Since arbitrary currying is no longer allowed `level` could
be replaced with the boolean flag which identifies if curried
`self` should be skipped or not.
When diagnosing ApplyExpr, the existing implementation
tries to resolve the function subexpression independently
in the first place, without considering the argument
information. As a result, such resolved function type
may not produce the best diagnostic message.
This patch adds condideration of the number of arguments
to decide the better function subexpression for diagnostic
purpose.
Resolves: SR-7918, SR-7786, SR-7440, SR-7295, SR-5154.
