedure to build the expression...

sem_prag.ads (Build_Classwide_Expression): new procedure to build the expression for an inherited classwide condition...

2016-06-22  Ed Schonberg  <schonberg@adacore.com>

	* sem_prag.ads (Build_Classwide_Expression): new procedure to
	build the expression for an inherited classwide condition, and
	to validate such expressions when they apply to an inherited
	operation that is not overridden.
	* sem_prag.adb (Primitives_Mapping): new data structure to
	handle the mapping between operations of a root type and the
	corresponding overriding operations of a type extension. Used
	to construct the expression for an inherited classwide condition.
	(Update_Primitives_Mapping): add to Primitives_Mapping the links
	between primitive operations of a root type and those of a given
	type extension.
	(Build_Pragma_Check_Equivalent): use Primitives_Mapping.
	* sem_ch6.adb (New_Overloaded_Entity): Remove call to
	Collect_Iherited_Class_Wide_Conditions in GNATprove_Mode. This
	needs to be done at freeze point of the type.
	* freeze.adb (Check_Inherited_Conditions): new procedure to
	verify the legality of inherited classwide conditions. In normal
	compilation mode the procedure determines whether an inherited
	operation needs a wrapper to handle an inherited condition that
	differs from the condition of the root type.  In SPARK mode
	the routine invokes Collect_Inherited_Class_Wide_Conditions to
	produce the SPARK version of these inherited conditions.
	(Freeze_Record_Type): For a type extension, call
	Check_Inherited_Conditions.

From-SVN: r237698