2010-10-22  Robert Dewar  <dewar@adacore.com>

	* checks.adb (Apply_Predicate_Check): Remove attempt at optimization
	when subtype is the same, caused legitimate checks to be missed.
	* exp_ch13.adb (Build_Predicate_Function): Use Nearest_Ancestor to get
	inheritance from right entity.
	* freeze.adb (Freeze_Entity): Use Nearest_Ancestor to freeze in the
	derived type case if the ancestor type has predicates.
	* sem_aux.ads, sem_aux.adb (Nearest_Ancestor): New function.
	* sem_prag.adb (Check_Enabled): Minor code reorganization.

From-SVN: r165807