Number of the active parameter (where the cursor is) or -1 if in none
Range starting before opening parentheses until after closing parentheses.
Start of the function itself.
True if the function is UFCS or a member function of some object or namespace. False if this is a global function call.
True if cursor is in template parameters
Start of the whole call going up all call parents. (foo.bar.function having foo.bar as parents)
Range starting before exclamation point until after closing bracket or before function opening bracket.