In certain cases of conversions to interface types, the compiler
generates a special function to handle the conversion. In cases where
such a function has an extra accessibility-level formal and the target
type of the conversion has a designated type that comes from a limited
view (via limited_with_clause), the resolution of the type conversion
wasn't retrieving the needed nonlimited view, which resulted in the call
to the interface conversion function not being expanded and hence not
being passed the needed actual for the accessibility level.

Tested on x86_64-pc-linux-gnu, committed on trunk

2019-12-18  Gary Dismukes  <dismukes@adacore.com>

gcc/ada/

	* sem_res.adb (Resolve_Type_Conversion): Add handling for access
	types with designated operand and target types that are
	referenced in places that have a limited view of an interface
	type by retrieving the nonlimited view when it exists.  Add ???
	comments related to missing limited_with_clause handling for
	Target (in the non-access case).