[Ada] Illegal copy of limited object

[Ada] Illegal copy of limited object

This patch fixes a spurious copy of a limited object, when that object
is a discriminated record component of a limited type LT, and the enclosing
record is initialized by means of an aggregate, one of whose components is a
call to a build-in-place function that returns an unconstrained object of
type T.

2018-05-31  Ed Schonberg  <schonberg@adacore.com>

gcc/ada/

	* checks.adb (Apply_Discriminant_Check): Do not apply discriminant
	check to a call to a build-in-place function, given that the return
	object is limited and cannot be copied.

gcc/testsuite/

	* gnat.dg/limited1.adb, gnat.dg/limited1_inner.adb,
	gnat.dg/limited1_inner.ads, gnat.dg/limited1_outer.adb,
	gnat.dg/limited1_outer.ads: New testcase.

From-SVN: r261009