ada: Fix predicate involving array indexing rejected in generic package
The indexing is rejected with the message:
error: reference to current instance of type does not denote a type
when it is applied to a prefix which is the current instance of the type
to which the predicate is applied.
There is already a specific handling of component selection for this case
present in Find_Selected_Component, so this adds an equivalent specific
handling of indexing for this case to Analyze_Indexed_Component_Form.
gcc/ada/ChangeLog:
PR ada/117569
* sem_ch4.adb (Analyze_Indexed_Component_Form): Do not rewrite the
node as a type conversion if it is the current instance of a type
in a generic unit.
* sem_ch8.adb (Find_Selected_Component): Restrict the special case
of the current instance of a type to a generic unit.