checks.ads, checks.adb (Selected_Range_Checks): No range check is required for a conversion between two...

2007-04-06  Thomas Quinot  <quinot@adacore.com>
	    Ed Schonberg  <schonberg@adacore.com>
	    Gary Dismukes  <dismukes@adacore.com>

	* checks.ads, checks.adb (Selected_Range_Checks): No range check is
	required for a conversion between two access-to-unconstrained-array
	types.
	(Expr_Known_Valid): Validity checks do not apply to discriminants, but
	to discriminant constraints on discriminant objects. This rule must
	apply as well to discriminants of protected types in private components.
	(Null_Exclusion_Static_Checks): If No_Initialization is set on an
	object of a null-excluding access type then don't require the
	the object declaration to have an expression and don't emit a
	run-time check.

From-SVN: r123554