[Ada] Spurious visibility error in inlined function

[Ada] Spurious visibility error in inlined function

This patch corrects the use of tree replication when inlining a function
that returns an unconstrained result, and its sole statement is an
extended return statement. The use of New_Copy_Tree ensires that global
references saved in a generic template are properly carried over when
the function is instantiated and inlined.

2019-07-03  Hristian Kirtchev  <kirtchev@adacore.com>

gcc/ada/

	* inline.adb (Build_Return_Object_Formal): New routine.
	(Can_Split_Unconstrained_Function): Code clean up.
	(Copy_Formals,Copy_Return_Object): New routines.
	(Split_Unconstrained_Function): Code clean up and refactoring.

gcc/testsuite/

	* gnat.dg/inline15.adb, gnat.dg/inline15_gen.adb,
	gnat.dg/inline15_gen.ads, gnat.dg/inline15_types.ads: New
	testcase.

From-SVN: r272980