2017-04-25  Ed Schonberg  <schonberg@adacore.com>

	* sem_ch3.adb (Derive_Subprogram): Implement rule in RM 6.1.1
	(10-15): if derived type T with progenitors is abstract,
	and primitive P of this type inherits non-trivial classwide
	preconditions from both a parent operation and from an interface
	operation, then the inherited operation is abstract if the parent
	operation is not null.
	* sem_disp.ads, sem_disp.adb: replace function Covers_Some_Interface
	with Covered_Interface_Op to yield the actual interface operation
	that is implemented by a given inherited operation.

2017-04-25  Javier Miranda  <miranda@adacore.com>

	* exp_ch4.adb (Expand_N_Op_Expon): Relocate left
	and right operands after performing the validity checks. Required
	because validity checks may remove side effects from the operands.

2017-04-25  Javier Miranda  <miranda@adacore.com>

	* exp_attr.adb (Attribute_Unrestricted_Access):
	Do not disable implicit type conversion.  Required to generate
	code that displaces the pointer to reference the secondary
	dispatch table.

2017-04-25  Pascal Obry  <obry@adacore.com>

	* prj-attr.adb, snames.ads-tmpl: Add package Install's
	Required_Artifacts attribute.

From-SVN: r247202